Electric Energy is not a non-renewable natural energy resource that is mined or pumped from the ground. Electric Energy is a manufactured product. Actually, electricity is a "secondary energy source". We manufacture it from the conversion of other "primary energy sources" like coal, natural gas, oil, nuclear power and other natural sources. The energy sources we use to make Electric Energy can be renewable or non-renewable, but Electric Energy itself is neither renewable or non-renewable. Electric Energy is manufactured in electric generators, and then transmitted by copper wire long or short distances to where that power is utililzed. In today's high-technology world, the utilization of Electric Energy is everywhere around us.

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Electric Energy is considered by many experts to be the most important source of power consumed by industry, commercial buildings, institutions and homes. It is supplied by generating stations. Traditional generating stations manufacture power in electrical generators. This is accomplised by turning those generators with turbines that are in turned by a number of sources. In the case of fossil-fuel burning stations, energy sources such as coal, oil, natural gas (actually, any source of fuel that is carbon based) are used to boil water. That water is boiled into high pressure steam. This high pressure steam is what turns the turbines that turns the generator that in turn manufactures Electric Energy.

But there are other ways to create electricity not using fossil fuels. Electric Energy can also be created using nuclear reactors to boil water and then generate power in the same way as mentioned above. The same process of turbines turning electrical generators and generating power also takes place in hydroelectric power plants that use falling water to turn electrical generators.

Renewable sources of Electric Energy such as wind work on the same principle. Geothermal plants use high pressure steam and heat from under ground to turn turbine-generators. Finally, power can be created from solar radiation through photovoltaic cells.

§ History of Electricity Books

The History of Electricity is fascinating. Despite what you have learned, Benjamin Franklin did not "invent" electricity. In fact, the History of Electric Energy did not begin when Benjamin Franklin at when he flew his kite during a thunderstorm or when light bulbs were installed in houses all around the world.

So, what is electricity? The truth is that electricity, like natural resources, has always been around because it naturally exists in the world. Lightning, for instance, is simply a flow of electrons between the ground and the clouds in the form of static electricity. When you touch something and get a shock, that is really static electricity moving toward you.

Hence, electrical technology like motors, light bulbs, and batteries aren't needed for electic power to exist. They are just creative inventions designed to harness and use electric power.

In the rich History of Electricity, the first discoveries were made back in ancient Greece. Greek philosophers discovered that when amber is rubbed against cloth, lightweight objects will stick to it. This is the basis of static shock.

The History of Electricity. We've all heard of famous people like Benjamin Franklin and Thomas Edison, but there have been many other inventors throughout time that play a crucial part in the story of electric power.

Imagine a world without electricity. No computers. No televisions. None of the modern "conveniences" we take for granted.

In the late 19th Century electricity was a new marvel. People had known about electricity for many years. Benjamin Franklin first achieved world renown for his experiments with electricity, including work with his famous kite and key. Until just over a century ago there was no way for electricity to be harnessed for practical use. It was in the late 1870s when America's greatest inventor -- Thomas Alva Edison -- developed and built the first electricity generating plant in New York City.

Soon numerous electric companies were competing to supply power in the nation's major cities. The focus was on business customers, although some wealthy homeowners had electric lighting installed. Because generation capacity was so limited most homes could only have three or four electric lights. And homeowners often had to turn off one light before they could turn on another.

By 1920 all of the nation's major cities had competing electric companies, each with its own sets of poles and wires. In order to bring service to more people, states began adopting laws providing for a single electric company in each city. From these laws grew the "regulatory compact" which formed the foundation of the electric utility industry in the U.S. for nearly eight decades.

Efforts to understand, capture, and tame electricity began in the 18th century. For the next 150 years, dozens of "natural scientists" in England, Europe, colonial America, and later the United States analyzed electricity in nature, but producing it outside of nature was another matter. That didn't happen on any large scale until the late 19th century. Setting the stage for widespread commercial use of electricity were international researchers engaged in pure scientific research, and entrepreneurial businessmen who made their own major discoveries or produced, marketed, and sold products based on others' ideas.

