Energy Solutions for Off-grid Applications - dena€¦ · Off-grid applications with renewable...

Energy Solutions for Off-grid Applications

www.german-energy-solutions.de/en

Providing electric power and heat for regions without grid power or connected to a weak grid interconnection

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Imprint

PublisherDeutsche Energie-Agentur GmbH (dena) German Energy AgencyChausseestrasse 128 a, 10115 Berlin, Germany

E-mail: [email protected]: www.dena.de

Status05/2017

Design and [email protected]ße 20/21, 30159 Hannover, Germany

Cover image©fotolia/Thor Jorgen Udvang

TextFlorian SchmidtDavid SchönheitMichael Kober

All rights reserved. Any use is subject to consent by dena.

All content has been prepared with the greatest possible care and is provided in good faith. dena provides no guarantee regarding the cur-rency, accuracy and completeness of the information provided. dena accepts no liability for damages of a tangible or intangible nature caused directly or indirectly by the use of or failure to use the informa-tion provided, unless dena can be proven to have acted with intent or gross negligence. This publication was funded by the Federal Ministry for Economic Affairs and Energy.

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1. Table of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3. Development needs energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Regions affected by energy poverty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Energy solutions for off-grid regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Renewable energies: versatile and sustainable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4. Areas of application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5. Electricity generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Photovoltaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Domestic use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Commercial and industrial use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Community-scale use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Wind energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Domestic use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Commercial and industrial use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Community-scale use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Small hydropower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Hybrid systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Off-grid island systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

6. Heating and cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Solar thermal energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Domestic use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Commercial and industrial use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Community-scale use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Near-surface geothermal energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

7. Generation of electricity and heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Bioenergy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Domestic use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Commercial and industrial use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Community-scale use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

8. Non-technical aspects of a successful project implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Public support and promotion schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Financing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Large-scale projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Small-scale and end-user financing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

9. Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Photovoltaics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 How it works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Further types of PV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Solar thermal technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Operating principle and different types of solar collectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Cooling systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Table of Content

TABLE OF CONTENT

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Wind energy technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 How it works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Output of wind power plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Onshore wind energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Small wind turbines in off-grid regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Bioenergy technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Classification of bioenergy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Hydropower technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Technologies and applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Small hydropower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Environmental requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Geothermal energy technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Near-surface geothermal energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Storage and grid technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Batteries (electrochemical storage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

10. German Energy Solutions Initiative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

11. Addresses of institutions/associations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Institutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Renewable energies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Solar energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Wind energy technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Bionergy technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Hydropower technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Geothermal technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Storage and grid technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Other institutions and partners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40German authorities and ministries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

12. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

13. Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

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TABLE OF FIGURES

1. Table of Figures

Figure 1: Diesel prices and electrification rates in selected African countries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Figure 2: Publication structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Figure 3: A schoolboy in Zambia studying after sunset using a solar lantern that was charged during the day. . . . . . . . . 10Figure 4: The solar PV system installed at the Travessia Beach Lodge in Mozambique . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 5: The grid-connected PV system on the roof of the Food Lover’s Market in Dar es Salaam . . . . . . . . . . . . . . . . . 11Figure 6: Four wind turbines installed at the Diavik diamond mine in Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 7: Eigg Island, Scotland: the Scottish island, which has a population of around 100, has been operating

its own island grid since 2008 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Figure 8: Modern island hybrid system for energy supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Figure 9: Installation of the island hybrid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Figure 10: Installation of a river hydropower turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Figure 11: Mobile renewable energy hybrid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Figure 12: Solar thermal energy system for domestic water heating in a detached house . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 13: Diagrams of a solar oven, panel cooker and parabolic solar cooker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 14: Parabolic solar cookers in Tibet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 15: Fresnel collectors installed on the roof of the building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 16: Solar thermal rooftop installation of the brewery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 17: Ontario, Canada: the largest Canadian system to date for solar heating and cooling . . . . . . . . . . . . . . . . . . . . . . 21Figure 18: Large-scale solar thermal facility in the „Indian Silicon Valley“ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 19: Diagram of a photovoltaic solar cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 20: Rooftop PV installation with self-tracking system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 21: Composition of a solar collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Figure 22: Wind turbine in Yzeron, Rhône Alpes, France, with a rotor diameter of ca. 7 m and a capacity of 10 kW,

which is achieved at nominal wind speeds of 11 metres per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Figure 23: Unlike natural gas, biogas can be generated close to the end consumers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Figure 24: Construction of a typical small hydroelectric power plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Figure 25: Natural near-surface temperature distribution in the depths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Figure 26: Horizontally installed geothermal heat collectors to provide heating for a single-family household . . . . . . . . . 34Figure 27: Batteries can be integrated well into an off-grid hybrid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6

Safe access to clean and affordable energy is a central prerequisite for sustainable development and the fight against poverty. This is also anchored in the sustainable development goals laid down by the United Nations. After all, over 70 % of people in the least developed countries and in sub-Saharan Africa live without or with only inade-quate access to the grid. But in more developed countries, too, and in the industrialised nations, there are consumers who are not connected to the central energy supply sys-tem, for example in the mountains or at sea.

In order to supply as many people and areas as possible with clean and affordable energy, off-grid applications working in conjunction with renewable energies present an ideal solution. They provide an independent energy supply, above all in vast rural areas or remote mountain and desert regions, because they do not require access to the grid and are not dependent on an energy supply com-pany or subject to possible fluctuations in electricity prices. At the same time, they are relatively cost-effective, since the grid does not have to be expanded and no fuel is needed.

Off-grid applications with renewable energies therefore also contribute towards achieving global climate goals. This is because they replace the outmoded diesel genera-tors which are usually used for off-grid power generation.

PREFACE

If there are no fundamental changes to the current politi-cal and technological situation, the International Energy Agency estimates that 1.4 billion people will still be with-out access to electricity in 2030. And by then, there will still be 2.9 billion people who are not yet cooking with clean energy – thereby exposing themselves to harmful soot emissions and the risk of burns. These figures under-line the magnitude of the task that lies ahead.

We must find solutions for the energy sector now in order to facilitate economic development and protect the cli-mate. Germany is already actively working toward an international energy reform – for example, through numerous pilot projects worldwide. Thanks to its decades of experience and innovative companies in the field of renewable energies, Germany is well-equipped to face these challenges.

This publication aims to provide an overview of the possi-ble ways of providing, integrating and storing off-grid electricity, heat and cooling from renewable energies. Practical examples and pilot projects provide applica-tion-based insights for the benefit of private users, small businesses, farmers, industrial corporations and munici-palities.

In order to achieve a sustainable supply of energy, we must share our knowledge and learn from one another on a global scale. Let us work together to achieve this goal.

