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Renewable and Nonrenewable energy sources
Transcript of Renewable and Nonrenewable energy sources
This is not pure oil, though, as it has impurities and many different types of hydrocarbons. These are separated out by the refining process.
Crude oil is not the only type of oil, but it is the main type of oil that is used because of how easy it is to access. Oil Sand There are deposits of sand and sandstone in which extremely thick, crude oil called bitumen lies.
This bitumen is unconventional because it is more costly to transport and refine than crude oil. However, with increasing oil prices, vast deposits of oil sands are becoming a possible source of oil. Oil Shale Oil shale is a mixture of hydrocarbons within a fine-grained rock which did not receive enough heat to transform into petroleum. The hydrocarbons remain in a lower-energy form called kerogen, which is useless for energy as it is.
However, once the shale is heated to a certain degree, it turns into a viable source of low-quality energy, along with combustible gas.
Because of rising oil prices, oil shale has also become a possible new source of energy. Oil shale cannot be used to produce petroleum. However, it can be used as a low-quality source of heat. There are large deposits of oil sands in Canada, and debates rage as to whether they should be exploited. This oil is
then sent to
be refined... Refinement The oil is then transported by pipeline, oil tanker, or truck to a refinery. There it is heated, which separates the different hydrocarbons by boiling point. The oil is then sent away to be put to use.
It is used as fuel, for heating, and making plastics and other products. The oil is separated into separate types of hydrocarbons, from gas and gasoline to diesel and heavy residue. Advantages Cheap Oil is cheap and easy to extract and refine into an inexpensive source of energy. Supply There is an ample supply of crude oil, enough to last us anywhere from 40- to 90-some more years. Technique We have been using oil for a long time, and the technology is much more efficient than it was in the 1840s when we started refining. Transport Oil is easy to transport via pipeline, tanker, or truck within countries and throughout the world, making it easier to get it where energy is needed from where oil is plentiful. Storage Oil can easily be stored and used at a time when it is needed. This may seem mundane, but some energy sources, such as solar, are only produced at certain times, and cannot be stored as of yet. Disadvantages Pollution When fossil fuels are burned, they release CO2. Also, massive amounts of water and air pollution are created in the production of oil. In addition to both of these, oil spills from tankers can pollute vast expanses of the environment. Wasteful The government subsidies on oil that keep prices low encourage wastefulness. These low prices also discourage the use of alternative sources of energy. Finite Since oil takes millions of years to form, the reserves of oil are finite, and will not renew in the foreseeable future. That means that when we run out of oil, we will run out forever. Air Pollutants When burnt, fossil fuels produce CO2 and other Greenhouse gases, which can contribute to Global Warming. In addition, they can release other pollutants, such as sulfur dioxide and nitrogen oxides (causes of acid rain), heavy metals (biological and ecosystem pollutants) and volatile organic compounds. Pollution from Extraction Extracting oil disturbs the surrounding environment with mining roads and oil spills. For example, in the Russian Tundra, oil drilling operations and their vehicles have cut ruts in the ground that do not heal over quickly. This, in addition to the pollution of the land has led to a large amount of degradation. Oil Spills When oil tankers, pipelines, or drilling rigs have an accident, hundreds of thousands of gallons of oil can be released into the environment to harm it.