Electricity Personalities

Benjamin Franklin

Franklin was an American writer, publisher, scientist and diplomat, who helped to draw up the famous Declaration of Independence and the US Constitution. In 1752 Franklin proved that lightning and the spark from amber were one and the same thing. The story of this famous milestone is a familiar one, in which Franklin fastened an iron spike to a silken kite, which he flew during a thunderstorm, while holding the end of the kite string by an iron key. When lightening flashed, a tiny spark jumped from the key to his wrist. The experiment proved Franklin's theory, but was extremely dangerous - He could easily have been killed.

Galvani and Volta

In 1786, Luigi Galvani, an Italian professor of medicine, found that when the leg of a dead frog was touched by a metal knife, the leg twitched violently. Galvani thought that the muscles of the frog must contain electric energy. By 1792 another Italian scientist, Alessandro Volta, disagreed: he realised that the main factors in Galvani's discovery were the two different metals - the steel knife and the tin plate - apon which the frog was lying. Volta showed that when moisture comes between two different metals, electric power is created. This led him to invent the first electric battery, the voltaic pile, which he made from thin sheets of copper and zinc separated by moist pasteboard.

In this way, a new kind of electric power was discovered, electric power that flowed steadily like a current of water instead of discharging itself in a single spark or shock. Volta showed that electric power could be made to travel from one place to another by wire, thereby making an important contribution to the science of electric power. The unit of electrical potential, the Volt, is named after Volta.

Italian physician Girolamo Cardano wrote about electric energy in De Subtilitate (1550) distinguishing, perhaps for the first time, between electrical and magnetic forces. In 1600 the English scientist William Gilbert, in De Magnete, expanded on Cardano's work and coined the New Latin word electricus from elektron, the Greek word for "amber". The first usage of the word electric energy is ascribed to Sir Thomas Browne in his 1646 work, Pseudodoxia Epidemica.

Gilbert was followed in 1660 by Otto von Guericke, who invented an early electrostatic generator. Other pioneers were Robert Boyle, who in 1675 stated that electric attraction and repulsion can act across a vacuum; Stephen Gray, who in 1729 classified materials as conductors and insulators; and C. F. du Fay who first identified the two types of electric energy that would later be called positive and negative.

The Leyden jar, a type of capacitor for electrical energy in large quantities, was invented at Leiden University by Pieter van Musschenbroek in 1745. William Watson, when experimenting with the Leyden jar, discovered in 1747 that a discharge of static electricity was equivalent to an electric current.

In 1752, Benjamin Franklin promoted his investigations of electrical energy and theories through the famous, though extremely dangerous, experiment of flying a kite through a storm-threatened sky. A key attached to the kite string sparked and charged a Leyden jar, thus establishing the link between lightning and electric power. Following these experiments he invented a lightning rod. It is either Franklin (more frequently) or Ebenezer Kinnersley of Philadelphia (less frequently) who is considered as the establisher of the convention of positive and negative electricity.

Franklin's observations aided later scientists such as Michael Faraday, Luigi Galvani, Alessandro Volta, André-Marie Ampère, and Georg Simon Ohm whose work provided the basis for modern electrical technology. The work of Faraday, Volta, Ampere, and Ohm is honored by society, in that fundamental units of electrical measurement are named after them.

Volta discovered that chemical reactions could be used to create positively charged anodes and negatively charged cathodes. When a conductor was attached between these, the difference in the electrical potential (also known as voltage) drove a current between them through the conductor. The potential difference between two points is measured in units of volts in recognition of Volta's work.

In 1800 Volta constructed the first device to produce a large electric current, later known as the electric battery. Napoleon, informed of his works, summoned him in 1801 for a command performance of his experiments. He received many medals and decorations, including the Légion d'honneur.

By the end of the 19th century electrical engineers had become a distinct profession, separate from physicists and inventors. They created companies that investigated, developed and perfected the techniques of electrical transmission, and gained support from governments all over the world for starting the first worldwide electrical telecommunication network, the telegraph network. Pioneers in this field included Werner von Siemens, founder of Siemens AG in 1847, and John Pender, founder of Cable & Wireless.

