1

Energy and Environment

Environmental Impacts of Renewable Energy-Part II

Dr. Hassan ArafatDepartment of Chem. Eng.

An-Najah University

(these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden)

Biofuels as

energy source

• CO2-neutral – photosynthesis:

{CH2O} + O2 => CO2 + H2O

Combustion:{CH2O} + O2 =>

CO2 + H2O + energy

3

Wood, energy crops, waste,

dung etc.

Micro-algae and

oilseed crops

Alcohol fuels

Biogas

Syngas

Gasoline

Bio-diesel

Biological conv.

Direct combustion

Thermal conv.

Chemical conv.

Motor vehicles,

H2 fuel for fuel cell

Cooking

Heating

Steam generation

Electricity generation

H2 fuel for fuel cell

Motor vehicles

Motor vehicles

Pathways for production of biofuels

Potential causes of concern associated with biomass/biofuels

• LAND– Land use conflict - fertile land is used based on

cash oriented use, cash crops for export or food production. Pressure on farmers to cut down forest and cultivate virgin soil

– Deforestation - local wood extraction exceeds local production also due to land clearance

– Desertification - when forest are cut down and the surface of the ground is exposed. Evapotranspiration increases and the soil dries

– Erosion - gradual wearing away of land by water and wind

– Visual impact– Reduction in biological diversity– Typically high input of energy required (fertilisers,

harvesting processing)Source: Boyle et al. 2003; Baguant J., Life Cycle Assessment of Sugar Cane Bioenergy Systems for Electricity Production, PROSI Magazine – Jan. 1998 – No. 348 – Research, online paper available at

http://www.prosi.net/mag98/348jan/energ348.htm

5

Clearance

Cut downTypical

native

Chilean forest

Desertification : more surface exposed. Evapotranspiration

New plantation

Even worst: a cheaper way

No need to cut down the trees, No transportation needed,

Less man power.

Burning of virgin forest.

7

Potential causes of concern associated with biomass/biofuels

• New agricultural land, less retention of water in soil, desertification (higher evapotranspiration)

• Use of scarce water • Improper irrigation of energy crops => soil

salinity • Ground water pollution due to fertilisers• H2O for biogas production and distilleries =>

production of waste water rich in N2, phosphorous and potassium. These nutrients stimulate the growth of plant – eutrophication (depletion of O2 in lakes and rivers)

Source: Boyle et al. 2003; Baguant 1998

8

Potential causes of concern associated with biomass/biofuels

• Local effects - indoor pollution (biomass for heating)

• Regional effects - the main pollutants, SO2 and NOx. Soil and water acidification, damage to fish population, degradation of plants, effects on human respiratory function.

• Global effects: emissions of GHG– sugar cane bio-energy systems like the bagasse to

electricity fuel chain are in fact net emitters of CO2 – but compared to coal used for power generation,

the avoided CO2 (i.e. not emitted to the atmosphere) with sugar cane biomass can vary between 0.96 kg CO2/kWh and 1.10 kg/kWh

Source: Boyle et al. 2003; Baguant 1998

9

Potential causes of concern associated with biomass/biofuels

Most of biofuels in developing countries are used in households, having a more direct impact.

• Respiratory infections• Chronic obstrction lung diseases• Low birth

weights• Cancer• Eye

problems0

10

20

30

40

50

60

70

Exposure(GEE)*

Ruralindoor

Ruraloutdoor

Urbanindoor

Urbanoutdoor

GEE is the Global exposure equivalent, based on the pollutants concentration and the hours of exposed to the pollutant

Particulate Exposures in Developing CountriesParticulate Exposures in Developing Countries

Source: Boyle et al. 2003; Baguant 1998

10

Only production and combustion of biofules on a sustainable

basis is CO2-neutral

Positive impacts of biofuels as energy source

• Reduction of greenhouse gas (GHG) emissions along with odor by landfill gas extraction for bioenergy

• Reduction of NOx emissions

• Reduction of sulphur oxides emissions – using biomass for 5% of a coal-fired power

plant’s heat input would reduce SO2 emissions by aprrox. 5%

• Avoided emissions & landfill requirements by municipal solid waste combustion (MSWC) technology

