Renewable energy effectively utilizes natural resources in a way that can be naturally replaced and replenished. Renewable energy can be obtained using a variety of different technologies, including solar power, wind power, geothermal energy, tidal energy, hydroelectric utilities, biomass and biofuels. Renewable energy is becoming a viable investment opportunity as the global demand for finite fossil fuel resources have increased, while known reserves are beginning to decline.

The environmental benefit of renewable energy is largely dependent on the technology being used. In some cases, such as the pollution that is associated with burning biomass, the benefits of being a renewable resource can be outweighed by negative environmental factors. Despite some shortcomings of certain renewable technologies, the use of any renewable energy helps to curb the output of carbon dioxide into the atmosphere, which is the leading greenhouse gas contributing to global climate change.

Renewable Energy Technologies:

Solar
Solar energy is derived from the sun in the form of thermal energy and light. While the majority of useable energy on the planet is derived indirectly from the sun (in the form of wind and hydro power, as well as energy stored in form carbon bonds resulting from photosynthesis), renewable solar energy generally concerns energy purposefully harvested using different types of technology. Methods for collecting and storing solar energy can be as simple as a greenhouse, or involve complicated arrays of photovoltaic cells.

Wind
Wind energy is most often collected through the use of a wind mill, also called a wind turbine, a technology that has been utilized for thousands of years. Modern wind mills are able to transfer mechanical energy into electricity. These wind turbines have been implemented on a large scale in high density “wind farms.” Wind turbines can also be used on a smaller scale through rooftop wind turbines or community wind farms. Despite their lack of emissions, wind turbines have been criticized on several accounts, as they are often considered aesthetically unappealing, and they can potentially be detrimental to migratory bird routes.

Biofuel
Biofuel is any fuel, solid, liquid or gas derived from an organic source (most often plant matter) that has recently died. This differentiates biofuel from other organic sources of energy such as fossil fuels, which are considerably older. Combusting biofuel releases what was originally solar energy stored in carbon bonds during the process of photosynthesis as a useable form of energy, which in the form of burning firewood makes biofuel one of the oldest forms of fuel. Today, biofuel can come in many different varieties, from biomass such as woodchips, distilled liquid fuels such as ethanol, and biogas such as methane gas.