ch 14: renewable energy

feed-in-tariff

• requires utilities to buy electricity produced by homeowners and businesses from renewable energy sources at a guaranteed price

• used in germany, great britain, 47 other countries

passive solar heating system

• without the use of mechanical devices, captures sunlight directly within a structure and uses it to heat the structure

active solar heating system

• captures energy from the sun by pumping a heat-absorbing fluid such as water or an antifreeze solution through special collectors, usually mounted on a roof or on special racks that face the sun

advantages of active solar heating

1. medium net energy

2. very low emissions of CO2 and other air pollutants

3. very low land disturbance

4. moderate cost

disadvantages of active solar heating

1. need access to the sun 60% of time during daylight

2. sun can be blocked by trees and other structures

3. high installation and maintenance costs for active systems

4. need backup systems for cloudy days

solar thermal system

• uses various methods to collect and concentrate solar energy in order to boil water and produce steam for generating electricity

advantages of solar thermal systems

1. high potential for growth

2. no direct emissions of CO2 and other pollutants

3. lower costs w/ natural gas turbine backup

4. source of new jobs

disadvantages of solar thermal systems

1. low net energy and high costs

2. needs backup or storage system on cloudy days

3. requires high water use

4. can disrupt desert ecosystems

solar cell

• device that converts solar)energy directly into electrical energy

• aka photovoltaic (PV) cells

advantages of solar cells

1. little or no direct emissions of CO2 and other air pollutants

2. easy to install, move around, expand as needed

3. competitive cost for newer cells

disadvantages of solar cells

1. need access to sun

2. need electricity storage system or backup

3. low net energy but likely to improve

4. solar-cell power plants could disrupt desert ecosystems

wind energy

• kinetic energy from blowing winds can be captured and converted to electrical energy by devices called wind turbines

• as aa turbine’s blades spin, they turn a drive shaft that connects to the blades

• drive shaft then turns an electric generator, which produces electricity

advantages of wind power

1. high net energy

2. widely available

3. low electricity cost

4. little or no direct emissions of CO2 and other air pollutants

5. easy to build and expand

disadvantages of wind power

1. needs backup or storage system for when winds die down unless connected in a national electrical grid

2. visual pollution

3. low-level noise

4. can kill birds if not properly designed/located

geothermal energy

• heat stored in soil, underground rocks, and fluids in the earth’s mantle

advantages of geothermal energy

1. medium net energy and high efficiency at suitable sites

2. lower emissions than burning fossil fuels

3. low operating costs at favorable sites

disadvantages of geothermal energy

1. scarcity of cost-effective sites

2. noise

3. CO2 emissions

advantages of solid biomass

1. widely available in some areas

2. moderate costs

3. medium net energy

4. no net CO2 increase if harvested, burned, replanted sustainably

5. plantations can help restore degraded lands

disadvantages of solid biomass

1. contributes to deforestation

2. clear-cutting can cause soil erosion, water pollution, and loss of habitat wildlife

3. can open ecosystems to invasive species

4. increases CO2 emissions if harvested and burned unsustainably