Source: EREN, Renewable Electricity from Plant Material,

BIOPOWER, Department of Energy, 2002

Positive impacts of biofuels

as energy source• Provision of clean gas (biogas) for cooking,

heating etc. • Biomass energy crops can improve water

& soil quality and also improve biodiversity• Some energy crops can be used

for the treatment of wastewater• Reduction of water pollution by animal

waste, fertilisers and pesticides• Job creation/rural development

Source: EREN, Renewable Electricity from Plant Material,

BIOPOWER, Department of Energy, 2002

13

Positive impacts of biofuels as energy source

• According to EPA estimation, cars burning pure methanol & ethanol can reduce VOC emissions from the tailpipe by 85 to 95%, while CO emissions by 30 to 90%

• Both methanol & ethanol are likely to be key hydrogen fuels for fuel cells.

Cumulative CO2 benefits of ethanol compared to RFG in 2010 (NREL)

Bioenergy Information Network (BIN), A gateway to information about fast growing trees, grasses and residues for fuels and power, online

publications, last updated 08.02.02 available at http://bioenergy.ornl.gov/doeofd/biowin/stratgy.html

GHG emission intensities for selected fuels,

g CO2/kWh electric

Source: Boyle et al. 2003

Conventional coal

960-1300 Biomass 37-166

Advanced coal

800-850 Photovoltaic 30-150

Oil 690-870 Hydroelectric 2-410

Gas 460-1230 (220 CHP)

Wind 11-75

Nuclear 9-100

15

Costs of electricity with and without external costs

Electricity Source Generating Costs1 External Costs2 Total Costs

(cents per kilowatt-hour)

Coal/lignite 4.3–4.8 2–15 6.3–19.8

Natural gas (new) 3.4–5.0 1–4 4.4–9.0

Nuclear 10–14 0.2–0.7 10.2–14.7

Biomass 7–9 1–3 8–12

Hydropower 2.4–7.7 0–1 2.4–8.7

Photovoltaics 25–50 0.6 25.6–50.6

Wind 4–6 0.05–0.25 4.05–6.25

1For the United States and Europe.2Environmental and health costs for 15 countries in Europe.Source: Worldwatch Institute, State of the world 2003.

16

Energy & Employment

Germany: wind energy has a share of around 5 % of electricity generation and employs ~ 100,000 people, whereas nuclear power supplies 30 % of the electricity and employs only 38,000 people [Jochen Twele, Windenergie – Technik & Repowering, BWE, Berlin 2002.]

Source: Jochen Twele, Windenergie – Technik & Repowering, BWE, Berlin 2002

17

Other major environmental problems

• Water• Waste• Chemicals• Consumerism…

18

Water availability, in 1000 m3/inhabitant/year

Source: UNEP, 2002

Very low –

1 to 2,

Medium – > 5 to 10, High – > 10 to 20, Very high – > 20

Catastrophically low– < 1,

> 2 to 5, Low –

19

Selected water

stressed countries

Effluent from water desalination plant, Kuwait

Source: WCD 2000

20

Water pollution

Effluent from water desalination plant, Kuwait

21

Consumerism

• How much does one own?• How much of the things one has – one

does not need• How much of the things one actually

needs – one cannot find

September 12, 2001, vice president Cheyenne:

“If you are patriotic – go and buy something American”

22

Waste generation/disposal

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

Coal Oil Gas Wood Nuclear Solar PV

Ash FGD waste Gas sweetening waste Radioactive waste Toxic waste

million tonnes / GWeWaste generated annually in fuel preparation and plant operation

• History• Current

status• Mechanism

• Impacts • Mitigation

– No disposal of power plant waste law

23

Waste generation/disposal

Source: EEA 2003

24

Waste generation/disposal

Source: EEA 2003

25

Waste generation/disposal

Waste dump, Mexico

26

Soil degradation

Source: EEA 2003

27

Conclusion

• All energy sources and methods of conversion have environmental impacts

• Fossil fuels have the highest impacts, but RETs are not environmentally neutral either

• Nevertheless if externalities were included in energy costs – RETs would prove to be cheaper than conventional sources

28

Conclusion

• …and in order to achieve long term sustainability of human civilisation a shift to renewables is necessary

• Additionally, most of the renewables are available in developing countries and could be used to allow ”leap frogging” development of these countires (instead of transferring dirty technologies of industrialized world)

29