The late 19th and early 20th century produced such giants of electrical engineering as Nikola Tesla, inventor of the polyphase induction motor; Samuel Morse, inventor of a long-range telegraph; Thomas Edison, inventor of the first commercial electrical energy distribution network; George Westinghouse, inventor of the electric locomotive; Charles Steinmetz, theoretician of alternating current; Alexander Graham Bell, the inventor of the telephone and founder of a successful telephone business.

How to Save Electricity is a popular question. It involves energy conservation and lessens real dollars and preserves a public resource. Here are some ways to cut energy costs without compromising your lifestyle too much.

Control heating and cooling costs

In some climates, heating and cooling represent the largest part of household energy use. In many climates, running your air conditioner at 78 instead of 72 will earn 40% of your cooling bill. You don't have to freeze or roast to death in order to use less energy and earn money. Here are a few tips:

· How to Save Electricity? Make sure your filters are clean. Check with the manufacturer of your equipment or with your utility company to see if filters on your units need to be cleaned.

· Don't heat or cool when no one is home. If you are going to be gone for more than a half an hour, you can turn your heating or cooling off or down. Don't turn off the heat in a cold climate because that may result in the pipes breaking.

· Supplement your main unit with portable units Running a fan can help you use less air conditioning. Using portable heaters when you are asleep or otherwise staying in one room can mean less use of heat if it means that you don't have to use the main unit.

· Try setting your thermostat to run less frequently Turn your air conditioner up a degree or two or your heater down a degree or two and see if you still can be comfortable.

· Time your opening and closing of windows and drapes to reduce heading and cooling costs. On cold, sunny days, opening curtains and drapes while leaving windows closed will help you heat your home. Opening the windows on summer nights helps cool your home. Buying storm windows in some climates reduces heating costs.

· Check for holes in your roof and in your pipes. This can help reduce up to 10 per cent of your heating and cooling costs.

Get How to Save Electricity ideas from your utility company
Utility companies are among the few businesses who hope that you use less of their product. Most power companies are anxious to postpone construction of new power plants, so they strongly encourage customers to use less power.
Utility companies offer energy audits, tips, and other help for customers who want to reduce energy consumption. Call your local utility or log onto their website to see what they have to offer.

Other tips:

· Consider How to Save Electricity by increasing your energy efficiency when buying appliances Appliances are labeled with energy usage comparison tables. Look at these figures. Also, you may be able to buy an adapter to make your older appliances more energy efficient.

· Turn off appliances that no one is using Turning off TV's, lamps, computers, VCR's, ovens, and other appliances that no one is using can reduce electric energy consumption. Even turning them off for short periods can produce noticeable results.

· See if an alternative energy company is available In California, electrical deregulation is beginning to result in alternative providers of electric power. This is a trend that should increase nationally. See if that option is available to you.

· Install low-flow heads in your water closets. Also, check your water heater's temperature and set it for 120 degrees. Putting insulation over your water heater and pipes can also help.

· Wash and dry only full loads of clothing or dishes

How to Save Electricity may not make you rich, but it will help you cut down some on your costs and will help prevent blackouts and power shortages in your community.

Are your company's profits being eroded by escalating energy costs? Can you gamble that your energy costs will go down in the future? What are you doing about preparing and protecting your company from spiraling energy costs?

Do you have the knowledge of the dynamic market with the right equipment that will make the 'smart decisions' and make an effective difference in your energy consumption and see your energy bill go down?

Do you know about the latest technologies that you can implement now?

These "How to Save Electricity" questions can be answered by our new Industrial, Commercial & Institutional Energy Efficiency Handbook. This 100+ page book is jammed with practical information on reducing energy consumption, increase Energy efficiency by using modern technologies such as variable frequency drives, high efficiency electrical devices, energy efficient lighting, energy management control systems, metering and management systems, as well as fan, pump and blower efficiency improvements. We will also list Federal, State, utility and Canadian government programs that will reduce your energy consumption and increase your energy efficiency.

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Green electricity is a term describing what is thought to be environmentally friendly sources of electricity. Typically, this refers to renewable and non-polluting energy sources.

