APES Chapter 16 Review
Green Roods
Save energy, improve air quality, reduces storm water runoff, provides bird habitats
*CAFE Standards*
*Corporate Average Fuel Economy* -Government mandated standards for fuel efficiency *1973-1985 fuel efficiency rose sharply * *Since 1985, average fuel efficiency for new vehicles has decreased by about 21 MPG* -Government did not increase standards after 1985 -SUVs and trucks became more popular
Green Architecture
-Better architecture and energy saving building practives could save 30-40% of global energy -Green architecture takes advantage of: natural lighting, passive solar heating, geothermal heat pumps, cogeneration, solar hot water heaters, natural ventilation, recycled building materials, energy efficient lighting, rainwater collection, efficient water use
Future of Solar
-Currently 0.2% of electricity, but if tax breaks and other subsidies are used, it could eventually provide 16% by 2040 -Can now print cells like printing a newspaper (flexible and light) at half the cost of rigid panels -Could become most widely used form of energy withing two decades -Estimates are that if solar cells are put on just 4% of the world's desert, it could supply the entire world with energy -Solar industry could become one of the world's largest -Germany (even though it is cloudy and rainy) is the largest producer of solar energy --Huge governmental investment
Energy waste
-Energy Conservation- Decrease in energy use based on reducing unnecessary waste of energy -Energy Efficiency- Measure of how much work can be gained from each unit of energy -84% of all commercial energy used in the US is wasted. 41% is unavoidable because of degradation (2nd law of Thermodynamics). 43% is unnecessary waste because of inefficiency -Energy waste in the US costs about $570,000 per minute -Reducing energy waste quickest, cleanest, and often the cheapest way to provide more energy, reduce pollution and environmental degradation, slow global warming, and increase economic and national security
Diesel
-Energy efficient diesel- 30% more fuel efficient, 20% less CO2 -Diesel fuel can be made from coal, plant material, and cooking oil -Hybrid- Electric diesel cars would be more efficient than gasoline hybrids
International Standards
-Europe, Japan, China, and Canada have much higher fuel efficiency standards than the US -The US raised CAFE standards to 35 mpg by 2020, but that will still keep them well below other countries
Hydrogen
-Fuel cells that combine hydrogen gas and oxygen to produce electricity and emit water -Would eliminate air pollution problems and reduce climate change (produces no carbon dioxide)
Geothermal
-Heat stored in soil, underground rocks, and fluids -Used to heat and cool buildings as well as produce electricity -Estimated that using 1% of the heat in the upper 5km of earth's crust could provide 250 times more energy than oil and natural gas reserves
Problems with Hydrogen
-Hydrogen is chemically locked up in water and organic compounds- takes energy to separate it (net energy yield will always be negative) -Fuel cells are very expensive -Produces no carbon dioxide directly, but the energy to separate hydrogen uses conventional energy sources -Pure hydrogen and pure oxygen are explosive
Hydrothermal Reservoirs
-Iceland has done this for decades -Drill wells into reservoirs to extract steam and hot water which is used to heat buildings and produce electricity -Cool water is pumped back to be reheated -US is the largest producer of geothermal energy (mostly in California, Nevada, Utah, and Hawaii) -Releases 1/6 as much carbon dioxide as a natural gas power plant
Major energy wasters
-Incandescent lightbulbs- Use only 5-10% of the energy it draws to produce light (90-95% wasted as heat) -Internal Combustion Engine- Wastes 94% of energy in its fuel -Nuclear Power Plant- Wastes 83% of energy in nuclear fuel (92% when entire nuclear fuel cycle is included) -Coal-fired Power Plant- Wastes 66% of energy from coal (75-80% if energy to access and transport coal is included
Wind Power
-Indirect form of solar energy (difference in heating between equator and poles combined with earth's rotation) -Today's turbines can generate 20 times more energy than those produced in the 1980's -2nd fastest growing source of energy -Germany hopes to get 30% of its electricity from wind by 2030 -Capturing only 1/5 of the wind energy at the world's best sites would generate more than 7 times the amount of electricity currently used in the world
Industry
