Part Four, Issue 10

1. Part Four, Issue 10 Sustainable Energy: Is the Answer Blowing in the Wind?

2. Objectives After reading the assigned chapter and reviewing the materials presented the students will be able to understand: • What are the main sustainable sources of energy? • What is their potential and actual role in U.S. and global energy production?

3. Introduction • Renewable energy technologies presently include those that employ wind, solar, geothermal, biomass, and hydroelectric dams to produce power. • Hydroelectric dams have harmful effects on rivers by preventing the migration of fish. • The construction of dams often displaces people: as many as 2 million in the case of China’s Three Gorges Dam.

4. Advantages, and Disadvantages of Renewable Energy • Advantages: • They are replenished by natural processes. • They cause no direct air or water pollution since no combustion is involved. • They require no shipment of fuels, so environmental disasters will not occur. • They require no storage or use of toxic materials. • Disadvantages: • Must produce electricity instead of a more “portable” fuel such as gasoline or diesel. • Solar power depends on sunlight. There must be a supplemental energy source at night. • Both a minimum and maximum (56 miles per hour for safety reasons) wind speed is required for wind power. Limited to where persistent wind occurs. • In 1999, for the first time, the world installed more wind capacity than nuclear capacity.

5. Energy Consumption • Energy consumption can be measured in British Thermal Units (BTU), typically as units of 1 quadrillion BTU (1 quad BTU). • U.S. energy consumption increased from 66.4 quad BTU in 1970 to 100.2 quads in 2004. • Wind and solar energy generation in 2004 was .143 quad BTU and .063 quad BTU respectively.

6. Can Sustainable Sources Provide the Total U.S. Electricity Demand? • U.S. energy consumption is commonly divided into sectors: industry (33%), commercial (18%), residential (21%), and transportation (28%). • Wind farms (9,100 MW) were the second largest source of new power generation built in the U.S. in 2005, after new natural gas plants. • Florida Power & Light was the biggest operator of wind farms with 3, 192 MW capacity. • A 1.5 MW wind turbine can generate 4 million KW hours per year - enough to supply 400 average homes. • According to the U.S. Energy Information Administration, in 2004 the U.S. consumed 3, 953, 000, 000, 000 KW hours of electricity.

7. Economics of Wind Energy • The cost of wind power is affected by 3 factors: • Average wind speed (power increases as the cube of wind speed). • Interest rates. • Federal wind subsidy of 1.9 cents per KW hour. • The Federal Wind Production Tax Credit (PTC) passed in 1994 provides 1.9 cents per KW hour generated for the first 10 years of a wind turbine output. • The power must be shipped by transmission lines from the generation site to the site of consumption. This limits the distance that electricity can be efficiently transported.

8. Wind Energy in Hawaii • Imported oil supplied about 80% of Hawaii’s energy needs. • A state law mandates that 9% of electricity should come from renewable energy by 2010. • A greater use of Hawaii’s abundant renewable energy resources would help to insulate the state against fossil fuel price escalations and supply disruptions. • Harvesting techniques of sugar are not compatible with wind cogeneration - the burning of cane fields could damage wind turbines.

9. Solar Power Development in Hawaii • Solar power systems to generate electricity are not yet cost effective in Hawaii. • The government and utilities have provided incentives for individual customers to install solar assisted systems. • It has resulted in more than 30,000 systems installed statewide. There is more room for expansion of solar capacity.

10. Summary • Renewable energy technologies presently include those that employ wind, solar, geothermal, biomass, and hydroelectric dams to produce power. • Advantages: They are replenished by natural processes. They cause no direct air or water pollution since no combustion is involved. They require no shipment of fuels, so environmental disasters will not occur. They require no storage or use of toxic materials. • Disadvantages: Must produce electricity instead of a more “portable” fuel such as gasoline or diesel. Solar power depends on sunlight. There must be a supplemental energy source at night. Both a minimum and maximum (56 miles per hour for safety reasons) wind speed is required for wind power. Limited to where persistent wind occurs. In 1999, for the first time, the world installed more wind capacity than nuclear capacity. • Energy consumption can be measured in British Thermal Units (BTU), typically as units of 1 quadrillion BTU (1 quad). • U.S. energy consumption is commonly divided into sectors: industry (33%), commercial (18%), residential (21%), and transportation (28%). • The power must be shipped by transmission lines from the generation site to the site of consumption. This limits the distance that electricity can be efficiently transported.

11. Home Work •  1. What are the current renewable energy technologies? • 2. What are the units of energy consumption? • 3. What limits the distance that electricity can be efficiently transported?