Green electricity includes natural energetic processes which can be harnessed with little pollution. Anaerobic digestion, geothermal power, wind power, small-scale hydropower, solar power, biomass power, tidal power and wave power fall under such a category. Some versions may also include power derived from the incineration of waste.

Wind Electricity
The winds that blow across the UK can be harnessed by turbines to provide Green electricity. Wind turbines sited in suitable locations already provide a small, but growing percentage of the UK's electricity, and are used successfully all around the world. In fact wind power is the world's fastest growing energy source! Wind turbine technology has greatly improved over the last ten years, making wind turbines quieter and more efficient so that electricity generated from the wind is now often competitive with traditional coal-fired and nuclear power stations. Wind turbines are also beginning to be built at sea — in the future much of our electricity could come from these offshore windfarms.

Solar Electricity
Many people believe that we don't get much solar Green electricity here in the UK. In fact solar power is already being used to provide essential power for many types of equipment being used in both remote and urban areas across the country. A solar photovoltaic (PV) module works by converting sunlight directly into electricity (even on cloudy days) using semiconductor technology. The vast majority of solar modules available today use "waste" silicon from the computer chip industry as the semiconductor material. They can be integrated into buildings and even made into roof tiles virtually indistinguishable from normal tiles.
Solar Electricity can also be used to heat water directly using specially designed collectors. Even in winter a useful amount of hot water can be produced from roof top collectors. A third way to use solar energy is simply to design buildings to make maximum use of the sun. Using this so-called 'passive solar' approach, much of the energy that we currently use for heating, lighting and air conditioning can be saved.

Hydro Electricity
Water turbines have been used to provide Green electricity for over 100 years and presently provide over 1% of the UK's electricity. Although most of the possible sites for large hydropower stations in the UK have already been developed, there is a large potential for smaller schemes. These can either use a small dam or work as a 'run of the river' system which has a minimal impact on the local environment.

Wave Electricity
Many different devices have been designed over the years to try and capture some of this huge energy resource — the latest one has recently started generating Green electricity on the isle of Islay, off the West Coast of Scotland. In this machine waves hitting the shore are channelled into a large tube to power a specially designed turbine. With the proper support, wave power could provide a significant proportion of the UK's electricity needs in the future.

Tidal Electricity
Tidal power has been used in Britain for over a thousand years — at the time of the Doomsday book over 5,000 tide powered mills were recorded. Unlike other Green electricity renewable energy sources, which depend on the weather, tidal power is as predictable as the tides themselves. One way to capture tidal energy is to build a barrage across an estuary, storing water behind it as the tide rises and then releasing the stored water through turbines at low tide. Several sites around the UK could be suitable for this type of tidal system, the largest being the Severn Estuary. Another way is to use 'marine current turbines', which work like underwater wind turbines, harnessing tidal currents instead of the winds.

Geothermal Electricity
Geothermal energy comes from hot rocks deep underground. In some parts of the world steam comes to the surface and can be used to run steam turbines to produce Green electricity directly. In other places water can be pumped down and heated by the rocks to make steam. Geothermal energy can also be used to provide hot water and heating for buildings.

Biomass Electricity
Either agricultural wastes or specially grown plants can be used as a fuel to run small Green electricity power stations. As plants grow they absorb carbon dioxide (the main gas responsible for climate change) which is then released when the plants are burnt. So using biomass does not add any extra carbon dioxide into the atmosphere. Specially grown 'energy crops' provide not only an environmentally sound source of electricity, but also an important new opportunity for farmers.

Landfill gas Converted to Electricity
As rubbish decomposes in the landfill sites where our household waste is dumped, it gives off methane gas. This gas can be captured and burnt in a gas turbine to produce Green electricity. Burning the gas does give off carbon dioxide but since methane, which is emitted from the landfill site, is in fact a much more powerful greenhouse gas it is better to burn it than to allow the methane to escape into the atmosphere. There are already many landfill gas systems operating in the UK.

