The main benefits of geothermal heating
Term geothermal power refers to heat stored in the earth, and geothermal heating is basically a direct use of the heat stored from the earth to heat our homes, offices, or for any other heating application. Geothermal heating is lately gaining in popularity, and currently more than 30 GW of geothermal heating capacity has been installed around the world. This is still almost negligible on global scale as it accounts for only 0.07% of global primary energy consumption but things have lately been definitely moving in the right direction.
In order to take a full advantage of geothermal power certain part of the world has to be underlain by relatively shallow geothermal resources. The best example of this is Iceland that is using full richness of its hot geothermal spots to harness energy. Currently there are five countries in the world (El Salvador, Kenya, the Philippines, Iceland, and Costa Rica) that generate more than 15% of their electricity from geothermal sources but I'll focus in this article primarily on geothermal heating.
Many people do not know that direct geothermal heating has far better efficiency compared to geothermal electricity generation, mostly because it doesn't require such demanding temperatures like geothermal electricity generation does. Now I will try to explain as simply as possible the principle on how does the geothermal heating work.
First what you need to know is that the most important part in this whole geothermal thing story are the geothermal pumps. Geothermal heating uses geothermal heat pumps to force the transfer of heat from the ground to the desired heating application. The usual geothermal heat pump has an outdoor unit called condenser and an indoor unit that's called an evaporator coil. What we also need to transform heat from one source to another is refrigerant, that is usually in form of highly pressured liquid. As this highly pressured liquid circulates underground it absorbs heat from the ground and, on its return, the now warmer fluid passes through the heat pump which uses electricity to extract the heat from the fluid, and the re-chilled fluid is sent back through the ground to continue this cycle. This extracted heat is then used to heat our homes and offices.
It also has to be said that geothermal heat pumps are practically built on the same working principle like regular heat pumps, and the only big difference is that geothermal heat pumps extract heat from the earth instead from outdoor air like regular heat pumps do.
What are the main benefits of geothermal heating? The main benefit of geothermal heating is definitely energy conservation. If you cover current energy related media more closely you probably already know how energy conservation is one of the most important goals in modern energy and world's attempts to go green. Energy conservation is definitely big advantage of geothermal heating systems because geothermal heating systems use between 25% to 50% less electricity than conventional heating or cooling systems. As you can see geothermal heating systems, where available, are one of the best options to go green.
Energy conservation is the main benefit of geothermal heating but is definitely not the only one. Geothermal heating has virtually no environmental impact, and is fully ecologically acceptable. Once installed, maintenance costs are very low not to mention how much more value do geothermal heating systems add to your property if you later decide to sell it. In humid conditions geothermal heating systems are just what the doctor ordered because they maintain around 50% relative indoor humidity. They are ideal to use for under floor heating which is very popular these days. And also, they are very silent, not like some air conditioning devices that are often noisy.
Types of solar panels
Solar panels transform solar energy into current electricity, which is the prime purpose of any solar energy device. As science and technology forge ahead, there were several types of solar panels invented and distributed within energy industry. Moreover, modern advancements allow production and usage of solar energy not only on large enterprises, but in households. Solar energy becomes more and more available; one of the recent trends is embedding solar panels into small gadgets and devices. Therefore, the variety of solar panels is likely to encourage major improvements in everyday livelihood.
First of all, solar panels might be classified according to their capacity. Three main types might be recognized:
1.Universal panels, which might be used in field environments. Such panels are usually appreciated by travelers, who are eager to deal with active and ecotourism.
2.Small panels, which are embedded in small devices (such as mobile phones, electronics, etc).
3.Solar cell panel, which might be usually seen on solar energy plants.
In addition, the whole range of solar panels might be divided in three groups according their structure. In this context, there are photovoltaic cells, solar power stations and solar collectors. Each type might compete in popularity and distribution, which is why they are worth considering in details.
Photoelectric converter may be defined as a device processing power via the photovoltaic effect. Solar panel is formed, when several photoelectric converters are united. Photoconductivity is a main factor, which defines optical properties, and, therefore, the effectiveness of the panel. This phenomenon is preconditioned by the internal photoelectric effect, which occurs while irradiating the semiconductor with sunlight. Nowadays the United States are world leader in usage of photoelectric converters, which hold 405 share on the global market. A lot of companies also deal with producing materials, required for photoelectric converters. They are HEMLOCK and USA MEMC, AsiMi, SGSil (the Unied States), Wacker (Germany), Tokuyama Soda, Mitsubishi MaterialPoly Si, Sumitomo Titanium (Japan) and Italy MEMC (Italy).
