Five Essential Renewable Energy Systems
While the United States currently relies on fossil fuels (coal, oil, and natural gas) for energy, renewable energy is quickly growing to alleviate reliance on the planet’s finite amount of resources. Renewable systems such as solar, wind, hydroelectric, bioenergy, and geothermal energy have made recent advancements in popularity due to their potential for more efficient deployment and cost.
Solar energy, being the most accessible from any location, has been dropping in cost since 2008 according to the United Sates Department of Energy. A typical solar panel can produce about 200 Watts of electricity, but this varies depending on the solar panels efficiency and size.
The installation cost of solar photovoltaic (PV) energy systems on a utility-scale has dropped from $5.70 per Watt of generation power in 2008 to $2.34 per Watt in 2014. With a 60% reduction in price, installed capacity has soared from nearly 0 Gigawatts in 2008 to 10 GW in 2014. As of now there are 27 GW in development, making solar energy on a utility-scale a rapid growing market.
Distributed solar energy systems involve the same hardware as the utility-scale, but generates power where it is consumed such as in a residential neighborhood. Distributed solar energy has dropped in installation costs as well. It was roughly $9 per Watt in 2008 in comparison to the $4 per Watt it has reduced to at the end of 2014. With nearly 800,000 installations in 2015, solar energy has become a system more available on smaller and larger scales.
Even with these advancements, solar energy systems can only grow so large. Physical space limits potential output, and roof panels need help as they are not powerful enough to power an entire household on their own. Research into stable ocean platforms has shown potential for massive solar farms that use the available space found next to the coast.
Wind, previously harnessed by windmills, creates energy through large wind turbines. At 30 meters tall where they can reach faster, less turbulent winds, a standard turbine with a 2.5-3 MW capacity can produce 6 million kWh in a year. According to the European Wind Energy Association, that is enough to power 1,500 average European households. Furthermore, an offshore turbine with a 3.5 MW capacity can power 3,312 households, doubling the power of an onshore turbine.
Multiple turbines create a wind plant/farm which are equipped by several electric providers. This has been more cost effective since 2000, as the Energy Department shows cost per kWh decreased to 5-10 cents. The Roscoe Wind Farm in Texas is currently the third largest in the world. It is owned by E.ON Climate and Renewables, has 634 turbines, and an installed capacity of 781.5 MW. Wind power accounts for 4.4% of U.S electric generation and continues to rise with cost decreases and advancements in offshore turbines.
Offshore turbines take longer to develop, and the sea is a more hostile environment. Off the coast of Scotland, an innovative wind farm called the European Offshore Wind Deployment Centre will generate 92.4 MW once completed. It begins constructions in 2017 and expects output the following year.
Hydropower generates roughly 10% of the U.S’s energy. It is the most efficient and inexpensive method of creating energy, with the price per kWh sitting at 7 cents. The first hydropower plant was built in 1879 at Niagara Falls, powering the streetlights at night. Now, the largest hydropower plant in the U.S is at the Grand Coulee Dam on the Columbia River in northern Washington. It produces 21 billion kWh’s of electricity annually which is enough power to supply 2.3 million households with electricity for one year.
The majority of electricity produced in Washington is through hydroelectric facilities. Modern turbines can convert 90% of available energy into electricity, but comes with the obstacle of location. They are built on bodies of water stable enough to support a dam without ruining the ecosystem. Most hydropower facilities are found on the west coast and middle-east of the United States, centralized around the rivers.
Pumped-storage hydropower is becoming increasingly popular, as it can continuously supply electricity during peak seasons of demand. The Department of Energy is focusing on pumped-storage because it is a utility-scale grid storage system that supplies its reservoir using energy created by the hydropower plant.
People have used bioenergy for thousands of years; burning wood to create warmth, cook, and create energy. Wood is still the largest bioenergy resource in use, but new sources are becoming popular such as energy crops (fast growing trees and grasses), agricultural residues, waste materials, forest biomass, and methane.
Bioenergy plants are located throughout the U.S due to its limitless nature. The components used can be found in any area, making bioenergy one of the most available sources of energy. The direct-fired system is the most popular utility-scale system, simply burning biomass for a direct energy output. However, micro-turbines as small as a refrigerator are producing an output of 25-500 kW for more personal uses. Bioenergy is still being perfected and is seen as a replacement for fossil fuels burned in commercial and personal transportation.
According to the Union of Concerned Scientists, bioenergy resources totaling just under 680 million dry tons could be made available and sustainable in the U.S by 2030. This is enough to produce 54 billion gallons of ethanol or 732 billion kWh of electricity (19% of total power consumption in 2010).
Heat from the Earth is clean, sustainable energy that can be found in shallow ground or a few miles beneath the surface. While it is useful as a renewable energy source, locations are limited and fixed.
Most geothermal reservoirs in the U.S are located in western states, Alaska, and Hawaii. California generates the most electricity from geothermal energy through its 33 plants, accounting for 90% of the nation’s geothermal electricity. Nevada, Hawaii, and Utah are the only other states with geothermal power plants. The United States has more geothermal electricity than any other country, but only makes up .5% of electricity production.
The EPA states geothermal pumps are the most energy efficient, clean, and cost effective system for temperature control. Advancements in transportation and piping allow for geothermal energy use in a larger area. The Wayang Windu Geothermal Power Plant in Indonesia is a flash steam power plant, and one of the largest in the world. It has a total installed capacity of 227 MW, generating more power for the country’s 249.9 million citizens. Development of flexible piping has expanded the geothermal energy’s reach, and further research is advancing transportation of this energy.
Renewable energy systems are becoming more cost-effective with time, and replacing fossil fuels as a primary source of energy. These five are not the only renewable resources and further development will reveal more efficient ways of using clean, enduring sources of energy.
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