To generate biodiesel, the raw oil is subjected to a process called �transesterification.� This refining method uses of an industrial alcohol (ethanol or methanol) and a catalyst (substance that speeds up the chemical reaction) resulting to a conversion of the oil into a fatty-acid methyl-ester fuel (biodiesel).
It can be utilized in single pure form however it may require engine alterations to avoid maintenance and performance troubles. It is most commonly mixed with conventional petroleum diesel fuel at any level to reduce detrimental automobile emissions. When biodiesel is combined with petroleum diesel, it brings in a fuel that is compatible with diesel engines, reduce imported petroleum needs and decrease toxic emissions. A combination of 20% bio- and 80%- conventional diesel will greatly lessen carcinogenic emissions and gases which can worsen global warming. Lower-level biodiesel blends, such as 2% bio- and 98% diesel or 5% bio- and 95% diesel, are turning out to be increasingly common and widely used by the public as they become more aware of the many benefits.
Definition
Biodiesel is a renewable fuel made from farm products such as vegetable or animal oils, fats, or recycled cooking greases. Almost all biodiesels are derived from soybean oil; however sunflower oil, canola oil, recycled vegetable oils, and animal fats can also be used in the United States. A Safe and Clean Fuel
� Cleaner Emissions � The use of biodiesel lessens greenhouse emissions because carbon dioxide that is released from the combustion of biodiesel is neutralize by the carbon dioxide utilized while growing the feedstock.
� Non-hazardous � In terms of toxicity, biodiesel is the best alternative that has proven to be safe and not harmful to the environment. Various tests verified that biodiesel is biodegradable and nontoxic that poses no threat to human health.
� Simple � The automobile need not any complex modification or conversion. The biodiesel can be readily blended with conventional petroleum diesel in your fuel tank at any point in time.
� Renewable � Biodiesel is derived from 85% vegetable or animal oils/fats which are renewable sources.
� Sustainable � Aside from it biodegradability, biodiesel is also renewable in contrast to scarce fossil fuel use which is formed from the remnants of animals and plants that have lain in the earth for millions of years.
� Nonflammable � In contrast to gasoline which ignites immediately at any lower temperature, biodiesel will only ignite at a very high temperature.
� Appropriate for Your Engine � A number of tests reveal that biodiesel is more lubricating than any conventional diesel to both the fuel injection pump and engine.
� Available � Currently in the United States, there are roughly 600 fleets that use biodiesel blends in their diesel engines. Moreover, various blends of biodiesel at approximately 800 areas are available nationwide.
� Affordable � The geographic area, base organic material (soybean, corn, etc) and supplier will greatly determine the price of biodiesel. It varies depending on the said determinants. It does not also require purchasing new vehicles to shift from conventional diesel to biodiesel. On the side of the fleets, acquisitions of new spare parts supply or rebuilding stations need not to be done by the manager.
The term "biomass" refers to organic matter that has stored energy through the process of photosynthesis. It exists in one form as plants and may be transferred through the food chain to animals' bodies and their wastes, all of which can be converted for everyday human use through processes such as combustion, which releases the carbon dioxide stored in the plant material. Many of the biomass fuels used today come in the form of wood products, dried vegetation, crop residues, and aquatic plants. Biomass has become one of the most commonly used renewable sources of energy in the last two decades, second only to hydropower in the generation of electricity. It is such a widely utilized source of energy, probably due to its low cost and indigenous nature, that it accounts for almost 15% of the world's total energy supply and as much as 35% in developing countries, mostly for cooking and heating.
Biomass is one of the most plentiful and well-utilised sources of renewable energy in the world. Broadly speaking, it is organic material produced by the photosynthesis of light. The chemical material (organic compounds of carbons) are stored and can then be used to generate energy. The most common biomass used for energy is wood from trees. Wood has been used by humans for producing energy for heating and cooking for a very long time.
Biomass has been converted by partial-pyrolisis to charcoal for thousands of years. Charcoal, in turn has been used for forging metals and for light industry for millenia. Both wood and charcoal formed part of the backbone of the early Industrial Revolution (much northern England, Scotland and Ireland were deforested to produce charcoal) prior to the discovery of coal for energy. Wood is still used extensively for energy in both household situations, and in industry, particularly in the timber, paper and pulp and other forestry-related industries. Woody biomass accounts for over 10% of the primary energy consumed in Austria, and it accounts for much more of the primary energy consumed in most of the developing world, primarily for cooking and space heating.
It is used to raise steam, which, in turn, is used as a by-product to generate electricity. Considerable research and development work is currently underway to develop smaller gasifiers that would produce electricity on a small-scale. For the moment, however, biomass is used for off-grid electricity generation, but almost exclusively on a large-, industrial-scale.
Biomass, Defining green or environmentally sustainable biomass-generated electricity has proved difficult and contentious. Biomass can be so broadly defined to include unsustainably harvested forest timber, contaminated waste wood, municipal solid waste, and tires. Some definitions include landfill gas, while some do not. Environmental groups are pushing for a more narrow definition of biomass green power which excludes burning garbage and limits biomass to sources such as forest-related harvesting residue, landscaping and right-of-way trimmings, and agricultural crops and crop by-products. Additionally, biomass must be burned cleanly to be green, and this is not a given. Burning landfill gas is viewed by environmentalists as an environmentally sound practice, but many object to characterizing it as biomass energy.
Landfill Gas, Landfills produce methane gas which is a powerful greenhouse gas if vented un-burnt to the atmosphere. While burning landfill methane gas is not pollution-free, it is much better to burn it than vent it. Burning landfill gas to produce electricity also reduces fossil fuel use, another plus.
There are two issues that affect the evaluation of biomass as a viable solution to our energy problem: the effects of the farming and production of biomass and the effects of the factory conversion of biomass into usable energy or electricity. There are as many environmental and economic benefits as there are detriments to each issue, which presents a difficult challenge in evaluating the potential success of biomass as an alternative fuel. For instance, the replacement of coal by biomass could result in "a considerable reduction in net carbon dioxide emissions that contribute to the greenhouse effect." On the other hand, the use of wood and other plant material for fuel may mean deforestation. We are all aware of the problems associated with denuding forests, and widespread clear cutting can lead to groundwater contamination and irreversible erosion patterns that could literally change the structure of the world ecology.