Oil spills in the ocean can coat birds, making them sink, and poison other organisms. Offshore Drilling Offshore oil rigs can decrease the direct environmental degradation that oil operations produce in fragile ecosystems. However, they can leak or spill into the ocean, polluting it and harming the wildlife of a large area. Electricity Some of the refined oil is sent to oil-burning factories, where it is used to heat water, boiling it to steam, running a turbine that produces electricity. Resource Management Alternatives The best way to conserve our oil resources is to phase out production and use of oil in favor of more renewable, such as hydro or solar. However, this may not be the most appealing method of conservation. Reduction We could also reduce the amount of fossil fuels we consume. This could be done by finding alternatives for plastic/reducing plastic use, using less electricity, and traveling less, among others. Efficiency Developing new technology may lead to a drop in the usage of fossil fuels. More efficient cars are a big deal, and efficient factories could produce more electricity from less oil. However, there is only so much energy that can be obtained from oil. $ Money $ If we reduce the government subsidies on oil, then we can encourage companies to be more frugal with fossil fuels, and perhaps find other ways of producing energy. International
Governmental action If we can get governments of the world to agree on carbon taxes, energy taxes, or any number of other ways to preserve our supplies of fossil fuels for the future, it will be the most successful. Use Because of its ease of exploitation and high energy concentration, oil is the most used source of energy on our planet, and has been since the mid-1950s. Coal Process Formation Coal forms like oil, except that it is formed from land plants. The plants die and are trapped beneath layers of soil or mud. This eventually changes the composition of the coal in a process called carbonization. Unlike the processes that form oil, coal isn't heated to change its composition. Lignite Lignite is the lowest rank of coal, and is a light brown color. Its rank is based on its age, and it is from the Tertiary Period: the youngest of all coal. Because of its high moisture content and inefficiency, it is mostly burned in electricity-generating factories, often close to the source. Bituminous Bituminous coal is the next rank of coal, with 60-80% of it made of carbon. It can is the most dangerous type to mine because it can release gases that cause explosions. It is often used in blacksmithing and other areas where intense heat is needed. It can be put through a process to become "coke", a processed form of coal that is more pure and safe. Anthracite The highest grade of coal, anthracite is hard and shiny. It is more expensive than the other types of coal because it offers much more energy per weight when burned, and burns cleanly with little soot. It is used in domestic stoves, in charcoal water-filters, and metallurgy. Its high price makes it mostly uneconomical to be used in electricity production. Peat Peat is partially decayed and carbonized coal found in bogs. It is often burned on a local level for heat in houses, but is not used on a wide-scale because it is extremely inefficient. It is also sometimes used to soak up oil spills and to condition soil for farming. Energy Production After it is extracted by either surface mining or in tunnels, the coal is transported to a power plant. There, it is burned in a boiler, which boils water to turn a turbine and produce electricity. The ash is filtered out of the smoke before it comes out of the smokestacks. Advantages Cheap Like oil, coal is cheap to extract and use as an energy source. It requires essentially no refinement. And with many government subsidies, it becomes a cheap and easy source of energy. There is a supply of 225-900 years' worth of coal that we can mine. This is a very significant amount, and in that time we could find more coal or find other energy sources. Plentiful Coal has a high net-energy gain, meaning that a certain amount of coal produces more energy than it takes to mine and transport that same amount of coal. This makes coal very attractive to companies. Efficient The mining and combustion technology is very well established, and has been for a long time. It would cost a lot of money to make the change from coal to another energy source. Technique Disadvantages Pollution Coal, like oil, pollutes the environment when it is burned and mined, and disturbs the environment where the operations take place. Wasteful Also like oil, subsidies on coal can make it seem better than it is, and cause companies to waste and become complacent with the pollution associated with coal. Dangerous The soot, radioactive particles, and toxic metals released by coal can cause major problems for people. The World Health Organization estimated an annual 1 million deaths from coal pollution in 2011. Also, coal is dangerous to mine. Air Pollutants Coal is much dirtier than oil when it is burned. It releases not only CO2, sulfur dioxide, and nitrogen oxides like oil, but also soot, which can cause respiratory problems, radioactive particles which can cause cancer, and mercury and other heavy metal toxins into the air. This makes coal a very harmful pollutant. However, some methods can mitigate this problem. Mining Pollution Strip-mining coal digs big pits in the land, into which the toxins in coal flow. This not only displaces wildlife, but poisons them. The removal of topsoil and the use of vehicles in the wild lead to less vegetation, which can lead to erosion, destroying the ecosystem further. Pollution Reduction Air pollution coming from coal-burning power plants can be reduced by catching the most toxic pollutants coming out of the smokestacks. However, these methods are expensive, and so companies are reluctant to resort to them. Resource Management Resource Management? Since coal is so common on Earth, we will not run out of it in the near future. However, in a few hundred years' time, we will be grateful we did. Also, we should ration our use because of the pollution it creates. Efficiency Increase
Pollution Reduction If we can increase the amount of energy we get from a certain amount of coal, even a small increase will be huge in the long run.
Pollution control on smokestacks is already a reality, but stricter laws on power plant pollution could help keep the environment clean and people healthy. Use Less If we use less electricity, we can use less coal. Also, using many different alternatives in addition to coal will help extend our supply of coal.
