Renewable Power Generation

Wind Energy Systems: Fastest growing segment of renewable energy

business (up 75% in capacity since 1990) Possible limitations to acceptance-

Visual pollution Noise TV interference Harm to raptors

Good complement to solar- (low solar = high wind ??)

Renewable Power Generation (cont.) Wind Energy Systems:

Market growth- 15% in 1998; 38% in 1999 Public Utilities Regulatory Policies Act (PURPA) requires

utilities to purchase power Energy Tax Credits available

Estimated that 5 -15% of TOTAL ELECTRICAL needs of United States by 2020 provided by Wind Power !!

(currently 0.1 %)

Renewable Power Generation (cont.) Wind Energy Systems:

Wind machine sizing/cost per kW-1981: 25 kW; $ 2,600/kW

1999: 1 MW (1000 kW) $ 800/kW

California is leading state in US (1,600 MW)5% of PG & E power currently is wind energy

Large growth in European community due to high energy prices, environmental concern, fuel security

Renewable Power Generation (cont.) Wind Energy Systems:

Typical system is comprised of- Rotor (many different shapes) Generator Voltage regulator Synchronous inverter (for large AC applications) Batteries

Renewable Power Generation (cont.) Wind Energy Systems:

Location of site critical Consistent winds = best overall efficiency If wind too high- excess power dumping High support structure to take advantage of wind

currents free from “ground effect’ Fewer blades more efficient at low wind speeds

Renewable Power Generation (cont.) Wind Energy Systems:

Rotor style vs. efficiencyMAXIMUM THEORETICAL 59%

Multi-blade for water pumping applications 7% 2-3 blade “horizontal axis”

Altamont Pass machines: 100-200 kW each

Darrieus Eggbeater “vertical axis” Altamont Pass machines: 250 kW each

Renewable Power Generation (cont.) Wind Energy Systems:

Potential for growth is HUGE !! (i.e. Table 12-4) Installed cost for power- $ 1,000/kW $ 0.05 – 0.06/kWh power generating cost !!

Renewable/Alternative Energy Systems Ground Source Heat Pumps

“GeoExchange” with earth: stable temperature 55 – 70 F available as

HEAT SOURCE or HEAT SINK

Heating mode: HEAT SOURCEheat from refrigeration compressor

Cooling mode: HEAT SINK standard air conditioning unit with heat rejection to buried condenser loop.

Renewable/Alternative Energy Systems Ground source heat pumps:

Capability to supply domestic hot water, radiant floor heating and forced air cooling systems.

Downside: all-electric system subject to cost of kwh from utility system.

Upside: 25 year warranty

25 – 50% overall energy savings

Renewable/Alternative Energy Systems Ground source heat pumps:

Installation requirements-

vertical systems: several hundred foot deep holes with polyethylene piping 6 holes required for 2,000 sq ft home

horizontal systems: Long trenches at grade level with polyethylene piping Buried under reservoir, lake or pond

Renewable/Alternative Energy Systems Ground source heat pump systems:

Installed Cost- $ 20,000 – 25,000 for 2,000 sq ft home.

Renewable/Alternative Energy Systems Solar Thermal Electric systems:

Solar energy “focused” on central point; steam produced to run turbine/generator for electrical power. Parabolic troughs with local receiver Parabolic dishes with local receiver Central receivers with heliostats