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Environmental Impacts of Renewable Energy: Part I

Explore the environmental impacts of hydroelectricity, including irreversible changes to landscapes, habitat destruction, and seismic risks, with a focus on large dam construction.

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Environmental Impacts of Renewable Energy: Part I

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  1. Energy and Environment Environmental Impacts of Renewable Energy-Part I Dr. Hassan Arafat Department of Chem. Eng. An-Najah University (these slides were adopted, with modification, from Ms. Paulina Bohdanowicz , KTH Institute, Sweden)

  2. Hydropower – large dams Average dam age – 35 yrs; 2/3 in developing countries World population of dams, by country (total of 45000 – in 2000) Source: WCD 2000

  3. Hydropower – large dams Construction time 5-10yrs. 160-320 new large dams per year; ~1700 large dams under construction in the past years Source: WCD 2000

  4. Potential causes of concern associated with hydroelectricity – construction phase • IRREVERSIBLE ENVIRONMENTAL IMPACTS • Local pollution • Modification of primary watersheds - radical change of landscape (inundation of large areas, deflection of rivers, creation of new infrastructure, loss of productive land/soils) - 20th century dams flooded appr. 0.5 million km2 of land – area of Spain • Destruction of habitats - threat to flora and fauna (extinction of some species, appearance of new species) - at least 20% of the world’s more than 9 000 fresh water fish species have become extinct, threatened or endangered in recent years

  5. Potential causes of concern associated with hydroelectricity – construction phase • Resettlement of local inhabitants (political and cultural conflicts, economic compensation) - large dams in 20th century – 40-80 million people worldwide, 3 Gorges Dam alone 1 million) • Loss of cultural/historical property • Pressure on natural resources • Often unpredictable effects

  6. Potential causes of concern associated with hydroelectricity – construction phase • China’s Three Gorges dam - the largest and the most powerful dam in the world • It will stretch 2 kilometers across the Yangtze River, stand 185 meters high, and create a 600-kilometer lake behind it

  7. Potential causes of concern associated with hydroelectricity - operation phase • Risk of seismic activity • In 1930, first case of seismic activity related with impounding was realised in Mead reservoir created by Boulder dam, USA • 70 such induced seismic effects have been known so far • 5 Richter or more in scale – 11 reservoirs • 6 Richter or more in scale – 4 reservoirs • Temporary phenomenon • Risk of dam failure (20th century – world except China – 10 000 people; China alone 1975 – 250 000 people) Source: Hydropower and Environments: Present context and guidelines for future action, Vol III, p.1-90

  8. Potential causes of concern associated with hydroelectricity - operation phase • Changes in river flow regime – up and down stream • Deterioration of water quality - possible health risks (dumping of municipal sewage and industrial waste, waterborne diseases in stagnant waters) • Loss of freshwater due to sedimentation • An estimated 0.5–1% of the total fresh water storage capacity of existing dams is lost each year to sedimentation in both large and small reservoirs worldwide. This means that 25% of the world’s existing fresh water storage capacity may be lost in the next 25-50 years in the absence of measures to control sedimentation. This loss would mostly be in developing countries and regions, which have higher sedimentation rates Source: Hydropower and Environments: Present context and guidelines for future action, Vol III, p.1-90

  9. Potential causes of concern associated with hydroelectricity - operation phase • Fish kills • No direct benefits for local communities, electricity usually transferred over long distances • Changes in local climate (large mass of stagnant water) • Possible emissions of methane (degradation of flora/organic matter in stagnant water)

  10. GHG emission from reservoirs • The gross emissions from reservoirs may account for between 1%-28% of the global warming potential of GHG emissions Source: WCD 2000

  11. Potential causes of concern associated with hydroelectricity - dismantling phase • Local landscape never returns to the initial state • Major risk of inundation and destruction • New change of environmental conditions • Disposal of the parts

  12. Positive environmental impacts of hydropower • Virtually no CO2 produced • Little other effect on the atmosphere (little local increase in water vapour, temperature effects, possible CH4 emission) • Negligible noise pollution • Limited risk of explosion, fire or emission of noxious chemicals • Dam construction can prevent flooding

  13. Solar energy

  14. Potential causes of concern associated with solar energy - unit construction • Use of toxic materials in manufacture of solar thermal, PV cells & batteries (cadmium, arsenic, hydrogen selenide gas) • Production and transport of parts (energy)

  15. Potential causes of concern associated with solar energy – facility location • Large scale systems only applicable to locations with high solar irradiation and sun availablity • Sequestration of large land areas (when constructed as grid-connected central station systems - 5 acres – 0.02km2 - of land per 1 MW of capacity) • 1 acre = 4046.8m2 • 1 hectare = 0.01 km2

  16. Large scale solar-thermal The largest ‘solar thermal-electric’ installation of its kind in the world, the Luz project in California’s Mojave Desert, has a peak output of some 350 MW and occupies several km2 of land Source: Godfrey et al, 2003

