Energy Use and Conservation

Energy categories  Nonrenewable –Once used up, not replenished (on a human time scale) –Fossil fuels, nuclear  Renewable –Able to replenish if used in a sustainable manner –Wood, manure, ethanol  Nondepletable –We will never run out (on a human time scale) –Wind, solar, geothermal, hydro*  Commercial (bought and sold)  Subsistence (gathered by individuals for immediate needs)

Energy Use by Source WorldUnited States

US electricity generation

Energy conservation  Conservation: moderating or eliminating wasteful or unnecessary energy consuming activities.  How is this different from energy efficiency? Examples with automobiles: –Conservation activities would involve carpooling, public transportation, driving less, driving slower –Efficiency would involve technologies to improve fuel burning efficiency (raise mpg)

 84% of all US commercial energy wasted  41%: wasted automatically due to degradation (2nd law thermodynamics)  43%: inefficient power plants, vehicles, motors, light bulbs, etc.  How can we improve this?  What will it take for people and industry to improve? Necessity drives improvement action… During the oil embargo in the 1970s, legislation was enacted to increase conservation, research alternative energy sources and increase fuel efficiency (require higher MPG in vehicles)

allows nonrenewable fuels to last longer gives time to phase in renewable energy decreases dependence on oil imports reduces environmental damage slows global warming saves money National Appliance Energy Conservation Act (late 70s, 1987) © Brooks/Cole Publishing Company / ITP Reducing Waste

Green Building and Living  Insulation  Passive solar  Active solar  Energy efficient appliances  "Green" roofs  Compact fluorescent light bulbs Heat loss from a home. Many homes and buildings in US are so full of leaks that their heat loss in cold weather and heat gain in hot weather are equivalent to having a large window-sized hole in the wall of the house. CFLs are up to 75% more efficient than traditional incandescent light bulbs. They can last 10 times longer and throw off 75% less heat, which may lower home cooling costs.

Industrial energy saving  Industry accounts for approximately 42% of energy consumption in the US.  One strategy: cogeneration –Two useful forms of energy are produced by the same fuel source –Bank of America Tower in NYC: 80% of power and all of its heat from an on-site cogeneration plant powered by natural gas.

Transportation  Transportation accounts for ¼ of US energy consumption.  Between 1973 and 1985 the average fuel efficiency of vehicles increased greatly due to government mandated CAFÉ (corporate average fuel economy) standards.  Fuel efficiency decreased due to consumer choice in vehicles between 1988 and 2006 (the bigger is better trend)  Not so fun fact: the average efficiency of new vehicles purchased in 2006 was 22 mpg; the Ford Model T of 1908 got 25 mpg! The new American Dream.

Saving energy in the transportation sector  Have consumers pay the real cost of a gallon of gas –If real costs were included in the price of gas, it would be approximately $11-$20 per gallon…realistic?  More/greater tax breaks for purchasing fuel efficient vehicles  Improve and extend public transportation  Improve motor efficiency of public transportation vehicles  Move toward cleaner burning fuels for public transportation

How can we improve transportation efficiency?  More efficient engine systems  Smaller engines (eg V6 instead of V8)  Hybrid systems (gas and electric)  Electric systems

Comparing some conventional and hybrid vehicles Conventional gas  Toyota Camry –MPGs: 35/25 (30) –Base cost= $23,000  Ford Escape –MPGs: 28/23 (25.5) –Base cost: $22,000  Kia Optima –MPGs: 35/24 (29.5) –Base cost= $21,000  Ford Fusion –MPGs: 33/23 (28) –Base cost= $21,000  Toyota Highlander –MPGs: 25/20 (22.5) –Base cost= $28,000 Hybrid version   Toyota Camry –MPGs: 43/39 (41) –Base cost= $25,000   Ford Escape –MPGs: 34/31 (32.5) –Base cost: $30,000   Kia Optima –MPGs: 40/35 (37.5) –Base cost= $25,000   Ford Fusion –MPGs: 41/36 (38.5) –Base cost= $28,000   Toyota Highlander –MPGs: 28/28 –Base cost= $38,000