Waste Incineration Electricity
The UK generates an enormous amount of waste, and space at landfill sites is quickly running out. The best solution would be to recycle as much of the waste as possible, but instead incinerators are being constructed to burn the waste. In some cases the energy is being used to generate green electricity. However many environmentalists are still concerned about the emission of harmful dioxins and also about the loss of a valuable resources that could have been recycled. You can read about Greenpeace's views on incineration.
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How Electricity Works is a very common question. Electric power is as common to us as running water in many areas, especially in industrialised countries. Despite this, there is a great deal of ignorance about this strange force and how it comes about.

If you can picture an atom as a sphere, imagine how electricity works in the nucleus in the centre that contains at least one proton and at least one neutron. The proton is positively charged. In orbit around the nucleus is at least one electron which is negatively charged. The reason they have these opposite charges takes us deep into quantum physics. We know that the neutron is made up of quarks and the electron is an elementary particle (it is not made up of anything and is a particle in its own right), but the reason why they have opposite charges is a matter beyond my meagre capabilities and, in any case, this area is at the fringes of human knowledge.

Atoms may contain several protons and electrons. This variation is what separates elements from each other and how electricity works. Although described as sub-atomic particles, electrons have the properties of both particles and waves. In theory at least they could be both at the same time.

If an atom has no electric charge, i.e. it is neutral, then it contains the same amount of protons as electrons. In some materials - most metals for example - the electrons' orbit around the nucleus is quite loose and they can spin away from the atom. When this happens the atom becomes positively charged because protons are in the majority within the atom. A free electron can join another atom. When this occurs then its new host atom becomes negatively charged because the electrons are in the majority (assuming the atom was neutral in the first place).

When it comes to asking how electricity works, The key thing to remember here is that opposites attract. The greater the difference between the number of electrons and protons, the greater the attraction will be. This is called potential difference. If we therefore can manage to produce a negative charge at one end of a copper wire and a positive charge at the other end, free electrons would move towards the positive end. As electrons leave those atoms nearest the positive end, they leave behind positively charged atoms. Electrons from neighbouring atoms will be attracted towards these positive atoms thus creating yet more positive atoms in their wake. This continuing transfer of electrons is called current. The greater the potential difference, or voltage to use its measuring unit, the greater the force of the flow of electrons - or current.

Electric power can be supplied as direct current (e.g. from car batteries) or as alternating current (e.g. household mains).

Often an electrical product requires a different voltage to the one that is supplied from mains electric power. In these cases, a transformer is required. The use of transformers is very common along power lines and in electrical devices. As well as the step-up transformers that increase voltage - transformers can also reduce voltage. These step-down transformers can be found at utility substations where the very high voltages required to push electrons through long transmissions wires are reduced for local consumption.

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Today, more than half of the electricity generated in the world comes from coal. For the foreseeable future, coal will continue to be the dominant fuel used for electric power production. The low cost and abundance of coal is one of the primary reasons why consumers benefit from some of the lowest electricity rates of any free-market economy.

The key challenge is to remove the environmental objections to the use of coal in tomorrow’s power plants. New technologies being developed in the Fossil Energy program could virtually eliminate the sulfur, nitrogen, and mercury pollutants released when coal is burned. It may also be possible to capture greenhouse gases emitted from coal-fired power plants and prevent them from contributing to global warming concerns.

Research is also underway to increase the fuel efficiency of coal-fueled power plants. Today’s plants convert only a third of coal’s energy potential to electricity. New technologies in Energy’s Fossil Energy program could nearly double efficiency levels in the next 10-15 years. Higher efficiencies mean even more affordable electricity and fewer greenhouse gases.

While coal is the nation’s major fuel for electric power, natural gas is the fastest growing fuel. More than 90 percent of the power plants to be built in the next 20 years will likely be fueled by natural gas. Natural gas is also likely to be a primary fuel for distributed power generators – mini-power plants that would be sited close to where the electricity is needed.

Energy’s Fossil Energy program is developing natural gas-powered fuel cells for future distributed generation applications. Fuel cells use hydrogen that can be extracted from natural gas or perhaps in the future from biomass or coal.