Using less can lead to less health problems and environmental degradation, too. Natural Gas Nuclear Process Extraction There are some naturally occurring radioactive elements in the Earth's lithosphere. Uranium -235 and plutonium-239 are mined for fuel, but only a small amount per amount of waste soil is obtained. However, these can last very long as fuel and a little uranium or plutonium can produce a lot of energy. Enrichment Some of the plutonium or uranium molecules are then enriched into a more readily reactive isotope. Only about 3% of the fuel in the reactor is this enriched uranium or plutonium. Reaction The fuel is then used in the reactor to heat water used to drive a turbine, producing electricity. However, in a nuclear power plant, a first closed system cools the reactor core where the fuel reacts, and a second system takes that heat to drive the turbine. This increases safety. Types Reactors are categorized based on what they use to regulate the nuclear reaction and to transfer heat out of the system. A boiling water reactor (BWR) for instance, boils water in the reaction chamber, while a pressurized water reactor uses pressurized water to transfer heat, a safer approach. Graphite-moderated reactors use graphite to transfer energy and keep the fuel rods safe. Disposal Once the fuel has been used for a few years, it is stored on-site in a containment pool of water to cool. The spent fuel rods are then transferred to storage containers of steel or concrete. Plans have been made to store spent fuel safely in vaults or underground, but no such methods have been implemented so far. Advantages Clean Uranium is mined in the same way as any metal, but some additional techniques can cause far less environmental impact than traditional surface or pit mining. Also, nuclear energy uses less land, and causes less pollution than oil or coal . Air Pollution/Waste Nuclear power plants release some radioactive gases/particles, but these are in miniscule amounts that have less effect on health and the environment than those naturally in the environment. Also, the whole process emits one-sixth the amount of CO2 as coal power. However, solid waste from reactors is produced, which in not insignificant in amount and is susceptible to terrorism. Mining Pollution If pit mining or in-situ leaching is used to obtain the uranium for the reactors, the environmental effects can be minimized. Even using conventional mining techniques, the degradation of land is much less than with coal or oil. However, nuclear does use a lot of water, not only to mine, but also to refine and use as a source of power. Land Not only does the mining of uranium use less land than mining coal, nuclear power plants can be placed in rural areas that are already disturbed, as opposed to renewable sources of energy, which must be close to the source. Supply There is an incredibly large supply of uranium and plutonium in the earth's crust, and it is relatively easy to get to these deposits. According to Scientific American, the economically accessible uranium deposits could last us at least 200 years. That is not even accounting for new mining and reactor technologies. Safe Despite the bad press on nuclear power's risk of dangerous meltdowns, the actual risk is very low. There are many layers of protection between a meltdown and the outside world. The coolant pumps run on separate generators, and can pull water from surrounding lakes or rivers. Besides, the reactor is inside a shielded container inside a larger concrete containment building. Only 15 reactors in the world are high-risk, because they are built similar to Chernoblyl. Disadvantages Expensive The advanced safety features of nuclear energy come at a cost. Nuclear is much more expensive for the amount of energy than other energy sources. Also, nuclear doesn't have the massive subsidies that coal and oil do, so it cannot even compete on the scale other sources of energy do. Inefficient Nuclear power has a very low net energy yield. This means that of the energy put into the process -- gas used in trucks and machinery, and other energy in other steps of the process -- is only slightly higher than the energy coming out of the plant as electricity. In fact, it takes more energy to produce nuclear power than is received out of it. Dangerous Though the risk from nuclear meltdowns is low, there is still a risk. Also, when a big meltdown does happen, it can be catastrophic, such as what happened at Three Mile Island, Fukushima, and Chernobyl. In addition to this, terrorist attacks and sabotage can lead to big disasters and meltdowns. For example, a virus in a computer in a uranium refinery almost caused one of the centrifuges to spin out of control, and could have caused a meltdown or explosion if it wasn't stopped in time. Dangerous
