Power Plants 2020+Power Plant Options for the Future

and the Related Demand for Research

Statement of the VGB Scientific Advisory Board

2010

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Power Plants 2020+

Contents

1 Introduction 3

2 Generation Structure in the European High-Voltage Grid 4

2.1 Overview 42.1.1 Modern Fossil-fired Power Plants 52.1.2 Nuclear Power 52.1.3 Power Production based on Renewable Energies 6

2.2 Availability and Costs of Different Power Production Options 6

2.3 Costs of the Different Electricity Generation Options 7

2.4. Interaction within the Energy Supply System 92.4.1 Overview 92.4.2 Research Topics 10

2.5 Conclusion for the Generation Structure until 2020 11

3 Hard Coal/ Lignite Fired Power Plants 12

3.1 Coal Combustion 123.1.1 Efficiency Increase and Process Optimisation 123.1.2 Plant Optimisation and Increase in Flexibility 133.1.3 Carbon Capture and Storage Technology 143.1.4 Increase of Acceptance for the Fossil-fired 14 Share of the Generation Portfolio

3.2 Coal Gasification/IGCC Technology 153.2.1 Gasification and Gas Cleaning 153.2.2 CCS Technology 153.2.3 Hydrocarbons- and H2-Production 153.2.4 Increase of Acceptance 16

3.3 Material Development and -Optimisation 16

4 Regenerative Power Production Systems 17

4.1 Wind Energy 174.1.1 Research Topics 17

4.2 Solar Energy 184.2.1 Research Issues 19

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5 Nuclear Power 20

5.1 Generation III Reactors (GEN III) 20

5.2 Generation IV Reactors (GEN IV) 205.2.1 High-Temperature Reactors for Nuclear Process Heat Production 215.2.2 Fast Reactors 21

5.3 Research Demand 21

5.4 Summary and Perspective 23

6 Chemical Storage 24

6.1 Overview 24

6.2 Research Demand 24

6.3 Research Demand for ‘Chemical Storages‘ other than H2 25

6.4 Localisation of ‘Chemical Storages‘ in the European Net 26 and Feed-in of Regenerative Energy

Annex:

Members of the VGB Scientific Advisory Board 28

Members of the Editorial Committee “Power Plants 2020+” 32

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Power Plants 2020+

1 Introduction

Based on the investigations of the climate researchers collaborating under the umbrella of the Intergovernmental Panel on Climate Change (IPCC), the members of the VGB Scientific Advisory Board also share the opinion that electricity generation in Europe has to be switched to a maximum of low carbon generation technologies.

However, this target cannot be achieved in the short term and also not uniformly in all European countries due to the availability of resources required in energy conversion proces-ses, for reasons of national sovereignty and because of necessary quality.

Different European strategies exist according to natural potentials and attitudes towards nuclear power:

Countries like France, the United Kingdom or Sweden consider nuclear power as the most ·effective CO2-free resource for electricity generation;

Countries like Germany are striving for reduced CO · 2 emissions through further increasing the efficiency of fossil-fired power plants and through Carbon Capture and Storage (CCS);

Countries like Switzerland and Austria have a significant share of hydro power which ·might possibly be even extended;

Countries with suitable coastal regions like e.g. Denmark, the Netherlands, Great Britain ·and Germany support and boost wind power;

Countries in South Europe like e.g. Italy, Spain and Portugal dispose of solar energy that ·can be exploited.

This short overview already demonstrates that in the foreseeable future all generation options – nuclear power, fossil-fired power plants and renewable sources of energy – will continue to be applied. If, however, due to climate protection targets, energy conversion processes are to be to switched to CO2-free or -low carbon energy sources, comprehensive research ende-avours will be required in order to advance existing technology options and to adjust them to changing conditions.

This paper is bound to recommend individual fields of research from the viewpoint of the VGB Scientific Advisory Board for the period 2020 and beyond.

Firstly, the generation structure in the European high-voltage grid and its development until 2020 will be considered, then the research demand for

Hard coal- and lignite-fired power plants, ·

Renewables-based electricity generation (wind, solar energy) and ·

Nuclear-based electricity generation ·

will be outlined briefly, listing the main technology issues to be answered by researchers in order to increase efficiency and to settle any “loose ends”. Apart from generation technolo-gies, the options for storing electrical energy will also be dealt with. These options can con-tribute to make the feed-in of renewables-based electricity more permanent and sustainable.

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2 Generation Structure in the European High-Voltage Grid

2.1 Overview

The global financial and economic crisis that started in September 2008 also affected – alt-hough cushioned – the European energy sector. The consequences are manifold and can be characterised as follows:

Industrial enterprises throttled production and required clearly less electricity and heat, ·

Electricity consumption decreased over the complete year of 2009, in Germany alone ·by 6 %,

A lot of power plant projects had to be delayed due to financial problems, among them ·also large projects on the basis of renewable sources of energy.

Thus, compared to the growth rates assumed prior to the crisis, the increase in electricity generation until 2020 should be obviously smaller. It has to be supposed that the gross elec-tricity generation in the European high-voltage system that amounted to about 3,300 TWh in 2005 (Germany 585 TWh) will only increase to approximately 3,700 TWh in 2020 instead of 4,000 TWh as estimated before the crisis. The question arises whether and how the existing power plant park can be restructured by 2020 in order to cover the demand by meeting at the same time climate protection targets of minus 20 % greenhouse gases (EU) and minus 21 % CO2 (Germany) with reference to the 1990 values.

These figures reveal that all available sources of energy will have to make their individual contribution in order to meet demand and the politically agreed climate protection targets.

58 mm > 79 mm > 121 mm > 184 mm > 260 mm > 277 mm >

46 %

CO2-free

54 % Fossil firedpower plants

Nuclear and

Renewables

3,700 × 109 kWh

2005 2020

3,300 × 109 kWh

56 %CO2-free

Additional demand:400 × 109 kWh/aReplacement:800 × 109 kWh/a

Plus 12 % in 15 years (0.9 % per year)

44 %

Additional demandrenewables:

295,000 MW

Additional demandnuclear:

11,000 MW

Figure 1: Expected extension of power plants and its coverage for EU-27 (Source: VGB).

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Power Plants 2020+

Even if it would be managed to meet the increase in electricity generation through very am-bitious increases in renewable sources of energy, and even if above that the share of CO2-free nuclear power was kept constant by constructing new plants, this would not save a single tonne of CO2.

Therefore, the entire share of CO2-reduction in electricity generation would have to be reali-sed by fossil-fired power plants. This, however, could only be materialised by 2020 through a consequent and comprehensive power plant renewal programme, i.e. old plants with low ef-ficiencies will have to be replaced by highly efficient plants with cutting-edge technology.

Besides, central generation facilities will have to be advanced and further developed in order to enable them to cope with the increased feed-in of renewables-based electricity into elec-trical grids. They will have to compensate for the fluctuating and difficult to forecast diffe-rence between privileged feed-in-capacity and current demand, unless suitable storage opti-ons may become available that could store surplus renewables-based power. The existing pump-storage capacity is far from being sufficient, and the potential for new dams is in cen-tral Europe practically exploited. Therefore, conventional and nuclear power plants will have to operate more in load-following modes (including capability for steep load ramps, see chap-ter 2.4.1).

