Renewable Energy Chapter 16

Energy Waste Need to improve –Energy Conservation –Energy Efficiency 4 Major Energy Wasters –Incandescent light bulbs –Motor vehicles –Nuclear power plants –Coal fired power plants

Improving Net Energy Electricity from Nuclear Power Plant Uranium processing and transportation (57%) Uranium mining (95%) Power plant (31%) Transmission of electricity (85%) Resistance heating (100%) Uranium 100% 95%54% 17% 14% Waste heat 14% Passive Solar Window transmission (90%) Sunlight 100% 90% Waste heat

Ways to Save Energy: Industry Cogeneration –Combine heating & power Use steam for electricity then to heat building 75-90% efficiency Recycling materials –Steel: recycling uses 75% less energy Switch from incandescent to compact fluorescent or LED bulbs –Compact fluorescents: ¼ energy –LED: 1/7 energy Update electrical grids

Ways to Save Energy: Transportation Stricter Corporate Average Fuel Standards –2008: raised to 35 mpg by 2016 Increase fuel efficient car market Show consumer “hidden” gas prices –Subsides & tax breaks Tax break on fuel efficient cars

Ways to Save Energy: Cars Superefficient and ultralight cars Gasoline-electric hybrid car Plug-in hybrid electric vehicle Energy-efficient diesel car Electric vehicle with a fuel cellfuel cell

Ways to Save Energy: Buildings Insulate and plug leaks Use energy-efficient windows Stop other heating and cooling losses Heat houses more efficiently Use energy-efficient appliances Use energy-efficient lighting

Ways to Save Energy: Future Buildings Green architecture Living or green roofs Straw bale house

Renewable Energy Using resources that can be rapidly reproduced in the environment for energy Types –Solar –Water –Wind –Biomass –Geothermal –Hydrogen

Passive Solar Heating System

Active Solar Heating System

Solar Thermal Systems Large fields of solar collecting systems Great for sunny places –Deserts –Mojave is the largest Unfeasible for widespread use –High cost –Low net yields

Photovoltaic Photovoltaic Cells Converts solar power to electricity Increasing efficiency Top users: –Japan –China –Germany Great for developing countries –Minimal infrastructure need

Photovoltaic Cells Metal conductor with silicon backing to exchange electrons to generate electricity

Photovoltaic Cells Major issue… –Cost

Hydropower World’s leading renewable resource 20% of the world’s electricity –Norway (99%) –New Zealand (75%) –Canada (59%) –China (21%) –United States (6%)

Hydropower Large scale systems in danger –Silt build up –Methane emissions Decomposition

Hydropower Future Microhydropower generators

Wind Indirect solar energy source Use to turn turbines to generate electricity 2 nd fastest growing source of energy –2009 leaders: China United States Germany Wind Potential –Could produce 40x world’s current electrical use

Wind Denmark –Most energy efficient country –20% of electricity from wind

Farmers receive $3,000- $10,000 per year

Biomass Energy Plant material or animal wastes that can be burned as solid fuel or converted into liquid or gas biofuels

Solid Biomass Wood and other wood products 10% of heating and cooking (worldwide) –35% less developed –95% poorest Wood is only renewable if harvested at a slower rate than it is replenished

Biofuels Types –Biodiesel (vegetable oil) –Ethanol (ethyl alcohol from plants/plant waste) Big producers –United States (ethanol) –Brazil (ethanol) –European Union (biodiesel) –China (ethanol)

Biofuels Major Advantages: –Biofuel crops can be grown almost anywhere –If replenished at the same rate as they are used, no net increase in CO 2 emissions Also if no deforestation occurs to grow crops –Biofuels fit into current transport systems

Biofuels Most cars – up to 10 % ethanol 2001 or newer – up to 15% ethanol 15% plus ethanol – fuel flex vehicles

Biofuel Chevrolet Impala LS and LT 3.5 Class: Midsize Car Base price range: $20,830 - $21,440 Engine: 211-horsepower 3.5-liter V6 EPA mpg city/highway (gasoline): 21/31 EPA mpg city/highway (E85 ethanol): 16/23

Geothermal Energy Stored heat in: –Soil –Underground rock –Fluids in Earth’s mantle

Geothermal Heat Pumps Heat & cool by exploiting temperature difference Ground constant temperature year round –3-6 meters –50-60 ⁰F

Hydrothermal Reservoirs Drilling wells to extract dry steam, wet steam, or hot water from deep underground reservoirs Uses –Heating –Aquaculture –Electricity United States largest producer –California –Nevada –Utah –Hawaii

Hydrogen 2H 2 + O 2  2 H 2 O + energy Eliminates most air pollution & global warming threats

Hydrogen Energy Problems Hardly any hydrogen gas in atmosphere –Takes energy & money to produce gas Expensive –Fuel cells CO 2 levels dependent on method of hydrogen production –Use electricity to decompose water