Biomass has to be considered in the search for an alternative source of energy that is abundant in a wide-scale yet non-disruptive manner, since it is capable of being implemented at all levels of society. Although tree plantations have "considerable promise" in supplying an energy source, "actual commercial use of plantation-grown fuels for power generation is limited to a few isolated experiences." Supplying the United States ' current energy needs would require an area of one million square miles. That's roughly one-third of the area of the 48 contiguous states. There is no way that plantations could be implemented at this scale, not to mention that soil exhaustion would eventually occur. Biomass cannot replace our current dependence on coal, oil, and natural gas, but it can complement other renewables such as solar and wind energy.
According to Flavin and Lenssen of the Worldwatch Institute , "If the contribution of biomass to the world energy economy is to grow, technological innovations will be needed, so that biomass can be converted to usable energy in ways that are more efficient, less polluting, and at least as economical as today's practices." When we have enough government support and have allotted enough land for the continuous growth of energy crops for biomass-based energy, we may have a successful form of alternative energy. But "as long as worldwide prices of coal, oil and gas are relatively low, the establishment of plantations dedicated to supplying electric power or other higher forms of energy will occur only where financial subsidies or incentives exist or where other sources of energy are not available." Although it is currently utilized across the globe, biomass energy is clearly not capable of sustaining the world's energy needs on its own.
Geothermal energy is defined as heat from the Earth. It is a clean, renewable resource that provides energy in the U.S. and around the world in a variety of applications and resources. Although areas with telltale signs like hot springs are more obvious and are often the first places geothermal resources are used, the heat of the earth is available everywhere, and we are learning to use it in a broader diversity of circumstances. It is considered a renewable resource because the heat emanating from the interior of the Earth is essentially limitless. The heat continuously flowing from the Earth�s interior, which travels primarily by conduction, is estimated to be equivalent to 42 million megawatts (MW) of power, and is expected to remain so for billions of years to come, ensuring an inexhaustible supply of energy. (1) Figure 2: The Formation of a Geothermal Reservoir
A geothermal system requires heat, permeability, and water. The heat from the Earth's core continuously flows outward. Sometimes the heat, as magma, reaches the surface as lava, but it usually remains below the Earth's crust, heating nearby rock and water � sometimes to levels as hot as 700�F. When water is heated by the earth�s heat, hot water or steam can be trapped in permeable and porous rocks under a layer of impermeable rock and a geothermal reservoir can form. This hot geothermal water can manifest itself on the surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock. This natural collection of hot water is called a geothermal reservoir.
Figure 3: Typical Direct Use Geothermal Heating System Configuration
1.3. What are the different ways in which geothermal energy can be used?
Geothermal energy can be used for electricity production, for commercial, industrial, and residential direct heating purposes, and for efficient home heating and cooling through geothermal heat pumps. For a video presentation on the different ways to use geothermal energy, visit http://geothermal.marin.org/video/vid_pt5.html.
Geothermal Electricity: To develop electricity from geothermal resources, wells are drilled into a geothermal reservoir. The wells bring the geothermal water to the surface, where its heat energy is converted into electricity at a geothermal power plant (see below for more information about the different types of geothermal electricity production).
Heating Uses: Geothermal heat is used directly, without involving a power plant or a heat pump, for a variety of applications such as space heating and cooling, food preparation, hot spring bathing and spas (balneology), agriculture, aquaculture, greenhouses, and industrial processes. Uses for heating and bathing are traced back to ancient Roman times. (2) Currently, geothermal is used for direct heating purposes at sites across the United States. U.S. installed capacity of direct use systems totals 470 MW or enough to heat 40,000 average-sized houses, according to the GeoHeat Center Web site, http://geoheat.oit.edu/.
The Romans used geothermal water to treat eye and skin disease and, at Pompeii, to heat buildings. Medieval wars were even fought over lands with hot springs. The first known "health spa" was established in 1326 in Belgium at natural hot springs. And for hundreds of years, Tuscany in Central Italy has produced vegetables in the winter from fields heated by natural steam. (See the Geothermal Education Office Web site, http://geothermal.marin.org/).
A few examples of geothermal direct use applications today are at the Idaho Capitol Building in Boise http://idptv.state.id.us/buildingbig/buildings/idcapital.html, Burgett Geothermal Greenhouses in Cotton City, New Mexico http://geoheat.oit.edu/directuse/all/dug0144.htm, and Roosevelt Warm Springs Institute for Rehab in Warm Springs, Georgia http://www.rooseveltrehab.org/index.php
Figure 4: Geothermal Heat Pump Diagram
Geothermal Heat Pumps (GHPs): Geothermal heat pumps take advantage of the Earth�s relatively constant temperature at depths of about 10 ft to 300 ft. GHPs can be used almost everywhere in the world, as they do not share the requirements of fractured rock and water as are needed for a conventional geothermal reservoir. GHPs circulate water or other liquids through pipes buried in a continuous loop, either horizontally or vertically, under a landscaped area, parking lot, or any number of areas around the building. The Environmental Protection Agency considers them to be one of the most efficient heating and cooling systems available.
Animals burrow underground for warmth in the winter and to escape the heat of the summer. The same idea is applied to GHPs, which provide both heating and cooling solutions. To supply heat, the system pulls heat from the Earth through the loop and distributes it through a conventional duct system. For cooling, the process is reversed; the system extracts heat from the building and moves it back into the earth loop. It can also direct the heat to a hot water tank, providing another advantage � free hot water. GHPs reduce electricity use 30�60% compared with traditional heating and cooling systems, because the electricity which powers them is used only to collect, concentrate, and deliver heat, not to produce it. For more information about GHPs, please visit www.geoexchange.org and http://www.igshpa.okstate.edu.
Figure 5: Flash Power Plant Diagram
1.4. How does a geothermal power plant work?
There are four commercial types of geothermal power plants: a. flash power plants, b. dry steam power plants, c. binary power plants, and d. flash/binary combined power plants.
a. Flash Power Plant: Geothermally heated water under pressure is separated in a surface vessel (called a steam separator) into steam and hot water (called �brine� in the accompanying image). The steam is delivered to the turbine, and the turbine powers a generator. The liquid is injected back into the reservoir.