R&D programs aimed at maintaining the operating capability of the nation’s existing nuclear power plants and developing the next generation of nuclear technologies. Nuclear energy is the world’s largest source of emission-free electricity. The Nuclear Energy program is working to develop cost-efficient technologies that further enhance nuclear safety, minimize the generation of nuclear waste, and further reduce the risk of proliferation.

To meet the rising electric power demand of the 21st century, significant improvements in America’s electric system are necessary. Blackouts serve as a powerful reminder of the critical role electricity plays in the everyday lives of people.

Electrical Engineers and Scientists alike seek to develop new technologies for the storage of energy and the transmission of energy that will contribute to energy efficiency of the electric industry. For instance, the copper wires used in typical transmission lines lose a percentage of the electricity passing through them because of resistance, which causes the wires to heat up. But "superconducting" materials have no resistance, and if they are used to transmit electricity in the future, very little of the electricity will be lost.

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Solar electricity is created by using Photovoltaic (PV) technologyby converting solar energy into solar electricity from sunlight. Photovoltaic systems use sunlight to power ordinary electrical equipment, for example, household appliances, computers and lighting. The photovoltaic (PV) process converts free solar energy - the most abundant energy source on the planet - directly into solar power. Note that this is not the familiar "passive" or Solar electricity thermal technology used for space heating and hot water production.

A PV cell consists of two or more thin layers of semi-conducting material, most commonly silicon. When the silicon is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC). The electrical output from a single cell is small, so multiple cells are connected together and encapsulated (usually behind glass) to form a module (sometimes referred to as a "panel"). The PV module is the principle building block of a PV system and any number of modules can be connected together to give the desired electrical output.

PV equipment has no moving parts and as a result requires minimal maintenance. It generates solar electricity without producing emissions of greenhouse or any other gases, and its operation is virtually silent.

What is PV power used for?

PV systems supply solar electricity to many applications in the UK, ranging from systems supplying power to city buildings (which are also connected to the normal local solar power network) to systems supplying power to garden lights or to remote telecom relay stations.

The main area of interest in the UK today is grid connect PV systems. These systems are connected to the local solar electricity network. This means that during the day, the solar electricity generated by the PV system can either be used immediately (which is normal for systems installed on offices and other commercial buildings), or can be sold to one of the electricity supply companies (which is more common for domestic systems where the occupier may be out during the day). In the evening, when the electrical system is unable to provide the electricity required, power can be bought back from the network. In effect, the grid is acting as a Solar electricity energy storage system, which means the PV system does not need to include battery storage.

Grid connect PV systems are often integrated into buildings. PV technology is ideally suited to use on buildings, providing pollution and noise-free solar power without using extra space. The use of photovoltaics on buildings has grown substantially in the UK over the last few years, with many impressive examples already in operation.

PV systems can be incorporated into buildings in various ways. Sloping rooftops are an ideal site, where modules can simply be mounted using frames. Photovoltaic systems can also be incorporated into the actual building fabric, for example PV roof tiles are now available which can be fitted as would standard tiles. In addition, PV can also be incorporated as building facades, canopies and sky lights amongst many other applications.

Stand-alone photovoltaic systems have been used for many years in the UK to supply solar electricity to applications where grid solar power supplies are unavailable or difficult to connect to. Examples include monitoring stations, radio repeater stations, telephone kiosks and street lighting. There is also a substantial market for PV technology in the leisure industry, with battery chargers for boats and caravans, as well as for powering garden equipment such as solar electricity fountains. These systems normally use batteries to store the solar power, if larger amounts are required they can be combined with another source of power - a biomass generator, a wind turbine or diesel generator to form a hybrid power supply system.

PV technology is also widely used in the developing world. The technology is particularly suited here, where electricity grids are unreliable or non-existent, with remote locations often making PV power supply the most economic option. In addition, many developing countries have high solar radiation levels year round.

Types of PV Cell

Monocrystalline Silicon Cells:
Made using cells saw-cut from a single cylindrical crystal of silicon, this is the most efficient of the photovoltaic (PV) technologies. The principle advantage of monocrystalline cells are their high efficiencies, typically around 15%, although the manufacturing process required to produce monocrystalline silicon is complicated, resulting in slightly higher costs than other technologies.