Solar power plant is a solar installation, which uses concentrated solar energy to drive other various machines: steam and gas turbines, thermoelectric cells, etc. Surprisingly, solar plants are used not only to generate energy, but facilitate other industries as well. Among other specific purposes it is appropriate to admit heating and desalination of sea water. The main point of plants structure is lenses, which help to concentrate energy. In particular, nowadays they are replaced with large mirrors due to big weight and high cost of the first ones. Mirrors are usually made of conventional glass or polished aluminum. Solar power plants are the prerogative of countries located in tropical areas (Montalto di Castro PV Power Plant and San Bellino PV Power Plant in Italy, Lopburi PV Power Plant in Thailand). However, the biggest one is located in Ukraine - Perovo Solar Power Station.
Solar collecting systems are low-temperature heating units, which are used for autonomous hot water supply both for residential and industrial premises. Solar collectors also might be divided into three types: flat (represented with element-absorber, which absorbs solar radiation), vacuum (laminated glass coating) and collector-concentrators (mirror surface).
Hydropower
Introduction
Hydropower is also referred to as the water power, and refers to power which derives from the force of energy of the moving water. Hydropower has very long history, and has been used since early days for irrigation, today hydropower is mostly used to generate electricity.
United States hydropower info
Hydropower is the most important renewable energy source in United States, which currently accounts for around 8% of nation's electricity. The biggest hydroelectric dams in the United States are found in the Northwest, the Tennessee Valley, and on the Colorado River. United States is currently fourth largest producer of hydroelectricity in the world, behind China, Canada and Brazil. The United States currently has more than 2,000 hydroelectric power plants which supply close to 50% of its total renewable electricity. The largest U.S. hydroelectric power plant is the 6,800-megawatt Grand Coulee power station on the Columbia River in Washington State. Idaho, Washington, and Oregon are US states that use hydroelectricity as their main power source, and hydroelectric plants exist in at least 34 US states. State of Washington leads the nation in hydropower and accounts for around 31% of the total U.S. generated hydropower. Hydropower has very long history in United States as the first U.S. hydroelectric power plant was opened almost 130 years ago, on the Fox River near Appleton, Wisconsin, on September 30, 1882. Most dams in the United States were built mainly for flood control and irrigation, and only a small percentage of all dams in the United States generates electricity. US can currently generate enough hydropower to supply electricity needs for close to 29 million households. In 2008, hydropower represented 2.5% of the total energy consumed in the United States.
Micro hydro systems info
Micro hydro systems are hydroelectric power installations that typically produce up to 100 kW of power, and are mostly used to provide power to an isolated home or small communities. In some areas micro hydro systems are used to complement for solar energy panels. This is because in the winter, when the amount of sunshine is at minimum, available hydropower is at its maximum. Micro hydro systems unlike large hydropower plants usually do not have a dam or reservoir because these systems compared to large hydropower plants require minimal flow of water to be available year-round. Micro hydro systems are very efficient because they require a very small amount of flow to generate electricity (around two gallons per minute should be enough). They are also very reliable, and their peak energy season is during the winter when water flow is the highest. Micro hydro systems are not connected with high costs. A small-scale hydro-power system in average costs from $1,000 – $20,000, depending on site electricity, requirements and location. Maintenance costs are also fairly low. Many energy experts believe small hydro systems would be one of the best energy options for developing countries because they are connected with low costs, and last for long time. The main disadvantage of micro hydro systems is low power in the summer months because during the summer months there is less flow. Another disadvantage is the fact that it is not that easy to find the suitable site to build these projects because you need to consider many factors like stream size, flow rate, distance from the power source, etc. Micro hydro systems use several different types of water turbines, depending on the head of water, the volume of flow, and other factors like the availability of local maintenance and transport of equipment to the site. For mountainous regions where a waterfall of 50 meters or more may be available, a Pelton wheel is mostly used. For low head installations, Francis or propeller-type turbines are used while very low head installations of only a few meters may use propeller-type turbines in a pit. Micro hydro systems have minimal environmental impact. Still, when building these systems constructors need to be cautious to ensure there will be no damaging impact on the nearby ecosystems.
Geothermal energy
Introduction
Geothermal energy should play much bigger role in supplying global energy demand in years to come. Geothermal energy is non-carbon based energy source that is environmentally friendly, and doesn't release harmful greenhouse gases into the atmosphere. Almost all energy experts agree that geothermal energy is very abundant renewable energy resource that has more than enough potential to satisfy energy needs of large part in the world.