Figure 6: Dixie Valley, NV, Flash Plant
b. Dry Steam Power Plant: Steam is produced directly from the geothermal reservoir to run the turbines that power the generator, and no separation is necessary because wells only produce steam. The image below is a more simplified version of the process.
Figure 7: The Geysers, CA, Dry Steam Plant
Figure 8: Dry Steam Plant Diagram
c. Binary Power Plant: Recent advances in geothermal technology have made possible the economic production of electricity from geothermal resources lower than 150�C (302�F). Known as binary geothermal plants, the facilities that make this possible reduce geothermal energy�s already low emission rate to zero. Binary plants typically use an Organic Rankine Cycle system. The geothermal water (called �geothermal fluid� in the accompanying image) heats another liquid, such as isobutane or other organic fluids such as pentafluoropropane, which boils at a lower temperature than water. The two liquids are kept completely separate through the use of a heat exchanger, which transfers the heat energy from the geothermal water to the working fluid. The secondary fluid expands into gaseous vapor. The force of the expanding vapor, like steam, turns the turbines that power the generators. All of the produced geothermal water is injected back into the reservoir.
Figure 9: Binary Power Plant
Figure 10: Burdett, NV, Binary Power Plant
d. Flash/Binary Combined Cycle: This type of plant, which uses a combination of flash and binary technology, has been used effectively to take advantage of the benefits of both technologies. In this type of plant, the portion of the geothermal water which �flashes� to steam under reduced pressure is first converted to electricity with a backpressure steam turbine and the low-pressure steam exiting the backpressure turbine is condensed in a binary system.
Figure 11: Flash/Binary Power Plant Diagram
Figure 12: Puna, HI, Flash/Binary
For more information about the above four types of power plants, access GEA�s Environmental Guide or Surface Technology Report.
In addition to different power plant technologies in use today, additional applications and technologies continue to emerge. The following are some commonly discussed as areas of future development:
Enhanced Geothermal Systems (EGS): Although the deeper crust and interior of the Earth is universally hot, it lacks two of the three ingredients required for a naturally occurring geothermal reservoir: water and interconnected open volume for water movement. Producing electricity from this naturally occurring hot, but relatively dry rock requires enhancing the potential reservoir by fracturing, pumping water into and out of the hot rock, and directing the hot water to a geothermal power plant. Research applications of this technology are being pursued in the U.S., France, Australia, and elsewhere. (3) EGS is also sometimes referred to as Hot Dry Rock. See further discussion of EGS in section 3.2.
Mixed Working Fluid/ Kalina System: As of January 2009 the Kalina System was being used at two power plants. The first is a small demonstration power plant operated as part of Iceland's Husavik GeoHeat Project. The second plant to use the Kalina System is in Germany at the Unterhaching Power Station. The Kalina cycle uses an ammonia-water mixed working fluid for high efficiency. The Kalina cycle is only one of the possible mixed working fluid approaches to possibly achieving greater heat transfer efficiency and/or lower temperature production of power. (4)
Figure 13: Kalina Power Plant in Husavik, Iceland
Distributed Generation: Geothermal applications can be sized and constructed at geographically remote sites in order to meet on-site electricity demands. Examples of remote geothermal power systems are at Chena Hot Springs in Alaska and at the Rocky Mountain Oil and Gas Testing Center (RMOTC) in Wyoming. In the first, the unit powers a remote resort, in the second the power supplies electricity to operate an oil field. For more information about the Chena Hot Springs Project, visit http://www.geo-energy.org/plantdetails.aspx?id=46x. For more information about the RMOTC project, visit http://www.rmotc.doe.gov/.
Supercritical Cycles : Supercritical fluids are at a temperature and pressure that can diffuse through solids. A supercritical fluid such as carbon dioxide can be pumped into an underground formation to fracture the rock, thus creating a reservoir for geothermal energy production and heat transport. The supercritical fluid used to form the reservoir can heat up and expand, and is then pumped out of the reservoir to transfer the heat to a surface power plant or other application. An example of work in this area is the Iceland Deep Drilling Project, and for more information on this effort visit http://www.iddp.is.
Introduction Heat from the earth can be used as an energy source in many ways, from large and complex power stations to small and relatively simple pumping systems. This heat energy, known as geothermal energy, can be found almost anywhere�as far away as remote deep wells in Indonesia and as close as the dirt in our backyards. Many regions of the world are already tapping geothermal energy as an affordable and sustainable solution to reducing dependence on fossil fuels, and the global warming and public health risks that result from their use. For example, more than 8,900 megawatts (MW) of large, utility-scale geothermal capacity in 24 countries now produce enough electricity to meet the annual needs of nearly 12 million typical U.S. households (GEA 2008a). Geothermal plants produce 25 percent or more of electricity in the Philippines, Iceland, and El Salvador. The United States has more geothermal capacity than any other country, with more than 3,000 megawatts in eight states. Eighty percent of this capacity is in California, where more than 40 geothermal plants provide nearly 5 percent of the state�s electricity.1 In thousands of homes and buildings across the United States, geothermal heat pumps also use the steady temperatures just underground to heat and cool buildings, cleanly and inexpensively.
The Geothermal Resource Below the Earth's crust, there is a layer of hot and molten rock called magma. Heat is continually produced there, mostly from the decay of naturally radioactive materials such as uranium and potassium. The amount of heat within 10,000 meters (about 33,000 feet) of Earth's surface contains 50,000 times more energy than all the oil and natural gas resources in the world.
The areas with the highest underground temperatures are in regions with active or geologically young volcanoes. These "hot spots" occur at plate boundaries or at places where the crust is thin enough to let the heat through. The Pacific Rim, often called the Ring of Fire for its many volcanoes, has many hot spots, including some in Alaska, California, and Oregon. Nevada has hundreds of hot spots, covering much of the northern part of the state. These regions are also seismically active. Earthquakes and magma movement break up the rock covering, allowing water to circulate. As the water rises to the surface, natural hot springs and geysers occur, such as Old Faithful at Yellowstone National Park. The water in these systems can be more than 200�C (430�F).
