Renewable Energy
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Renewable energy is energy that is derived from renewable sources, which can be used sustainably. The main renewable energy sources of today are hydroelectric, nuclear, biomass, biofuel, geothermal, Solar photovoltaic and wind. Moreover, the European Union classified natural gas as renewable as of February, 2022; furthermore Brookings Institute classified natural gas, along with hydroelectric and nuclear power as the three best sustainable power sources.(Brookings, 2021) However, there are major questions about the sustainability of solar photovoltaic technology, due to the high carbon costs of manufacture, the use of toxic metals in the panels, large scale habitat destruction for non rooftop solar and the absence of recycling for the toxic panels. One needs to be careful in use of the term "renewable", since every energy source has a carbon footprint, meaning that fossil energy is usually employed heavily in manufacture, maintenance and disposal of equipment. Each renewable energy source has its benefits and costs, and there is no single renewable energy source that can provide a complete substitute for fuels that are currently used such as coal. One proposed strategy for renewable energy to power the United States is the 25 x ’25 movement—twenty-five percent of energy in America will come from renewable sources by 2025. This plan would use multiple renewable energy sources to offset the use of coal. The European Union had also set a renewable energy goal, abbreviated 20/20/20. This stood for twenty percent of energy to come from renewable energy sources by 2020.
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Nuclear
Nuclear power is the generation of electricity from controlled reactions within the nucleii of atoms that release energy used to boil water, the steam from which drives a turbine to generate electricity . All commercial nuclear plants presently rely upon nuclear fission reactions. As of 2010, approximately 14 percent of the world's electricity was derived from nuclear power, chiefly centered in the United States (with 31% of the world's total nuclear power capacity), France (16%), and Japan (10%).
In 2022 The European Union has classified both nuclear and combined cycle natural gas plants as renewable.
The International Atomic Energy Agency (IAEA) reports that, as of November 21, 2012, there are 437 nuclear power reactors in operation in 30 countries, plus Taiwan. Another 64 reactors under construction in 14 countries which if operational today would increase the worldwide electrical generation capacity of nuclear power by 17%. One hundred and forty reactors have been permanently shut down since the beginning of commercial nuclear power in the 1950s; another 3 are in long term shut down.
In addition to electricity generation, nuclear power is presently used to power over 150 marine vessels, both civilian and military; and two countries (Russia and the USA) have deployed nuclear powered spacecraft. Because it does not result in the emission of any greenhouse gases, nuclear power has received increased support in recent years as an alternative to coal burning to reduce greenhouse gases.
The damage to several nuclear reactors at the Fukushima Daiichi plant in Japan in March 2011, following a devastating earthquake and tsunami, has led to increased attention to safety issues related to nuclear power. Subsequently, Germany announced its intention to phase out its nine nuclear power reactors by 2022. Other nations, most notably China, which has 26 new reactors under construction (November 2012), are increasing their use of nuclear power. It is notable that global safety data on deaths from power generation places nuclear and wind as the safest methods, with solar, coal burning, and hydroelectric posing greater risks of human death and adverse health impacts.
Research has been undertaken for many decades into nuclear fusion (an alternative form of nuclear energy to fission), which theoretically could generate significant power without many of the environmental concerns connected to fission. The time horizon for commercially viable nuclear fission electricity generation is highly uncertain and likely to be many decades away if achievable.Hydroelectricity
Hydroelectric power is energy created and captured when allowing water to move downhill. Water at higher elevations has more potential energy due to gravity and falling water is used to turn a turbine and generator which creates electrical energy. Often this process is facilitated by damming a river to ensure a constant supply of water that can be moved through the turbines. In general, hydroelectric energy output is consistent, although dry seasons can cause a decrease and rain and snow melt may greatly increase energy output. Five countries rely on hydroelectricity for more than half of their electric power: Brazil, Canada, Norway, Switzerland, and Venezuela. Paraguay derives 100% of its energy from hydroelectricity. Although hydroelectricity is beneficial to reduce carbon dioxide emissions, it causes other environmental impacts including habitat loss viaf looding and displacement of people by dam construction, as well asreduction of anadromous fish habitat. Hydroelelectricy does not require any fossil fuels to run the plant once it has been built. This makes the economics of hydroelectricity very favorable because it is not affected by rising oil prices. The most controversial hydroelectric plant is the Three Gorges Dam. While it has a capacity of 22,500 MW, it also displaces millions of people in the process and cost a host of environmental issues, from sedimentation to biodiversity loss. (Turner, 2007)
Nuclear
Nuclear fission power is the generation of electricity from controlled reactions within the nucleii of atoms that release energy used to boil water, the steam from which drives a turbine to generate electricity to supply electric grids. All present commercial nuclear plants presently rely upon nuclear fission reactions. As of 2010, approximately 14 percent of the world's electricity was derived from nuclear power, chiefly centered in the United States (with 31% of the world's total nuclear power capacity), France (16%), and Japan (10%). Nuclear fusion is a more promising form of energy generation; although it is not yet commercially developed, it is a process with virtually no waste products.