(Cont.) If a meltdown or other catastrophic event occurs at a reactor, it can cause mayhem for the environment. They harm living things within the area, but not only that, can get into wind and water and spread. They damage all types of tissue and can turn an area into a ghost town. Disposal Once Uranium is "used up", it is still radioactive, but no longer useful and must be stored safely for thousands of years until it is safe. This, as you can imagine, is a bit of a dilemma. There is no widely accepted way of storing radioactive waste for the long time necessary, and also no accepted way of decommissioning old plants. Resource Management Tech New technology, specifically in the enrichment process and reactor technology, could drastically increase the amount of energy we can get from our uranium reserves. Also, research into reusing depleted uranium could increase our supplies. Alternatives Nuclear power could be a great source of power in the future, but it would have to be supplemented by other sources. The inefficiency of nuclear puts it in the category of a secondary source, a source that can produce power when other sources cannot. Its cleanliness also makes it suitable for a world of more renewable, cleaner energy. Fusion Nuclear fusion works by building bigger molecules instead of breaking down unstable ones. It works by the same process as the sun, and fuses two hydrogen molecules to make a helium. However, no research has been able to recreate this in such a way that more energy comes out of the system than is needed to regulate the atoms colliding, so it isn't ready yet. Process Formation Natural gas is a mix of methane, ethane, propane, and hydrogen sulfide that forms in gaseous form along with crude oil. It can be extracted with crude oil, but needs different machinery and a specific pipeline. Instead, it is often burned away when the oil is extracted. Extraction Natural gas deposits lie above the oil deposits, which float above the water. When natural gas is exploited, it is pumped out much like oil, but a gas. the heavier hydrocarbons, the butane, propane, and ethane are liquefied and shipped in liquid form, while the methane is processed to remove the hydrogen sulfide. Power Production Natural gas can be burned just like oil, and burns much cleaner than oil or coal. However, most of it is not used to create electricity. Most of it is used to heat homes. Since it has twice the efficiency of coal or nuclear, and since it burns with much less CO2 than oil or coal, it is being used increasingly in electricity production. Power Plants A natural gas power plant works pretty much the same as does a coal, oil, or even nuclear plant. The gas is burned, boiling water which is used to power a steam turbine. Advantages Clean When burned, natural gas releases less greenhouse gases such as CO2, and also less pollution over all than coal or oil. This is very appealing when looking for clean sources of energy, which the U.S. and a lot of the world is. Energy Yield
and Cost Natural gas has a very high energy yield, and produces much more energy than is needed to get at the natural gas. It has the highest energy yield in transportation, and is surpassed in space heating only by passive solar heating (which will be discussed later). This efficiency makes it rather cheap, especially with the subsidies that the government places on it. Plentiful There is a lot of natural gas in the world, an estimated 125 year supply. That could last us a very long time, especially if we ration it and don't waste. However, there is a lot of natural gas wasted in today's economy because coal is so much more profitable. Uses Natural gas can not only be used to produce energy, but also to heat homes, to cook, and to be used in fuel cells, and even to power cars. Cheap modifications can be done to a car to make it run on clean, cheap natural gas, which can be piped to your home. Disadvantages Greenhouse
Gases Natural gas doesn't release a lot of pollutants, but it still releases a significant amount of CO2 when burned. Also, defective pipelines can leak out methane, which is a VERY potent greenhouse gas. Nonrenewable Despite its cleanliness and ample supply, natural gas is still the product of long-dead organisms, and is nonrenewable. When we use up our stores of natural gas or any nonrenewable resource, there will be no more for us. This is why we must find other sources and ration our usage. Wasted Because natural gas is not used as much today as oil or even coal, some companies who extract oil and must first get through the layer of natural gas above oil burn off the natural gas. This is what we see when we think of oil rigs, and it is extremely wasteful. That natural gas could have heated many homes, but instead, it's just wasted pollution. This happens a lot more than it should. Transportation Natural gas is tough to transport. Pipelines must be built to distribute it. To transport it long distances, it is converted to liquid natural gas, which can have dangerous explosions. All this decreases the usability of natural gas. Resource Management Tech Using natural gas in other technologies could conserve other sources of energy for where they are needed most. Also, it could increase the efficiency of natural gas, and decrease the danger of it. Don't Waste The biggest thing we can do to utilize the natural gas stores we have while still conserving it for future generations is to not waste it. Companies should pipe out natural gas as a promising commodity, instead of burn it off as a useless commodity. Conservation If we simply use less natural gas, either by using less energy or by using other resources, we can make it last longer and, if the alternate sources of energy we use are clean, we can reduce the strain on the environment. Renewable Resources Hydro Process Overview The sun powers most of the systems on Earth, including the water cycle. There is an extreme amount of energy in the movement of water over the surface of Earth, and it can be captured in a few ways. Dams Hydroelectric