Seismically active hotspots are not the only places where geothermal energy can be found. There is a steady supply of milder heat�useful for direct heating purposes�at depths of anywhere from 10 to a few hundred feet below the surface virtually in any location on Earth. Even the ground below your own backyard or local school has enough heat to control the climate in your home or other buildings in the community. In addition, there is a vast amount of heat energy available from dry rock formations very deep below the surface (4�10 km). Using a set of emerging technologies known as Enhanced Geothermal Systems (EGS), we may be able to capture this heat for electricity production on a much larger scale than conventional technologies allow.
If these resources can be tapped, they offer enormous potential for electricity production capacity. In its first comprehensive assessment in more than 30 years, the U.S. Geological Survey (USGS) estimated that conventional geothermal sources on private and accessible public lands across 13 western states have the potential capacity to produce 8,000�73,000 MW, with a mean estimate of 33,000 MW.2 State and federal policies are likely to spur developers to tap some of this potential in the next few years. The Geothermal Energy Association estimates that 132 projects now under development around the country could provide up to 6,400 megawatts of new capacity.3 As EGS technologies improve and become competitive, even more of the largely untapped geothermal resource could be developed. The USGS study found that hot dry rock resources could provide another 345,100�727,900 MW of capacity, with a mean estimate of 517,800 MW. That means that this resource could one day supply nearly all of today�s U.S. electricity needs.4
Not only do geothermal resources in the United States offer great potential, they can also provide continuous baseload electricity. According to the U.S. National Renewable Energy Laboratory, the capacity factors of geothermal plants�a measure of the ratio of the actual electricity generated over time compared to what would be produced if the plant was running nonstop for that period�are comparable with those of coal and nuclear power.5 With the combination of both the size of the resource base and its consistency, geothermal can play an indispensable role in a cleaner, more sustainable power system.
How Geothermal Energy Is Captured Geothermal springs for power plants. The most common current way of capturing the energy from geothermal sources is to tap into naturally occurring "hydrothermal convection" systems where cooler water seeps into Earth's crust, is heated up, and then rises to the surface. When heated water is forced to the surface, it is a relatively simple matter to capture that steam and use it to drive electric generators. Geothermal power plants drill their own holes into the rock to more effectively capture the steam.
There are three designs for geothermal power plants, all of which pull hot water and steam from the ground, use it, and then return it as warm water to prolong the life of the heat source. In the simplest design, the steam goes directly through the turbine, then into a condenser where the steam is condensed into water. In a second approach, very hot water is depressurized or "flashed" into steam which can then be used to drive the turbine.
In the third approach, called a binary system, the hot water is passed through a heat exchanger, where it heats a second liquid�such as isobutane�in a closed loop. The isobutane boils at a lower temperature than water, so it is more easily converted into steam to run the turbine. The three systems are shown in the diagrams below.
The choice of which design to use is determined by the resource. If the water comes out of the well as steam, it can be used directly, as in the first design. If it is hot water of a high enough temperature, a flash system can be used, otherwise it must go through a heat exchanger. Since there are more hot water resources than pure steam or high-temperature water sources, there is more growth potential in the heat exchanger design.
The largest geothermal system now in operation is a steam-driven plant in an area called the Geysers, north of San Francisco, California. Despite the name, there are actually no geysers there, and the heat that is used for energy is all steam, not hot water. Although the area was known for its hot springs as far back as the mid-1800s, the first well for power production was drilled in 1924. Deeper wells were drilled in the 1950s, but real development didn't occur until the 1970s and 1980s. By 1990, 26 power plants had been built, for a capacity of more than 2,000 MW.
Because of the rapid development of the area in the 1980s, and the technology used, the steam resource has been declining since 1988. Today, owned primarily by California- utility Calpine and with a net operating capacity of 725 MW, the Geysers facilities still meets nearly 60 percent of the average electrical demand for California's North Coast region (from the Golden Gate Bridge north to the Oregon border).6 The plants at the Geysers use an evaporative water-cooling process to create a vacuum that pulls the steam through the turbine, producing power more efficiently. But this process loses 60 to 80 percent of the steam to the air, without re-injecting it underground. While the steam pressure may be declining, the rocks underground are still hot. To remedy the situation, various stakeholders partnered to create the Santa Rosa Geysers Recharge Project, which involves transporting 11 million gallons per day of treated wastewater from neighboring communities through a 40-mile pipeline and injecting it into the ground to provide more steam. The project came online in 2003, and in 2008 provided enough additional electricity for approximately 100,000 homes. The city of Santa Rosa plans to further expand this program by increasing the amount of wastewater sent to the Geysers to nearly 20 million gallons per day.7
One concern with open systems like the Geysers is that they emit some air pollutants. Hydrogen sulfide�a toxic gas with a highly recognizable "rotten egg" odor�along with trace amounts of arsenic and minerals, is released in the steam. In addition, at a power plant at the Salton Sea reservoir in Southern California, a significant amount of salt builds up in the pipes and must be removed. While the plant initially started to put the salts into a landfill, they now re-inject the salt back into a different well. With closed-loop systems, such as the binary system, there are no emissions; everything brought to the surface is returned underground.
Direct use of geothermal heat. Geothermal springs can also be used directly for heating purposes. Hot spring water is used to heat greenhouses, to dry out fish and de-ice roads, for improving oil recovery, and to heat fish farms and spas. In Klamath Falls, Oregon, and Boise, Idaho, geothermal water has been used to heat homes and buildings for more than a century. On the east coast, the town of Warm Springs, Virginia obtains heat directly from spring water as well, using springs to heat one of the local resorts.8
In Iceland, virtually every building in the country is heated with hot spring water. In fact, Iceland gets more than 50 percent of its energy from geothermal sources.9 In Reykjavik, for example (population 115,000), hot water is piped in from 25 kilometers away, and residents use it for heating and for hot tap water.
Ground-source heat pumps. A much more conventional way to tap geothermal energy is by using geothermal heat pumps to provide heat and cooling to buildings. Also called ground-source heat pumps, they take advantage of the constant year-round temperature of about 50�F that is just a few feet below the ground�s surface. Either air or antifreeze liquid is pumped through pipes that are buried underground, and re-circulated into the building. In the summer, the liquid moves heat from the building into the ground. In the winter, it does the opposite, providing pre-warmed air and water to the heating system of the building.