Yours sincerely,

Andreas Kuhlmann, Chief Executive Deutsche Energie-Agentur (dena) German Energy Agency

2. Preface

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DEVELOPMENT NEEDS ENERGY

3. Development needs energy

Access to energy is a fundamental basis for economic and social development. Energy is a prerequisite for companies to manufacture and jobs to be created. It is required to grow food, to prepare meals, to heat homes and schools, to operate hospitals and to provide clean drinking water. Energy also makes global communication and mobility possible. Against the background of an increasing global population, the global demand for energy is also growing.1 However, this is leading to declining reserves of fossil fuels along with increasingly volatile oil prices. In many parts of the world, biomass such as wood does not grow in suffi-cient quantities to meet the human need for energy locally.

Regions affected by energy povertyIn 2014, nearly one fifth of the world’s population – approx. 1.2 billion people – had no access to electricity. In fact, nearly two fifths (38 %) of the people on the planet – around 2.6 billion people – do not even have clean cook-ing facilities and rely on wood, coal, charcoal, or animal waste to cook their food, breathing in toxic smoke. Over 95 % of the private individuals without access to electricity live in sub-Saharan-Africa or developing Asia.2 Eighty-four per cent of those affected live in rural areas with no con-nection to the public electricity grid. For the households affected, this has a direct impact on everyday life: for example, these households cannot – or can only sporadi-cally – reliably keep medicines cool and operate electric lights and TVs or charge mobile phones. Diesel generators are also not widely available or cannot be operated perma-nently due to price developments or restricted availability of fuel. That is why off-grid systems based on renewable energy technologies can help countries with high diesel prices and low electrification rates to support its popula-tion and economy with a clean and reliable energy supply. An example of countries in Africa is shown in Figure 1, which is based on a global market analysis by the Deutsche Energie-Agentur GmbH (dena) – the German Energy Agency.

1 BMWi, 20172 Se4all,2017

160

140

120

100

80

60

40

20

010% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Local diesel price [US$-cents] (11/2014)

Diesel prices and electrification rates in selected African countries

Electrification rate [% of population] (2013)

Figure 1: Bubble sizes correspond to the total population of the respective country. Own illustration. Sources: dena Market Analysis 2014 based on data from GIZ, EIA, IEA, World Bank (WDI).

Even in regions with a connection to the public electricity grid, sustainable access to electricity is not always guaran-teed. If the grids are unstable, the manufacturing industry, the hotel and catering industry, educational institutions and hospitals cannot work reliably and have to depend on emergency generators.

Political institutions around the world are focusing on eliminating energy poverty. 2014–2024 has been declared by the United Nations (UN) as the “Decade of Sustainable Energy for All”.3 If the over one billion people around the world who live in extreme poverty are to be able to achieve the necessary development, off-grid regions must be connected to the public energy supply, viable alternatives must be provided or the political and legal landscape for this must be created.

3 United Nations, 2017

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However, there are gaps in the public electricity grid, not only in developing countries and emerging markets but also in industrialised countries, such as remote mountain regions, large forests or expanses of water. Here, too, alternative solutions are needed to meet the energy requirement in these regions. Examples include the sea-sonal operation of gastronomic facilities such as ski huts, or the operation of scientific measuring stations.

Energy solutions for off-grid regionsAn off-grid energy supply – i.e. autonomous and inde-pendent of the public grid – is ideal in regions where it is not possible to connect to the public electricity grid or this is not planned due to the high development costs to con-struct electric-line systems, especially in remote rural areas. In many cases, diesel generators provide the neces-sary electricity in these areas and power individual homes or village communities via a local mini-grid. Furthermore, local electricity generation systems and storage technolo-gies are installed as a supplement to the public electricity grid if recurring power failures affect the local reliability of supply. What are known as back-up systems then bridge the times in which no electricity is available via the public grid.

Autonomous photovoltaics and small wind energy plants, as well as small hydroelectric power and bioenergy plants have a potential for application. The individual technolo-gies are described in the chapter “Technologies”.

Renewable energies: versatile and sustainableRenewable energies facilitate a versatile use of regionally available energy sources, both off-grid and as a local supplement to unreliable grids. They are low-emission and low-risk with sustainable availability, they replace expen-sive imported fuels or save fuel being transported over long distances, they protect the environment and human health and contribute to peace-keeping. Lower investment costs for generation and storage and high prices for fossil fuels mean that renewable energy technologies are already competitive in many regions of the world in comparison to domestic electricity prices or power generation using

diesel generators. Additionally, existing diesel generators can be combined with renewable energy technologies like photovoltaics. These so called hybrid systems can meet higher demands, provide electricity reliably and save a considerable amount of fuel and therefore money. A pro-ject supported by the Project Development Program (PDP) implemented by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH shows that the advantages for small-scale businesses can be extensive. The owners of a remote beach lodge in Mozambique installed a solar and storage system, saving approx. 10,950 litres of diesel a year, with the initial investment being amortised after three years. Besides that, improving the public image from having a green and clean lodge goes far beyond the sav-ings.

GIZ’s Project Development Programme (PDP) supports German companies as they explore new markets that are promising but still difficult and barely developed. On behalf of the German Federal Ministry for Economic Affairs and Energy (BMWi) and as part of the German Energy Solutions Initiative, PDP advises companies during the various phases of market positioning and project development.

Besides the PDP, the broad range of applications for renewables is shown within the dena Renewable Energy Solutions Programme (RES). Projects of the dena RES Programme are carried out worldwide and serve as flag-ship projects for renewable energy expertise in the fields of solar, wind, water, geothermal and bioenergy. All of the systems designed and implemented under this programme demonstrate the flexibility of German renewable energy technology (including energy efficiency measures) and know-how while working under local conditions and meeting discerning user-specific requirements.

The programme, coordinated by the dena, brings together growing international demand for German renewable energy technology and German companies with an interest in and the capacity to access attractive international mar-kets. The close coordination of dena ensures the installa-

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tion of unique, customised systems. Furthermore, dena initiates and oversees the transfer of the specific technol-ogy and application know-how.

Renewable energy systems that have been carefully designed, installed and professionally operated can pro-vide power and heat reliably. To increase the share of renewable energies in the electricity supply, storage capac-ities and load management can provide the flexibility needed and take on greater importance. The independence from fossil fuel price trends facilitates the calculation of operating and construction costs for renewable energy installations. If the public energy supply grid is expanded at a later date, autonomous systems can be connected afterwards and the energy generated can be fed into the public grid. In respect of promoting renewable energies, at least 164 countries had renewable energy targets in early 2015, and an estimated 145 countries had renewable energy support policies in place.4 Solar, wind, bioenergy as well as hydropower can, either individually or combined, provide energy for many applications independently of the public electricity supply.

Energy in the form of electricity enables a lot of equipment to be operated in rural regions, like providing the basic infrastructure for using and charging mobile phones and therefore facilitating communication. Photovoltaics, hydropower, wind energy, biodiesel and biogas can gener-ate electricity locally, be used directly to operate electrical equipment or be stored if required. Thermal technologies for using renewable energies facilitate hot water, heating, cooling and drying. Depending on the technology used, renewable energies can also be used directly for cooking or for mobility purposes.