  17. Potential causes of concern associated with solar energy – facility location • Visual intrusion in rural and urban environments • Need forcooling installation/cooling water • cooling water - scarce in regions where solar insolation is high (need for water conservation) • water use for solar thermal plants is similar to amounts needed for a comparably sized coal or nuclear plants, but depends on the type of cooling tower (wet, wet-dry, dry) • Require backup system - fossil back-up system and/ or thermal storage: a fossil back-up system is needed in order to guarantee the electrical power during times of low solar irradiance; thermal storage systems reduce the amount of fossil fuel consumed

  18. Potential causes of concern associated with solar energy – facility operation • fugitive losses of Heat Transfer Fluid • the HTF is a synthetic organic oil, which decomposes during operation; light decomposition products are volatile and find their way out of the system; proper maintenance of the installations minimizes fugitive losses (losses can be reduced to 0.09 %/a of the total HTF volume, which corresponds to 0.0043 g/kWhe) • venting of light decomposition product of HTF • the light decomposition products of the HTF have to be vented regularly (about 0.03 %/a of the total HTF volume corresponding to 0.0016 g/kWhe); these can be captured in a condenser • HTF losses • in case of losses of HTF the contaminated soil has to be treated properly,e.g. in a bioremediation process; in California, total HTF losses are in the order of 1 % annually

  19. Positive environmental impacts of solar energy • Low or no emissions of gaseous or liquid pollutants (if operated properly) • Reduced impact on atmosphere • No moving parts – mechanically safe • General area of land used lower than in case of conventional plants (in life cycle perspective) • Job creation • Energy independence and security

  20. Wind energy

  21. Potential causes of concern associated with the wind power • Facility construction • Production and transport of parts (energy) • Land use (a modern wind farm uses only 1% of the land occupied and the towers only 0.2%.) • The average wind farm requires 17 acres (0.068 km2) of land to produce one megawatt of electricity

  22. Wind farms • This wind farm, at Carno in mid-Wales, is one of the largest in Europe. It incorporates 56 wind turbines, each with a rotor diameter of 44 metres and a tower height of 31.5 metres. The total installed capacity is 33.6 MW, sufficient to provide power for some 25 000 homes • The Middelgrunden wind farm, completed in 2001, is located in the sea just off Copenhagen harbour in Denmark. It includes 20 two megawatt wind turbines, which provide 3% of the electricity consumption of the Copenhagen municipality Source: Godfrey et al, 2003

  23. Potential causes of concern associated with the wind power • Facility operation • Visual pollution (sensitive landscapes), flickering • Land erosion • Noise (mechanical and electrical equipment; aerodynamic) • 200 meters away from a wind turbine a normal noise level at wind speeds about 8m/s is 45 dBA • Denmark: minimum distance to households 200m • Sweden: wind turbines are usually not placed closer than 300-500 meter from nearest household.

  24. Environmental impacts of wind power

  25. Environmental impacts of wind power • Facility operation • Electromagnetic interferences • Need of back-up • Risk for birds ?

  26. Estimated annual bird deaths in the Netherlands Source: European Commission1999

  27. Environmental impacts of wind power • Facility dismantling • Waste materials

  28. Positive environmental impacts of wind power • No release of CO2, acidic gases, particulates or radioactive pollutants • When wind exchanges fossil fuel savings are in the range of 11 800-18 000 tons CO2 per year for a 5 MW wind farm (UK) • Water or fuel supplies not required • Land can be utilised • Job creation • Reduced dependency on conventional fuels

  29. Comparison between wind and conventional energy technologies • A case study from Alberta, Canada • Wind power - a single 600kW wind turbine producing 1.3 million kWh of electricity annually • Alberta Inter-connected System: • Coal – 89% • Natural gas – 8% • Hydro electricity – 3% • Natural gas power Source: Mc Culloch, Raynolds, Laurie, 2000

  30. Comparison between wind and conventional energy technologies Ground level ozone precursors GHG Emissions Acid rain precursors Source: Mc Culloch, Raynolds, Laurie, 2000

  31. Potential causes of concern associated with geothermal energy • Construction phase • Drilling of wells, usually in wild, naturally sensitive areas (noise; steam escaping while well testing; disposal of chilling fluids; accidents)

  32. Potential causes of concern associated with geothermal energy • Operation phase • Emissions (open vs. close loop system) • CO2, H2S, HCl, HF, NH3, CH4, H2 • Solid wastes and noxios fumes • Brines/sluge (silica compounds, chlorides, arsenic, mercury, nickel, and other toxic heavy metals, even radon) – ground water pollution • Risk of land subsidence/induced seismicity • Water confilct due to the necessity of large amount for cooling • Visual pollution

  33. Emissions from coal and oil fired plants and geothermal power plant Source: Environmental and Economic Impacts of Geothermal Energy” Geothermal Energy Programme website http://www.eren.doe.gov/geothermal/geoimpacts.html as accessed 2002-03-24

  34. Potential causes of concern associated with geothermal energy • Dismantling • Construction materials • Altered ecosystem and landscape

  35. Positive environmental impacts of geothermal power • Exists basically everywhere (low T, for the use through heat pumps) • Net positive effect on environment as compared with conventional plant of the same power output • Low (no) emissions • Limited land required for the plant itself • Geothermal drilling safer than oil or gas drilling (limited fire and explosion risk) • Wide range of utilities • Independent of weather and climate

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