In the simplest use of ground-source heating and cooling, a tube runs from the outside air, under the ground, and into a house's ventilation system. More complicated, but more effective systems use compressors and pumps�as in electric air conditioning systems�to maximize the heat transfer.
In regions with temperature extremes, such as the northern United States in the winter and the southern United States in the summer, ground-source heat pumps are the most energy-efficient and environmentally clean heating and cooling system available. Far more efficient than electric heating and cooling, these systems can move as much as 3 to 5 times the energy they use in the process. The U.S. Department of Energy found that heat pumps can save a typical home hundreds of dollars in energy costs each year, with the system typically paying for itself in 8 to 12 years. Tax credits and other incentives can reduce the payback period to 5 years or less.10
More than 600,000 ground-source heat pumps supply climate control in U.S. homes and other buildings, with new installations occurring at a rate of about 60,000 per year.11 While this is significant, it is still only a small fraction of the U.S. heating and cooling market, and several barriers to greater penetration into the market remain. For example, despite their long-term savings, geothermal heat pumps have higher up-front costs. In addition, installing them in existing homes and businesses can be difficult, since it involves digging up areas around a building�s structure. Finally, many heating and cooling installers are just not familiar with the technology.
However, ground-source heat pumps are catching on in some areas. In rural areas without access to natural gas pipelines, homes must use propane or electricity for heating and cooling. Heat pumps are much less expensive to operate, and since buildings are widely spread out, installing underground loops is not an issue. Underground loops can be easily installed during construction of new buildings as well, resulting in savings for the life of the building. Furthermore, recent policy developments are offering strong incentives for homeowners to install these systems. The 2008 economic stimulus bill, Emergency Economic Stabilization Act of 2008, includes an eight year extension (through 2016) of the 30 percent investment tax credit, with no upper limit, to all home installations of EnergyStar certified geothermal heat pumps.12
The Future of Geothermal Energy Geothermal energy has the potential to play a significant role in moving the United States (and other regions of the world) toward a cleaner, more sustainable energy system. It is one of the few renewable energy technologies that�like fossil fuels�can supply continuous, baseload power. The costs for electricity from geothermal facilities are also declining. Some geothermal facilities have realized at least 50 percent reductions in the price of electricity since 1980. A considerable portion of potential geothermal resources will be able produce electricity for as little as 8 cents per kilowatt-hour (including a production tax credit), a cost level competitive with new conventional fossil fuel-fired power plants.13 There is also a bright future for the direct use of geothermal resources as a heating source for homes and businesses in any location. However, in order to tap into the full potential of geothermal energy, two emerging technologies require further development: Enhanced Geothermal Systems (EGS) and co-production of geothermal electricity in oil and gas wells.
Enhanced Geothermal Systems. Geothermal heat occurs everywhere under the surface of the earth, but the conditions that make water circulate to the surface are found only in less than 10 percent of Earth's land area. An approach to capturing the heat in dry areas is known as enhanced geothermal systems (EGS) or "hot dry rock". The hot rock reservoirs, typically at greater depths below the earth�s surface than conventional sources, are first broken up by pumping high-pressure water through them. The plants then pump more water through the broken hot rocks, where it heats up, returns to the surface as steam, and powers turbines to generate electricity. Finally, the water is returned to the reservoir through injection wells to complete the circulation loop. Plants that use a closed-loop binary cycle release no fluids or heat-trapping emissions other than water vapor, which may be used for cooling.14
The Department of Energy, several universities, the geothermal industry, and venture capital firms (including Google) are collaborating on research and demonstration projects to harness the potential of hot dry rock. Australia, France, Germany, and Japan also have R&D programs to make EGS commercially viable. The DOE hopes to have EGS ready for commercial development by 2015 and is currently funding several demonstration projects.
One cause for careful consideration with EGS is the possibility of induced seismic activity that might occur from hot dry rock drilling and development. This risk is similar to that associated with hydraulic fracturing, an increasingly used method of oil and gas drilling, and with carbon dioxide capture and storage in deep saline aquifers. Though a potentially serious concern, the risk of an induced EGS-related seismic event that can be felt by the surrounding population or that might cause significant damage currently appears very low when projects are located an appropriate distance away from major fault lines and properly monitored. Appropriate site selection, assessment and monitoring of rock fracturing and seismic activity during and after construction, and open and transparent communication with local communities are also critical.
Co-production of Geothermal Electricity in Oil and Gas Wells. Oil and gas fields already under production represent another large potential source of geothermal energy. In many existing oil and gas reservoirs, a significant amount of high-temperature water or suitable high-pressure conditions are present, which could allow for the production of electricity and oil or gas at the same time. In some cases, exploiting these resources could even enhance the extraction of the oil and gas itself. An MIT study estimated that the United States has the potential to develop 44,000 MWs of geothermal capacity by 2050 by co-producing electricity, oil, and natural gas at oil and gas fields�primarily in the Southeast and southern Plains states. The study projects that such advanced geothermal systems could supply 10 percent of U.S. baseload electricity by that year, given R&D and deployment over the next 10 years.15
These exciting new developments in geothermal will be supported by unprecedented levels of federal R&D funding. Under, the American Recovery and Investment Act of 2009, $400 million of new funding was allocated to the DOE�s Geothermal Technologies Program. Of this $90 million is expected to go towards a series of up to 10 demonstration projects to prove the feasibility of EGS technology. Another $50 million will fund up to 20 demonstration projects for other new technologies, including co-production with oil and gas and low temperature geothermal. The remaining funds will go exploration technologies, expanding the deployment of geothermal heat pumps, and other uses. These investments will very likely produce great net benefits in the future.16
Endnotes: 1. Geothermal Energy Association (GEA) 2009. U.S. Geothermal Power Production and Development Update. 2. Williams, C.F., M.J. Reed, R.H. Mariner, J. DeAngelo, and S.P.Galanis Jr. 2008. Assessment of moderate- and high-temperature geothermal resources of the United States. U.S. Geological Survey fact sheet 2008-3082, 4. Washington, DC: U.S. Department of the Interior 3. See Note 1. 4. See Note 2. 5. National Renewable Energy Laboratory. Energy Technology Cost and Performance Data. 6. Calpine. The Geysers. 7. City of Santa Rosa, CA. Geysers Expansion. 8. Virginia Tech. Hot Springs in the Southeastern United States. 9. National Energy Authority and Iceland Ministry of Industries and Commerce. 2004. Energy In Iceland: Historical Perspective, Present Status, Future Outlook. 10. Department of Energy � Oak Ridge National Laboratory (ORNL). 2008. Geothermal (Ground-Source) Heat Pumps: Market Status, Barriers to Adoption, and Actions to Overcome Barriers. Report ORNL/TM-2008/232. 11. Ibid 12. Energy Star. Federal Tax Credits for Energy Efficiency. 13. California Energy Commission ( CEC) (June 2003). Comparative Cost of California Central Station Electricity Generation Technologies, Final Staff Report. 14. Office of Energy Efficiency and Renewable Energy (EERE). 2008a. An evaluation of enhanced geothermal systems technology. Washington, DC: U.S. Department of Energy. 15. Tester, J. et al. 2006. The Future of Geothermal Energy: Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century. Massachussetts Institute of Technology and Idaho National Laboratory. 16. See Note 1.