The following chapter is intended to provide an overview of the range of applications of renewable energy technolo-gies for electricity and heat supply as well as cooling, accompanied by practical examples from various coun-tries. Subsequently, the various technologies are eluci-dated and afterwards the brochure concludes with an analysis of the economical aspects and financing models.

4 REN21, 2017

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4. Areas of Application

AREAS OF APPLICATION

Figure 2: Publication structure. Own illustration.

The increased use of renewable energies and alternative concepts of energy production is of great significance for single households, businesses and communities since, after all, this is where a large part of the energy – in the form of electricity and heating – is consumed. Renewable energies can provide a reliable, economical, cost-effective and sustainable energy supply. Photovoltaic modules for generating electricity from sunlight and small wind plants can be combined intelligently in order to greatly reduce the annual electricity consumption. Other examples are fully automatic pellet heating systems, solar thermal energy plants for generating heat or for air conditioning and heat pumps, which can utilise near-surface geother-mal energy for heating. The following chapters give practi-cal information on off-grid applications for each renewable energy technology.

For each technology, applications will be described for domestic use, commercial and industrial use and commu-nity-scale use. For which uses each technology is applica-ble is depicted in Figure 2. Domestic use will cover appli-cations for individual households. Commercial and industrial use describes how technologies can be utilised for factory buildings, commercial complexes or agricul-tural facilities. Larger off-grid applications cover needs for multiple households or entire communities. This distinc-tion is important in order to decision-making a solu-tion-oriented guide that facilitates decision making depending on the prevailing situation and requirements.

Please note that generated electricity can always be con-verted into heating or cooling, e.g. by utilising a heat pump, or used for mobile application by transferring electricity to a battery. Also, thermal energy can serve as an energy source for electricity generation (e.g. steam turbines, dish stirling CSP, etc.).

However, only direct output will be considered, i.e. if a technology produces electricity or thermal energy as a direct output or if it can be directly integrated into a mobile application. Hybrid systems are described at the end of this chapter.

Especially electricity-generating renewable energy systems can easily be upgraded by a storage medium, in particular batteries. This eliminates the necessity for simultaneous energy generation and consumption and reduces the need for a diesel generator as backup. Generated electricity can be stored and used later. Storage technologies are men-tioned throughout the chapter and are discussed in greater detail at the end of the Technologies chapter.

Decisions about the correct implementation of RE projects should take the costs of the whole project cycle into account, i.e. from planning and implementation to the operation, maintenance and optimisation of the system, as well as the decommissioning and recycling of system components. Reliable partners are essential in all phases of a project. And whereas the choice of quality compo-

Domestic-scale use Community-scale use Technologies

Photovoltaic

Wind energy

Small hydropower

Bioenergy

Solar thermal

Near-surface geothermal energy

Bioenergy

Areas of application Commercial and industrial use

Heating/coolingHot water, room heating, cooking, building A/C

Process heat, drying of agricultural products, building A/C Hot water and building A/C

Mobile phones, lighting, computers, sewing machines, radios, TVs

Machines, computers, scientific measuring stations, water pumps, flour mills, seawater desalination

Phone and land mobile networks, mini-grids, street lighting and road sign illumination, maritime on-board electrical systems, medical devices, sea water desalination, standby systems in urban and rural areas, for unstable power grids

Electricity supply

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AREAS OF APPLICATION

nents can initially necessitate higher capital investment, these costs are more than outweighed by the lower operat-ing costs over the remaining term of the project. It is also important to involve experienced partners during project development and for O&M. Amongst other things, these partners have on-site experience in implementing projects, offer faster response times in the event of problems and engage in the transfer of know-how in order to build up local service infrastructures.

The deployment of renewable energy technologies is of great importance in off-grid regions. Traditionally, unsus-tainable, expensive and environmentally damaging forms of energy generation are used in remote areas, such as diesel generators. Renewable energies provide an alterna-tive with many advantages.

Advantages of renewable energy technologies ¡ Reliable, sustainable and cost-effective energy

supply. ¡ Potentially lower operating costs for electricity,

especially when “grid parity” is reached or sur-passed.

¡ Less dependence on imported energy and diesel for example.

¡ Increasingly lower dependence on power grid and lower energy costs.

¡ Local added value with new business models based on sustainable and reliable energy supply.

¡ Reduction in CO2 emissions. ¡ Smaller ecological footprint through efficient and

climate-friendly use of energy sources in the house.

¡ Higher quality of life due to less pollution, specifi-cally better in-house air quality.

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ELECTRICITY GENERATION

5. Electricity generation

Photovoltaics

Photovoltaic systems (PV) are used to generate electricity and are now one of the most environmentally friendly and efficient energy supply systems. German PV research and industry companies are working on the development of cell structures and production processes in order to fur-ther optimise application and reduce costs. In many coun-tries, the cost of generating electricity from solar energy is comparable with the consumer price for conventional electricity (“grid parity”), which can make self-supply profitable compared to purchasing electricity. PV modules are especially suited for mobile applications due to being easily scalable for every requirement.

The typical system of a domestic application consists of a rooftop installation. New areas of application are found in the integration of PV systems into the building itself, e.g. by incorporating PV into the roof, facade or windows. For example, to meet the annual requirement of a four-person family in Germany, an average household needs a PV system with a peak output of 3.5 to 4 kW. Depending on the PV technology used, this corresponds to a solar panel surface area of about 35 to 40 m2 or more. Intelligent systems technology can be used to optimise the energy consumption of households. By connecting to the grid, the excess electricity can be supplied directly to the grid oper-ator. Compared with an off-grid installation, the costs of a grid-connected system are lower, since it is not normally necessary to store energy, which also improves the sys-tem’s efficiency. Furthermore, electricity generation using PV together with storage solutions can be carried out off-grid (see “Storage and grid technology”). Mobile charg-ing stations or lighting systems are further applications for private consumers.

Small SHS of 1–10 W in size are called PicoPV systems (PPS). These integrated systems consist of a small solar module and a battery and are particularly suited for pow-ering lights, radios or small mobile communication devices. This can bring about significant improvements for the population in off-grid regions. Children, for instance, can continue to work on school assignments even through-out and after dusk.

Figure 3: A schoolboy in Zambia studying after sunset using a solar lantern that was charged during the day.

Commercial and industrial useIn trade and industry oftentimes the same PV-rooftop installations as in private households are deployed, ena-bling the roofs of factory buildings and commercial com-plexes to be used to generate electricity in order to power the facilities. This can be important even for grid-con-nected businesses, since the manufacturing, hotel and

Advantages of photovoltaic electricity generation ¡ Reliable and cost-effective electricity generation

independent from an existing grid. ¡ Easy to install, robust, modular design. ¡ A wide range of applications from very small sys-

tems, such as solar-powered pocket calculators, to electricity generation for domestic usage and large-scale installations with an output of several megawatts.

¡ No moving parts – the installations have a long service life.

¡ Quiet, emission-free electricity generation. ¡ Very environmentally friendly – silicon is the pri-

mary material used in the manufacture of PV cells and since it is the second most common element on earth, it is comparably inexpensive to obtain and the usage and disposal of silicon entails no danger to the environment.