The International Atomic Energy Agency (IAEA) reports that, as of November 21, 2012, there are 437 nuclear power reactors in operation in 30 countries, plus Taiwan. Another 64 reactors under construction in 14 countries which if operational today would increase the worldwide electrical generation capacity of nuclear power by 17%. One hundred and forty reactors have been permanently shut down since the beginning of commercial nuclear power in the 1950s; another three are in long term shut down.
In addition to electricity generation, nuclear power is presently used to power over 150 marine vessels, both civilian and military; and two countries (Russia and the USA) have deployed nuclear powered spacecraft. Because it does not result in the emission of any greenhouse gases, nuclear power has received increased support in recent years as the authentic renewable energy alternative to fossil fuels to mitigate greenhouse gases. The most promising source of future renewable energy is nuclear fusion, which produces no radioactive waste, and is currently under commercial scale feasibility development in France. This avenue deserves much more research and development funding from major nations.Geothermal
Geothermal energy is available in three forms: building heating and cooling using ground source or geothermal heat pumps, Enhanced Geothermal Systems, and electricity generation at high temperature geothermal locations. The simpler geothermal heat pump involves drilling wells into the Earth until achieving a constant temperature of about 55 degrees. To heat the buildings, a heat pump circulates air from the building down into the Earth to the constant 55 degree temperature and then brings the now-warmer air back into the building. The same heat pump cools the building in summer transferring the heat from the building into the Earth’s 55 degree heat sink. The other system is far more complex, and potentially could be utilized across the entire world. This process iscalled Enhanced Geothermal Systems (EGS) and involves drilling into the ground.Cold water is then pumped into heated rock and the pressure built up forces heat out of the rock into the water creating steam that is used to turn a turbine to make electricity. The water is cooled after spinning the turbine and pumped into the ground again, so there is no wasted water. Another use of geothermal energy is capturing heat from hot springs and using that to heat buildings and provide hot tap water. Iceland is the biggest user of this form of geothermal energy. Nearly every building is heated from hot springs in Iceland and about 50% of its energy needs are met through geothermal energy. Some positive aspects of this energy source is that it does not rely on weather events to provide power, and that it can be done at any time, unlike solar and wind.
Biomass/Biofuel
Biomass energy is obtained by burning organic material in the form of ethanol (biofuel), pellets, and gasification. Ethanol or biofuel can be made of different plant products, most commonly corn and sugar cane, but also grasses such as switchgrass. Ethanol is different from all of the other renewable energy sources because it is liquid. This makes ethanol particularly relevant to the energy sector because it can replace oil as fuel for cars and other machinery that rely on oil. Ethanol is made from plant sugars, which is why corn and sugar cane are most commonly used in the research and development of ethanol. There are some drawbacks to corn-based ethanol such as the environmental impacts dueto high water use, gas consumption for the farm vehicles, and possible increases in related food prices. In a sustainable manner of farming involving low-till agriculture, crop waste are returned to the soil, providing nutrients to the soil. Using crop residue to make ethanol removes nutrients from the soil, but industrial agriculture simply relies on fertilizers to replace natural nutrients, creating a whole new set of environmental hazards. Another environmental issue with corn is water usage. Corn requires a substantial amount of water, and the energy to pump water to the field can require substantial energy. There are also concerns about using corn as a fuel source because it competes with corn used for food.
In order to produce biomass energy, plant residue can be co-fired with coal to produce electricity. Biofuels have the potential to achieve carbon neutrality as a fuel source. The carbon dioxide that is emitted is taken out of the atmosphere by plant growth but some is then returned as it is burned. In the United States and other developed countries, biomass pellets are the most commercial form of burning biomass.
Wind
Wind energy uses wind turbines to convert mechanical energy through the movement of wind into electrical energy by spinning a turbine and generator. Turbines are placed to maximize the efficiency of turning the blades. Wind energy depends on wind produced through changing weather patterns. When placed in high wind locations, wind farms can capture great quantities of energy and is being implemented in many places to offset fossil energy used, as with solar and hydroelectric energy. Wind turbine bird mortality and bat mortality are significant adverse impacts of wind farms. One challenge facing wind power is vigorous community resistance to placing turbines nearby. The Not In My Backyard (NIMBY) principle limits areas that are ideal for wind power because of the perceived visual pollution. One alternative to this is Offshore Wind Power that does not significantly obscure views while still providing power. In fact, offshore wind power mathematically measures as one of the least renewable energy sources, since the life cycle greenhouse gas emissions of offshore wind is much higher than nuclear, hydroelectric, solar, combined cycle natural gas, or onshore wind.