It is not easy to make biofuels from food crops, mainly because it is controversial and it can raise the cost of corn and grain. This can influence the global food prices. On the other hand, making the alternative fuel from non-food crops or making it from waste wood is rather expensive. Next to that the process is chemical- and energy-intensive.
Now, a start-up company called Renmatix has the answer: use water to extract the sugars. The process, which involves supercritical water, isn�t that exotic. In fact, it�s already used to decaffeinate coffee and extract hops to make beer. Supercritical water is basically water heated beyond its boiling point under high pressure. At that point, the water becomes something between a liquid and a gas. The company puts wood chips in a chamber with the supercritical water. This breaks off some of the sugars, the ones with five carbon atoms. The wood is then sent to another chamber to release the remaining sugars. What�s left is lignin, a component of wood, which can be burned to provide energy for the whole process.
Once the sugars are extracted you can transform them into biofuels, which are largely ethanol. Ethanol can be mixed with gasoline which can power our cars. Ethanol is widely used in Brazil. There, Ethanol is made from sugar cane.
But that�s the problem: it�s a lot easier to get sugars from food, such as corn. Producing biofuels without stressing food supplies or putting more land under cultivation will be a tall order: the U.S. Environmental Protection Agency has proposed that the country produce 36 billion gallons of ethanol by 2022, 16 billion gallons of which has to be cellulosic biofuel. The Renewable Fuels Association says the current production is about 13 billion gallons. That�s why companies such as Renmatix are looking for plant material which we don�t eat.
Geothermal energy falls under the category of renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. Geothermal energy is derived from heat within the earth. People can use the steam and hot water created inside the earth to heat buildings or produce electricity. Wondering what makes the water so hot? Geothermal energy is produced in the earth�s core.
People utilize geothermal energy to heat their homes and to produce electricity. This is achieved by digging deep wells and pumping the heated underground water or steam to the surface. But we can also use the stable temperatures near the surface of the earth to heat and cool buildings.
Dr. Ernst Huenges is the head of Geothermal Research at the institute GFZ � German Research Centre for Geosciences. He is of the opinion, �The new methods deliver important decision-support for the selection of sites for future geothermal projects. With this we can considerably reduce the risk of expensive misdrills,� Geothermal energy is making its presence felt worldwide and Iceland is the best example of the utilization of geothermal power. In fact Iceland leads the world in the development of geothermal utilization. They have doubled their annual power supply capping it up around 500 MW as far as electricity supply is concerned. Germany is also emerging as a major user of geothermal energy. Germany is deriving its 100 MW of heat from geothermal energy. Italy is not far behind. A team of European scientists, in the region of Travale (Italy), is planning to tap the potential of localized geothermal reservoirs. If this project is completed it will produce energy akin to a potential of around 1,000 wind power plants. This is one of the projects discussed at the international final conference of �I-GET� (Integrated Geophysical Exploration Technologies for deep fractured geothermal systems) in Potsdam.
The European Union is also feeling the �heat� of geothermal energy. European nations are waking up to the potential of geothermal energy. This conference aimed at the development of state-of-the art technology with potential geothermal reservoirs. Seven European nations participated in this �I-GET� conference. They want to explore more and more geothermal reservoirs and utilize it for clean and green energy. The project �I-GET� could be a substantial step towards renewable energy source.
The newly developed techniques have been tried at four European geothermal locations. They are combining different geological and thermo�dynamic conditions. High-temperature reservoirs have been examined in Travale/Italien having metamorphic rocks and in Hengill/Island (volcanic rocks). They are also examining two deposits with medium-temperature in deep sediment rocks in Gro�-Sch�nebeck/Germany and Skierniewice/Poland.
The implications of the results of �I-GET� would be felt worldwide. Geothermal experts from Indonesia, New Zealand, Australia, Japan and the USA also participated in the �I-GET� project. There were 120 scientists and industry representatives from the 20 countries.
�Reliable geothermal technologies are in demand worldwide. Even countries with a long experience in geothermal energy such as Indonesia and New Zealand are interested in the results acquired in I-GET,� says Dr. Ernst Huenges. Therefore, we hope that this �I-GET� will give the necessary push to the geothermal research. GFZ is currently establishing an International Centre for Geothermal Research, which will, focus on carrying out application-oriented large-scale projects on a national and international level.
Solar Energy is the energy that is produced by the sun in the form of heat and light. It is one of the most renewable and readily available source of energy. The fact that it is available in plenty and free and does not belong to anybody makes it one of the most important of the non-conventional sources of energy. Solar energy has been used by people since ancient times by using simple magnifying glasses to concentrate the light of the sun into beams so hot they would cause wood to catch fire.
