Energy Resources

Fossil fuels or mineral fuels are fuels formed by natural resources such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years. These fuels contain high percentage of carbon and hydrocarbons.

Fossil fuels range from volatile materials with low carbon:hydrogen ratios like methane, to liquid petroleum to non-volatile materials composed of almost pure carbon, like anthracite coal. Methane can be found in hydrocarbon fields, alone, associated with oil, or in the form of methane clathrates. It is generally accepted that they formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth’s crust over hundreds of millions of years.

Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being formed. The production and use of fossil fuels raise environmental concerns. A global movement toward the generation of renewable energy is therefore under way to help meet increased energy needs.

The burning of fossil fuels produces around 21.3 billion tonnes (21.3 gigatonnes) of carbon dioxide per year, but it is estimated that natural processes can only absorb about half of that amount, so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year (one tonne of atmospheric carbon is equivalent to 44/12 or 3.7 tonnes of carbon). Carbon dioxide is one of the greenhouse gases that enhances radiative forcing and contributes to global warming, causing the average surface temperature of the Earth to rise in response, which climate scientists agree will cause major adverse effects.

Fossil fuels are of great importance because they can be burned (oxidized to carbon dioxide and water), producing significant amounts of energy. The use of coal as a fuel predates recorded history. Coal was used to run furnaces for the melting of metal ore. Semi-solid hydrocarbons from seeps were also burned in ancient times, but these materials were mostly used for waterproofing and embalming.

The principle of supply and demand suggests that as hydrocarbon supplies diminish, prices will rise. Therefore higher prices will lead to increased alternative, renewable energy supplies as previously uneconomic sources become sufficiently economical to exploit. Artificial gasolines and other renewable energy sources currently require more expensive production and processing technologies than conventional petroleum reserves, but may become economically viable in the near future.

Harvesting, processing, and distributing fossil fuels can also create environmental concerns. Coal mining methods, particularly mountaintop removal and strip mining, have negative environmental impacts, and offshore oil drilling poses a hazard to aquatic organisms. Oil refineries also have negative environmental impacts, including air and water pollution. Transportation of coal requires the use of diesel-powered locomotives, while crude oil is typically transported by tanker ships, each of which requires the combustion of additional fossil fuels.

Hydroelectricity is electricity generated by the production of power through use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide than fossil fuel powered energy plants. Worldwide, hydroelectricity supplies approximately 20% of the world’s electricity, and accounts for about 88% of electricity from renewable sources.
Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. In this case the energy extracted from the water depends on the volume and on the difference in height between the source and the water’s outflow.

Pumped storage hydroelectricity produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped storage schemes currently provide the only commercially important means of large-scale grid energy storage and improve the daily load factor of the generation system.

Hydroelectric plants with no reservoir capacity are called run-of-the-river plants, since it is not then possible to store water. A tidal power plant makes use of the daily rise and fall of water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods.

The major advantage of hydroelectricity is elimination of the cost of fuel. The cost of operating a hydroelectric plant is nearly immune to increases in the cost of fossil fuels such as oil, natural gas or coal, and no imports are needed.

Hydroelectric plants also tend to have longer economic lives than fuel-fired generation, with some plants now in service which were built 50 to 100 years ago. Operating labor cost is also usually low, as plants are automated and have few personnel on site during normal operation.
Reservoirs created by hydroelectric schemes often provide facilities for water sports, and become tourist attractions in themselves. In some countries, aquaculture in reservoirs is common. Multi-use dams installed for irrigation support agriculture with a relatively constant water supply. Large hydro dams can control floods, which would otherwise affect people living downstream of the project.

Wind power is the conversion of wind energy into a useful form, such as electricity, using wind turbines.Wind power produces about 1.5% of worldwide electricity use,and is growing rapidly, having doubled in the three years between 2005 and 2008. Several countries have achieved relatively high levels of wind power penetration, such as 19% of stationary electricity production in Denmark, 11% in Spain and Portugal, and 7% in Germany and the Republic of Ireland in 2008. As of May 2009, eighty countries around the world are using wind power on a commercial basis.

