Ch 16 BIOL 101. Iceland. aims to convert to an economy based completely on renewable energy. excellent sources of geothermal energy and hydropower

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1 Ch 16 BIOL 101 Iceland aims to convert to an economy based completely on renewable energy excellent sources of geothermal energy and hydropower It also uses imported fossil fuels weak link in their economy hope to be Kuwait of the North get rich by exporcng hydrogen fuel Buses, private cars, and the fishing fleet would convert to hydrogen Although behind schedule Icelanders strongly support this effort NaCons looking to move away from fossil fuels while ensuring a reliable source of energy Biomass and hydropower are well- established and widely used New renewables are less used and their technologies are scll being developed Solar, wind, geothermal heat, and wave In addicon to being inexhausible, renewables can: Diversify an economy s energy mix Create Green- collar jobs a major new source of jobs dealing with the design, installacon and management of renewable energies 1

2 80% of our energy comes from oil, coal, and natural gas In the U.S., most renewable energy comes from hydropower and biomass. Growing at much faster rates than convenconal sources Wind power fastest growing But began at low levels will take Cme to build up 2

3 Biomass organic material that makes up living organisms biomass energy from many types of plant and animal maser Wood from trees, charcoal from burned wood, and combuscble animal waste products Biopower biomass sources are burned, generacng heat and electricity Biofuels biomass sources are converted into fuels to power automobiles More than 1 billion people use wood from trees as their principal energy source In developing nacons, families gather fuelwood for heacng, cooking, and lighcng Fuelwood, charcoal, and manure account for up to 90% of energy use Biomass is only renewable when it is not overharvested. 3

4 Ethanol produced as a biofuel by fermencng carbohydrate- rich crops Ethanol is widely added to U.S. gasoline to reduce emissions Any vehicle will run well on a 10% ethanol mix In 2007, the U.S. produced 30 billion L (6.5 million gal) of ethanol in 100 ethanol plants Flexible fuel vehicles: run on 85% ethanol But very few gas stacons offer this fuel Biodiesel a fuel produced from vegetable oil, used cooking grease or animal fat SequenCal Biofuels Some people use straight vegetable oil in their diesel engines It is essencally carbon- neutral, releasing no net carbon into the atmosphere. Only if biomass sources are not overharvested Only if we don t use fossil fuels to produce biomass Economic benefits include: SupporCng rural communices Reducing dependence of fossil fuel imports Less costly Improved energy efficiency Reduces air pollutants such as sulfur dioxide 4

5 Health hazards from indoor air pollucon Rapid harvescng can lead to deforestacon, soil erosion, and desercficacon Growing crops exerts tremendous impacts on ecosystems Decreased biodiversity FerClizers and pesccides Land is converted to agriculture Biofuel is compecng with food produccon Corn supplies for food have dropped SubstanCal inputs of energy are required Fossil fuels? Hydroelectric (hydro) power uses the kinecc energy of moving water to turn turbines and generate electricity The storage technique impoundments harness energy by storing water in reservoirs behind dams Water passing through the dam turns turbines The run- of- river approach generates energy without greatly disrupcng the flow of river water 5

6 Hydropower has two clear advantages over fossil fuels for producing electricity: It is renewable: as long as precipitacon fills rivers, we can use water to turn turbines. It is clean: no carbon dioxide is emised (sort of) Hydropower is efficient It has an EROI of 10:1, as high as any modern- day energy source. Damming rivers destroys riverine habitats Natural flooding cycles are disrupted Sediment deposicon Thermal pollucon of downstream water Reducing fish populacons and aquacc biodiversity NaCons with large rivers and economic resources have used dams. But hydropower is not likely to expand. Most of the world s large rivers have already been dammed. People have grown aware of the ecological impact of dams. 6

7 Virtually all energy comes from the sun great potencal in solar energy scll developing technologies to efficiently capture it Passive solar most common way to harness solar energy Buildings designed to maximize direct absorpcon of sunlight in winter AcDve solar and keep cool in summer uses technology to focus, move, or store solar energy Low south- facing windows maximize heat in the winter Overhangs shade windows in the summer Thermal mass construccon materials that absorb, store, and release heat By heacng buildings in winter and cooling them in summer passive solar methods conserve energy and reduce costs 7