Domestic useSolar home systems (SHS) supply households with elec-tricity, e.g. to operate lights, radios, TVs, computers, sewing machines, etc. They generally have an output of up to 250 W and consist of a solar module, a battery and a charge regulator and – for greater loads – possibly also a DC/AC inverter, which facilitates the operation of AC devices. SHS are available as fully integrated, compact systems. The available output can be adapted to individual requirements. Moreover, SHS are easy to install and operate and have only low maintenance requirements. Prepayment systems, which are used by various consum-ers to utilise the generated energy and pay for it in small units, can easily be integrated.

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catering industry, educational institutions and hospitals need stable grids to operate reliably and therefore often depend on emergency generators during grid disruptions. Larger-scale autonomous PV systems comprising multiple solar modules connected in series are called Solar Resi-dential Systems. They provide power to hospitals and schools, for example.

For the tourist and hotel industry, electricity supply by renewable energy sources can have a huge impact on business development, as examples from the Project Development Programme (GIZ) show. The Travessia Beach Lodge decided to use solar power for electricity generation, instead of solely relying on an expensive, noisy and inefficient diesel generator. This reduces not only the time and money necessary to obtain fuel (saving approx. 10,500 litres annually) but also the ongoing operation and maintenance of the diesel generator. Conclusively, the initial investment will be paid off after only three years. Additional advantages are simplified operating of the lodge due to a more reliable energy supply, reduced noise level and benefits in terms of business reputation.

Figure 4: The solar PV system installed at the Travessia Beach Lodge in Mozambique. Asantys Systems GmbH.

Another example for the application of solar energy is the RES project in Tanzania, a country with great prerequi-sites for deploying PV, i.e. high levels of sun radiation. In order to be more independent of high electricity prices and reoccurring power outages, the Food Lover’s Market in Dar es Salaam decided to invest in a grid-connected roof-top PV system.

Figure 5: The grid-connected PV system on the roof of the Food Lover’s Market in Dar es Salaam. Deutsche Eco.

Travessia Beach Lodge, Mozambique Keven Stander “The construction of a PV system is a guarantee for clean energy from sustainable sources - this saves electricity costs and supports the green economy agenda.“

Example of application: PV-diesel hybridTravessia Beach Lodge, Asantys Systems GmbH, Mozambique

¡ Installed capacity diesel generator: 10 kVA ¡ Installed capacity PV: 7 kWp PV system with a

lead-gel battery ¡ Module type: 27 x Solarworld, Sunmodule Plus SW

260 Mono ¡ Inverter: SMA SB3600TL-21 (2x) und SI6.0H-11

(1x) ¡ Yearly yield: 6,200–7,300 kWh ¡ Yearly CO2 offset: 27 t ¡ Total cost: approx. € 30,000

Example of application: PV rooftop systemFood Lover’s Market, Tanzania

¡ Installed capacity approx. 15 kWp ¡ Module type: 64 x Heckert Solar NeMo P 230 Wp ¡ Inverter: SMA Tripower 15.000 TL ¡ Foundation: Schletter FlexXXL 4 x 16 modules ¡ Yearly yield: 20,600 kWh ¡ Yearly CO2 offset: approx. 8–10 t

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Community-scale useMoreover, PV-assisted pump systems can provide water for the rural population and cattle. These pumps are used to pump water from the spring to a higher water storage tank when the sun is shining. This means the water supply is also available for immediate use at night, obviating the need to use batteries. Furthermore, photovoltaics can provide electricity for water purifying systems to supply drinking water via solar ultrafiltration, as well as seawater desalination by driving pumps and PV-operated reverse osmosis.

Depending on the application, the modules are installed as complete systems fully configured and wired with invert-ers, charge regulators, batteries and other devices. Photo-voltaic systems can be designed as autonomous systems or as grid-connected installations. In autonomous systems, the energy yield corresponds to the energy requirements. If necessary, the energy is stored in rechargeable batteries or by means of heating water in a storage tank or supple-mented by means of an additional source of energy (hybrid system).

Wind energy

Just like PV modules, wind energy systems only generate electricity, which leads to a similar array of applications. However, there are important differences. As opposed to PV systems, which consist of connectable modules of application-defined sizes, the capacity of wind turbines cannot be adjusted in very small increments. Additionally, wind turbines have a higher minimum capacity. This limits the possibility to use wind energy for small, single applications, which is why wind turbines are much more suitable for (partially) powering entire buildings, indus-trial complexes and communities. While PV can easily be integrated into buildings or applications, wind energy often requires extra space specifically allotted to it, which also limits mobile applications.

Small to medium-sized wind turbines (with a rotor diame-ter of up to 20 m and an output of approximately 100 kW) offer a variety of possible applications in off-grid regions.

The advantages of wind energy ¡ Wind energy delivers clean and climate-friendly

electricity, often at competitive prices. ¡ Wind turbines cover a wide range of applications

from a few kW to several MW. ¡ Off-grid 10 kW turbines have the capacity to sup-

ply agricultural operations and small villages. ¡ Electricity generation even at night depending on

the local wind conditions. ¡ Wind power plants form the ideal basis for an

energy mix together with other renewable energy power plants, whether for the public grid, for hybrid power plants or for a mini-grid.

Domestic useSmall wind turbines can be used to generate electricity for households. Combined with storage technologies (see “Storage and grid technology”) small-scale turbines can assure all the energy needed in one or more households, e.g. for lighting, cooking, communication devices or other electric appliances. Small wind energy is actually used for special appliances and not widely used in the domestic area. Wind energy can provide quiet electricity and thus support or – depending on the prevailing wind condi-tions – replace conventional electricity sources, e.g. diesel generators.

Commercial and industrial useElectricity for factory buildings and commercial complexes can also be provided by wind turbines, which can be installed e.g. on or near buildings or at mines for electric-ity supply. For agricultural facilities, wind turbines can provide the power for operating water pumps. With larger sizes, wind turbines become increasingly relevant for buildings with greater energy demands, such as hotels and hospitals.

The electricity-generating output varies according to the prevailing wind conditions. Ideally, the wind speeds are measured over the course of a year in order to provide reliable forecasts for the future yield and facilitate the selection of the best plant configuration.

15


Figure 6: Four wind turbines installed at the Diavik Diamond Mine in Can-ada. Diavik Diamond Mine Enercon.

Example of application: wind energyDiavik Diamond Mine, Canada

¡ Installed capacity: 9.2 MW ¡ Wind turbines: 4 x ENERCON E-70, each 2.3 MW ¡ Yearly yield: 17 GWh ¡ Yearly CO2 offset: 12,000 t ¡ Used for: mine operation ¡ Total cost: $33 million

Community-scale useWith increasing size, wind energy can provide electricity for entire communities. Wind turbines function well within hybrid systems to complement the output of diesel generators or other renewable energy sources, e.g. PV.

Figure 7: Eigg Island, Scotland: The Scottish island, which has a popula-tion of around 100, has been operating its own island grid since 2008. The hybrid island system with an installed renewable generation output of 166 kW integrates solar energy, wind and hydroelectric power and battery stor-age. Two diesel generators serve as a backup. Energy costs have fallen by over 60 % since the conversion. Wind & Sun Ltd.