Geothermal power plants info
Geothermal power plants use geothermal energy of our planet to generate power, and most geothermal energy is found along major plate boundaries where earthquakes and volcanoes are concentrated. There are three basic types of geothermal power plants: 1.dry steam plants that use steam piped directly from a geothermal reservoir to turn the generator turbines. 2.flash steam plants that operate by taking high-pressure hot water from deep inside the Earth and convert it to steam to drive the generator turbines. 3.binary cycle power plants that operate by transferring the heat from geothermal hot water to another liquid, and afterward this second liquid is turned into the steam that drives turbines. The first geothermal power plant was built in Landarello, Italy in 1904. This plant became commercial in 1911. In 2007, all world's geothermal power plants supplied only 0.3% of global electricity demand. Geothermal power plants are predominantly built on the edges of tectonic plates but with the recent improvements in drilling and extraction techniques they should be able to cover much larger geographical range. Geothermal power plants require high investments but once built have very low maintenance and operational costs. The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California, United States. Currently operating geothermal power plants emit an average of 122 kg of CO2 per megawatt-hour of electricity, which is very small amount compared to the emissions of coal power plants. The construction of geothermal power plants can have negative environmental impact, it can affect the stability of the land, and even trigger earthquakes which of course can have negative effect on nearby ecosystems. Unlike other power plants geothermal power plants require minimal land, and not a lot of water. Geothermal plants use 3.5 square kilometers per gigawatt of electrical production compared to 32 square kilometers for coal power plants. Also, geothermal power plants use only around 20 litres of freshwater per MWh compared to more than 1000 litres per MWh for coal power plants.
Geothermal energy costs info
With the recent development in technology geothermal energy is becoming more cost-competitive with fossil fuels. Geothermal energy uses heat stored within the Earth to generate electricity, and therefore requires no fuel, meaning that is not affected with fluctuations in fuel prices. According to the data from the U.S. Department of energy a geothermal power plant built today would probably require about $0.05 per kWh. Operational and maintenance costs of geothermal power plants ($0.01 - $0.03 per kWh) are even lower than of coal power plants ($0.02 - $0.03 per kWh). Geothermal energy has high startup costs, with average geothermal power plant costing around $2500 per installed kW, which is almost twice as much compared to average natural gas power plant. However, geothermal plants do not need to worry about fuel costs, and over a typical 30-year plant life the fuel costs for a natural gas plant is likely to represent twice their initial capital cost so long-term speaking geothermal power plants can be a very reasonable investment, especially if there are some tax incentives involved. There are dozens of factors that influence the final cost of certain geothermal power plant. The most important factors are: * Costs of equipment and labor force * Terrain * Size of the plant * Power plant technology * Knowledge of the resource * Temperature of the resource * Chemistry of the geothermal water * Resource depth and permeability * Environmental policies * Tax incentives. Geothermal power plants are characterized by high investments (exploration, drilling, and installation) but once geothermal power plant is built operational and maintenance costs are fairly low ($0.02 - $0.03 per kWh).
Recent studies have calculated that the geothermal power plant construction (with drilling costs included) will cost about 2-5 million € per MW of electrical capacity, with the levelized energy cost of 0.04-0.10 € per kW·h. Enhanced geothermal systems have capital costs above $4 million per MW and levelized costs above $0.054 per kWh, according to the 2007 data. The geothermal heat pump system for average home should cost around $7,500 without the drilling. The cost of drilling is usually the biggest factor affecting the final price as the cost of drilling can vary from $10,000 to $30,000, or even more, mostly depending on the terrain.
Is geothermal energy economically viable?
Cost-competitiveness is one of the factors that will play very important role in determining the future of each renewable energy source, and geothermal energy is no exception. Currently in terms of production cost, geothermal energy is very respectable energy source with 6.5 cents per kilowatt-hour, which is very similar to production costs of wind energy. Coal and nuclear power are still economically most acceptable energy sources with their 4-5 cent/kWh generation costs but if we look at natural gas production costs at 7 cents and petroleum around 10 cents, geothermal energy certainly looks to be economically viable alternative energy source.