2.1.1 Modern Fossil-fired Power Plants

The focus will have to be on the construction of new plants with much higher efficiencies. However, this will not be sufficient to meet long-term climate protection targets, i.e. further steps will be required like e.g. CCS technology which will probably be available after 2020. CCS can also be retrofitted to existing power plants.

In order to meet demand and to be able to guarantee supply security at any time, about 170,000 MW will have to be built anew in Europe by 2020. This figure corresponds to about 200 large hard coal-, lignite- and gas-fired power plants (source: VGB PowerTech 12/2009).

In the past three years, real new construction only amounted to slightly more than 50 % of the calculated demand. Every cancellation or delay of any project, either in the field of rene-wables, nuclear power or fossil-fired plants, jeopardises climate protection targets. The same applies if electricity consumption will increase more until 2020.

2.1.2 Nuclear Power

CO2-free nuclear power remains indispensable in this energy mix. The further development and advancement of nuclear power forms the basis for a clean and secure future energy sup-ply in numerous European countries. Apart from Finland, France, Slovakia, Romania and Russia (e.g. at Kaliningrad) where nuclear power plants are already under construction, the United Kingdom, Italy, Switzerland, the Netherlands, Poland, Sweden, the Czech Republic, Lithuania, Slovenia, Bulgaria and Hungary have also launched or announced new nuclear construction programmes. The only countries which remain with phase-out decisions Germany, Belgium and Spain are striving for a prolongation of operating periods of nuclear power plants.

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Therefore, it can be assumed that due to the technically possible lifetime of nuclear plants, amounting to at least 50 to 60 years, in the coming decade only very few nuclear units will be decommissioned for technical reasons (namely in the UK), while new plants will only be commissioned after 2020 due to long planning and construction periods. A total of about 11,000 MW of new nuclear capacity have yet been announced in Europe to be completed by 2020 (capacity increases are not considered for reasons of simplicity).

E.g. in Germany nuclear power plants save every year about 150 million tonnes of CO2. This figure equals to the amount of CO2 emissions emitted annually by the entire German road traffic. This contribution to climate protection is for free and also increases security of supply.

2.1.3 Power Production Based on Renewable Energies

The EU targeted a share of renewables in final energy consumption of 20 % by 2020. According to current calculations, the major share of this extreme rapid development would have to be covered by wind energy. The portion of this source of energy will have to increase by a factor of eight between 2005 and 2020, requiring annual new construction of more than 5,000 on- and off-shore wind power plants.

A verification of this scenario jointly carried out with manufacturers of wind power plants turned out that about 40,000 MW of existing wind power plants will be decommissioned in Europe by 2020 due to aging. This is much more than e.g. the wind capacity currently instal-led in Germany.

Together with other renewable sources of energy like hydro power, biomass, biogas, solar thermal power plants, photovoltaics, geothermal energy and ocean energy, the total additio-nal power plant capacities required would amount to 295,000 MW in order to meet the European-wide targets.

This is an enormous challenge for manufacturers and operators. A look into the past makes it obvious: Annual new constructions would have to be increased by another third compared to capacity increases that have been realised since 2005, i.e. until 2020 about 800 billion Euros would have to be financed Europe-wide. The figure corresponds e.g. to one third of the German gross domestic product in 2009 (GDP).

2.2 Availability and Costs of Different Power Production Options

The high number of new renewables-based capacities to achieve the required portion of elec-tricity generation mainly results from the comparatively poor number of annual full load hours of wind power and photovoltaic plants. Due to natural conditions, wind and photovol-taic plants only produce power e.g. in Germany during approximately 20 and 10 % of all an-nual hours (8,760 h), respectively (source: BDEW 2009). Nuclear power plants, lignite-and hard coal-fired units accomplish much higher annual full load hours.

However, secure supply necessitates sufficient power plant capacity at any time. While “trus-ted”, i.e. planable electricity provided by nuclear, lignite-fired and hard coal-fired, but also gas-fired power plants amounts to more than 80 % of their respective nominal capacity, the “trusted” share of wind power even within the European interconnected grid only amounts to

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Power Plants 2020+

6 % (source: Deutsche Energieagentur 2005, www.DENA.de/dena-netzstudie). That means that for every MW of installed wind power 0.94 MW of conventional power plant capacity is needed as reserve to take over electricity production if wind does not blow.

2.3 Costs of the Different Electricity Generation Options

The organisation of the future energy mix must not only to be considered under the aspects of climate protection and security of supply, but also from the viewpoint of costs. Restructuring of the energy supply system has to be as cost-effective as possible in order not to unnecessa-rily endanger the competitiveness of European industrial sites.

Electricity generation costs that are based on different primary energy sources have been assessed in different studies; the OECD Study “Projected Costs of Electricity 2010” has com-piled a broad database from these sources (www.iea.org/publications).

The study, updated regularly, contains the costs from OECD countries for the power produc-tion options available in individual countries. Coal options also comprise CO2 separation cost. The study shows that

The cost level in Asia is clearly lower, ·

Nuclear energy is the most cost favourable energy conversion process in all regions, ·

On-shore wind can be competitive only under favourable conditions (America), and lies ·otherwise clearly above competitiveness (Europe, Asia),

Coal and gas (without CCS) can be competitive, ·

Annual full load hours of German power plants 2008

Source: BDEW

Nuclear

Lignite

Hard coal

Hydro

Natural gas

Wind

Oil

Pump storage

Photovoltaics

7 690

6 710

4 320

3 960

3 430

1 740

1 540

1 030

920

Availability1999 to 2008

Figure 2: Generation utilisation and energy availability of power plants at full load hours.

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including CCS results in an considerable increase in cost (up to 100 %), thus putting coal ·and gas on a comparable cost level like on-shore wind power,

The cost for off-shore-wind power plants are even higher (200 %) compared to the other ·generation options due to additional expenditures for foundations and grid connection.

The integration of CCS will make coal- and gas-based generation processes extremely expen-sive. Learning curve effects in connection with more stringent emission regimes for non-CCS-plants lead to the expectation that this technology could under these boundary conditions achieve market maturity in the next decade.

Whether additional cost for renewable sources of energy or CCS can be borne by the national economies will depend on the political decision making in individual states. Cost reduction potentials will have to be identified through research projects.

58 mm > 79 mm > 121 mm > 184 mm > 260 mm > 277 mm >

0

50

100

150

200

250

Nuclear Coal Coal w/CC(S)

Gas Wind Onshore

Nuclear Coal Coal w/CC(S)

Gas Wind Onshore

Nuclear Coal Coal w/CC(S)

Gas Wind Onshore

North America Europe Asia Pacific

CAN, MEX, USA, US EPRI AUT, BEL, CHE, CZE, DEU, Eurelectric/VGB, ESAA, JPN, KOR FRA, HUN, ITA, NLD, SVK, SWE

Median Line

US$/

MW

h

Figure 3: Full cost of electricity generation (including cost for CO2 separation of 30 $/t CO2 without transport and storage) of different electricity generation technologies for dif-ferent countries at an interest rate of 5 % (Source: OECD-International Energy Agency).