How rural areas can be provided with off-grid energy was demonstrated by a dena RES project in 2015. HEOS Energy GmbH installed two energy containers to supply the Mongolian University of Life Sciences with electricity. Mongolia has great prerequisites for exploiting wind and solar energy. The containers hold a battery system as backup and have PV modules mounted on top. Nearby, a small wind turbine was installed.

Figure 8: Modern island hybrid system for energy supply. HEOS Energy GmbH.

An example for wind energy usage in industry is the Dia-mond Mine in Canada. Four wind turbines were trans-ported to and installed at the Diavik Diamond Mine in Canada, 220 km from the Arctic Circle. For this challeng-ing endeavour, trucks had to transport the turbine parts across 400-kilometre long “ice roads” to get to the inland lake island on which the mine is located. The installed wind park is expected to replace about 10% of the diesel generator capacity, the only other energy source.

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Figure 9: Installation of the island hybrid system in Mongolia. HEOS Energy GmbH

some hydroelectric plants provide higher flexibility due to their storage capability. Similar to wind energy, hydro-power plants have a higher minimum capacity and are therefore not suitable for very small applications.

A RES project in Colombia exemplifies how hydropower can be used in off-grid regions. In 2015, Smart Hydro Power GmbH installed a river hydropower turbine and a PV system to power the irrigation pumps of a local rice farm. Previously, the pumps were solely operated by diesel generators. Now, 1,000 m3 of water can be transported from the river to the farm for one third of the cost. Thus, the installation will be amortised within five years. The setup of the system allows for modular expansion.

Example of application: wind-PV hybrid systemMongolian University of Life Sciences, Mongolia

Wind energy: ¡ Installed capacity wind: 15 kW ¡ Wind turbine: HEOS V15 ¡ Inverter: Smart!Wind SW-10 ¡ Yearly yield: 37 MWh ¡ Yearly CO2 offset: 25.9 t

PV: ¡ Installed capacity PV: 6.44 kW ¡ Module type: 28 x 230 Wp Heckert Solar ¡ Inverter: SMA STP 6.000TL-20 ¡ Yearly yield: 9.74 MWh ¡ Yearly CO2 offset: 6.8 t

Back-up system: ¡ Installed capacity and type, battery: Pb-Gel, 48 V

(24 x 2 V, 32 kW/16 k at 50 % DOD) ¡ Inverter: 3 x SMA Sunny Island 6.0-11 ¡ Installed capacity gasoline engine: 6.3 kW,

4-stroke OHV, 400V/3-ph

Small hydropower

Hydroelectric turbines also produce electricity and can cover applications similar to PV and wind energy or com-plement them in hybrid systems. The main difference is the more constant electricity supply provided by hydro-power plants, especially run-of-the-river plants. Also,

Advantages of hydropower ¡ It has base load capability and can provide grid

stabilisation: able to balance fluctuations in solar and wind energy by virtue of its constant availabil-ity and flexibility when the hydropower plant allows for water to be stored.

¡ Hydropower can promote regions which are not yet developed and connected to the grid and can provide decentralised energy.

¡ Proven technology.

Example of application:PV-hydropower hybrid systemRice farm irrigation, Neiva, Colombia

Hydropower: ¡ Installed capacity: 5 kW ¡ Generator: Permanent magnet generator ¡ Inverter: TriStar MPPT-60-600V-48 ¡ Yearly CO2 offset: 9 t

PV: ¡ Installed capacity: 2 kWp ¡ Modules: Yingli YL210P-26b ¡ Inverter: Studer XTM-400 ¡ Yearly yield: 2,815 kWh ¡ Yearly CO2 offset: 2.5 t

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Figure 10: Installation of a river hydropower turbine in Colombia. Smart Hydro Power GmbH.

Hybrid systems

Hybrid systems are autonomous off-grid systems which integrate more than one type of energy-generating tech-nology. They are used to supply off-grid power consumers with energy, can meet higher energy demands and provide electricity reliably, and are often used in off-grid systems with bigger capacities (from 500 kW). The connection of all electricity generators and consumers in DC operation enables a system to be designed or expanded flexibly and in a modular way using standard components. Common configurations consist of photovoltaics with diesel genera-tors (PV/diesel) or wind power with diesel generators (wind/diesel). Optionally, conventional diesel can be replaced with biodiesel. It is also possible to integrate a hydroelectric power plant into the system. If the energy requirement is high enough, larger hybrid systems, in particular with a conventional diesel generator, are eco-nomically attractive: they can run at lower costs than plants operated entirely on diesel.

There is a large market in complementing or replacing existing diesel generators in rural areas with renewable energy sources. Currently, there are an estimated 400 GW of diesel capacity (> 0.5 MW) in operation.

Figure 11: Mobile renewable energy hybrid system.

What are known as “energy containers” or “power contain-ers” are mobile variants of hybrid systems. With these, a wind turbine, solar module, battery (usually lithium-ion) and diesel generator are housed in a conventional freight container. Therefore, the hybrid system can be deployed quickly in changing locations.

A further technology also used for off-grid-applications is the fuel cell. Fuel cells generate electricity by a chemical reaction. A fuel cell has two electrodes, one positive and one negative, called, respectively, the anode and cathode. The reactions that produce electricity take place at the electrodes. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power fuel cell vehicles, including forklifts, automobiles, buses, boats, motorcycles and submarines.

Rice farm irrigation, Neiva, ColombiaCándido Herrera Gonzáles, SENA (Servicio Nacional de Aprendizaje):“This project is important and valuable for SENAʼs “La Angostura” training centre, located in the Huila region, wich is dedicated to training in the agribusi-ness sector. This enables our trainees, especially our experts, teachers and, supervisors, to get to know the companies and above all, to work with them.”

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Off-grid island systemsRenewable energies can also be used to construct off-grid island systems. Such mini-grids can power facilities rang-ing in size from individual buildings up to several small towns. In order to feed the electricity into the mini-grids, an inverter has to first convert the electricity into alternat-ing current (AC). Here, too, a storage module (e.g. a bat-tery, see “Storage and grid technology”) is integrated to ensure that electricity is available when required, even during periods of insufficient solar radiation or low wind speeds. As a rule, a mini-grid uses low AC voltage (220 or 380 V) with centralised generation and storage. The installed capacity is usually between 5 and 300 kW; larger systems are also possible.

If various technologies of energy generation – e.g. photo-voltaics, wind turbines, hydropower systems, batteries and diesel- or biofuel-powered electricity generators – are combined within an island system, a convenient, cost-ef-fective and long-term off-grid electricity supply system can be established. These systems provide electricity in a volume to meet the demands of relatively modern house-holds (lighting, refrigerator, telecommunications, water supply), to maintain public services (health centres, schools) and to develop small commercial operations. These systems are modular, can be expanded as electricity needs rise and can later be connected to the public grid.

A RES project in Angola is exemplary of how a combina-tion of different renewable energy sources can be utilised.