Multicrystalline Silicon Cells:
Made from cells cut from an ingot of melted and recrystallised silicon. In the manufacturing process, molten silicon is cast into ingots of polycrystalline silicon, these ingots are then saw-cut into very thin wafers and assembled into complete cells. Multicrystalline cells are cheaper to produce than monocrystalline ones, due to the simpler manufacturing process. However, they tend to be slightly less efficient, with average efficiencies of around 12%., creating a granular texture

Thick-film Silicon:
Another multicrystalline technology where the silicon is deposited in a continuous process onto a base material giving a fine grained, sparkling appearance. Like all crystalline PV, this is encapsulated in a transparent insulating polymer with a tempered glass cover and usually bound into a strong aluminium frame.

Amorphous Silicon:
Amorphous silicon cells are composed of silicon atoms in a thin homogenous layer rather than a crystal structure. Amorphous silicon absorbs light more effectively than crystalline silicon, so the cells can be thinner. For this reason, amorphous silicon is also known as a "thin film" PV technology. Amorphous silicon can be deposited on a wide range of substrates, both rigid and flexible, which makes it ideal for curved surfaces and "fold-away" modules. Amorphous cells are, however, less efficient than crystalline based cells, with typical efficiencies of around 6%, but they are easier and therefore cheaper to produce. Their low cost makes them ideally suited for many applications where high efficiency is not required and low cost is important.

Other Thin Films:
A number of other promising materials such as cadmium telluride (CdTe) and copper indium diselenide (CIS) are now being used for PV modules. The attraction of these technologies is that they can be manufactured by relatively inexpensive industrial processes, certainly in comparison to crystalline silicon technologies, yet they typically offer higher module efficiencies than amorphous silicon. New technologies based on the photosynthesis process are not yet on the market.

Typical PV System Configuration

The components typically required in a grid-connected PV system are illustrated below.

The PV array consists of a number of individual photovoltaic modules connected together to give the required power with a suitable current and voltage output. Typical modules have a rated power output of around 75 - 120 Watts peak (Wp) each. A typical domestic system of 1.5 - 2 kWp may therefore comprise some 12 - 24 modules covering an area of between 12 - 40 m2, depending on the technology used and the orientation of the array with respect to the sun.

Most PV modules deliver direct current (DC) electricity at 12 volts (V), whereas most common household appliances in the UK run off alternating current (AC) at 230 V. An inverter is used to convert the low voltage DC to higher voltage AC. Numerous types of inverter are available, but not all are suitable for use when feeding power back into the UK mains supply. Good suppliers and installers of grid-connect PV systems will be able to offer advice on suitability of commonly available models.

Other components in a typical grid-connected PV system are the array mounting structure and the various cables and switches needed to ensure that the PV generator can be isolated both from the building and from the mains. Again, good suppliers and installers of grid-connect PV systems will be able to offer advice on these aspects of the PV system.

Finally, a meter will be required to ensure that the system owner can be credited for any PV power fed into the mains supply.

Suppliers will normally offer a 12 months warranty on the system, together with 2 years on the inverter and a performance warranty of 10 - 25 years on the modules.

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Water Electricity is electricity obtained from hydropower. Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. Less common variations make use of water's kinetic energy or undammed sources such as tidal power. Hydroelectricity is a renewable energy source.

The energy extracted from water depends not only on the volume but on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is directly proportional to the head. To obtain very high head, water for a hydraulic turbine may be run through a large pipe called a penstock.

While many supply public power networks, some Water Electricity projects were created for private commercial purposes. For example, aluminium processing requires substantial amounts of power, and in Britain's Scottish Highlands there are examples at Kinlochleven and Lochaber, designed and constructed during the early years of the 20th century. Similarly, the 'van Blommestein' lake, dam and power station were constructed in Suriname to provide power for the Alcoa aluminium industry. In many parts of Canada (the provinces of British Columbia, Manitoba, Ontario, Quebec and Newfoundland and Labrador) hydroelectricity is used so extensively that the word "hydro" is used to refer to any power delivered by a power utility. The government-run power utilities in these provinces are called BC Hydro, Manitoba Hydro, Hydro One (formerly "Ontario Hydro"), Hydro-Québec and Newfoundland and Labrador Hydro respectively. Hydro-Québec is the world's largest hydroelectric generating company, with a total installed capacity (2005) of 31,512 MW.