Mainly, Solar energy can be used to convert it into heat energy or it can be converted into electricity. Solar energy can be converted into electricity by means of solar thermal energy and photovoltaic. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly. This form of energy can be used to power solar watches, calculators or traffic signals. They are often used in locations that are not connected to electricity grid. Solar heat energy can be used to heat water or space heating which means heating the space inside the building. Solar energy can be broadly categorized as active or passive solar energy depending on how they are captured and utilized. In active solar energy special solar heating equipment is used to convert solar energy to heat energy whereas in passive solar energy the mechanical equipment is not present. Active solar include the use of mechanical equipment like photovoltaic cells, solar thermal collectors or pumps and fans to trap the solar energy. Passive solar technologies convert solar energy to heat energy without use of active mechanical systems. It is mainly the practice of using windows, walls, trees, building placement and other simple techniques to capture or deflect the sun for use. Passive solar heating is a great way to conserve energy and maximizing it's utilization. An example of passive solar heating is what happens to your car on a hot summer day.
Environmental Impact
Although Solar energy is considered to be one of the cleanest and renewable sources of energy among the available sources but is has some environmental impacts too. Solar energy uses photovoltaic cells to produce solar power. However, manufacturing the photovoltaic cells to produces that energy requires silicon and produce some waste products. Inappropriate handling of these materials may lead to hazardous exposure to humans and the environment. Installing solar power plants may require large piece of land, which may impact existing ecosystems. Solar energy does not pollute the air when converted to electricity by solar panels. It is found in abundance and does not help in global warming.
Future Of Solar Energy
Solar technology is now poised to play a larger role in the future, thanks to new developments that could result in lower costs and improved efficiency. In fact, the solar PV industry aims to provide half of all new U.S. electricity generation by 2025. More and more architects are recognizing the value of active and passive solar and learning how to effectively incorporate it into building designs. Solar hot water systems can compete economically with conventional systems in some areas. Perhaps the future is here now. Shell has predicted that 50% of the world's energy will come from renewable sources by 2040. In recent years manufacturing costs of photovoltaic cells has dropped by 3-5% per year while government subsidies have increased. While to some such facts about solar energy seem trivial, this makes solar energy an ever-more affordable energy source. In the next few years it is expected that millions of households in the world will be using solar energy as the trends in USA and Japan show. Aggressive financial incentives in Germany and Japan have made these countries global leaders in solar deployment for years.
The power of the rise and fall of the sea level or tidal power, can be harnessed to generate electricity.
Tidal Power
Tidal power traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin; the sluice is then closed, and as the sea level drops, traditional hydropower technologies can be used to generate electricity from the elevated water in the basin. Some researchers are also trying to extract energy directly from tidal flow streams.
The energy potential of tidal basins is large � the largest facility, the La Rance station in France, generates 240 megawatts of power. Currently, France is the only country that successfully uses this power source. French engineers have noted that if the use of tidal power on a global level was brought to high enough levels, the Earth would slow its rotation by 24 hours every 2,000 years.
Tidal energy systems can have environmental impacts on tidal basins because of reduced tidal flow and silt buildup.
3 Ways of Using the Tidal Power of the Ocean
There are three basic ways to tap the ocean for its energy. We can use the ocean's waves, we can use the ocean's high and low tides, or we can use temperature differences in the water. 1. Wave Energy
Kinetic energy (movement) exists in the moving waves of the ocean. That energy can be used to power a turbine. In this simple example, (illustrated to the right) the wave rises into a chamber. The rising water forces the air out of the chamber. The moving air spins a turbine which can turn a generator.
When the wave goes down, air flows through the turbine and back into the chamber through doors that are normally closed.
This is only one type of wave-energy system. Others actually use the up and down motion of the wave to power a piston that moves up and down inside a cylinder. That piston can also turn a generator.
Most wave-energy systems are very small. But, they can be used to power a warning buoy or a small light house.
2. Tidal Energy
Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant.
In order for this to work well, you need large increases in tides. An increase of at least 16 feet between low tide to high tide is needed. There are only a few places where this tide change occurs around the earth. Some power plants are already operating using this idea. One plant in France makes enough energy from tides to power 240,000 homes.
3. Ocean Thermal Energy
The final ocean energy idea uses temperature differences in the ocean. If you ever went swimming in the ocean and dove deep below the surface, you would have noticed that the water gets colder the deeper you go. It's warmer on the surface because sunlight warms the water. But below the surface, the ocean gets very cold. That's why scuba divers wear wet suits when they dive down deep. Their wet suits trapped their body heat to keep them warm.
Power plants can be built that use this difference in temperature to make energy. A difference of at least 38 degrees Fahrenheit is needed between the warmer surface water and the colder deep ocean water.
Using this type of energy source is called Ocean Thermal Energy Conversion or OTEC. It is being used in both Japan and in Hawaii in some demonstration projects.
Today more than ever, the debate around the use of fossil fuels is putting out a lot of hot air. With climate change being challenged in Congress via the repeal of EPA regulatory authority, we face a mountainous climb back to ensuring our safety when it comes it air, water, and land quality. Only exacerbating the situation, a barrel of crude has reached $108, causing the cost of gasoline to float around $3.70. Without a doubt, the political climate is a hot one, no pun intended.
Moving forward, both the American people and their representatives are looking for solutions. Because there is no one perfect option, a number of alternative energy strategies are required to combat the ongoing energy crisis. Among them, wind power has grown in popularity.
In fact, according to the Wind Energy Association, �the U.S. wind industry represents not only a large market for wind power capacity installations, but also a growing market for American manufacturing.� All in all, the U.S. wind industry has added over 35 percent generating capacity over the past 4 years, more than nuclear and coal combined. The U.S. pursuit of wind energy is noted in the fact that we represent more than �20 percent of the world�s installed wind power.� What is Wind Power?
We�re all familiar with what wind is. Caused by the uneven distribution of heat on earth, air is put into motion. As explained by the Department of Energy, �During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, creating wind. At night, the winds are reversed because the air cools more rapidly over land than over water.�
The idea behind wind power is simple � harness this natural force and use it to generate electricity. Just like we learned in school, the movement of an object produces kinetic energy. This energy rotates the blades of a wind turbine, which spin to generate electricity in an electric generator. Benefits of Wind Power
One of the main benefits of wind power is the fact that it is a renewable resource. Simply put, as long as the sun is shining and we have an atmosphere, we�ll have a breeze. This provides comfort for those that are concerned about the energy independence and security regarding energy disruption here in the United States. Our turbines will continue to generate electricity as long we maintain them.