Relatively low production costs are not the only reason why geothermal energy is economically viable renewable energy source. The fact that geothermal energy doesn't depend on weather is probably her main economic advantage since this gives geothermal energy excellent base load electricity. Solar energy and wind energy do not have this advantage since sun doesn’t shine every day, nor does the wind blow all the time. Geothermal energy doesn't have this problems, heat from Earth's core is available all the time, meaning that with geothermal energy it is fairly easy to predict the amount of generated electricity. This may not seem that big deal to some of you but companies that signed long-term projects definitely want to have a certain data, without have to worry about factors like underproduction or "wasted" production which is often the case with solar and wind energy.
Now, let’s talk little about capital costs. Geothermal capital costs are relatively low. This is because geothermal energy projects usually require less land compares to wind or solar energy projects. Compared to nuclear and even coal power plants geothermal power plants also have one big advantage in form of fewer permits because they are less harmful to environment than nuclear and coal power plants. And since there are no emissions like this is the case with fossil fuels there is also no need to capture or sequester carbon emissions, a requirement that can add 40-60% to capital cost of fossil fuel projects.
Another big factor that makes geothermal energy economically viable is also very high load factor. Load factor is the difference between how much the generator is designed to produce and how much it actually produces. The smaller the difference, the higher the load factor. The load factor of conventional power stations is on average around 50%, wind farms have the load factor around 30-40%, while geothermal energy has load factor close to 90% due to the fact that geothermal energy is impervious to weather conditions.
As you can see geothermal energy is not only energy source recommended from the environmental point of view but also from economic point of view, since it can easily compete with most fossil fuels, and provide reliable source of energy to many parts of the world.
Biomass
Introduction
Biomass is currently one of the most popular renewable energy sources in th world and refers to biological material from living, or recently living organisms such as wood, waste and alcohol fuels. The question about whether world should use more biomass or not has stirred some controversies because there are many environmentalists who believe that using more biomass could do significant damage to our climate. Still, when compared to fossil fuels biomass is by far more environmentally friendly energy option.
How is biomass converted into useful form of energy?
Biomass is one of the renewable energy sources that is recently becoming increasingly popular. One of the reasons for this is the large number of biomass energy sources. The most popular biomass energy source is wood, but biomass energy sources also include garbage, waste, landfill gases, and alcohol fuels. When talking about converting biomass into useful form of energy it is important to explain that conversion technologies may produce the energy directly, in the form of heat or electricity, or convert it to another form, such as liquid biofuels. There are three basic conversion processes for converting biomass into useful form of energy: thermal conversion of biomass, chemical conversion of biomass, and biochemical conversion of biomass. Thermal conversion like the name suggests is all about heat, and in process of thermal conversion heat is the main factor that converts biomass into the useful form of energy. Chemical conversion uses different chemical processes to turn biomass into energy while biochemical conversion of biomass makes use of the enzymes of bacteria and other micro-organisms to break down biomass through the processes such as anaerobic digestion, fermentation and transesterification. Science is constantly looking for new methods to make these conversion processes more efficient. Currently biomass accounts for about 4% of the energy used in the United States, with wood being the dominant biomass energy source. In years to come this percentage should be significantly higher. At least this is what many energy experts predict.
Is biomass acceptable renewable energy option?
Is biomass acceptable renewable energy option or not? Well this question is certainly becoming hot topic among many energy experts, especially after the recent Massachusetts study and its conclusion that biomass power plants that use wood as fuel are likely to be worse for the climate than existing coal plants over the next several decades. If we look at the biomass industry in United States we can see that according to federal statistics power coming from biomass represents around 50% of all renewable energy produced in United States, with 90% of biomass coming from wood as the used fuel. The main problem with biomass is the fact that using wood as the fuel can result in even more greenhouse gases than by burning coal because as critics point out new trees do not grow overnight. Critics also point out that biomass plants create different forms of air pollution, including particulate matter. Supporters of the biomass say that biomass technology is proved renewable energy technology that can unlike solar and wind energy provide instant results. They point out that the problem of overharvesting can be solved with very strict regulation of what materials are harvested and how are they burned, which would be some sort of sustainable biomass. The concept of sustainable biomass looks to be connected with many flaws because large-scale biomass industry would require large quantities of residual material to feed the industry, and this would likely lead to harvesting whole trees from tracts or land that never would have been logged otherwise. If biomass would only be about burning waste wood then this would be an acceptable renewable energy option but waste wood alone isn't enough to support large-scale biomass industry. Thus, when it comes to biomass as an acceptable renewable energy option we must set some boundaries. Using wood waste is more than fine with me, but anything beyond that destroys too much trees, and we desperately need trees to absorb harmful carbon emissions.