California Solar Initiative begins January 1, 2007. More Information »

More energy to come from renewable sources

Wind is an important part of SDG&E's resource plan.

SDG&E is committed to planning for your future energy needs today. In 2003, SDG&E filed a long-term energy resource plan with the California Public Utilities Commission (CPUC) which calls for increased renewable energy supplies, among other sources, to meet the future energy needs of customers in SDG&E’s service area.

The increased renewable energy supplies called for in the long-term energy resource plan will ensure compliance with California Senate Bill 1078 which requires the state’s three investor-owned utilities, including SDG&E, to increase their purchases of power generated from renewable resources by 1 percent each year, reaching 20 percent of all purchased electricity by 2010.

SDG&E Issues Renewable RFO for 2008. More Information »

Solicitation for Information on Potential Renewable Resource Projects (TRCR)

AB 1969: RPS Tariff/Standard Contract for Water and Wastewater Facilities. More Information »

What Is Renewable Energy?

Renewable energy comes from resources that are considered to be constantly replenished and environmentally beneficial. They include wind, solar (including photovoltaic and solar thermal), biogas (landfill and sewage), biomass (technologies that burn primarily paper, wood, tree trimming and other similar “green” waste as fuel) and hydroelectric power technologies.

Wind
Wind turbines typically use two or three long blades to collect the energy in the wind and convert it to electricity. The blades spin as the wind blows over them and converts this movement into electricity as the spinning blades turn a connected generator.

Solar
There are two general ways to convert solar energy into electricity: photovoltaic and solar-thermal technologies.

Photovoltaic systems have wafers made of silicon or other conductive materials. When sunlight hits the wafers, a chemical reaction occurs, resulting in the release of electricity.

Solar-thermal technologies concentrate the sun's rays with mirrors or other reflective devices to heat a liquid to create steam, which is then used to turn a generator and create electricity.

Biogas (landfill and sewage)
Biogas is created when microorganisms cause organic waste, such as food wastes and paper, to decompose in landfills. In biogas energy projects, landfill gas is burned in boilers, reciprocating engines, and combustion turbines to produce electricity.

Biomass (“green waste”)
Biomass facilities use wood, paper, tree trimmings or other similar products as fuel. These products are burned, producing heat that is then used to turn a steam turbine, which in turn moves a generator to produce electricity. These facilities must meet all local and state emission requirements.

Geothermal
Uses heat from beneath Earth's surface to provide heat and generate electricity. There are currently three ways to generate electricity from geothermal resources: Dry Steam power plants, Flash Steam power plants and Binary power plants. In Dry Steam plants, dry steam is fed directly into a turbine for power production. Flash Steam plants use pressurized water from below ground to flash into steam to be run through the turbine with the excess water reinjected into the underground reservoir. Binary power plants transfer the heat of the geothermal fluid to a separate "working" fluid, which boils to vapor and is directed into a turbine for power production.

Hydroelectric Power Technologies
Hydroelectric power uses the movement of water to produce electricity. California law severely limits the types of hydroelectric power that can be considered as renewable due to growing concerns about effects on fish and other wildlife. These facilities must be smaller than 30 MW and typically consist of hydro generators placed in water aqueducts. The generator spins as water flows through the aqueduct, producing electricity.

SDG&E is committed to providing you with safe, reliable energy and exceptional customer service.

The links below contain further information on the type and amount of resources SDG&E currently has under contract.

• SDG&E's 20-year energy resource plan
• SDG&E's Renewable Contracts fact sheet
• SDG&E's 2008 Compliance filing
• SDG&E's 2008 RPS Procurement Plan

California Energy Commission’s Consumer Energy Center
US Department of Energy’s National Renewable Energy Laboratory