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2.4. Interaction within the Energy Supply System

2.4.1 Overview

In the conception of research topics after 2020 it is assumed that wind- and solar-based power, which will increase according to current forecasts, will lead to “natural”, but not yet solved requirements in connection with the controlling of the European high-voltage system: Grid operators must be enabled to compensate for the increasing share of fluctuating, sto-chastic energy. A large number of small, decentralised feed-in newcomers, consumers and storages will have to be integrated into the grid, preferably by applying common information technology, sometimes delineated as “virtual power plants”.

Seasonal, weekly, daily- and weather-related fluctuations of grid feed-in are quite remarka-ble according to scientific analysis. Therefore, further possibilities aiming at the compensation of grid fluctuations have to be urgently identified in addition to pump-storage plants and emerging “smart grids”. A statement of VDE1 characterises the situation as follows:

“Long-term storage with less than one cycle per week for compensating general weather conditions and seasonal fluctuations is hardly economically justified according to current criteria. However, long-term storages are the only means bearing the potential to sustainably replace thermal power plants yet needed for keeping reserves. Hydrogen storages or the con-version of today’s large barrier lakes into pumped-storage plants are the more cost-efficient technology options.” 2

Hence follows that completely new storage possibilities will have to be found in the long term on the basis of chemicals (cf. section 6). As long as such or other storage options are not yet available, existing coal- and nuclear-based electricity generation options would have in-creasingly to adjust to operation in the medium and peak load modes, because Europe-wide renewables-based electricity enjoys feed-in priority into the grid. The operation mode of con-ventional energy sources will be adjusted through:

Further development and retrofit of available coal-based technologies (i.e. taking proven ·process technology as basis for corresponding replacements) for medium and peak load operation,

Nuclear plants that can also be operated in the medium load range on demand. ·

The ’simple’ conception to shut down e.g. coal-fired power plants if wind power is supplied excessively, as it is possible with gas-fired power plants, is restricted due to the following drawbacks and side conditions:

It is not possible to shut down fossil-fired cogeneration power plants that are not only ·supplying power into electricity grid but which are simultaneously providing heat. The operation mode of using combined heat and power plants just to cover local heat de-mands can only be considered an emergency measure,

1 VDE / ETG – Task Force Energiespeicher: „Energiespeicher in Stromversorgungssystemen mit hohem Anteil erneuerbarer Energieträger“, Juni 2009; Herausgeber: VDE, Stresemannallee 15, 60595 Frankfurt

2 The potential of compressed air storages and battery systems as long-term storage for renewable sources of energy seems to be limited. Against this background, they are not considered in the following. However, it goes without saying that research is also required in these fields.

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Power Plants 2020+

Start-up and/or shutdown periods, ·

Minimum load requirements. ·

The weak points outlined above can already be noticed, although the bulk of wind power is still supplied by on-shore wind farms. The difficulties will even multiply if the anticipated additional wind power (40,000 MW in Europe and 10,000 MW in Germany) will be added by 2020.

Accordingly nuclear power plants display the technically most favourable load follow opera-tion. However, due to their high fix-cost structure they are not primarily used to control the grid for economic reasons.

2.4.2 Research Topics

In this situation the following research topics were identified:

As quickly as possible improvement of grid control capabilities of coal-fired power plants ·up to peak load operation in order to be able to integrate wind power;

Extension of operation regimes down to low minimum loads, minimization of startup and ·shutdown costs for all plants participating in load following operation;

Development of large power storage technologies on either physical or chemical basis for ·integration into the existing generation and grid structure;

58 mm > 79 mm > 121 mm > 184 mm > 260 mm > 277 mm >

Fast start-up, but very expensivein part-load operation.

Part load operation from 25 % possible.Economic also in low demand periods.

Intended for base load. Can be operated eco-nomically also in times of low load orhigh feed-in from renewables.

High Flexibilty of Conventional Power Plants: Gas, Nuclear, Hard coal and Lignite

Sprint Lurk Glide, Hover, Ascend

Gas New Hard coal Nuclear (Biblis), New Lignite (Neurath)

Biblis

Neurath

0%

20%

40%60%

80%

100%

0 10 20 30 40 50 60Min.

Capa

city

0%

20%

40%60%

80%

100%

0 10 20 30 40 50 60Min.

0%

20%

40%60%

80%

100%

0 10 20 30 40 50 60Min.

Capa

city

Capa

city

Figure 4: Load following operation of large power plants.

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Reliable IT connections between all modules of renewables-based generation for purposes ·of control, monitoring, visualisation and data storage, based on remote data transmission;

Improvement of electrical cable technologies especially for off-shore wind energy plants ·to the coast, especially in terms of losses, reliability, cost and environmental compatibility;

Extension of the high-voltage grid which mainly involves capacity improvements of cross- ·border transfer points along national borders.

2.5 Conclusion for the Generation Structure until 2020

Even if

electricity consumption will increase less than originally forecasted before the financial ·and economic crisis,

renewable sources of energy will be extended as described, ·

nuclear-based generation will slightly increase, ·

all possibilities will be exploited to acquire CO · 2 certificates outside the EU (Joint Implementation/ Clean Development Mechanisms),

the EU CO2 reduction target of minus 20 % by 2020 will not be achieved if the major share of CO2 reduction is not being performed by fossil-fired power plants. And this, however, can only be accomplished if power plant renewal programmes are being implemented with high in-vestments in latest coal and gas projects.

In summary that means:

The annual extension of renewables would have to be increased by at least one third. Grid ·and storage capacities would have to be enlarged in parallel.

Planned nuclear projects must be realised in due time, existing capacities must continue ·operation and should increase their individual capacities.

Nearly all new fossil-fired (gas and coal) projects that have been announced concretely ·have to be realised by 2020.

In Europe about 475,000 MW of new generation capacity will have to be installed by 2020. The entire cost will easily go beyond the billion (1012) Euro range.

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3 Hard Coal/Lignite Fired Power Plants

In the field of central coal-based electricity generation, two technology lines are of decisive importance:

Coal combustion and ·

Coal gasification. ·

Combustion is the coal technology that can be described as state of the art and which has to be further developed from this position. Although coal gasification is applied worldwide in chemical plants, this technology cannot be labelled as being proven for power plant applica-tion. The main advantage of gasification is the simultaneous utilisation of coal being conver-ted into gaseous and liquid fuels and into chemical base substances.

3.1 Coal Combustion

In the field of coal combustion, the development strategies launched for the decade 2011 to 2020 will have to be supplemented by additional requirements of climate protection. Hence efficiency increases will have to remain in the focus of attention because enlarged plant ef-ficiency will also result in improved economic efficiency and will save coal reserves at the same time. This is the basis to introduce CCS technology, because only high thermal conver-sion efficiency can lead to acceptable total net efficiencies that can compensate the high, inevitable efficiency losses caused by CO2 separation procedures.

Issues like

Efficiency increase and process optimisation, ·

Optimisation of operation and increased flexibility, ·

Introduction of CCS technology and ·

Improved acceptance for the fossil share of the generation portfolio ·

have already been addressed by researchers and will have to be continued in the period up to 2020. In this context the following individual objectives will have to be pursued.