-Industry accounts for 30% of world energy consumption (38% for US) -Co generation (Combined Heat and Power)- producing heat and electricity from the same fuel source --This can increase energy efficiency from 30-40% to up to 80%. It also emits 1/3 less less CO2 -Energy-wasting electric motors- Only run at full speed. Replacing could save the equivalent of 150 coal power plants of energy -Recycling- It takes 75% less energy to produce steel from recycled than from virgin ore. Cement industry could cut energy use by 42% -Lighting- From incandescent to fluorescent and LED
Existing Buildings
-Insulate plugs and leaks- up to 1/3 of heated air escapes -Energy efficient windows -Other heating and cooling losses -Heat houses more effectively -- Passive solar heating, geothermal heat pumps -Heat water more efficiently- solar H2O heaters, tankless water heaters -Energy efficient appliances -Energy efficient lighting
Wind Energy Challenges
-Locations with greatest wind potenetial are often located far away from heavily populated areas (need to expand the current grid system) -If winds die down, it requires a back up energy source --Could store wind energy with plug-in hybrids or passing it through water to make hydrogen fuel cells --Could store it in the form of compressed air -Does occasionally result in the death of birds (40,000 birds a year) but other sources like windows, buildings, and electrical transmission towers kill over 1 billion birds a year -Perceived as noisy and ugly --Farmers can earn $3,000-$10,000 per turbine per year
Geothermal Heat Pump
-Loop of pipes -In winter extracts heat from ground -In summer deposits heat in ground
Is Ethanol the Answer?
-Made through distillation of sugars from sugarcane, corn, and switchgrass -Gasogol- 10-23% ethanol with gasoline can be burned in conventional engines -E85- 85% ethanol (flex fuel) -Brazil is the 2nd largest ethanol producer (behind US) --45% of Brazil's vehicles run on ethanol --Saved $50 billion in oil costs since 1970's (10 times investment in ethanol) -In the US, ethanol is made from corn --Huge government subsidies -Net energy is only 1.1-1.5 units per unit of fossil fuel -May increase climate change because of huge amounts of nitrogen fertilizers used to produce corm (greenhouse gas nitrous oxide)
Energy Transition
-Need to : improve efficiency, use a mix of renewable energy resources, and include environmental costs into market places -Supply-side (hard path)- finding more nonrenewable resources -Demand-side(soft path)- reducing energy waste and depending on a mix of renewable resources -Make a shift from centralized macropower systems to smaller, decentralized micropower systems
Photovoltaic (PV) Cells
-Often called "solar cells" -Thin wafers of purified silicon with trace amounts of metals that allows them to focus as semiconductors to produce electricity -Can be connected to the grid (earn money back from power company) or to batteries (store energy) -Safe, quiet, little maintenance, produce no pollution, last as long as a commercial power plant -Good tool for developing countries not connected to an electrical grid
Energy Accounting
-Only energy that really matters is *net energy*. (Must combine the efficiencies of all steps in the process)
Biomass
-Plant materials and animal wastes that can be directly burned or converted into gas or liquid bio-fuels -Supplies 10% of world's energy (35% in developing countries and 95% in poor countries) -Wood chips and waste can be burned to produce electricity and heating systems (half of the heating in Sweden, 80% of downtown St.Paul, Minnesota) - Wood is renewable as long as it is not harvested faster than it is grown (choose fast growing plants/trees) -Can also use waste materials from crop harvests
Biodiesel and Ethanol
-Produced from plants and plant waste -Reduces dependence on imported oil -Crops not used faster than they are replenished (no net increase in carbon dioxide emissions) -Can be distributed through existing networks -Problems: Decreases biodiversity (monocultures), soil degradation (erosion, nutrient leaching), raise food prices
Hydropower
-Relies on the water cycle (indirect form of solar energy) -Most common means of production is to build a dam and create a reservoir -3rd cheapest way to produce energy (when environmental costs are considered) -Global warming could have an impact on this -Micro-hydropower- small and placed in stream (low cost, almost zero environmental impact)
Hybrid Vehicles
