Nuclear Energy

What is Nuclear Energy?  
Nuclear energy is energy that comes form the nucleus (core) of an atom. Atoms are the particles that make up all objects in the universe. Atoms consist of neutrons, protons, and electrons. Nuclear energy is released from an atom through one of two processes: nuclear fission. In nuclear fusion, energy is released when the nuclei of atoms are combined or fused together. This is how the sun produces energy. In nuclear fission, energy is released when the nuclei of atoms are split apart. Nuclear fission is the only method currently used by nuclear plants to generate electricity. 
What is Uranium?  
The fuel by nuclear power plants for fissioning is uranium. Uranium is the heaviest of the 92 naturally occurring elements and is classified as a metal. It is also one of the few elements that are easily fissioned. Uranium was formed when the earth was created and is found in rocks all over the world. Rocks that contain a lot of uranium are called uranium ore, or pitchblende. Uranium, although abundant, is a nonrenewable energy source. 

Two forms (isotopes) or uranium are found in nature, uranium-235 and uranium-238. These numbers refer to the number of neutrons and protons in each atom. Uranium-235 is the form commonly used for energy production because, unlike uranium-238, its nucleus splits easily when bombarded by a neutron, causing its nucleus to split apart into two atoms of lighter weight. 

At the same time, the fission reaction releases energy as heat and radiation, as well as releasing more neutrons. The newly released neutrons go on to bombard other uranium atoms, and the process repeats itself over and over. This is called a chain reaction. 
The Nuclear Fuel Cycle 
The steps-from mining the uranium ore, through its use in a nuclear reactor, to its disposal-is called the nuclear fuel cycle. 

  • Mining – The first step in the cycle is mining the uranium ore. Workers mine uranium ore much like coal miner mine coal-in deep underground mines or in open-pit surface mines. A tone of uranium ore in the United States typically contains three to ten pounds of uranium. 
  • Milling – After it has been mined, uranium or is crushed. The crushed ore is usually mixed with an acid, which dissolves the uranium, but not the rest of the crushed rock. The acid solution is drained off and dried, leaving a yellow powder called yellowcake, consisting mostly of uranium. This process of removing uranium form the ore is called uranium milling. 
  • Conversion – The next step in the cycle is the conversion of the yellowcake into a gas called uranium hexafluoride, or UF6. The uranium hexafluoride is then shipped to a gaseous diffusion plant for enrichment. 
  • Enrichment – Because less than one percent of uranium ore contains uranium-235, the form used for energy production, uranium must be processed to increase the concentration of uranium-235. This process-called enrichment-increases the percentage of uranium-235 from one to five percent. It typically takes place at a gaseous diffusion plant where the uranium hexafluoride is pumped through filters that contain very tiny holes. Because uranium-235 has three fewer neutrons and it one percent lighter than uranium-238, it moves through the holes more easily then uranium-238. This method increases the percentage of uranium-235 as the gas passes through thousands of filters. 
  • Fuel Fabrication – The enriched uranium is taken to a fuel fabrication plant where it is prepared from the nuclear reactor. Here, the uranium is made into a solid ceramic material and formed into small barrel-shaped pellets. These ceramic fuel pellets can withstand very high temperatures, just like the ceramic tiles on the space shuttle. Fuel pellets are about the size of your fingertip, yet each one can produce as much energy as 120 gallons of oil. The pellets are sealed in 12-foot metal tubes called fuel rods. Finally, the fuel rods are bundled into groups called fuel assemblies. 
  • Nuclear Reactor – The uranium fuel is now ready for use in a nuclear reactor. Fissioning takes place in the reactor core. Surrounding the core of the reactor is a shell called the reactor pressure vessel. To prevent heat or radiation leaks, the reactor core and the vessel are housed in an airtight containment building made of steel and concrete several feet thick. The reactor core houses about 200 fuel assemblies. Spaced between the fuel assemblies are movable control rods. Control rods absorb neutrons and slow down the nuclear reaction. Water also flows through the fuel assemblies and control rods to remove some of the heat from the chain reaction. The nuclear reaction generates heat energy just as burning coal or oil generates heat energy. Likewise, the heat is used to boil water into steam, which turns a turbine generator to produce electricity. Afterward, the steam is condensed back into water and cooled in a separate structure called a cooling tower. This way, the water can be used again and again. 
  • Spent Fuel Storage – Like most industries, nuclear power plants produce waste. One of the main concerns about nuclear power plants is not the amount of waste created, which is quite small compared to other industries, but the radioactivity of some of that waste. The fission process creates radioactive waste products. After about three cycles, these waste products build up in the fuel rods, making the chain reaction more difficult. Utility companies generally replace one-third of the fuel rods every 12 to 18 months to keep power plants in continuous operation. The spent fuel is usually stored near the reactor I a deep pool of water called the spent fuel pool. During storage, the spent fuel cools down and begins to lose most of its radioactivity through radioactive decay. In three months, the spent fuel will lose 50 percent of its radiation; in one year, 80 percent; in 10 years, 90 percent. The spent fuel pool is intended as a temporary method for storing nuclear waste. Eventually, the spent fuel will be reprocessed and/or transported to a permanent federal disposal site. 
  • Reprocessing – Spent fuel contains both radioactive waste products and unused nuclear fuel. In fact, about one-third on the nuclear fuel remains unused when the fuel rod must be replaced. Reprocessing separates the unused nuclear fuel from the waste products so that it can be used in a reactor again. Currently, American nuclear power plants store the spent fuel in spent fuel pools-without reprocessing. Why? Mainly because reprocessing is more expensive than making new fuel from uranium ore. If uranium prices rise significantly or storage becomes a bigger problem, reprocessing may gain favor in the industry. 