3.1.1 Efficiency Increase and Process Optimisation

Efficiencies of pulverised fuel-fired power plants, either hard coal or lignite, can only be furt-her improved if on the one hand the live steam parameters are augmented and on the other hand individual components of the whole plant are systematically optimised.

Higher process parameters (mainly the increase of live steam temperatures from 600/620 to 700/ 720 °C) require development and application of nickel base alloys. A lot of important R&D projects are already under way in this field (COMTES700, 725 HWT GKM, etc.). However, development is still needed in order to test such new high-temperature materials for their long-term suitability and to qualify their manufacturing (shaping and welding). It is expected that this increase in live steam temperature will enhance electrical power plant net efficiency

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from currently 46 % to more than 50 % by 2020. Key developments could be new base alloys, composite materials and/or coating technologies.

Exploitation of these improvement potentials will have to start with the redesign of each component of the entire water/ steam cycle. This applies to the mechanical layout of compo-nents (e.g. the optimisation of gas and steam turbine blades) as well as to the minimisation of auxiliary power demand (e.g. speed-variable electrical drives).

Other individual measures are to be mentioned as examples for research topics:

Further development of waste heat recovery systems (arrangement and materials), ·

Improvement of measuring accuracy (maximising recapture from measurement ·uncertainties),

Further optimisation of lignite pre-drying and integration into the power plant process ·and

Broadening the application range of lower-cost materials for boilers and turbines. ·

The introduction of superconductors in electrical equipment can further increase conversion efficiency and above all it highly reduces specific material expenditure (copper).

The following economic advantages are expected from the introduction of superconductors for generators, electrical motors, cables and transformers: Material savings of more than 50 %, resulting in smaller dimensions and weights also for cranes, foundations, buildings, plant efficiency increase of 0.5 to 1.0 % points, corresponding to a capitalised efficiency gain of 50 to 100 % of the generator cost. Comparable electricity production costs and higher generator voltages should be possible in the long term.

Technical advantages are the increase in the maximum generator capacity from some 2000 to about 3,000 MVA, higher stability, smaller reactances, more idle power in unexcited operati-on, higher overload, higher asymmetric load tolerance, and the options to avoid hydrogen cooling especially in the case of generators and to avoid oil cooling for more transformers, thus minimising fire loads.

3.1.2 Plant Optimisation and Increase in Flexibility

Plant operations can be further optimised and plant dynamics, namely load following behavi-our and plant availability can be improved. Plant lifetime can be prolonged through extended application of digital control technology and more online condition monitoring.

Apart from pressure and temperature as important design parameters, lifetime of high-tem-perature components in coal- and gas-fired power plants is highly determined by the gra-dients according to which a plant is being started up and shut down or has to adjust its output. These design parameters will have to be much better harmonised in order to achieve optimum results especially with a view to the increasing demand to follow fluctuating load requirements (e.g. feed-in of wind power). Monitoring measurements (e.g. future precision measurement of temperatures above 700 °C to +/-1 °C using fixpoint thermocouples) are an important precondition to forecast power plant lifetime.

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Integration of lifetime calculations into control technology (“ageing management”) also calls for exact knowledge about characteristics of materials and their dependency on operating conditions. In parallel, operation simulation software tools should be developed further in order to optimise operation. Improvement of boiler cleaning devices is also an important issue for plant availability.

Investigations into minimisation of efficiency losses in part load operation and reduction of minimum loads are additional possible fields of research.

3.1.3 Carbon Capture and Storage Technology

If fossil primary sources of energy will continue to keep their large share in electricity gene-ration, then it will be inevitable to apply CCS (carbon capture and storage) technology. Since currently no clear advantage can be identified for none of the three options (pre-combustion, oxy-combustion, post-combustion), all three technologies should be developed. The drop of total plant efficiency associated to the application of CCS is the pivotal point for research and development both under ecological as well as economical aspects. This drawback must be minimised.

Concrete R&D is required to further advance the oxy-combustion process and the air separa-tion process itself. The oxy-combustion process requires optimisation of materials applied in the entire flue gas path and investigation of the accumulation of harmful substances along the flue gas path. Concerning post-combustion CCS processes, the application of scrubbing agents (degradation, energy demand for regeneration etc.), the separation process itself (heat transfer) and the integration into the power plant (provision of steam, integration of waste heat, etc.) have to be enhanced.

Supplementary process alternatives of the so-called second generation, aiming at the utilisa-tion of separated CO2 (e.g. “carbonate-looping” or “chemical-looping”) should also be inves-tigated in parallel. These developments will also be covered by current programmes, however, they cannot be considered as completed. Therefore, research has to be intensified in this field. However, it can be ascertained that the CO2 market will remain tiny in comparison to the amount of CO2 emissions released by power plants.

Transport and storage of separated CO2 can be technically realised and has been applied e.g. in the USA and Canada for a number of years in the oil production industry (“enhanced oil recovery”). CO2 has also been stored and monitored for some 15 years in other projects like e.g. in the Sleipner oil field in the North Sea.

Further research is needed to investigate CO2 storage in saline aquifers and the acceptance of such storage options.

3.1.4 Increase of Acceptance for the Fossil-fired Share of the Generation Portfolio

New fossil fired power plant constructions are more and more under pressure due to public acceptance problems. These problems will even increase when introducing CCS technology. Consequently a major portion of research should be devoted to technical variants as well as improvement of environmental protection and safety. Partial aspects could be the reduction

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of building height (to improve appearance) and an intensified employment of monitoring systems. Another important aspect is the safety case of CO2 transport and storage. Definition and explanation of “capture readiness” for new construction is also an important partial aspect.

3.2 Coal Gasification/IGCC Technology

Supplementing coal combustion, coal gasification can also be used to generate electricity (Integrated Coal Combined Cycle, IGCC). In future, however, generation of gaseous and liquid fuels as well as the production of base chemicals could play an important role (in centralised gasification plants) in order to improve supply security.

3.2.1 Gasification and Gas Cleaning

For both the above-mentioned applications, the “gas island” is vital (gasifier, quench/ partial quench, waste heat recovery and gas scrubbing), requiring further and more intensive R&D in order to reach economic parity. Depending on the individual application of the generated gas, its composition (H2, CO, CO2 and/ or CH4) has to be optimised. Development of materials is also important in this field (metallic and ceramic materials under chemically reducing condi-tions) and also further development of gas scrubbing processes (sulphur components etc.)

Co-gasification of biomass has to be further supported to improve the CO2 balance.

3.2.2 CCS Technology

Classical gasification with subsequent CO-shift reaction leads to high CO2 and H2 compo-nents in the gas, with the hydrogen being able to be utilized for electricity production in Integrated Coal Gasification Combined Cycle-(IGCC) power plants. This would require deve-lopment of a gas turbine for hydrogen combustion. However, special attention would have to be paid to NOX abatement.

3.2.3 Hydrocarbons- and H2-Production

Improvement is also needed in this field, because with classical thermal and physical methods, air separation consumes a lot of energy. This problem can partly be solved if the required O2 would be provided by electrolysis. While the oxygen would be used in the gasification proce-dure the valuable hydrogen could be used as intermediate energy storage, for the production of synthetic fuels or for direct energetic utilisation (fuel cell, H2-gas turbine etc). Energetic utilisation could take place at the gasification site or decentralised when fed into gas grids.

