Renewable Energy

Conserving Energy

• Compact fluorescent light bulbs• Insulation• Reducing Air infiltration (air leak)• More efficient washing machines (less water)• More efficient air conditioners• Sod roofs• Orient homes to allow sun in winter and shade in

summer• TURN OFF APPLIANCES

Cogeneration

- Production of electricity and steam/hot water in the same plant

- Net energy of primary fuel ↑ from 30-35% to 80-90%.

Solar Energy

• Passive heat absorption • Active solar systems

Photovoltaic Cells

• Capture solar energy and directly convert it to electrical current

• Photoelectric effect- materials absorb photons and release electrons.

Biomass: Wood

• Wood, wood chips, bark, branches, leaves, starchy roots, and other plant/animal material.

• Wood burning in past=90% of energy• Incomplete burning = CO and ↓air quality

*Wood-burning Stoves*

• PROS– Adequate wood supplies

(North)

• CONS – Smoke= high CO levels– Decreased air quality– Ranked high on

Environmental Protection Agency list for health risks.

– carcinogenic

Efficient combustion chambers/catalytic combustors can eliminate most of problem by recapturing heat and removing waste products.

Biomass

• Dung– Burn dried manure– Increases food shortage

in poor countries– 90% of heat and

nutrients lost when burned

– Use it for methane= efficient fuel source

• Crop Plants– Anerobic digestion of

plant sugars– Ethanol (grain) and

methanol (wood)– Biofuel

Wind Energy

• Fastest growing renewable energy source• 1/3 of land use and 5X as many jobs than coal

Advantages-Short planning and construction time-Modular (more turbines can continually be added)-No fuel costs-No emmissions

Drawbacks - intermittent - inconsistent wind (16-60mph) - High bird mortality - no method for transfer - high volt power lines -split water into gases

Hydropower

• Falling water produced 40% of world’s electric power in 1925.

• Enormous dams• Could produce as much

energy as 25 large nuclear plants

• Problems– failure= floods– Ecosystem destruction– Human displacement

Tidal/Wave Energy

• Tidal station- similar to a hydropower dam

• 13 hour tidal differential poses problem

• Problem– Flooding of seawater

behind dam• Destroy rich shoals• Breeding grounds • Food source for birds• Heavy siltation• Scouring of sea floor