Example of application: hybrid systems using PV, wind energy, solar thermal energyMissionary station Sambo, Angola

PV-wind hybrid island system: ¡ Installed capacity PV: approx. 12.5 kWp ¡ Module type: 16 x SUNSET Twin 130 ¡ Inverter: SUNSET SUN3Grid® 6000 with Mini-

Grid SUNisland ¡ Solar batteries: Bloc OPzV 2000, 2000 Ah, 48

Volt; Bloc Battery 500 Ah, 24 Volt ¡ Installed capacity wind: 1 kW ¡ Wind generator: WG 1803 ¡ Used for: solar street lamps, 2 solar refrigerators,

20 lamps (damp room)

Deep-well water supply system (PV-operated):

¡ Installed capacity: 4.7 kWp

Solar thermal water heating system: ¡ Solar collectors: SUNSET SUNblue® 25 ¡ Gravity storage: 300 litres, including a heat

exchanger


The missionary station Sambo near Huambo uses a variety of technologies, including a PV-operated deep-well water supply system, a PV-wind hybrid system to power lamps and refrigerators and a solar thermal system to heat water.

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Solar thermal energy

Solar thermal energy is used for heating rooms and water, for cooling or dehumidifying air, for process heating and for drying purposes. It reduces energy costs for thermal energy, saving on fossil fuels for heating.

6. Heating and cooling

www.renewables-made-in-germany.com

SOLAR THERMALSOLAR THERMAL

www.kbb-solar.com

Areas of application for solar heating

Heating water for detached housesThis is the most common application for solar thermal ener-gy worldwide. In Europe, these systems are designed to provide 100 % of the warm water required in summer and 50–70 % in winter. They consist of a large collector with a surface area of 3 to 6 m2 and a boiler with a capacity of 200 to 400 litres for storing the heated water needed by a family of four.

Solar thermal energy systems for domestic water heating in a detached house: 1) Collector – 2) Solar storage tank – 3) Boiler – 4) Solar station with integrated solar controller – 5) Hot water consumer (e.g. shower)

1

2 3

5

4

Systems for heating tap waterSystems for heating tap water are typically designed to heat all domestic water throughout the summer period. In the winter months, the hot water is heated mainly by a heat gen-erator (a boiler, usually operated with gas, oil, wood or a heat pump), which is supported by the solar thermal ener-gy system on sunny days. This means that around 60 % of the annual heating requirements for heating water are pro-vided by the solar thermal energy system. The collector area required to do so depends on the weather conditions in the country in question.

Combi-systemsThe solar collector area of combi-systems is larger. These systems also help to heat the building in spring and autumn. Here, too, the collector area required depends on the weath-er conditions in the country concerned and on consumer

demand. The solar component of the total heating require-ment of the building is typically 20–30 % depending on how well the building is insulated and how much heat is required. However, there are also special solar houses that cover over 50 % and up to 100 % of the total heating requirement by means of solar thermal energy.

Provision and storageIn order to be able to use solar thermal energy on a larger scale, local and/or district heating grids must be set up and connected to sufficiently large storage tanks. Huge tank vol-umes are necessary if the solar heat is to be used via a dis-trict heat grid so as to enable entire residential districts to be supplied with heating and for the heat stored in the summer to be also available at cooler times of the year. For example, the heat can be stored in underground water-bearing seams (aquifers).

Providing process heat for industrial applicationsThere is enormous potential for solar thermal systems in the area of process heating: some 30 % of the industrial heat-ing demand is within a temperature range below 100 °C. Solar thermal energy can be supplied either at a supply level (industrial hot water or steam network) or at process level. The systems technology required for high temperatures is still relatively expensive; by contrast, process heating at tem-peratures of between 20–100 °C can be provided relatively quickly and can be developed at comparatively low cost. In future, it should be possible to achieve temperatures of up to 250 °C.

Project exampleIn Eichstaett in Germany, one of the roughly 100 pilot systems worldwide is supplying a brewery with water heated by solar thermal energy. In order to increase the economic viability of the brewery’s processes, the production processes were adjusted to suit the sun’s level of intensity. The system oper-ates with evacuated tube collectors on a collector surface area of 900 m² and two 60 m³ solar panels.

OutlookThe importance of solar heating technology has long been underestimated. With increasing energy prices and the devel-opment of innovative solar heating systems, increased devel-opment is to be expected in the future. The use of solar ther-mal energy in apartment blocks, hospitals, hostels, hotels and in industry is becoming more and more important.

Wagner & Co Solartechnik GmbH

Wagner & Co Solartechnik GmbH

Wagner & Co Solartechnik GmbH Bosch Thermotechnik GmbH

Figure 12: Solar thermal energy system for domestic water heating in a de-tached house: (1) collector, (2) solar storage tank, (3) boiler, (4) solar sta-tion with integrated solar controller, (5) hot water consumer (e.g. shower) Source: www.solarpraxis.de

Solar cookers concentrate the energy from solar radia-tion at the focal point of a parabolic reflector. Box-type designs (solar ovens) and panel cookers are also used. Concentrating the sunbeams creates high temperatures at the focal point, where a pot or pan can be placed to cook food. Solar cookers have the advantage that they save on firewood and the time needed to collect it. Additionally, they are mobile, user-friendly applications which can be deployed wherever needed. However, the cooker can only be used during the day, from around an hour after sunrise to an hour before sunset.

Figure 13: Diagrams of a solar oven, panel cooker and parabolic solar cooker.

Advantages ¡ Secure heat supply in comparison to, for example,

fire places or gas stoves. ¡ Reduced consumption of fossil fuels, considerable

savings in heating bills and more plannable heat-ing costs.

¡ Tried-and-tested technology that operates quietly and at a high level of efficiency.

¡ Simple technology with few moving parts and low maintenance requirements.

¡ Generation and consumption of heating/cooling in the same place, which reduces the need for infra-structure.

Domestic useHeating water for detached houses is the most common application for solar thermal energy worldwide. In Europe, these systems are designed to provide 100 % of the warm water required in summer and 50–70 % in winter. They consist of a large collector with a surface area of 3 to 6 m2 and a boiler with a capacity of 200 to 400 litres for storing the heated water needed by a family of four.

Systems for heating tap water are typically designed to heat all domestic water throughout hot periods. In colder months, the hot water can be heated mainly by a heat generator (a boiler, usually operated with gas, oil, wood or a heat pump), which is supported by the solar thermal energy system on sunny days. This means that around 60 % of the annual heating requirements for heating water are provided by the solar thermal energy system. The required collector area depends on the local weather conditions and individual water consumption.

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ing solar energy. Within a dena RES project, Industrial Solar GmbH together with Reach Renewables Ltd. installed a Fresnel solar thermal system on the roof of the corporate building of MTN to provide cooling for air conditioning and processors.

Figure 15: Fresnel collectors installed on the roof of the building.