Hydrocarbons can also be generated from coal/ biomass gasification. The resulting synthetic gas can also either be used to produce a gas similar to natural gas which could then be fed into the gas grid, or to produce e.g. liquid fuels via Fischer-Tropsch-Synthesis.

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3.2.4 Increase of Acceptance

As with combustion technology, the public acceptance of coal gasification needs to be impro-ved. The generation of synthetic fuels and chemical base substances could promote argu-ments in favour of gasification because of their supply safety aspect. The large variety of in-put substances ranging from refinery residues over all coal grades up to biomass is another particular advantage. Fluctuating power load requirements could be met by adjusting electri-city and/or fuel generation according to demand.

3.3 Material Development and -Optimisation

Optimisation and further development of coal combustion and gasification technologies re-quire development and testing of materials to be used in different application ranges. This applies to cost-efficient materials for state-of-the-art technologies and high-temperature materials for 700 °C and beyond. Special endeavours are required to stabilise micro structure and material phases to guarantee high material strengths over long-term operations. Besides, corrosion-resistant materials are to be developed to be applied in the CCS process chain.

Manufacturing and process technology as well as material behaviour under multi-axial ten-sion loads and its calculation tools are also important R&D aspects here.

These activities should be harmonized with the R&D policy of Fachverband Dampfkessel-, Behälter- und Rohrleitungsbau (FDBR, Association of Steam Boiler, Pressure Vessel and Piping Manufacturers).

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4 Regenerative Power Production Systems

4.1 Wind Energy

Wind utilisation must be extended in order to meet the requirements of the European Union within the scope of its energy and climate package until 2020. By the end of 2009 a total of 21,164 wind power plants with an output of 25,777 MW were in operation in Germany alone. At that time, the installed capacity in Europe amounted to 74,767 MW and worldwide to 157,899 MW.

The capacity of future off-shore wind farms will be better than current on-shore units, which on average have a utilisation of 20%. These off-shore parks will be erected in distances of up to 100 km off the coast. The plants (all structures and systems) require light-weight construc-tions for logistical reasons and component strength. Experience yet made is based on medium class machine sizes (2 to 3 MW) that were erected on-shore or in regions close to the coast in shallow waters. Plants of the 5 to 6 MW range with tower heights of more than 100 m and rotor diameters of more than 120 metres are now becoming state of the art.

These plants and especially future generations of wind power plants after 2020 will need optimised structures and systems.

4.1.1 Research Topics

Main Structure, Rotors and Drive Train

Wind power plants see extreme dynamic stress with high load cycle numbers. Therefore light-weight constructions and corresponding materials and/or material systems with low specific weight, high strength and durability against environmental influences (corrosion, erosion) and high damage tolerance are needed. Consequent advancement of plant technology is thus of utmost importance to enhance technical availability. Apart from reliability, economic con-siderations also take into account parameters like weight, cost and efficiency. Especially off-shore wind power plants need innovative and low-cost foundations and erection concepts. Optimisation has to involve design, foundation, on-shore pre-fabrication, transport and in-stallation. Effective and safe solutions will have to be developed.

Rotor Blades

Capacity increases require longer rotor blades and a related increase in tower height. High load cycle numbers also enlarge the tendency to fatigue of composite materials and they are also decisive for plant lifetime. Research activities are needed aiming at optimised rotor bla-des, more corrosion-resistant surface coatings as well as for the automation of manufactu-ring processes.

The development of high-resolution and automated systems for the monitoring of rotor blade surfaces has to be accelerated. In the field of aerodynamics and aero acoustics research is required aiming at increasing efficiency and reduction of noise emissions. Measurements of turbulence fields near the rotor surfaces are needed to determine the real stress of rotors.

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Drive Train

The increase of output yields an increased torque in the drive train. Correspondingly, drive train, gear and generator are to be advanced. Currently two concepts are being employed: Gear or direct drive. In the field of e.g. gears the number of gear stages has to be reduced. The maintenance effort will have to be decreased in general to improve availability and reliability. This can be achieved through improved design principles, corresponding materials and adjus-ted manufacturing process as well as less component weights.

Condition Monitoring Systems

Highly efficient condition monitoring systems are needed to detect damages in due time and to restrict damages to limited areas through corresponding measures, thus preventing propa-gation of damages to other components. These systems support early detection of relevant changes to plant condition (especially for off-shore plants) in order to be able to plan main-tenance or replacement measures in due time.

4.2 Solar Energy

Utilisation of solar energy for electricity generation cannot yet be compared with the deve-lopment stage of wind power. However, it has a similarly high technical potential. Solar-based electricity generation is differentiated between photovoltaics (PV) and solar thermal electri-city (STE), often called concentrating solar power (CSP). Worldwide, at the beginning of 2010 around 20 GW of PV and approximately 1 GW of STE were installed.

One extraordinary feature of PV is its decentralised nature with small unit capacities. PV can also convert direct as well as indirect radiation in contrast to STE, which can only utilise di-rect sunlight. Although PV can theoretically be used in all climatic zones, both technologies mainly make sense in the vicinity of the Earth’s desert belt, where sunlight radiation density is higher.

Data on electricity generation costs vary according to technology and source. Currently the installed capacity of STE is lower, however, in terms of electricity generation costs an advan-tage of 0 to 50 % in comparison to PV can be quoted. STE-based electricity can have a higher value if it is fed into the grid more according to load demands in co-operation with inter-mediate thermal storages.

At the beginning of 2010 the capacity of the worldwide STE projects was said to amount to approximately 20 GW. From a European viewpoint it seems to be possible that in the medium term a similarly high amount of STE energy from the Mediterranean and North Africa could be fed into the European power grid as from the wind plants along the Atlantic and Baltic coasts. This approach has been formalised in the so-called “Desertec” project, under which STE plants (among others) are supposed to generate electricity in North Africa, and which might then be transported via high-voltage Direct Current lines to Europe.

It is expected that photovoltaics will grow annually by 10 GW in the period 2010 to 2015.

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4.2.1 Research Issues

The research demand of PV and STE is very different. Although cost reduction and increase in efficiency are the prime objectives in both technologies, STE is still in a much earlier stage of its learning curve than e.g. wind power or PV. Consequentially STE needs much more research and development.

Photovoltaics

In the case of PV current research endeavours and progress mainly refer more to production technologies and assembly logistics than to the actual electricity generation technology (mi-cro power plant engineering).

Line Focusing STE Systems

A high fraction of the costs of STE systems are investment costs. More cost-effective concen-tration technologies are thus the key to the reduction of overall system costs. It is expected that new approaches (e.g. parabolic trough system, Fresnel reflector systems, pneumatically formed mirror foils) will clearly improve this technology.

Apart from the concentrators, the absorber tubes play a key role. If oil is to be abandoned as heat carrier and if new systems with direct evaporating systems and thus higher conversion rates in the evaporation process should be employed, absorbers will have to be developed with less thermal losses for higher surface temperatures.