Solar
Direct solar energy is provided by incident solar radiation. It can be used for thermal applications using solar collectors, passive building design, generation of electricity using solar photovoltaic panels, and solar thermal energy. This energy is most efficient in areas of intense sun, such as deserts. Solar energy is dependent only on the availability of solar energy and is therefore unreliable for large expanses of the globe. Solar energy needs to be complemented when the sun is hidden by clouds, during darkness or when stored energy is depleted. Solar photovoltaic energy can be stored by charging batteries or other systems, while solar thermal energy can be stored in masonry or circulating water and can therefore be used for some time after the sun becomes temporarily unavailable. Solar panels have the adverse environmental impact of containing large amounts of arsenic and other toxic heavy metals, which can find their way into the soil from wildfires, rain leaching and improper disposal. Large solar arrays have a downside of extensive habitat destruction, particularly in desert environments, where desert crust soils take about a century to regenerate from disturbance. Solar power has economic limitations that have halted widespread use, its main challenge being that fossil fuels and nuclear power are still comparatively inexpensive. However, private homeowners and businesses have independently installed solar panels for other social or personal reasons. Solar farms are presently as of 2022 not economically sustainable compared to the other chief forms of renewable energy (i.e. nuclear, hydroelectric, combined cycle natural gas and wind). Many major solar farms are presently on the verge of bankruptcy due to the absence of economic viability, including the massive Topaz plant and Berkshire Hathaway plants in California); this absence of fundamental economic viability stems from the low percentage of time reliability (about seven percent of the time are they productive) and upon the much lower costs of operation and construction of nuclear, wind, geothermal, combined cycle natural gas and hydroelectric.
Renewable Energy Policy
Between 1989 and 2004, the European Union and the United States have each spent an average of about 200 million dollars (US) per year on research and development of renewable energy sources. Each member country of the European Union has its own energy strategies. For example wind energy is dominant in Denmark, while Germany has a more diverse renewable energy portfolio involving wind, solar, and biomass. The European Union has a basic renewable energy policy, but it usually defers to each member country to set its own standards. The European Union advocates for research and development, while setting renewable energy goals for its members. Germany has conducted the most aggressive wind and solar programs, which policies have effectively driven up electricity prices and caused numerous blackouts from depriving the electric grid from adequate base load.
The United States uses less renewable energy in its energy portfolio than parts of Europe. As leadership had changed in 2008 in Congress and in the White House, more attention was shifted to subsidizing renewable energy sources. A bill that passed the U.S. House of Representatives and was defeated to in the Senate is the American Clean Energy and Security Act of 2009. The bill would have created emissions caps that applies to seven greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride. The goals of the bill for all industries that produce mass amounts of greenhouse gases (over 25,000 tons) are 3% under 2005 levels by 2012, 17% under 2005 levels by 2020, 42% under 2005 levels by 2030, and 83% under 2005 levels by 2050. The reasons the Bill was defeated included: (a) a disproportionate impact on low and middle income earners would have resulted; (b) the reliability of the energy grid would be compromised by creating an insufficient base load, a circumstance that actually resulted in California, which enacted a similar measure, without providing sufficient base load; and (c) the recognition that China and India produce the preponderance of the greenhouse emissions, thus making the Bill largely a symbolic gesture.
When the federal government seemed ineffective, some states implemented their own energy standards. Most notable is California, which has adopted the Renewable Portfolio Standard committing to derive electricity from renewable energy sources, mainly solar power. In addition California and four other states, have committed to a policy mechanism called feed-in tariffs which are designed to promote the use of renewable energy sources. Feed-in tariffs compel electric grid utilities to buy renewable electricity to provide power to its customers.
See Also
References
- Randolph, J. and G. M. Masters. (2008). Energy for Sustainability: Technology, Planning, Policy. Washington: Island Press.
- Brookings Institute (2021) Why the Best Path to a Low-Carbon Future is Not Wind or Solar Power.
- (2009). Tap into Earth's Temperature Control with Geothermal Systems. Workbench, 65, 8.
- Hildebrant, Pete. (2009). Drill, Baby, Drill. E the Environmental Magazine. 20: 44-45.
- Jennifer L.Turner. 2007. In Deep Water: Ecological Destruction of China's Water Resources. in Erik Roswell Peterson and Rachel Posner Water and energy futures in an urbanized Asia: sustaining the tiger. CSIS
- Simpson, Tom. (2009). Biofuels: The Past, Present, and a New Vision for the Future. BioScience 59: 926.
- Marty, Diane. (2000). Burning Biomass. E: The Environmental Magazine. 11: 12-14.
- Manwell, James F., Jon G. McGowan and Anthony L. Rogers. (2009). Wind Energy Explained: Theory, Design and Application. Second Edition. pg.1-5.
- Blok, Kornelis. (2004). Renewable energy policies in the European Union. Energy Policy 34: 251-255.
- (2009). How Geothermal Energy Works. Union of Concerned Scientists. Retrieved from http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-geothermal-energy-works.html.