Importance

Water Electricity power supplies 20% of world electricity. Norway produces virtually all of its energy from hydro, while Iceland produces 83% of its requirements (2004), Austria produces 67% of all power generated in the country from hydro (over 70% of its requirements). Canada is the world's largest producer of Water Electricity and produces over 70% of its electric power from hydroelectric sources.

Apart from a few countries with an abundance of it, hydro capacity is normally applied to peak-load demand, because it can be readily stored during off-peak hours (in fact, pumped-storage hydroelectric reservoirs are sometimes used to store power produced by thermal plants for use during peak hours). It is not a major option for the future in the developed countries because most major sites in these countries having potential for harnessing gravity in this way are either being exploited already or are unavailable for other reasons such as environmental considerations.

Regions where thermal plants provide the dominant supply of power utilize Water Electricity to provide the important functions of load following and regulation. This permits thermal plants to be operated closer to thermodynamically optimal points rather than varied continuously, which reduces efficiency and potentially increases pollutant emmissions. Concurrently, hydro plants are then utiliized to provide for hour-to-hour adjustments and to respond to changes in system frequency and voltage (regulation), with no additional economic or environmental effect.

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How Is Electricity Made? A generator manufactures electricity. In a generator, something causes the shaft and armature to spin. An electric current is generated, as shown in the picture (lighting bolt).

Lots of things can be used to make a shaft spin - a pinwheel, a crank, a bicycle, a water wheel, a diesel engine, or even a jet engine. They're different sizes but it's the same general idea. It doesn't matter what's used to spin the shaft - How is Electricity Made, is all the same.

Electric generators are essentially very large quantities of copper wire spinning around inside very large magnets, at very high speeds.

A commercial utility electric generator -- for example, a 180-megawatt generator at the Hawaiian Electric Company's Kahe power plant on Oahu -- can be quite large. It is 20 feet in diameter, 50 feet long, and weighs over 50 tons. The copper coils (called the "armature") spin at 3600 revolutions per minute. Although the principle is simple (copper wire and magnets), it's not necessarily easy!

Steam turbine generators, gas turbine generators, diesel engine generators, alternate energy systems (except photovoltaics), even nuclear power plants all operate on the same principle - magnets plus copper wire plus motion equals electric current. The electricity produced is the same, regardless of source.

So, when it comes to How Is Electricity Made, where do all the different fuels come in when it comes to How Electricity Is Made? It's all a question of how to get (and keep) the system moving (i.e. how to keep the copper wire spinning around). In a steam power plant, fuels (such as petroleum, coal, or biomass) are burned to heat water which turns into steam, which goes through a turbine, which spins...turning the copper wire (armature) inside the generator and generating an electric current.

When it comes to How Is Electricity made, power stations need large amounts of energy to turn the turbines. Most use heat energy produced from burning coal. Others use wind energy or moving water. The spinning turbine causes large magnets to turn within wire coils - these are the generators. The moving magnets within the coil of wire causes the electrons (charged particles) to move within the coil of wire. This is electricity.

Steam turbine generators, gas turbine generators, diesel engine generators, alternate energy systems (except photovoltaics), even nuclear power plants all operate on the same principle - magnets plus copper wire plus motion equals electric current. The electricity produced is the same, regardless of source.

How Is Electricity made? It is not important to consumers, who expect their electricity to be available whenever they plug in an appliance, turn a switch, or open a refrigerator. Satisfying these instantaneous demands requires an uninterrupted flow of electricity. In order to meet this requirement, utilities and nonutility electricity power producers operate several types of electric generating units, powered by a wide range of fuel sources. These include fossil fuels (coal, natural gas, and petroleum), uranium, and renewable fuels (water, geothermal, wind, and other renewable energy sources).

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