Wind Wind Energy Transformation _______________ Æ _______________ Æ _______________ What is wind energy? In reality, wind energy is a converted form of solar energy. The sun's radiation (light) heats different parts of the earth at different rates‐most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth's surface, and cooler air is drawn in to replace it. The result is wind. Air has mass, and when it is in motion, it contains the energy of that motion ("kinetic energy"). The bottom line is that as long as we have sun, we will have wind. And with wind, we have enough available energy to meet all of our electricity needs. Where is the US wind energy? Areas along the Rocky Mountains have outstanding sustainable wind energy. The highest potential for wind energy includes the coastal regions of the Atlantic, Pacific, Gulf of Mexico as well as the Great Lakes. Texas, Kansas, Nebraska, North and South Dakota, Montana, and Wyoming are the best interior locations. Ohio has marginal available wind energy. The price of wind generated electricity is approximately $0.08/kw. What is a wind turbine and how does it work? A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use. Wind electric turbines generate electricity for homes and businesses and for sale to utilities. Pros and cons Advantages of Wind Energy Disadvantages of Wind Energy Is a “free” source of energy Requires constant and significant amounts of wind Produces no water or air pollution Wind farms require significant amounts of land Wind farms are relatively inexpensive to build Can have a visual impact on Landscapes Land around wind farms can have other uses Hydropower Hydropower Energy Transformation _______________ Æ _______________ What is hydropower energy? Generating hydroelectricity starts with the water cycle providing seasonal rain and runoff from snow pack. The runoff from rain and snow collects in lakes, streams and rivers and flows to dams downstream. The water funnels through a dam, into a powerhouse and turns a large wheel called a turbine. The turbine turns a shaft that rotates a series of magnets past copper coils in a generator to create electricity. The water then returns to the river. From the powerhouse, transmission lines carry electricity to communities. How much hydropower is available? As long as there is water, there can be energy. Hydroelectric power doesn't necessarily require a large dam – some hydroelectric power plants just use a small canal to channel the river water through a turbine. A small or micro‐ hydroelectric power system can produce enough electricity for a home, farm, or ranch. For that reason, there is enough hydropower to meet ~10% of the electricity needs in the U.S. This number could change though. Studies are underway attempting to capture the energy of ocean waves. If these studies prove beneficial, we could have an additional 5% of our energy from hydropower. The price of hydropower is about $0.03/kw. Where is hydropower located? The best sites for hydroelectric plants are swift‐flowing rivers or steams, mountainous regions and areas with heavy rainfall. Although, any state can create hydropower, the best regions for hydropower are west of the Rocky Mountains (1), the Missouri‐Arkansas Mississippi River Valley (2), and the Appalachian mountain region (3). Pros and cons Advantages of Hydropower Abundant, clean, and safe Easily stored in reservoirs Relatively inexpensive way to produce energy electricity Offers recreational benefits like boating, fishing, etc Disadvantages of Hydropower Can have a significant environmental impact Can be used only where there is a water supply Best sites for dams have already been developed Expensive to build dams Solar Power Solar Power Energy Transformation _______________ Æ _______________ What is Solar Power energy? The sun has produced energy for billions of years. Solar energy is the sun’s light rays (solar radiation) that reach the earth. To capture solar energy, we use photovoltaic cells (PV). These PV cells are made of a material that when struck by sun light release electricity (their electrons start moving). How much Solar Power energy is available? While a vast amount of solar energy strikes the Earth’s atmosphere, not nearly so much can actually be captured for use at the Earth’s surface. Once solar radiation starts passing through Earth’s atmosphere, much of it is either scattered as it bounces off air molecules, water and dust, or it is absorbed into ozone, water and carbon dioxide molecules. This absorption of solar energy by molecules in the atmosphere is why we feel cooler when a cloud comes overhead and casts a shadow. Even with this loss, enough energy arrives at the Earth to meet our demands for a whole year ‐ if only we could harness it properly. Where is Solar Power energy located? Zone 1 has the most sun light with zones 5 and 6 having the least amount. As the map shows, the best locations are in southern California (zone 1), Nevada (2), Arizona (2), New Mexico (2), and the western part of Texas (2). The cost of solar energy is about $0.22/KW. Pros and cons Advantages of Solar Energy Unlimited supply Causes no air or water pollution Disadvantages of Solar Energy May not be cost effective although advance in technology are quickly bringing the cost down. Storage and backup are necessary Reliability depends on availability of sunlight Geothermal Geothermal Energy Transformation _______________ Æ _______________ Æ _______________ What is geothermal energy? The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. For this reason, there is enough geothermal energy to meet all of our energy needs. Where is geothermal energy located? Most geothermal reservoirs are 2‐3 miles underground with no visible clues showing above ground. Geothermal energy can sometimes find its way to the surface in the form of volcanoes, hot springs, and geysers. Most of the geothermal reservoirs in the United States are located in the western states. California is the state that generates the most electricity from geothermal energy. The Geysers dry steam reservoir in northern California is the largest known dry steam field in the world. The field has been producing electricity since 1960. The best geothermal conditions operate above 150oC. These locations are primarily in the western half of the U.S. The cost for producing geothermal energy is ~$0.05/KW. Pros and cons Advantages of Geothermal Energy Provides an unlimited supply of energy Produces no air or water pollution Disadvantages of Geothermal Energy Start‐up/development costs can be expensive Maintenance costs, due to corrosion, can be a problem