Waste Repository 
Most scientists believe the safest way to store nuclear waste is in rock formations deep underground called geological repositories. In 1982, the U.S. Congress agreed and passed the Nuclear Waste Policy Act. This law directed the U.S. Department of Energy to site, design, construct, and operate America’s first repository by 1998. The repository stores radioactive waste from nuclear power plants and from defense weapons plants. The same law also established the Nuclear Waste Fund to pay for the repository.  

People who use electricity from nuclear power plants pay 1/10 of a cent for each kilowatt-hour of nuclear-generated electricity they use. An average household, which uses about 7,500 kilowatt-hour a year, would contribute $7.50 a year to the fund if it got all its electricity from nuclear power.  

The nation has collected $14 billion into the fund since 1982. In 1987, Congress passed the Nuclear Waste Policy Amendments Act. Among others things, this act proposed Yucca Mountain, Nevada as the nation’s first repository site. If the current plan is approved, nuclear waste will be sealed in steel canisters and stored in vaults located 1,000 feet below the surface. Current projections are that it may open about 2010. Yucca Mountain is being studied as a repository site because it is dry and geologically stable (the chance of erupting volcanoes or earth-quakes is very slim). Yucca Mountain site is also isolated. Few people live in the area. Although utility companies currently sore their nuclear waste in pools of water at the power plant, some companies will run out of storage space in the next year or two.  

Utility companies are asking the Department of Energy to accept responsibility for the waste. The Department of Energy would need to store the waste in a temporary facility prior to its final burial at the repository. 
Nuclear Energy Use 
Nuclear energy is an important source of electricity-second only to coal-providing almost 18 percent of the electricity in the U.S. At the end of 1997m there were 107 nuclear power plants operating in the U.S. No new plants are planned for the future. Worldwide, however, nuclear energy is a growing source of electrical power. Nuclear energy now provides about 17 percent of the world’s electricity. The U.S., France, Japan, and Germany are the world leaders. France gets 75 percent of its electricity from nuclear power. 
Nuclear Energy and the Environment 
Nuclear power plants have very little impact on the environment. Generating electricity from nuclear power produces no air pollution because no fuel is burned. Most of the water used in the cooling processes is recycles. In the future, using nuclear energy may become an important way to reduce the amount of carbon dioxide produced by burning fossil fuels and biomass. Carbon dioxide is considered the major greenhouse gas. People are using more and more electricity. Some experts predict that we will have to use nuclear energy to produce the amount of electricity people need at a cost they can afford. Whether or not we should use nuclear energy to produce electricity has become a controversial and sometimes highly emotional issue. 
Nuclear Safety 
The greatest potential risk from nuclear power plants is the release of high-level radiation. In the United States, plants are carefully designed to contain radiation, and emergency plans are in place to alert and advise nearby residents if there is an accident. Two serious accidents have occurred since the industry began over 30 years ago-Three Mile Island in the Unites States (1979) and Chernobyl in the Soviet Union (1986).  

