As a renewable energy source, biomass energy can be used directly, indirectly once, or converted into other forms of energy such as biofuels, providing the greatest environmental benefits. Examples include electricity produced from solar, wind, geothermal, biogas, qualified biomass, and small low-impact hydropower sources. To qualify as green energy, this renewable energy source must also exceed what is required by regulation or otherwise. In other words, green energy is voluntary or surplus to regulation. Customers typically purchase green energy because of its zero-emissions characteristics and the benefits of reducing carbon emissions.
Renewable energy includes resources that rely on fuel sources that are self-renewing in the short term and do not degrade. Such fuel sources include the sun, wind, moving water, organic plants and waste (qualified biomass), and the heat of the earth (geothermal). While the benefits of renewable energy are numerous, some renewable energy technologies can have environmental impacts. For example, large hydropower sources can have environmental trade-offs in areas such as fisheries and land use.
Conventional energy includes the burning of fossil fuels (coal, natural gas, and oil) and the nuclear fission of uranium. Fossil fuels have environmental costs from mining, drilling, or extraction, and they emit greenhouse gases and air pollution when burned. While nuclear power generation does not emit greenhouse gases during the production of electricity, it does require the mining, extraction, and long-term storage of radioactive waste.