Thermal storage systems are among the most important advantages of STE in comparison to PV and wind. The current thermal oil technology uses liquid storage systems. If, however, higher process efficiencies are to be realised through direct evaporation, new storage techno-logies have to be developed in parallel, mainly latent heat storage.

Point Focusing STE Systems

Due to their potentially higher energy density, point focusing STE systems have a theoretically higher efficiency potential than line focusing systems. However, due to technical difficulties and also higher cost, this technology has commercially fallen behind parabolic trough sys-tems. The potential of the so-called solar tower concept is very high and this approach should not be neglected.

On the one hand receiver technology (e.g. ceramic absorbers, pressurised air absorbers, “beam down concepts”) and related system technology have to be developed. The theoretically high efficiency potential of the solar tower concept can only be realised in connection with gas turbine technology. Costs mainly have to be reduced through standardisation, effective cont-rol and optimised sizes of the so-called heliostats.

Finally it has to be mentioned that point focusing systems are the key to generate hydrogen on the basis of solar energy. Solar chemical processes for direct generation of hydrogen are much more promising in terms of efficiency than two-stage generation via solar power and high-temperature electrolysis.

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5 Nuclear Power

Any holistic assessment of the environmental compatibility of nuclear power has to take into account – apart from the lacking of climate-relevant greenhouse gases during operation – also emissions and residues caused by nuclear plant construction itself.

Experience shows that radioactive emissions occurring under normal plant operation are neg-ligible, i.e. these emissions are far less than the variation of natural radiation background. Radioactive exposure of plant personnel can also be considered as unproblematic due to in-tensive research and exposure monitoring. Radioactive residues from power plant operation can also be conditioned emission-free and can be stored safely in special interim structures.

Principally spent nuclear fuel or waste can be stored for good in geological formations. Since the time constants of geological stability e.g. of rock salt are by orders of magnitude higher than the radioactive half-life period of all sufficiently active nuclides of radioactive waste, it can be reasonably excluded that the biosphere will ever be jeopardised at any time. After some 10,000 years, the radioactivity of final storage products will have decreased to the level of natural uranium deposits, whereas e.g. rock salt formations remain stable over hundreds of millions of years.

Concepts are also being pursued which enable on the one hand partitioning, P, and on the other hand transmutation, T, i.e. conversion in the reactor by catching neutrons, thus trans-forming the “minor actinides” with long radioactive half-life periods into lighter isotopes with short radioactive half-life periods (but then higher activities). P&T technology will still require considerable research including experiments in view of the reprocessing procedure that will have to be adjusted, also in view of fuel element development as well as core design.

5.1 Generation III Reactors (GEN III)

The current advancement of nuclear reactors comprises the following development lines:

Evolutionary advanced light water reactors (e.g. EPR, MIR-1200, ABWR), ·

Revolutionary light water reactors with increased passive safety characteristics ·(AP-1000, KERENA),

Modular (small) nuclear reactors with even more inherent safety characteristics. ·

5.2 Generation IV Reactors (GEN IV)

Provided that nuclear power will keep its central position to cover in future the worldwide highly increasing demand in primary energy, it seems to be necessary to realise innovative nuclear energy technology. These reactors might increasingly incorporate principles of natural law (like gravity) for their safety functions that will reliably work in case of accidents without additional external energy.

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5.2.1 High-temperature Reactors for Nuclear Process Heat Production

High-temperature reactor HTR technology is an important module in the long term for envi-ronmentally competitive and resource saving electricity generation and energy conversion. The fact that HTRs are the only CO2-free high-temperature source for industrial applications is of particular interest. Apart from electricity generation it could also be used in numerous chemical processes, e.g. for generating hydrogen through hot steam electrolysis or for syn-thesis-, fuel gas- and fuel (methanol) production based on coal. This would lead to a reduc-tion of CO2 emissions of at least 40 % with reference to the entire fuel cycle and to currently employed coal upgrading processes.

In addition, HTRs are - due to their inherent safety properties - also suited as a heat source for decentral heating and even district heating systems in the low temperature range. Prototypes have only recently been completed in Japan and China. Especially in Japan, hydro-gen will soon be produced on a prototype scale with nuclear process heat in the HTTR 30 test facility. In the USA, the HTR is the core of the “Next Generation Nuclear Plant” (NGNP) pro-ject, supported by the US Department of Energy. This project is also aiming at hydrogen generation.

High-temperature reactors are already part of the GENERATION-IV programme that is also being supported by the European Union in view of future sustainable utilisation of nuclear power.

5.2.2 Fast Reactors

In the period after 2020 fast reactors should also be available. It remains to be seen how the economic efficiency of these nuclear reactors will develop in comparison to light water- and heavy water reactors, who have an economic advantage as long as uranium (and thorium, which is four times more abundant in the Earth’s crust than uranium) prices remain low.

Breeder reactors open up the full potential for further utilisation of the U-238 isotope, which forms 99.275 % of natural uranium and which all other reactor types can only use as additi-ve. With this technology, the total worldwide electricity demand could be covered economi-cally for several 100 years.

For sustainability reasons, it will also be needed to save resources within the nuclear fuel supply chain. For reasons of non-proliferation of former weapon plutonium, recycling in bree-der reactors can become a preferred choice. Therefore, France, the EU, Japan, China, Russia, India and Korea are pursuing the long-term advancement of fast breeder technology. India has developed a multi-stage policy involving breeders for utilising thorium deposits.

5.3 Research Demand

The “Sustainable Nuclear Energy Technology Platform” SNETP of the EU is currently compiling the short- and medium-term research demand in the field of nuclear energy. Examples are projects in the field of aging mechanisms, human factors, fuels, capacity increase, probabilis-tic safety analysis, waste minimisation, proliferation resistance, structure materials, safety proof and modelling.

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Special research demand was identified in the fields of

Lifetime management for long-term operation up to 60 or 80 years, ·

Specifically adjusted to individual damage mechanisms for individual components, ·

Influence of fast neutrons, thermal fatigue, corrosion, ·

Safety- and accident research; ·

Further improvement of economic efficiency through ·

Further increase of unit size, ·

Higher burnups, ·

Modular/series manufacturing (short construction periods); ·

Nuclear fuel technologies, ·

Investigation of the characteristics of current cladding tube materials under ·high burnup;

Development of innovative cladding tube materials for high burnup and higher ·coolant temperatures,

Investigations in alternative fuel cycles (e.g. thorium); ·

Thermo hydraulics/reactor physics, ·

Improved calculation codes for thermo hydraulic/reactor physical analyses, ·

Extension of the data bases and modelling possibilities e.g. for thermo hydraulic/ reactor ·physical extreme conditions (departure from nucleate boiling, neutron flux oscillation),

Securing of effectiveness of passive components for heat release in GEN III-reactors, ·

Investigations in the stability of boiling water reactors; ·

Materials technology, ·

Generation III: ·

Advancement of methods and concepts proving integrity of components by taking into ·account, fluid characteristics and neutron radiation and material condition,

Generation IV: ·

Same as for fossil-fired power plants because the same material group is being ·employed,

Development of materials with low sensitivity against neutron radiation, ·

Development of materials for hydrogen generation (iodine-/sulphur process). ·

The main targets of these research activities are the further improvement of plant safety as well as improving economic efficiency, minimising remaining knowledge uncertainties as well as providing more efficient – theoretical as well as experimental – evidence. Increased proli-feration resistance always has to be on the agenda.