At Three Mile Island, about half the uranium fuel melted when water to the reactor core was inadvertently cut off. A small amount of radioactive material escaped into the surrounding area before the mistake was discovered. But due to the safety design features of the plant-multiple barriers contained most of the radiation-no one was injured or died as a result of this accident.  

However, the accident at Chernobyl was far more serious. It happened when two explosions blew the top off the reactor building. A lack of containment structures and other design flaws caused the release of a large amount of radioactive material into the surrounding area. More than 100,000 people were evacuated from their homes and about 200 workers were treated for radiation sickness and burns; 31 or them died.  

Could a Chernobyl-type accident occur at an American nuclear plant? Many experts say no. Old soviet nuclear plants do not have the safety systems and containment chambers that are standard on all American plants. American operators are also better trained than their Eastern European counterparts to respond to any problems that may occur. 


What is Hydrogen?
Hydrogen is the simplest element. A hydrogen atom has only one proton and one electron. It is also the most abundant gas in the universe, and the source of all the energy we receive from the sun. The sun is basically a giant ball of hydrogen and helium gases. In a process called fusion, four hydrogen atoms combine to form one helium atom, releasing energy as radiation.  

 This radiation energy is our most abundant energy source. It gives us light and heat and makes plants grow. It causes the wind to blow and the rain to fall. It is stored as chemical energy in fossil fuels. Most of the energy we use originally came from the sun. 

 Hydrogen as a gas (H2), however, doesn’t exist naturally on earth. It is found only in compound form. Combined with oxygen, it is water (H2O). Combined with carbon, it forms organic compounds such as methane (CH4), coal, and petroleum. It is found in all growing things-biomass. It is one of the most abundant elements in the earth’s crust. 

 Most of the energy we use today comes from fossil fuels. Only seven percent comes from renewable energy sources. But people want to use more renewable energy. Usually it is cleaner, and we won’t run out of it. We won’t run out of hydrogen either. 

Every day, we use more fuel, principally coal, to produce electricity. Electricity is a secondary source of energy. Secondary sources of energy-energy carriers-are used to store, move, and deliver energy in easily usable form. We convert energy to electricity because it is easier for us to transport and use. Try splitting an atom, building a dam, or burning coal to run your TV. Energy carriers make life easier. 

Hydrogen is one of the most promising energy carriers for the future. It is a high efficiency, low polluting fuel that can be used for transportation in places where it is difficult to use electricity. Since hydrogen gas is not found in its nature state on earth, it must be manufactured. There are several ways to do this. 
How is Hydrogen Made? 
Industry produces the hydrogen it needs by a process called steam reforming. High-temperature steam separates hydrogen from the carbon atoms in natural gas (CH4). The hydrogen produced by this method isn’t used as a fuel, but in the manufacture of fertilizers and chemical s and to upgrade the quality of petroleum products. 

This is the most cost-effective way to produce hydrogen today, but it uses fossil fuels both in the manufacturing process and as the heat source. Another way to make hydrogen is by electrolysis-splitting water into its basic elements, hydrogen and oxygen. Electrolysis involves passing an electric current through water to separate the atoms (2H2O + electricity = 2H2 +O2). Hydrogen collects at the negatively charged cathode and oxygen at the positive anode. 