A second benefit is linked to the concern of climate change. While many forms of energy, namely fossil fuels, produce large emissions, wind energy is � in essence � a clean source of energy. After being installed, wind farms are able to produce large amounts of electricity for long amounts of time, offsetting their initial cost and serving as a long-term investment for communities and private businesses.
Tied to the last benefit, the increase use of wind energy means less fossil fuels are needed for electricity production. This, in effect, means even less carbon emitted into the atmosphere, as well less water use at fossil fuel plants. With the reduction in demand, there is a parallel drop in money spent on fuel, saving tax payer dollars.
In addition to the benefit of clean energy, wind energy also promotes job growth here in the United States. As President Barack Obama acknowledged, �when you only have 2-3 percent of the world�s oil reserves, why wouldn�t you want to develop alternative sources of energy that are cleaner and more efficient and that produce manufacturing jobs?�
Finally, as the Department of Energy points out, because the relative ease of installing wind farms, farmers and other people who live in areas ideal for wind farms can invest in projects to help keep them financially afloat and independent. Some Obvious Drawbacks
However, in the spirit of even handedness, it�s important to point out some clear drawbacks of wind energy.
First, the installation of wind turbines requires the use of fossil fuels in the first place. Roads may need to be built and ships will have to set sail to build wind farms on land and ocean. This requires energy, the production of resources for building, and the use of heavy machinery.
Secondly, there�s the concern of aesthetics and noise pollution. Many people think of wind farms as �unsightly� things, causing visual obstruction of the natural environment. Likewise, wind turbines are known to make �whoosing� noises � just like the propellers of a plane. Granted most wind farms are not in residential areas, some of the people who do live near them complain about these issues.
Like all things, turbines can also break. Few have caught fire and other have leaked lubricating fluids due to age and harsh conditions, according to the Department of Energy. Usually these instances are very rare, but they occur nonetheless.
Lastly, there have been a number of reported deaths of birds and bats due to wind farms. Because of these instances, �The wind energy industry and the U.S. government are researching ways to reduce the impact of wind turbines on birds and bats.� So What�s the Conclusion?
Regardless of the downfalls, wind energy should be a part of a large, more comprehensive energy plan. As the DOE argues, �the negative impacts have to be balanced with our need for electricity and the overall lower environmental impact of using wind for energy relative to other sources of energy to make electricity.�
Nothing is perfect, but that�s just the way the wind blows!
What is solar energy? Solar energy is the radiant energy produced by the Sun. It is both light and heat. It, along with secondary solar-powered resources such as wind and wave power, account for the majority of the renewable energy on Earth.
The Earth receives 174 petawatts(PW) of solar radiation at the upper atmosphere. 30% of that is reflected back to space and the rest is absorbed by clouds, oceans and land masses. Land surfaces, oceans, and atmosphere absorb solar radiation, which increases their temperature. Warm air containing evaporated water from the oceans rises, causing convection. When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds and causes rain. The latent heat of water condensation increases convection, producing wind. Energy absorbed by the oceans and land masses keeps the surface at an average temperature of 14�C. Green plants convert solar energy into chemical energy through photosynthesis. Our food supply is completely dependent on solar energy. After plants die, they decay in the Earth, so solar energy can be said to provide the biomass that has created the fossil fuels that we are dependent on. Humans harness solar energy in many different ways: space heating and cooling, the production of potable water by distillation, disinfection, lighting, hot water, and cooking. The applications for solar energy are only limited by human ingenuity. Solar technologies are characterized as either passive or active depending on the way the energy is captured, converted, and distributed. Active solar techniques use photovoltaic panels and solar thermal collectors to harness the energy. Passive techniques include orienting a building to the Sun, selecting materials with thermal mass properties, and using materials with light dispersing properties.
Our current dependence on fossil fuels is slowly being replaced by alternative energies. Some are fuels that may eventually become useless, but solar energy will never be obsolete, controlled by foreign powers, or run out. Even when the Sun uses up its hydrogen, it will produce useable energy until it explodes. The challenge facing humans is to capture that energy instead of taking the easiest way out by using fossil fuels.
Tidal energy, or tidal power, is a little known and little used energy source. Yet it is a very old energy source, dating back to the middle ages in Europe. Tidal energy is created by the relative motion of the Earth, Moon, Sun, and the gravitational interactions between them. Every coastal region has two high and two low tides in each approximate 24 hour period. A big advantage of tidal energy is its predictability. The size and time of tides can be predicted very efficiently.
Tidal energy is little used around the world. In order for electricity to be generated, differences between high and low tides must consistently reach 16 feet. There are few regions in the world where this occurs. There are currently no tidal energy facilities in the United States although there is potential in the Pacific Northwest and the Atlantic Northeast.
Harnessing Tidal Energy.
Barrage or Dam. There are only three barrage tidal plants in the world. Essentially, a barrage is built which forces tidal flows through turbines, creating electricity. When the water levels on both sides of the barrage are significantly different, gates are opened, allowing water to flow through and activate the turbines. The Rance Tidal Plant in France is a prime example of the barrage method of tidal energy. Tidal Turbines. A relatively new technology, tidal turbines are very similar to wind turbines but underwater. They are positioned strategically at entrances to bays or rivers, among others, where currents are fast. Because seawater is much denser than air, a single tidal turbine can produce significantly more energy than a wind turbine of the same size.
Environmental Impact.
Tidal energy is a renewable resource, but the classic, barrage method of harnessing tidal energy has some negative environmental impacts. Most notably, tidal power plants upset fish migrations and, by disrupting water flows, can upset entire estuarine ecosystems. Tidal turbines however, because they do not block water flow, may be a viable answer to these concerns.
How Tidal Compares to Solar.
Tidal turbines are a very efficient source of energy, and that is an advantage over solar to this point. However, there are only 40 locations in the world where tidal power is feasible. The sun shines everywhere. Nonetheless, they are both certainly part of the solution. While I support solar energy wholeheartedly, tidal power could be a great source for green energy. Especially for northern coastal regions where the sun is not as prevalent. I live in Oregon and I�ve personally witnessed the dramatic turn of tides (I�m talking about starfish clinging on at eye-level during low tide!)
How It Works