Example of application: solar thermal coolingMobile Telephone Networks (MTN), South Africa

¡ Installed capacity approx. 275 kWth (cooling) ¡ Absorber: SCHOTT PTR 70 ¡ Fresnel collectors: 2 strings, each 11 modules ¡ Collector surface: 484 m2 ¡ Yearly yield: 391 MWh ¡ Yearly CO2 offset: 47 t

Additionally there is enormous potential in providing process heat for industrial applications using solar thermal systems: some 30 % of the industrial heating demand is within a temperature range below 100 °C. Solar thermal energy can be provided either at supply level (industrial hot water or steam network) or at process level. The sys-tem technology required for high temperatures is still relatively expensive; by contrast, process heating at tem-peratures of between 20–100 °C can be provided relatively quickly and can be developed at comparatively low cost. In the future, it should be possible to achieve temperatures of up to 250 °C.

One example for the utilisation of solar thermal process heat is the brewery Hofmühl brewery in Eichstätt, Ger-many. A solar thermal system is supplying the brewery with hot water. In order to increase the economic viability of the brewery, the production processes were adjusted to

Figure 14: Parabolic solar cookers in Tibet.

For purposes on a larger scale, e.g. community cooking or large kitchens, the need for a physical separation between the kitchen and the reflector arises. The reflectors can be used to generate steam which is conducted into the kitchen. An advantage of steam is that it can serve as a storage medium.

Commercial and industrial useSolar thermal energy has a variety of industrial and com-mercial applications. It can be used for heating drinking water (e.g. for hotels and hospitals), heating, cooling or dehumidifying the air, for providing process heat, for drying purposes, e.g. agricultural products, and for seawa-ter desalination.

For industrial use (on a smaller scale also for households), solar thermal energy, obtained through a collector, can make a significant contribution to operating air condition-ing systems. The advantage of this technology is that the need for cooling is greatest when the sun is most intense, whereby neither heat nor cold need to be stored over a long period. In addition to the immediate saving in fossil fuels, this also reduces the peak period power loads in summer. The increasing desire for a higher living standard and the trend of constructing buildings with large glass facades will probably increase the demand for environ-mentally friendly air conditioning systems. They present a reliable alternative, especially in warmer countries in which the power grids reach their limits as a result of the power demand of electrically operated cooling systems at peak times.

In South Africa, Mobile Telephone Networks (MTN) makes use of the country’s excellent conditions for exploit-

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suit the sun’s level of intensity. The system operates with evacuated tube collectors on a collector surface area of 900 m2 and two 60 m2 solar panels. It reaches process heat temperatures of up to 130 °C and replaces the use of roughly 45,000 litres of heating oil annually.

Figure 16: Solar thermal rooftop installation of the brewery. Hofmühl brewery in Eichstätt. Krones AG.

A final example is The Oxford Gardens Retirement Village, a retirement home in Ontario, Canada, which is supplied with cooling and heating by a solar thermal system that was installed by s-power. In 2011, the award-winning project was able to save 52 % of the energy required by the facility. It is also the largest solar thermal installation in Canada.

Figure 17: Ontario, Canada: the largest Canadian system to date for solar heating and cooling.www.s-power.de/Enerworks Inc

Community-scale useIn order to be able to use solar thermal energy on a larger scale, local and/or district heating grids must be set up and connected to sufficiently large storage tanks. Huge tank volumes are necessary if the solar heat is to be used

via a district heat grid so as to enable entire residential districts to be supplied with heating and for the heat stored in the summer to be also available at cooler times of the year. For example, the heat can be stored in under-ground water-bearing seams (aquifers).

As part of the dena RES Programme of the dena a large-scale solar facility was realised: the business hotel “Novo-tel Bengaluru Techpark” in India, which previously required approx. 17,000 litres of diesel per year to heat water, was equipped with 100 elevated solarthermic col-lectors. The solar facility on the hotel roof is connected with a 6,000-litre buffer tank, which provides approx. 60-degree hot water to the 215 hotel rooms, the restaurant kitchen and the hotel‘s own laundry. The facility, which was opened on 23 December 2014, covers about half of the hotel’s hot water requirements, thereby reducing its annual CO2 emissions by 30 tonnes.

Figure 18: Large-scale solar thermal facility in the “Indian Silicon Valley”. Bosch Solarthermie GmbH

Novotel Bengaluru Techpark in Bangalore, India Puneet Dhawan, General Manager Delegate, ibis and Novotel Bengaluru Techpark:“We are delighted to partner with Bosch who is helping us reduce our carbon footprint. Novotel’s initiative underscores the urgency that is needed for us to direct our efforts, to change our production and consumption patterns in line with the goal of pro-tecting our planet, its people and their environment.”

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Near-surface geothermal energy

Near-surface geothermal energy can be exploited for generating heating or cooling. Applications are therefore similar to solar thermal technologies and bioenergy in terms of heating purposes.

Geothermal energy is often used in combination with a heat pump to bring the temperature to the required level, e.g. for providing warm water. The electricity necessary for the operation of the heat pump can be provided by renew-able energy, e.g. wind energy or PV, which makes geother-mal energy suitable for hybrid systems. Depending on the specific technology used, plants of different sizes – from small residential units to larger complexes – can be sup-plied with heat or cold. The temperature level obtained by near-surface geothermal energy installations is usually insufficient for industrial processes. More information can be found in the geothermal energy section of the “Technol-ogies” chapter.

Example of application: solar thermalNovotel Bengaluru Techpark in Bangalore, India

¡ Collectors: 100 x Bosch Solar 3000 TF ¡ Collector surface area: 208 m² ¡ Buffer tank: 6,000 l ¡ Annual yield collector surface: 194.58 MWh/a ¡ Reduction in CO2 emissions: 30,000 kg/a

HEATING AND COOLING

Advantages of geothermal energy ¡ Near-surface geothermal energy plants have few

moving parts, generally low maintenance require-ments and user-friendly operation.

¡ Depending on the installation there is no extra above-ground space required.

¡ Geothermal energy is a constant supply of energy, independent of climate, seasons and weather con-ditions.

¡ The consistent temperature of the earth can pro-vide cooling in the summer and heating in the winter.

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Bioenergy

The predominant source of bioenergy is wood in the form of firewood, wood chips and pellets. Ovens and boilers – fed manually, partly or fully automatically with electroni-cally regulated firing systems – have been developed to contribute to a combustion process free from harmful substances at particularly high efficiency rates of up to 90 % and more.

Bioenergy, in the form of biomass or biogas, can not only be used to generate electricity or heat separately but also in a combined heat and power plant (CHP), through which very high degrees of efficiency can be reached. The waste heat produced by the electricity generation can be utilised for various purposes.

7. Generation of electricity and heating

Advantages of bioenergy ¡ Bioenergy is virtually CO2 neutral. It only gives off

the amount of carbon dioxide which the plants absorbed during growth. In terms of CO2, it is irrelevant whether wood decays in the forest or is used to produce energy.

¡ In addition, biomass is storable and flexible in use. ¡ Biomass is able to balance fluctuations in solar

and wind energy by virtue of its flexibility and con-stant availability.

¡ Biomass is available in almost all countries. ¡ The use of biomass helps to reduce problems of

waste disposal, while at the same time providing valuable energy.