 Hydrogen produced by electrolysis is extremely pure, and electricity from renewable energy sources can be used, but it is very expensive at this time. Today, hydrogen from electrolysis is ten times as costly as natural gas and three times as costly as gasoline per Btu. 

 On the other hand, water is abundant and renewable, and technological advances in renewable electricity could make electrolysis a more attractive way to produce hydrogen in the future. 

There are also several experimental methods of producing hydrogen. Photoelectrolysis uses sunlight to split water molecules into its components. A semiconductor absorbs the energy from the sun and acts as an electrode to separate the water molecules. 

 In biomass gasification, wood chips and agricultural wastes are super-heated until they turn into hydrogen and other gases. Biomass can also be used to provide the heat energy. Scientists have also discovered that some algae and bacteria produce hydrogen under certain conditions, using sunlight as their energy source. Experiments are underway to find ways to induce these microbes to produce hydrogen efficiently. 
Hydrogen Uses 
At the present time, hydrogen’s main use as a fuel is in the NASA space program. Liquid nitrogen is the fuel that has propelled the space shuttle and other rockets since the 1970’s. Hydrogen fuel cells power the shuttle’s electrical systems, producing pure water, which is used by the crew as drinking water. 

In the future, however, hydrogen will join electricity as an important energy carrier. Hydrogen can be made safely from renewable energy sources and is virtually non-polluting. It is also versatile; it can be a fuel for “zero-emissions” vehicles, to heat homes and offices, to produce electricity, and to fuel aircraft. Cost is the major obstacle. 

The first widespread use of hydrogen will probably be as an additive to transportation fuels. Hydrogen can be combined with gasoline, ethanol, methanol, and natural gas to increase performance and reduce pollution. Adding just 5 percent hydrogen to gasoline can reduce nitrogen oxide (NOX) emissions by 30 to 40 percent in today’s engines. 

An engine converted to burn pure hydrogen produces only water and minor amounts of NOX as exhaust. A few hydrogen-powered transportation systems we have today? (Just think of the thousands of filling stations across the country, and production and distribution systems that serve them.) Change will come slowly to this industry, but hydrogen is a versatile fuel; it can be used in many ways. 

For example, hydrogen is a natural as aircraft fuel. Its high-energy contents mean reduced weight and fuel consumption compared to current jet fuel. Plus, it is non-polluting. And converting to hydrogen fuel would be much easier for aircraft-the infrastructure (support system) is simpler. The space shuttle uses hydrogen fuel cells (batteries) to run its computer systems.  

The fuel cells basically reverse electrolysis-hydrogen and oxygen are combined to produce electricity. Hydrogen fuel cells are very efficient and produce only water as a by-product, but they are expensive to build. With technological advances, small fuel cells could someday power electric vehicles and larger fuel cells could provide electricity in remote areas. 

Because of cost, hydrogen will not produce electricity on a wide scale in the near future. It may, though, be added to natural gas to reduce emissions from existing power plants. As the production of electricity from renewables increases, so will the need for energy storage and transportation. Many of these sources-especially solar and wind-are located far from population centers and produce electricity only part of the time. Hydrogen may be the perfect carrier for this energy. It can store the energy and distribute it to wherever it is needed. It is estimated that transmitting electricity long distances is four times more expensive than shipping hydrogen by pipeline. 
The Future of Hydrogen 
Before hydrogen can take its place in the U.S. energy picture, many new systems must be designed and built. There must be large production and storage facilities and a distribution system. And consumers must have the technology to use it. The use of hydrogen raises concerns about safety. Hydrogen is a volatile gas with high energy content. Early skeptics had similar concerns about natural gas and gasoline-even about electricity. People were afraid to let their children too near to light bulbs. As hydrogen technologies develop, safety issues will be addressed. Hydrogen can be produced, stored, and used as safely as other fuels. The goal of the U.S. Department of Energy’s Hydrogen Program is for hydrogen to produce ten percent of our total energy demand by the year 2030. Hydrogen can reduce our dependence on foreign oil and provide clean, renewable energy for the future. 