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5.4 Summary and Perspective

Development of the past years has shown that acceptance for nuclear power is lacking in some countries although it is hardly likely that severe accidents will occur. Therefore, future nuclear power utilisation has to strive for solutions that are proving plant safety over the entire fuel cycle. The industrialised countries have a special function in this process and need to take a role as technology leader.

Today, nuclear power is covering about 6 % of the worldwide energy demand, i.e. 14 % of worldwide electricity generation. In the EU some 9 % of energy demand and 28 % of electri-city generation are met by nuclear power. This is mainly due to its intrinsic high energy den-sity, which is – apart from economic advantages – particularly suited to minimise the mate-rial flow.

In the meantime it has been proven by economic studies that nuclear power will keep its significant leading position in the worldwide electricity and heat industry when comparing the costs with gas- and coal-fired power plants equipped with CCS as well as with renewable sources of energy like wind and biomass.

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6 Chemical Storage

6.1 Overview

Hydrogen (H2) generation by electrolysis is one approach to achieve high-capacity energy storage. It still needs corresponding research activities. Commercial utilisation requires con-version efficiencies that have yet only been achieved on laboratory scale.

A promising option seems to be hot electrolysis called “HotElly”, where water vapour is being decomposed electrolytically at temperatures > 800 °C. Such a technology seems to be con-ceivable when combining power plant and electrolysis technology on one site. In such cases steam at 800 °C or more and at 30 bar pressure can be provided not only as agent for elec-trolysis but also as process steam at marginal cost for heating of electrolysis cells if e.g. wind-based electricity is missing due to calm.

Hydrogen is a highly efficient storage medium with reference to its mass unit. However, the system efficiency of common electrolytic splitting of H2O and subsequent re-conversion into electricity has to be clearly increased.

Apart from extending the H2 path, it is also possible to directly use surplus electricity from renewables-based generation (i.e. without H2) for operating energy-intensive electrolysis pro-cesses (e.g. production of caustic soda, aluminum etc.). This requires “operation” of the corre-sponding technologies in peak- or medium load mode, which still needs to be researched and developed. In such cases the basic substances generated are “chemical storages” instead of hydrogen. However, the economic value of these substances has to be considered in such a way that re-conversion into electricity, although technically possible, is not sensible in any case. The basic substances – generated through electrolysis – are mostly subject to timely fluctuations in demand, thus the “only” possibility is synchronisation of electricity generation and electricity consumption on the basis of renewables.

The technical potential of chemical storages has to be investigated with priority.

6.2 Research Demand

The following options are available to minimise average CO2 emissions of electricity supply and simultaneously to minimise grid fluctuations:

Hydrogen is generated as “chemical storage” by hot electrolysis using surplus renewables- ·based power; research demand mainly comprises

Thermally-induced electrolysis´ cell elongation in order to detect and control operation ·risks,

Supply of hot steam > 800 °C and 30 bar pressure through coal-fired steam generators ·or high-temperature reactors,

Selection of temperature and pressure layout data in accordance with suitable materials ·to maximise efficiency,

Maximisation of efficiency in accordance with wind power fluctuation. ·

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Hydrogen can be re-converted into electricity according to demand. One reconversion process using hydrogen (H2) that has been “drafted theoretically on paper” is the combination of SOFCs (Solid Oxide ceramic Fuel Cells) and a combined cycle process (expectation: hel ≈ 70 %). Both technological steps have not yet been state of the art for the desired large-scale size (e.g. 300 MWel).

Hydrogen is produced as a chemical base substance from surplus renewables-based power and later utilised in other production processes (e.g. synthetisation of hydrocarbons, produc-tion of ammonia (NH3) and/ or utilisation as reduction agent instead of CO) in order to de-crease the “CO2 mortgage” of these secondary base substances. This, however, requires that corresponding technologies can be operated in peak, medium or seasonal (campaign) opera-tion. These options will have to be investigated and - if necessary - the required technical steps would have to be identified.

The “production flexibility” yet emphasised as advantage of IGCC technology, namely the complementary generation of electricity and hydrocarbons (especially alcohol), could only display its full advantages if the hydrogen is generated from CO2-free electricity instead of being produced thermo-chemically from fossil fuels. Mainly the following fields need to be researched:

Gas turbine (operated with H · 2 and air as combustion medium) and

Scaling up of all steps to the required size. ·

The oxygen produced from electrolysis can be utilised in chemical processes or it can be of energetic advantage in the oxyfuel process provided it will be possible to re-convert H2 in a gas turbine of the IGCC process with air. One example for chemical process application of O2 is its utilisation in steel production processes.

In total the storage potential of these technologies could be equal to the capacity of pump storage plants.

6.3 Research Demand for ‘Chemical Storages‘ other than H2

Due to its physical properties, hydrogen is not the optimum seasonal storage; the possibilities mentioned above, i.e. conversion into substances that can be easily liquefied like methane, methanol or ammonia, would have to be applied if longer periods (e.g. from winter to summer months) should be compensated. Corresponding technologies are already available today; however, questions typical for power grid control like storage capacity and load change cha-racteristics of corresponding systems would have to be investigated and made available. Besides, its efficiency with reference to H2 and the energy needed for its production would have to be improved.

Particularly attractive seems to be ammonia (NH3) as chemical storage medium because con-trary to methane and methanol it uses nitrogen instead of carbon to bind hydrogen. Thus, no CO2 can occur when re-converting the storage medium into electricity.

Ammonia disposes of a high storage density and is an excellent option as basic chemical. This applies in particular to the field of ammonia production as artificial fertilizer. Fertilizer

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production from hydrogen and nitrogen is technically mature (“Haber-Bosch procedure”) and is being applied worldwide on a large scale (2,000 t/day = 500 MW energy equivalent). The high reaction temperature is even advantageous because waste heat at this temperature level can be better utilised in connection with power plant processes than e.g. in methanol production.

Decomposition (“combustion”) of ammonia into nitrogen and hydrogen is probably the most ambitious step of hydrogen storage technology, because the conventional process step causes considerable nitrogen oxide formation. Even with the aid of a catalyst, ammonia is only de-composed at higher temperatures (> 500 °C) (SCO process: “Selective Catalytic Oxidation”) thus requiring downstream SCR technology (SCR: “Selective Catalytic Reduction”) in order to reduce NOx emissions. Therefore, it is desirable to convert ammonia into electrical energy using fuel cells. Research has already yielded high-temperature fuel cells (SOFC) enabling conversion of ammonia chemical energy into electricity on a laboratory scale. Besides, rese-arch activities are under way aiming at the electrolytic decomposition of ammonia. Another promising approach is autothermal catalytic cracking of ammonia with a small portion of the ammonia being combusted in order to cover the energy demand of the cracking.

It can be concluded that the utilisation of ammonia as hydrogen storage is mainly realised by large-scale proven technologies that can be easily adjusted to meet demands of hydrogen storage. Research demand particularly exists to increase efficiency in the field of high-pres-sure ammonia synthesis.