¡ Agricultural regions benefit from the creation and safeguarding of jobs in agriculture and forestry, as well as throughout the entire production process.

¡ The use of bioenergy decentralises energy produc-tion and creates a material and energy cycle.

Figure 19: Biomass CHP Plant in Pfaffenhofen, Germany: waste convey-ance on biomass boiler (boiler front)

Domestic useOn a small scale, bioenergy can provide power for house-holds. The resultant exhaust heat of CHP plants can be used for room heating and to provide hot water. If the combined electricity and heat production takes place in a compact, decentral plant and not in a large-scale CHP plant, this is referred to as an apartment block-type ther-mal power station (BTTP). Micro BTTP plants, sometimes referred to as “thermal power stations”, are suitable for use within a building. They cover the lowest output seg-ment of all CHP systems (0.8–10 kWel). BTTP plants supply small, single buildings with heat and electricity, i.e. they are suitable for multiple-family dwellings, detached houses and for small commercial properties. The output of these systems is such that they can cover the average base load of electricity and heat for a single-family dwelling.

A programme in Nepal provides an example for the appli-cation of bioenergy. From 1997–2011, the German devel-opment bank Kreditanstalt für Wiederaufbau (KfW) helped the government of Nepal to build systems that produce biogas based on cow manure. The systems consist

GENERATION OF ELECTRICITY AND HEATING

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GENERATION OF ELECTRICITY AND HEATING

Community-scale useWith the increasing size of bioenergy plants, multiple households can be supplied with electricity and heat. The electricity produced can be fed into the public grid or it can be used to provide power to off-grid rural settlements. Waste heat produced by this electricity generation is then, for instance, utilised in local and district heating grids. It can also be used in downstream systems for additional power generation.

Example of application: bioenergySprings in Otoineppu, located on Hokkaido, Japan

¡ Installed capacity: 350 kW ¡ Wood biomass boiler: LCS-RV 300/350 ¡ Yearly used wood mass: 516 t ¡ Yearly yield: 485 MWh (thermal energy) ¡ Yearly CO2 offset: 163 t

of a subterranean tank (reactor) filled with organic materi-als (e.g. excreta) and a pipe system which directs the produced gas to the combustion points. The gas is used to operate cookers and lights. Just two or three cows provide enough manure to operate a small plant. The funds were provided by the Alternative Energy Promotion Centre (AEPC) which coordinates the funding policy for alterna-tive energies in Nepal. Approximately 300,000 plants have been installed so far as part of the funding pro-gramme.

Commercial and industrial useBioenergy can also serve as an independent power supply for industrial and commercial areas. The heat produced by CHP plants can be used to dry agricultural products or heat stables and greenhouses. Waste heat is made availa-ble to industrial processes as vapour or heat. It can also be used to produce cooling for industrial purposes, for refrig-erated warehouses or for cooling buildings.

A dena RES project in Japan shows how bioenergy can be applied. In 2014, the Nolting Holzfeuerungstechnik GmbH, in a joint venture with ECOS Consult GmbH, installed a wood-fired heating system in Otoineppu, located on Hokkaido. The temperature of the springs, pre-heated by geothermal energy, is further increased by the system, which also provides heating for the building. This completely eliminated the reliance on fossil fuels. Instead, regionally obtained wood chips are utilised.

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NON-TECHNICAL ASPECTS OF A SUCCESSFUL PROJECT IMPLEMENTATION

8. Non-technical aspects of a successful project implementation

In order to successfully implement a sustainable off-grid project, the consideration of a number of non-technical aspects is of critical importance: these range from basic questions about (co-) financing the project, the issues of attracting, employing and possibly qualifying staff, all the way to the regulatory environment, the government’s subsidy regime and community involvement. Further-more, comprehensive and exact demand data as well as access to spares and repair services are fundamental for the endeavour’s success.

Depending on the technology, the site and/or the align-ment of the system should be analysed carefully to ensure optimum yields, for example in wind energy, hydropower or photovoltaics. With wind energy, it is to make sure the wind conditions are optimal; with hydropower, to be considered the flow characteristics of the water, the water level and the characteristics of the bank. With photovolta-ics, the ideal alignment to the sun has to be ensured and shade avoided. Depending on the technology, system size and prevailing legal situation, legal aspects relating to construction, protection of nature and bodies of water must be checked and taken into account. For example, the tower heights of wind turbines may be limited by regional legislation. The design and implementation of the off-grid project must be in harmony with the overall rural electrifi-cation plan in the region.

Whether a project will be successful in the long term also depends on whether the staff on site are suitably trained and qualified. The capacities of local partners in terms of installation, operation and maintenance of the system still need to be developed, particularly in remote regions with limited market structures. Technical training must be provided using specific case studies and practised.

Professional knowledge and experience are required for the planning and design of off-grid systems. With this in mind, a reliable technology supplier should be selected that can help with the energy requirements analysis and cast a critical eye over the initial design proposals and optimise them if necessary.

Public support and promotion schemes

Public institutions and government bodies can play a vital role in the funding of off-grid power supply solutions, for example by enacting the appropriate statutory framework. However, in most cases the approach to funding renewa-ble energies is fundamentally different from that applica-ble to conventional energy technologies. Governments can designate areas that will not be considered for a grid expansion and operate a special funding policy here. Governments can provide funding or put it out to public tender. In another variant, governments establish a rural

Good demand data Least cost design

Subsidy commitment

Competent and dedicated PMU

Light-handed and simplified regulation

Access to spares and repair service over long term

Community awareness/ Involvement

Maximise opportunites for productive applications

Explore opportunites for international cofinancing

Consistent with rural electrification plan

Training to providers, users, government staff

Practical technology choices

Government ownership

Sustainable off-grid project

Appropriate delivery mechanisms

Source: World Bank, Designing Sustainable Off-Grid Rural Electrification Projects, 2008

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NON-TECHNICAL ASPECTS OF A SUCCESSFUL PROJECT IMPLEMENTATION

energy fund and offer to help with investments in the electrification of off-grid areas with grants on a first-come-first-serve basis. Another option is that an energy provider nominated by the government operates an off-grid island network at state-defined energy prices, but receives fund-ing from the state to offset the increased generation, operation and maintenance costs. Mixed models can also be very successful. In Sri Lanka, for example, micro-loans from the government combined with direct subsidies ensure that rural solar home systems are very widespread; over 100,000 Solar Home Systems (SHS) have been installed under the programme. Planning and building regulations along with preferential customs duties for relevant product lines can also have a positive effect on the establishment of off-grid projects.

Financing

Careful financial planning is also vital. Various project and consumer financing models are available. A distinction is drawn between general project plans that can access appropriate capital (tourism or telecommunications indus-try projects) and those that are primarily funded by means of loans or public subsidies. Micro-financing institutes (MFI) can offer loans to buy solar home systems. The energy requirement, consumption and affordability are taken into account in the decision to invest and the prepa-ration of the micro-financing plan.

The following DEG - Deutsche Investitions- und Entwick-lungsgesellschaft programmes offer financing for projects: “Business Support Services” - measures that support investments contribut

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