Large-scale wind farms are typically connected to the local electric power transmission network; smaller turbines are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy as a power source is attractive as an alternative to fossil fuels, because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions; however, the construction of wind farms (as with other forms of power generation) is not universally welcomed due to their visual impact and other effects on the environment

Wind power is non-dispatchable, meaning that for economic operation all of the available output must be taken when it is available, and other resources, such as hydropower, and standard load management techniques must be used to match supply with demand. The intermittency of wind seldom creates problems when using wind power to supply a low proportion of total demand. Where wind is to be used for a moderate fraction of demand, additional costs for compensation of intermittency are considered to be modest. Studies of a pan european power grid, show that wind can be used to meet eg 70% of load, over a wide area of interconnected grids, and then the costs of electricity delivered into the consuming country are comparable to present day power costs.

Wind and hydroelectric power generation have negligible fuel costs and relatively low maintenance costs; in economic terms, wind power has a low marginal cost and a high proportion of capital cost. The estimated average cost per unit incorporates the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors (including cost of risk), estimated annual production, and other components, averaged over the projected useful life of the equipment, which may be in excess of twenty years. Energy cost estimates are highly dependent on these assumptions so published cost figures can differ substantially.

Wind energy in many jurisdictions receives some financial or other support to encourage its development. A key issue is the comparison to other forms of energy production, and their total cost. Two main points of discussion arise: direct subsidies and externalities for various sources of electricity, including wind. Wind energy benefits from subsidies of various kinds in many jurisdictions, either to increase its attractiveness, or to compensate for subsidies received by other forms of production which have significant negative externalities.

Compared to the environmental effects of traditional energy sources, the environmental effects of wind power are relatively minor. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources.

The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months of operation.

Energy resources fall into two main categories, often called renewable and non-renewable energy resources. Renewable resources are also often called alternative sources of energy as they are not as widely used today as some non-renewable energy resources. But, as its name suggests, these resources won’t last forever.

Estimates do vary, because we do not know where all the resources are and we do know how quickly we will use them. Collectively, this information advances the scientific understanding of energy resources, contributes to plans for a balanced and secure energy future, and facilitates the strategic use and evaluation of resources. The remaining world energy resources are large, compared to world energy consumption.

Advantages of renewable sources of energy are relatively cheap and most are easy to get and can be used to generate electricity. Ultimately the Sun is the source of most energy resources available to us. Global warming theories that do focus on mankind’s contribution point towards the important side-effects of human energy consumption, such as greenhouse gases added to the earth’s atmosphere. Even that amount is also only a minute amount of the sun’s total energy output, due to the small solid angle the earth’s outline makes with the sun.

Solar power is the conversion of sunlight into electricity. Sunlight can be converted directly into electricity using photovoltaics (PV), or indirectly with concentrating solar power (CSP), which normally focuses the sun’s energy to boil water which is then used to provide power. The Sun’s energy can be gathered anywhere, but obviously more can be gathered in areas on or near the Equator. Because there is no burning involved, there are no polluting gases. The simple types use flat collector panels that are mounted on the south facing roof or wall. The panels have a transparent cover to admit sunlight.

Many of the Sun’s rays are scattered by the Earth’s atmosphere or reflected by clouds. But some solar radiation can be collected by special panels and used to heat water. Photovoltaic cells are made of semiconductors, similar to those used to make computer chips. One other application of solar power is that it can be used as an alternative water heating system. Water circulates through channels or pipes inside a solar panel situated on the roof of a home or building. The inside is usually painted black, because black surfaces readily absorb heat. The water is heated, then the hot water is pumped to a heat exchanger that extracts the heat for use within the house.

Solar power is a predictably intermittent energy source, meaning that whilst solar power is not available at all times, we can predict with a very good degree of accuracy when it will and will not be available. Some technologies, such as solar thermal concentrators with an element of thermal storage, have the potential to eliminate the intermittency of solar power, by storing spare solar power in the form of heat; and using this heat overnight or during periods that solar power is not available to produce electricity. This technology has the potential to make solar power “dispatchable”, as the heat source can be used to generate electricity at will. Solar power installations are normally supplemented by storage or another energy source, for example with wind power and hydropower.

Solar energy is not available at night, making energy storage an important issue in order to provide the continuous availability of energy.Wind power and solar power can be complementary, in locations that experience more wind in the winter and more sun in the summer, but on days with no sun and no wind the difference needs to be made up in some manner.

Solar energy can be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems.

Energy how long can it last and where can it come from? – oil from the middle east? Wind and solar power what is the best way we can move forward?