dams are built in rivers, creating a massive reservoir behind them, and they feed on the potential energy of all that stored water, running it through turbines into the river below. This technology is widely accepted and provides a large amount of the world's power, but there are some drawbacks. Tidal Energy The open ocean and other "still" bodies of water aren't so still, and waves can be very energetic. Many methods of obtaining energy from waves have been proposed and used, from floating buoys to underwater wind turbines. Also proposed is using the conduction currents of the ocean to drive turbines within a column of water. However, wave technology is not widely accepted or used, and only a few wave farms exist worldwide. Power Transportation It is problematic to transfer all the electricity produced with wave power from off the coast to where it is needed, and is the biggest hurdle to develop wave power. Hydroelectric dams don't have this problem, but they have other, more difficult problems. Hydro-dams Advantages Wave Power Resource Management Tech Advances in technology could reduce the degradation of habitat and agriculture by hydroelectric dams. Government New policies could lead to a more widespread usage of wave power, and less removal of people from their land to make dams. Shifting Focus We should change from big dam projects which cause a lot of habitat destruction, to more smaller dams, and less invasive dams. Also, we should phase more wave power into use. Solar Process Solar Farms A solar farm is a power producing plant made of either a bunch of mirrors pointing at a tower to melt salt and turn a turbine, a bunch of mirror troughs that concentrate sunlight on a tube of water, or a field of photovoltaic panels. Solar Water-Heater In a solar water-heater, water is run through pipes in a panel in the sun so they soak up heat from sunlight. That water is then used for household tasks, or to heat the house. Passive Solar Heating Passive heating is based on the concept of letting the sun heat the house when it is needed, and letting air or the earth cool the house when it is too hot. One way is to let sun in in the winter, when it is low in the sky, and to block the sun in the summer, when it is high. Another is to use a greenhouse and a series of vents to heat/cool the house. Another idea is to use the Earth to regulate the temperature of the house throughout the seasons. Advantages Efficient Solar, has a relatively high net-energy. The most efficient way to use solar energy is on an individual basis, such as passive and active solar heating for houses, and photovoltaic roofs. There is an infinite supply of heat and light from the sun, so it is a great long-term source of energy to take advantage of. Renewable Solar doesn't release any greenhouse gases (besides producing the technology), and has an overall low habitat displacement. However, large solar farms could degrade the deserts where they are placed. Environment Solar could eliminate our dependence on fossil fuels for energy. This would be a great leap forward in our sustainability and the cleanliness of our environment. Fossil Fuels Disadvantages Cost Some solar technology is rather expensive. For example, photovoltaics are still a little expensive for homeowners. Also, solar farms are expensive to set up. Needs Sun Solar technology is nothing without the sun. In places where there is not enough sun, solar would not be viable, and other sources of energy would be needed to fill the gap. Land Use Solar farms and any solar power for mass production of energy would take up a lot of space, and could displace people, agriculture, or habitat. Resource Management Renewable Since solar energy comes from the sun, it is constantly replenished, and fuels all life on Earth. We can use as much as we want without fear of it running out, but we must be careful not to harm the Earth's natural systems in the process of obtaining this huge source of energy. Geothermal Biomass Process Sources Biomass fuel can be made out of specially grown crops, wood, crop wastes, or animal manure. Advantages Cheap Because of the nature of biomass. It is relatively inexpensive to either collect waste biomass or grow crops for production of biomass. Clean If the biomass is harvested and used sustainably, no more CO2 will escape into the atmosphere than was captured by the plants. This makes it carbon nuetral. Sustainability/
Supply Since so much plant life thrives on Earth, there is a large amount of biomass that we can grow. Biomass can last us forever as an energy source, because plants grow back, as long as we don't overuse what the ground can grow. Disadvantages Unsustainable? If the biomass is harvested unsustainably, then we could run out, and it would release excess CO2 into the atmosphere. Environment Biomass plantations could deplete the soil of the area, produce runoff and erosion, and many other effects of agriculture. The effects of cutting trees from pre-existing forests or other vegetation removal could be even worse, especially if they are unsustainable. Competition Biomass plantations could compete for space with farms, leading to one of a few possible outcomes. Either, plantations gain more land and we suffer food shortages, farms win and we have less energy from biomass, or wilderness areas are cleared for both and all kinds of terrible effects happen. Burning Biomass is often burned on open fires