The following issues should be investigated primarily concerning the re-conversion of ammo-nia for electricity:

Decomposition of ammonia at low temperatures, ·

Autothermal ammonia reformation, ·

Ammonia fuel cell. ·

If ammonia-based re-conversion into power can or has to be dispensed with because of too high costs, short- and medium-term surplus wind power can contribute to improve other CO2 emission balances of different industrial processes. Therefore, such processes have to be ana-lysed and to be opened up, i.e. processes that consume in the short term considerable amounts of electricity and will produce a storable base material (e.g. production of caustic soda, chlo-rine, aluminum production).

6.4 Localisation of ‘Chemical Storages‘ in the European Net and Feed-in of Regenerative Energy

The options outlined above can preferably be realised on large chemical sites that mostly have an own power plant at their site and are employed within the scope of co-generation as base load plant providing medium pressure process steam. Such a power plant type is able to supply all year round medium pressures and temperatures needed for chemical synthesis. Energy is favourably transferred via High-Voltage Direct Current HVDC. Among others, first wind parks are equipped with this technology and connected to the electrical grid.

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In addition to conventional HVDC with grid-connected converter and overhead power lines HVDC with self-controlled converters and polymer cables will have to be used. The connec-tion of off-shore wind plants requires seabed cable lines stretching over tens to several hun-dreds of kilometres.

Currently HVDC technology with self-controlled converters and polymer cables is available up to 1,000 MW and slightly above 300 kV voltage. Cables are much more accepted by the public than overhead power lines, thus making it easier to find routes. However, the costs of cable lines are very much higher than the expenses for overhead power lines.

A number of research issues have to be settled in connection with electrolysis systems and their integration into the existing structure:

Grid connection of a site and assessment of the transmission losses over distance, ·

Adapting the very high voltages of 300 kV to electrolysis cells voltages of some 1.2 V, ·

Controllability of the entire system, ·

Feed-in of residual energy if only a part is electrolysed, ·

Dimensioning and design of the entire system. ·

All steps outlined jointly have the potential to form the basis for new plants to be erected after 2020.

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Members of the VGB Scientific Advisory Board (June 2010)

Chairman:Dr. Johannes Lambertz Chairman of the Board, RWE Power AG, Essen Germany

Vice Chairman:Prof. Dr.-Ing. Eberhard Roos Stuttgart University Department of Mechanical Engineering State Materials Testing Institute (MPA) Germany

Members:

Prof. Dr. Christina Berger Technical University Darmstadt Chair and Institute for Materials Science (IfW) Germany

Prof. Dr.-Ing. Hans-Jörg Bauer Karlsruhe Institute of Technology Institute for Thermal Fluid Machinery Germany

Prof. Tadeusz Chmielniak Silesian University of Technology Institute of Machines and Power Generation Poland

Prof. Dr. William D’Haeseleer Katholieke Universiteit Leuven Energy Institute Belgium

Prof. Dr. Kim Dam-Johansen Technical University of Denmark Dept. of Chemical Engineering Denmark

Prof. Dr. Bernd Epple Darmstadt Technical University Department for Energy Systems and Energy Engineering Germany

Prof. Dr. Hans Fahlenkamp Dortmund University Faculty for Bio- and Chemical Engineering Chair for Environmental Engineering Germany

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Prof. Dr. Klaus Görner University Duisburg-Essen Chair of Environmental Process Engineering and Plant Design Germany

Prof. Dr. Markus Haider Technical University Vienna Institute for Energy Systems and Thermodynamics Austria

Prof. Dr. Thomas Hartkopf TU Darmstadt Institute of Electrical Energy Systems Department of Renewable Energies Germany

Prof. Dr. Antonio Hurtado Technical University Dresden Institute for Energy Engineering Chair for Hydrogen- and Nuclear Technology Germany

Prof. Dr. Mikko Hupa Abo Akademi Process Chemistry Centre Combustion and Materials Chemistry Finland

Prof. Dr. Johannes Janicka Technical University Darmstadt Mechanical and Process Engineering Department of Energy and Power Plant Engineering Germany

Prof. Emmanouil Kakaras National Technical University of Athens Laboratory of Steam Boilers and Thermal Plants Department of Mechanical Engineering Greece

Prof. Dr. Alfons Kather Technical University Hamburg-Harburg Institute of Energy Systems Department of Thermal Power Plants and Marine Engines Germany

Prof. Dr.-Ing. Reinhold Kneer RWTH Aachen University Energy and Process Engineering Germany

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Prof. Dr. Hans-Joachim Krautz Brandenburg Technical University Cottbus Chair Power Plant Engineering Germany

Prof. Dr. Reinhard Leithner Technical University Braunschweig Institute for Heat- and Fuel-Technology Germany

Prof. Dr. Bernd Meyer Technical University Bergakademie Freiberg Chair Energy Process Technology and Thermal Residues Treatment Germany

Prof. Dr. Günter Scheffknecht Stuttgart University Institute of Process Engineering and Power Plant Technology Germany

Prof. Dr. Viktor Scherer Ruhr-Universität Bochum Faculty of Mechanical Engineering Department of Energy Plant Technology Germany

Dr. Mihael Sekavcnik University of Ljubljana Faculty of Mechanical Engineering Slovenia Germany

Prof. Dr.-Ing. Hartmut Spliethoff Technical University Munich Institute of Energy Systems Germany

Prof. Dr.-Ing. George Tsatsaronis Technical University Berlin Institute of Energy Technology Energy Technology and Environmental Protection Germany

Prof. Dr.-Ing. Harald Weber Rostock University Institute of Electrical Power Engineering Germany

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VGB Offices:

Dr.-Ing. Karl Theis VGB PowerTech e.V. Essen · Germany

Dr.-Ing. Ludger Mohrbach VGB PowerTech e.V. Essen · Germany

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Members of the Editorial Committee “Power Plants 2020+”

Dr. Johannes Lambertz Chairman of the Board RWE Power AG, Essen Germany

Prof. Dr.-Ing. Eberhard Roos Stuttgart University Department of Mechanical Engineering State Materials Testing Institute (MPA) Germany

Prof. Dr. Hans Fahlenkamp Dortmund University Faculty for Bio- and Chemical Engineering Chair for Environmental Engineering Germany

Prof. Dr. Klaus Görner Duisburg-Essen University Chair of Environmental Process Engineering and Plant Design Germany

Prof. Dr. Markus Haider Technical University Vienna Institute for Energy Systems and Thermodynamics Austria Germany

Prof. Dr. Antonio Hurtado Technical University Dresden Institute for Energy Engineering Chair for Hydrogen- and Nuclear Technology Germany

Prof. Dr.-Ing. Harald Weber Rostock University Institute of Electrical Power Engineering Germany

Dr.-Ing. Karl Theis VGB PowerTech e.V. Essen · Germany

Dipl.-Ing. Ulrich Langnickel VGB PowerTech e.V. Essen · Germany

Dr.-Ing. Ludger Mohrbach VGB PowerTech e.V. Essen · Germany

VGB Scientific Advisory Board Klinkestraße 27–31 · 45136 Essen · Germanywww.vgb.org E-Mail: info@vgb.org