There are several forms of renewable energy. Solar and wind offer homeowners the best opportunity to generate their own electricity. Check with your local utility to see if it is possible to buy ‘green’ electricity generated from one of these sources.
- Solar – Solar power is generated through photovoltaic solar cells made of semiconducting materials that absorb sunlight, causing electrons to flow which produces electricity. Solar cells can range in size from one-half inch to 4 inches, each producing between one and two watts. When connected to other solar cells into a single module they form an array. Currently, solar energy provides less than 1 percent of the energy needed by electricity users in the US.
- Solar (for water heating) – Installing a solar hot water heater is one way you can reduce your energy consumption today. They can be used in any climate and the renewable fuel they use is the radiation from the sun. Solar water heating systems include storage tanks and solar collectors. They are available in three configurations: a flat-plate collector; integral collector-storage system; and evacuated-tube solar collector.
- Wind – The most ideal (and attainable) conditions for wind energy generation occur at about 100 feet above ground, where faster, more stable wind can be found. Turbines can be installed on land (often in farmer’s fields) and offshore (where winds are even stronger). These huge units consist of a tower onto which a rotor blade is mounted. As the wind turns the rotor, it spins a shaft which feeds energy into a generator. One large-scale wind turbine can provide energy for between 225 and 300 homes.
- Geothermal – The upper 10 feet of earth’s surface sustains temperatures between 50 and 60 degrees F nearly all the time. The heat within this thin upper layer has the potential to provide 50,000 times more energy than the combined resources of all the world’s oil and gas resources. Geothermal energy can be used to provide direct heat, can regulate building temperatures (heating and cooling), and can be used to create electricity.
• Biomass – Biomass energy is derived from the chemical energy contained in organic materials (stored in plants through photosynthesis). Biomass energy can be used to produce fuel and electricity. The most important benefit of biomass is that waste materials (such as paper mill residue, lumber mill waste, and municipal waste) can be used to create energy. Biomass currently provides about 3 percent of the energy used by Americans.
- Ocean – There are two main sources of energy associated with the ocean: mechanical and thermal. Wave energy (mechanical) is created by extracting power directly from the surface of waves, which are created when the wind blows over the surface of the ocean. Ocean thermal energy generation (OTEC), on the other hand, is a way of harnessing the sun’s heat stored in ocean waters and works best when the temperature difference between surface and deep water is 36 degrees F or more.
- Hydropower – Using mechanical processes, hydropower (also known as hydroelectricity) harnesses water’s energy by directing or channeling it through penstocks and turbines, which rotate to create energy that is fed into a generator. It is the world’s largest source of renewable energy, with over 150 countries using hydropower for electricity generation.
- Hydrogen – Hydrogen is the most plentiful gas in the universe and has the highest energy content by weight and lowest energy content by volume of all known fuels on earth. To harness the energy in hydrogen cells, hydrogen is electrochemically combined with oxygen, which produces electricity and heat. The only byproduct is clean water vapor.
✔ Purchase Green Electricity or RECs – Buying green electricity through your utility company is an effective way to encourage and support the expansion of renewable energy. While often sold at a premium, green electricity can help you bring your household carbon footprint closer to zero.
RECs are tradable, non-tangible energy commodities that represent proof that 1 megawatt-hour (MWh) of electricity was generated from an eligible renewable energy resource (renewable electricity).