The Nature of Electricity 
Electricity is a little different from the other sources of energy that we talk about. Unlike coal, petroleum, or solar energy, electricity is a secondary (not primary) source of energy. That means we must use other (primary) sources of energy to make electricity. It also means we can’t classify electricity as a renewable or nonrenewable form of energy. The energy source we use to make electricity may be renewable or nonrenewable, but electricity is neither. 
Making Electricity 
Almost all electricity made in the United States is generated by large, central power plants. These plants typically use coal, nuclear fission, natural gas, or other energy sources to produce heat energy which superheats water into steam. The very high pressure of the steam (75-100 times normal atmospheric pressure) turns the blades of a turbine. (At a hydroelectric plant, the force of falling water turns the blades.) The blades are connected to a generator which houses a large magnet surrounded by a coiled copper wire. The blades spin the magnet rapidly, rotating the magnet inside the coil and producing an electric current. The steam, which is still very hot but back to normal pressure, now goes to a condenser where it is cooled into water by passing it through pipes circulating over a large body of water or cooling tower. The water then returns to the boiler to be used again. Power plants can capture some of the heat from the cooling stream. In old plants, the heat was simply wasted. 
Moving Electricity from power Plants to Homes 
We are using more and more electricity every year. One reason electricity is used so much, it’s easy to move from one place to another. Electricity can be produced at a power plant and moved long distances before it is used. Let’s follow the path of electricity from power plant to a light bulb in your home. 

  • First, the electricity is generated at the power plant. Next, it goes by wire to a transformer that “steps up” the voltage. A transformer step up the voltage of electricity from the 2,300 to 22,000 volts produced by a generator to as much as 765,000 volts (345,000 volts is typical). Power companies step up the voltage because less electricity is lost along the lines when the voltage is high. 
  • The electricity is then sent on a nationwide network of transmission lines made of aluminum. Transmission lines are the huge tower lines you may see when you’re on a highway. The lines are interconnected. Should one line fail, another will take over the load. 
  • Step-down transformers located at substations along the lines reduce the voltage to 12,000 volts. Substations are small buildings or fenced-in yards containing switches, transformers, and other electrical equipment. 
  • Electricity is then carried over distribution lines which bring electricity to your home. Distribution lines may either by overhead or underground. Overhead distribution line are the electric lines that you see along streets. 
  • Before electricity enters your house, the voltage is reduced again at another transformer, usually a large gray can mounted on an electric pole. This transformer reduces the electricity to the 120 volts that are needed to run the light bulb in your home. 
  • Electricity enters your house through a three-wire cable. The “live wires” are then brought from the circuit breaker or fuse box to power outlets and wall switches in your home. An electric meter measures how much electricity you use so the utility company can bill you. 
  • The time it takes for electricity to travel through these steps–from the power plant to the light bulb in your home–is a tiny fraction of one second! 

Power to the People 
Everyone knows how important electricity is to our lives. All it takes is a power failure to remind us how much we depend on it. Life would be very different without electricity–no more instant light from flicking a switch; no more television; no more refrigerators; or stereos; or video games; or hundreds of other conveniences we take for granted. You could almost say the American economy runs on electricity. It’s the business of electric utility companies to make sure electricity is there when we need it. How do they do it? First, some terms: reliability, capacity, base load, power pools, and peak demand. 

