In contrast,
renewable energy resources such as
wind and solar energy-are constantly
replenished, safer for the
environment, and will never run out.
Most renewable energy comes either directly or indirectly from the sun. Sunlight, or solar energy, can be used directly for heating and lighting homes and other buildings, for generating electricity, and for hot water heating, solar cooling, and a variety of commercial and industrial uses.
The sun's heat also drives the winds, whose energy, is captured with wind turbines. Then, the winds and the sun's heat cause water to evaporate. When this water vapor turns into rain or snow and flows downhill into rivers or streams, its energy can be captured using hydroelectric power.
Along with the rain and snow, sunlight causes plants to grow. The organic matter that makes up those plants is known as biomass. Biomass can be used to produce electricity, transportation fuels, or chemicals. The use of biomass for any of these purposes is called bioenergy.
Please follow the links below to educate yourself about the benefits of using renewable energy resources.
Biomass
The term "biomass" can describe many different fuel types from such sources as trees; construction, wood, and agricultural wastes; fuel crops; sewage sludge; and manure. Agricultural wastes include materials such as cornhusks, rice hulls, peanut shells, grass clippings, and leaves. Trees and fuel crops (i.e., crops specifically grown for electricity production) can be replaced on a short time scale. Agricultural wastes, sewage sludge, and manure are organic wastes that will continue to be produced by society. For these reasons, biomass is considered a renewable resource.
Environmental Impacts
Air Emissions Biomass power plants emit nitrogen oxides and a small amount of sulfur dioxide. The amounts emitted depend on the type of biomass that is burned and the type of generator used. Although the burning of biomass also produces carbon dioxide, the primary greenhouse gas, it is considered to be part of the natural carbon cycle of the earth. The plants take up carbon dioxide from the air while they are growing and then return it to the air when they are burned, thereby causing no net increase.
Biomass contains much less sulfur and nitrogen than coal; therefore, when biomass is co-fired with coal, sulfur dioxides and nitrogen oxides emissions are lower than when coal is burned alone. When the role of renewable biomass in the carbon cycle is considered, the carbon dioxide emissions that result from co-firing biomass with coal are lower than those from burning coal alone.
What is Switchgrass?Switchgrass (Panicum virgatum) is a summer perennial grass that is native to North America. It is a natural component of the tall-grass prairie which covered must of the Great Plains, but which also was also found on the prairie soils in the Black Belt of Alabama and Mississippi. Many people do not realize that the natural vegetation of the Black belt was grassland, and not forest like most other parts of the southeastern USA.
Because it is native, switchgrass is resistant to many pests and plant diseases, and it is capable of producing high yields with very low applications of fertilizer. This means that the need for agricultural chemicals to grow switchgrass is relatively low. Switchgrass is also very tolerant of poor soils, flooding and drought, which are widespread agricultural problems in the southeast.
What does all this mean in terms of renewable energy?
If it is used to produce energy, it will reduce the risk of global warming by replacing fossil fuels (coal, natural gas and oil). When fossil fuels are burnt, carbon is removed from below ground (gas and oil wells and coal mines) and release into the atmosphere as carbon dioxide (CO2). This is a greenhouse gas that increases the risk of global warming. In contrast, switchgrass (like all other plants) removes CO2 from the atmosphere and incorporates it into plant tissue, both above and below the ground.
The accumulation of carbon, especially below the ground, is known as carbon sequestration, and is considered to be a very important strategy for reducing atmospheric CO2. Switchgrass is unquestionably one of the best crops for doing this. When above-ground switchgrass is harvested and burned for energy, CO2 is once again returned to the atmosphere from where it was originally obtained by the plant, but it will have reduced the need for some fossil fuel. Therefore, CO2 is obviously just being recycled by use of switchgrass for energy, making this process CO2-neutral (or actually CO2- negative if soil carbon sequestration is considered), compare to fossil fuels that add CO2 to the atmosphere. When compared to low grade coal, burning switchgrass for energy will probably result also in less toxic emissions, such as the oxides of sulfur and nitrogen.
Wind
Wind is created because the sun heats the Earth unevenly, due to the seasons and cloud cover. This uneven heating, in addition to the Earth's rotation, causes warmer air to move toward cooler air. This movement of air is wind.
Wind turbines use two or three long blades to collect the energy in the wind and convert it to electricity. The blades spin when the wind blows over them. The energy of motion contained in the wind is then converted into electricity as the spinning turbine blades turn a generator. To create enough electricity for a town or city, several wind turbine towers need to be placed together in groups or rows to create a "wind farm."
Environmental Impacts
Air EmissionsEmissions associated with generating electricity from wind technology are negligible because no fuels are combusted.
Water Resource UseWind turbines in areas with little rainfall may require the use of a small amount of water. If rainfall is not sufficient to keep the turbine blades clean, water is used to clean dirt and insects off the blades so that turbine performance is not reduced.
Water DischargesWind turbines do not discharge any water while creating electricity.
Solid Waste GenerationWind technologies do not produce any substantial amount of solid waste while creating electricity.
Land Resource UseWind turbines generally require the use of land, although they may also be sited offshore. Land around wind turbines can be used for other purposes, such as the grazing of cattle or farming.
When wind turbines are removed from land, there are no solid wastes or fuel residues left behind. However, large wind farms pose aesthetic concerns and wind turbines that are improperly installed or landscaped may create soil erosion problems. Wind farms can also have noise impacts, depending on the number of wind turbines on the farm. New blade designs are being used to reduce the amount of noise. Bird and bat mortality has been an issue at some wind farms. Improvements to wind turbine technologies and turbine siting have helped mitigate bird mortality. Research on impacts to bats is now underway.