or in inefficient stoves. These can pollute and release more CO2 and soot than more efficient ones. Resource Management Sustainability Producing biomass sustainably means only taking as much as can be replenished by natural processes or by farming methods that are not harmful to the environment. This would make biomass energy last virtually forever. Efficiency If we can improve the efficiency of the process, we will need less biomass material overall. This can be done by increasing the efficiency of biomass generators, engineering more efficient plants, and using other sources of biomass to supplement plantations. Plant It would be optimal to the sustainability of biomass energy to not obtain biomass from forests and other wilderness areas, but if we did, it would have to be removed in such a way that it didn't disturb the area, and that it would grow back before we harvested more. This would also lead to biomass being sustainable. Process Overview There is a lot of heat energy in the earth's crust. It comes from magma, radioactive particles, and the sun. Geothermal energy takes advantage of this, and uses the heat to create electricity and heat homes. Commercial In geothermal plants, water heated by the Earth's interior is taken in by pipes, and is either transfered to heat buildings or to turn turbines, creating electricity. Domestic Systems are available that use the subsurface heat of the ground to regulate the temperature of a house or other building. Water or coolant is pumped through pipes underground, collecting heat from the ground and bringing it to the house. It works the opposite way to expel heat from the house in winter. Advantages Clean Commercial geothermal releases very little CO2, and domestic geothermal releases no CO2. They both use and disturb very little land. Renewable Domestic geothermal energy is literally endless, and commercial geothermal is renewable if the water in a hot aquifer is not all used at once. Cheap/
Efficient If they are situated at good sites, geothermal plants can have a moderate net energy, and be relatively cheap. Disadvantages Rare There are not many sites in the world that have enough geologic activity to support geothermal energy, at least not economically. Depletable Commercial geothermal can be depleted if the aquifer of hot water is used up faster than the cold water pumped down can be heated up. This means that that site is no longer viable, and must be left. Pollution Commercial geothermal operations still pollute and emit CO2, and are not as quite as clean as solar or wind. Resource Management Use Sparingly Commercial geothermal is only useful at certain sites, and domestic geothermal is only useful for small to medium buildings. If we keep it to that, it will be fine. Small Small, domestic geothermal systems are both economically and ecologically sound. They are efficient, and pay for themselves. If more homes used them, we could increase our sustainability. Conservation If commercial sites don't use up the aquifers that feed them, then they won't run out, and geothermal can provide steady power for years to come. How it Works The reservoir stores water for the dam, which is directed through the penstock and through the turbine. The turbine turns, generating electricity. The water is released through the output to the river. How it Works With buoys, the up-and-down power of the waves runs the electric generator in the buoy, creating electricity. This is only made useful by the numbers of buoys, anchored offshore in "wave farms". Other Ways for Waves Other methods of capturing wave power have been thought up, including a turbine powered by the waves compressing air through a turbine and turbines powered simply by the back-and-forth flow of water. Wave Power Disadvantages Long-Lived Hydroelectric dams can last for a long time, and in this time need little maintenance. Cheap Dams are a cheap source of energy. Once the dam itself is built, the amount of money needed to exploit the hydroelectric power is very low. Efficient Dams have a high net energy gain, and are very efficient. It takes quite a bit of energy to build a dam, but not much to run it. Clean Hydroelectric power doesn't produce as much greenhouse gases in most cases as nonrenewables. However, the reservoirs of some dams can produce methane. Flood Control Dams can block a lot of flooding that travels downriver, saving people from losing their properties. Recreation/Agriculture The reservoir of a hydroelectric project can provide areas for fishing and boating, as well as important water to allow agriculture to flourish in the area. Costs It is very expensive to build a hydroelectric dam, and requires a lot of materials and labor. Money is made up in the end because of its cheap electricity, but money must be put into the project upfront. Habitat Flooding the area behind the dam to make a reservoir destroys that habitat, displacing many species. It also makes it harder for fish to get through the dam. Emissions In tropical areas, plants and other organisms will decay in the reservoir, releasing vast amounts of CO2 and often methane. These greenhouse gases can add strain on the environment. People Dam projects move people away from an area just as they provide opportunities to move to it. To produce the reservoir for a dam, often many families will be displaced, sometimes without compensation. Nutrient Flow Just as dams provide water for