  • Reliability is the capability of a utility company to provide electricity to its customers 100 percent of the time. A reliable electric service is without blackouts or brownouts. To ensure uninterrupted electric service, laws require most utility companies to have 15-20 percent more capacity than they need to meet peak demands. This means a utility company whose peak load is 12,000MW, would need to have about 14,000 MW of installed electrical capacity. This helps ensure there will be enough electricity to go around even if equipment were to break down on a hot summer afternoon. 
  • Capacity is the total quantity of electricity a utility company has online and ready to deliver when people need it. A large utility company may operate several plants to generate electricity for it customers. A utility company has seven 1,000-MW (megawatt) plants, eight 500-MW plants, and 30 100-MW plants has a total capacity of 14,000-MW. 
  • Base-load Power is the electricity generated by utility companies around-the-clock, using the most inexpensive energy sources–usually coal, nuclear, and hydropower. Base-load power stations usually run at full or near capacity, 
  • When many people want electricity at the same time, there is a Peak Demand. Power companies must be ready for peak demands so there is enough power for everyone. During the day’s peak, between 12:00 noon and 6:00 p.m., additional generating equipment has to be used to meet increased demand. This equipment is more expensive to operate. These peak load generators run on natural gas, diesel or hydro and can be running in seconds. The more this equipment is used, the higher our utility bills. By managing the use of electricity during the peak hours, we can help keep costs down. 
  • The use of Power Pools is another way electric companies make their systems more reliable. Power pools link utilities together so they can share power as it is needed. A power failure in one system can be covered by a neighboring power company until the problem is corrected. There are nine regional power pool networks in North America. The key is to share power rather than lost it. 

The reliability of U.S. electric service is excellent, usually better than 99 percent. In some countries, electric power may go out several times in a day. Power outages in the United States are usually caused by such random occurrences as lightning, a tree limb falling no electric wires, or a car hitting a utility pole. 

Renewable Energy Review: Wind

What is it? Wind can be considered a form of solar energy; the uneven heating and cooling of the atmosphere causes wind. Wind power is the use of air flow through wind turbines to power generators for electric power. This is an excellent alternative to fossil fuel, and it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions during operation. Wind power also consumes no water and uses little land. It is inexpensive, causes little disruption to the land it uses, and can be collected both on- and offshore. Additionally, it has a low life carbon footprint—builders can expect to breakeven on carbon output (work back the energy it took to create the wind turbines) in around eight months.

How is it sourced? Wind flow is captured by wind turbines, which convert the energy into electricity. Wind farms consisted of many individual wind turbines, which are often connected to the electric power transmission network. When the wind blows, the turbine’s motion catalyzes generator power.

How is it used? Wind power is used to generate electricity for a variety of situations. Additionally, the power generated by a wind farm is not restricted by location.

Are there any downsides? Wind power is variable—it is consistent from year to year but may have significant variation over shorter lengths of time. This means that it is often used in conjunction with other electric power sources; it is necessary in order to provide a reliable supply. Wind farms can also harm or kill birds and bats, and the turbines may be loud for those living close to them.


Renewable Energy Review: Geothermal

What is it? Geothermal energy is derived from the heat of the Earth itself. It can be sourced close to the Earth’s surface, eliminating the need for excessive and destructive digging. However, the heat source itself is derived from deep within the Earth’s core—around 4,000 miles down. At this part of the planet, temperatures may reach over 9,000 degrees Fahrenheit. The heat emanates from the core to the surrounding rock. Humans have utilized geothermal energy for millennia—it is the cause of hot springs, and ancient Romans harnessed its power for space heating.


How is it sourced? Geothermal power plants harness these heat sources to generate electricity. There are three types of power stations—dry steam, flash steam, and binary cycle power stations.


How is it used? Geothermal energy can be part of a commercial utility energy solution on both large and small scales. This may include everything from heating office buildings and manufacturing plants to growing greenhouse plants. It can also be used to heat water at fish farms and aid in several industrial processes, such as pasteurizing milk.


Are there any downsides? Geothermal energy, though sustainable, can cause some minor environmental issues. In the most extreme cases, geothermal power plants can cause small earthquakes. Moreover, there are very heavy costs associated with building and developing geothermal power plants, and the energy availability is highly location-specific. This type of power is only sustainable if the reservoirs are properly managed.