-Replacing the US fleet would cut US oil consumption by 70-90% (eliminate need for foreign oil imports) and reduce CO2 emissions by 27% --If the vehicles were recharged by wind, solar, or hydro power CP2 emissions would drop by 80-90%
Solar Cookers
-Small scale -Focuses and concentrates sunlight to cook food -Coist only $2-10 to build -0 pollution way to cook
The Grid and Industry
-The grid wastes hge amounts of energy. Converting to a digitally controlled network could save $100 billion per year -Dow Chemical is on track to cut its energy consumption in half by 2015. Their energy savings will equal the amount used by the entire nation of New Zealand --These energy efficiency improvements cost Dow $1 billion dollars, but have saved about $5 billion already
Solar Thermal System
-Transform energy from the sun into high-temperature thermal energy which can be used to heat water and produce steam and generate electricity -Central Receiver System- Mirrors (heliostats) track the sun and focus sunlight on a central heat collection tower (power tower) -Sunlight can also be focused on oil filled pipes -Theses systems have high costs, low energy yields, and few sustainable sites
Ocean Tides and Waves
-Turbines placed in tidal zones to harness the power of the tides -Chains of floating steel tubes can be installed along coasts with continuous waves that get energy from up and down motion (In Portugal this produces enough electricity for 15,000 homes)
Fuel Cells
-Twice as efficient as internal combustion engines -Use hydrogen gas as a fuel to produce electricity with no carbon dioxide emissions
Straw Bale Houses
-Type of superinsulated home -Made by stacking compact bales of straw (renewable resource) then covering the outside with plaster
Is Biodiesel the Answer?
-Vegetable oil from soybeans, sunflowers, etc... -Type of plant used impacts how much biodiesel can be produced -40% more efficient than conventional gasoline engines -Could produce 10% of US diesel fuel needs
Californian Model
-Very powerful/influential (on its own, it would be the world's 5th largest economy) -Uses less energy per person than any other US state --Average US citizen uses 12,000 kWh of energy per day --Californians use less than 7,000 kWh (save $800 per person) -Higher electricity rates (promotes energy efficiency) -California has decreased carbon dioxide emissions by 30%
Super-insulation
-When a house is so heavily insulated and airtight that heat from direct sunlight, appliances, and human bodies can warm it with little or no use of a heating system -Air to air heat exchangers prevents indoor air pollution -Costs 5% more to build (this cost is made up within 5 years). Can save $50,000-100,000 over a 40 year period -Super-insulated houses in Sweden use 90% less energy than similar homes in America
Offshore Wind Farms
-Wind speeds are often stronger and steadier over water -Installation costs are higher -Critics site "visual pollution" --Cape Cod, Massachusetts --Lake Michigan
Passive Solar Heating
Absorbs and stores heat from the sun directly withing a well insulated structure without the need for pumps or fans to distribute
Active Solar Heating
Absorbs energy from the sun by pumping heat absorbing fluid (such as water) through collectors on the roof
Transportation
Accounts for 2/3 of US oil consumption, and is a major cause of air pollution and CO2 emissions
Cost of Solar Energy
Costs are expected to go down as mass production begins
LEED Certification
Prime candidate are schools. Green building techniques save money over the long run (although they do cost more upfront)
Fuel Efficient Vehicles
Should be at least 35 mpg --Ex. Toyota Prius -Fuel efficient cars are only 1% of new vehicle sales -True cost of gas could be estimated at $16 per gallon when all factors are taken in to considerations -Government does not incentivize fuel efficiency through subsidies and tax breaks --Ex. Small business could buy a $50,000 Hummer and get a $25,000 tax deduction. Buying a $22,000 hybrid would only provide a $3,100 tax deduction
Governmental Controls
To ensure a sustainable future: -Keep prices of selected energy resources low to encourage use --Currently R&D (2007) $159 million for solar energy, $303 million for nuclear energy, and $427 million for coal -Keep prices high for slected resources to discourage use -Emphasize consumer education --Inform about incentives and advantages
Green Building Certifications
US Green Building Council's- Leadership in Energy and Environmental Design (LEED) -Accredited more than 25,000 buildings -Four leverls: Certified, Silver, Gold, and Platinum