agriculture, they stop silt and nutrients which are very important to farming from flowing downriver. This can also create a load of sediment within the reservoir, causing problems there as well. Collapse If there's a flood, if there's an earthquake, or for no reason at all, a dam may collapse. That would be devastating for the land downriver, as a massive wave of water washes everything away. Advantages Disadvantages Bountiful There is a lot of potential energy in the waves of the ocean, so there is great potential for future energy there. Clean Wave power doesn't produce any greenhouse gases besides the waste in the production of the buoys or other generators. This makes it among the cleanest of all the sources of energy. Safe Wave power has a great potential to be safe for wildlife. It doesn't displace land, and also doesn't cause harm to plants or animals. Expensive Because it is such a new technology, and because it isn't widely used, wave power generators (buoys, turbines, etc.) are much more expensive per unit of energy than other sources. New Wave power is still a relatively new technology, and is untried. This means that the major industries don't exactly trust it to deliver as much energy safely as other sources of energy. There are quite a few ways of utilizing the sun's direct energy. These include photovoltaic cells, solar "farms", solar water heaters, and passive solar heating. Overview Photovoltaics A photovoltaic panel consists of many wafers of silicon. Light causes electrons to travel between those wafers, creating an electrical current. Enough of these together can create a considerable amount of energy. Storage Solar can obtain energy during the day, but no viable way has been put into practice to store that energy during the night or when there is less sun than can power enough homes. New Solar has been around for a while, but it is not as tried-and-true as coal or oil, and companies are not as willing to try it as they are to fall back on these old nonrenewables. Wind Process Wind Turbines The wind turbine itself is very simple. It is a pinwheel on a stick, and the pinwheel turns an electric generator. This produces electricity when the wind blows, which is sent through the cable. A gearbox makes sure the generator is getting the most power for how fast the blades are turning. Alternatives: Offshore To avoid using land, and to take advantage of the steady offshore wind currents, some plans have been made for offshore wind farms. However, they have not yet become feasible because of complaints from cities for loss of view, and the bigger problem of sky-high installation and maintenance costs. Maybe later, guys. Advantages Clean Wind is very clean, and has a very small footprint. It only disturbs the small piece of land where the pole touches the ground, and produces no emissions. There is an infinite supply of wind energy, so it will last us when all the nonrenewables have been phased out. Renewable Wind is safe, which lets it get permits a lot faster than coal, nuclear, gas, or oil factories. This makes it possible to shut down polluting plants faster. Fast Setup The land beneath wind turbines can be used for farming, or any other activity, since it is not disrupted. Land Use Disadvantages Birds Wind turbines can interfere with the paths of migratory birds, and kill 40,000 birds a year. However, this is miniscule in comparison to the 100 million birds housecats in the US kill each year. Also, new turbines reduce bird fatalities. Land Use Solar farms and any solar power for mass production of energy would take up a lot of space, and could displace people, agriculture, or habitat. Resource Management Review Wind energy is a promising, renewable, clean energy source that could be used a lot all over the world. However, it has some fundamental drawbacks that require it to be supplemented with other sources. Our future could have a lot of wind power, but not all. Backup/Storage When the wind isn't blowing, backup energy sources are needed to fill out energy needs. Also, we should have a way to store the exscess energy. Overview The winds of Earth are also powered by the sun, making wind power indirectly powered by the sun. The main way, as of yet, of capturing the wind's energy is wind turbines. These turbines are placed in groups called wind farms. Alternatives: Smaller To avoid the loss of much of the electricity from wind farms that happens on the way to people's home, some people have installed wind turbines at their own homes. This is a great idea, as it reduces waste, and if enough people do it, it could reduce the need for energy in the first place. Wind Farms The main way that wind turbines are utilized is in vast arrays, often in farming land. This very efficient, and can take advantage of steady windy areas. Also, it barely disrupts the area. This produces the most amount of energy for a least amount of area for all wind technology. Consumption The biomass is then either burned as is, or fermented to produce ethanol, biodiesel, or methanol. These are burned for energy, or are used to power cars. Biofuels Crops grown for biomass can be fermented, much like beer or wine, and are then either used as high-grade fuel, or used to power vehicles and equipment. Use Biofuel is burned for domestic heat, for electricity, or for cooking. For electricity, it is burned in power plants that are almost identical to those used for coal and oil.