Renewable Energy Review: Bioenergy

What is it? Bioenergy is a type of renewable energy derived from biomass to create heat and electricity. It is also used to produce liquid fuels used for transportation, such as ethanol and biodiesel. Bioenergy creates “biofuels,” such as ethanol and biodiesel. Biomass is defined as any organic material which has stored sunlight in the form of chemical energy—this can include everything from wood, wood waste, and straw to manure and other byproducts of various agricultural products.


How is it sourced? Bioenergy is sourced in a variety of ways. Users can directly burn the biomass or capture the methane gas produced by natural decomposition of organic material.


How is it used? Bioenergy can be used in vehicles (ethanol and biodiesel) and in farm operations, working to convert waste from livestock into electricity. This is done using a small, modular system. Additionally, manufacturing facilities can be equipped to burn biomass directly, allowing for the recycling and reuse of material (for example, paper mills can use wood waste to produce electricity and steam for heating). If equipped, towns can also tap the methane gas created by the anaerobic digestion of organic waste in landfills.


Are there any downsides? Bioenergy generates the same amount of carbon emissions as fossil fuels. However, the plants grown as biomass remove a roughly equal amount of CO2 from the atmosphere, helping to keep the environmental impact relatively neutral. However, organizations such as Greenpeace and the Natural Resources Defense Council have critiqued the use of bioenergy for the harmful impact it may have on forests and the climate (as a result of the CO2 emissions).

Renewable Energy Review: Hydroelectric

What is it? Hydroelectricity is produced from hydropower, which is derived from the energy of falling or fast-moving water. It is produced in 150 countries and, in 2015, produced nearly 17% of the world’s total electricity. It also produced around 70% of all renewable electricity. Hydroelectricity’s low cost makes it a competitive source of renewable electricity; the power plants consume no water, and the project produces no direct waste and has a considerably lower output level of greenhouse gasses than fossil fuel energy plants..


How is it sourced? The most popular form of harnessing hydroelectric power is by capturing the kinetic energy of flowing rivers. This is done through the utilization of a series of dams, which are constructed to store water in a reservoir. When released the water flows through turbines, producing electricity. The water is cycled between lower and upper reservoirs to control electricity generation. Hydroelectric power can also be harnessed through “run-of-river hydropower.” In this method, a portion of a river is funneled through a channel, thus eliminating the need for a dam.


How is it used? Though the use of hydroelectric power is dependent on geographic location, it is used to supply electricity in a variety of situations—from farm and ranch operations to individual buildings and towns.


Are there any downsides? There are some minor environmental consequences associated with the use of hydropower. Interventions in waterways, such as damming and changing flow, can impact the habitat of thousands of species. Additionally, building the plants themselves is an expensive project, and widespread droughts are likely to exponentially increase the cost of hydroelectric power.


Renewable Energy Review: Solar

What is it? Solar power is the conversation of energy from sunlight into electricity. This is done by either directly using photovoltaics, indirectly using concentrated solar power, or a combination. With the exception of geothermal and hydrogen, the sun plays an essential role in most types of renewable energy. In capturing the sun’s energy directly, technology can convert this power into heat, illumination, electricity, and cooling systems. Solar power is an extremely reliable source of energy, thus providing essential energy security. It can also provide energy independence to those who purchase personal solar panels. Additionally, solar power creates a lot of jobs—between two and three times more than the coal and natural gas industries.


How is it sourced? Photovoltaic (PV) systems use solar cells to convert sunlight into electricity. This coverts light into electricity using semiconducting materials. Additionally, the sun’s heat can be concentrated by mirror-covered dishes that are focused to boil water in a conventional steam generator to product electricity.


How is it used? The application of solar power is seemingly endless. Users can install personal and commercial solar power systems in the form of rooftop equipment or field array panels. Users can also purchase solar energy generated by an offsite commercial solar installation.


Are there any downsides? When the sun sets or is heavily shaded, solar PV panels stop producing electricity. This necessitates the creation of batteries to store electricity produced by solar panels for later use. Additionally, up-front costs can be intimidating, and personal panels do not work on every type of roof. However, when it comes to environmental impact, or lack thereof, solar energy is peerless.


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