During the day, there is a constant supply of radiation coming from the sun. The amount of radiation is considerable, but presently low cost commercial solid state solar cells only convert about 11% of the solar radiation into electricity. There are already laboratory solar cells that are 40% efficient, and in the future even higher efficiencies may be possible. Solid state solar cells are very attractive because they have no moving parts and are very simple. Because sunlight is free, this makes the technology very attractive especially in countries that have difficulty buying fuel. The downside of solid state solar cells is that when the sun goes down, there is no electricity being produced. Batteries can be used, but present batteries are only about 60-80% efficient in storing the electricity. Just as with wind turbines, if solar panels are linked into a large grid system, such fluctuations are not as much of a disadvantage.
A second method of using the sun's radiation is to convert it into high temperature thermal energy and then use conventional steam turbines, gas turbines or Stirling engines to generate electricity. Such methods are already 30-50% efficient in converting the sun's radiation into electricity. There are also efficient solid state thermoelectric converters being researched. If a fluid is heated, a large amount can be stored for operation of the plant during the night or cloudy days. As well, a backup fuel fired heater can be used, but this is only economical when the power plant is highly efficient.
A third desirable method is to use the sun's rays produce a fuel. This fuel could then be used at a later date. Hydrogen could be produced but it is difficult to store. An ideal fuel to produce would be ethanol or natural gas which could be used in a fuel cell at a later date to generate electricity or be used in other applications that require fuel. The solar cell would recycle the carbon dioxide from the atmosphere back into the ethanol or natural gas fuel. Such a solar cell might use genetically engineered bacteria to do the job.
Theoretically much of the thermal energy required in society could come from solar energy. Practically so far it has been considered too intermittent a source. Solar collectors for this purpose can be quite simple, but storage of the thermal energy during periods when the sun isn’t shining has so far been considered expensive compared to cheap fossil fuel. This situation could dramatically change when fuel prices go up in the future.
SOLAR POWER
WIND POWER
There is enough energy in the blowing winds to generate a substantial proportion of the electrical energy requirements in the world. In windy areas, the cost to produce electricity is already less than using fossil fueled combined cycle powerplants. One of the major problems with wind turbines in the past has been durability. Often serious wind storms would damage many units. Newer units appear to be built stronger. Another large problem is the extremely variable speed of the wind. Wind turbines may provide peak power in times when the electricity is not required. Storage of the electricity is expensive. If wind turbines are linked into a large grid system, such fluctuations are not as much of a disadvantage. Of course if a major proportion of our electricity would be generated this way, that would create major problems. Wind turbines in the past resulted in bird kills however it appears that with newer one’s this may not be a problem. Wind turbines are also noisy and can be unsightly. Still there are major advantages in tapping into a source of inexpensive power that can be converted into electricity in such a simple device as a wind turbine.
FUEL CELLS
Fuel cells, which can convert chemical energy directly into electricity, have been proposed as a replacement for other methods of generating power from fossil fuels for 100 years. Till recently there have been numerous difficulties in commercializing them however. Will these problems be overcome in the new century? If the problems can be overcome, fuel cells will likely be the favored technology of the future for all CHP as well as large centralized powerplants. Not only do fuel cells produce reasonable efficiencies at the smaller sizes, they will likely be able to run quietly, need infrequent maintenance and emit little pollution.
A fuel cell works similar to a battery. In a battery, electricity is generated as a result of a fixed amount of substance undergoing a chemical change inside the cell. In a fuel cell, a continuous flow of chemical substance flows through the cell and is made into electricity. While a battery has a limited amount of electricity it can produce per cycle, a fuel cell can produce electricity as long as more fuel is pumped through it.
Solid oxide fuel cells will likely be the favored fuel cell for CHP [2]. Small solid oxide fuel cells will be about 50% fuel to electricity efficient, medium powerplants 60% efficient, and large one's up to 70% efficient. Their efficiency is good from about 15%-100% power. Most solid oxide fuel cells utilize both hydrogen and carbon monoxide fuel inside the cell. This means that they can readily operate on hydrocarbon fuels such as coal gas, gasoline, diesel fuel, jet fuel, alcohol, and natural gas. The efficiency of the solid oxide fuel cell used in CHP applications will be higher than the polymer electrolyte fuel cells for two major reasons. The first reason is that the hydrocarbon fuel is reformed into hydrogen and carbon monoxide fuel largely inside the solid oxide fuel cell. This results in some of the high temperature waste thermal energy being recycled back into the fuel. The second reason is that air compression is not required. Especially on smaller systems, this results in a higher amount of net electricity being produced and quieter operation.
Most polymer electrolyte fuel cells that are being developed for automobiles and CHP use hydrogen gas as a fuel. It is not likely that we will have hydrogen pipelines supplying homes and businesses in the near future. This means that hydrogen will often be extracted from hydrocarbon fuels in CHP systems. Because the polymer electrolyte fuel cell operates at a low temperature, there is no waste thermal energy recycling in the reformer. Air compression to about 3 atmospheres or higher must be used to have a reasonable power density [3]. On small systems this results in a substantial loss of efficiency. Small polymer electrolyte fuel cells will be about 35% fuel to electricity efficient, medium powerplants 40% efficient, and large one's up to 45% efficient.
Because of the high temperatures that the solid oxide fuel cell must run , they may not be practical for sizes much below 1,000 watts or when portable applications are involved. Several companies in the world are presently working on direct alcohol fuel cells. In this type of fuel cell, the alcohol is not reformed but used directly in a very simple type of fuel cell. This fuel cell is ideal for portable equipment such as power tools, laptop computers, portable phones, and emergency generators. For more information on fuel cells read the web-booklet "The Future of Fuel Cells"
MAJOR TECHNOLOGIES FOR PRODUCING POWER
Electricity and mechanical power are largely used for powering our modern industrialized society. These are not stored in some natural form on earth in any great quantity. Other forms of energy must be converted. Different conversion technologies must be used. With some methods the electricity or mechanical power is produced directly in a single process. In others there are multiple steps involved.
Hydro turbines ..convert moving water from river and ocean dams into electricity
Wave generators ..use floats that move up and down with waves and produce electricity
Solar cells ..solid state materials that produce electricity directly from solar radiation impact
Thermocouples ..also called thermoelectric devices that produce electricity by heating dissimilar metals
Thermionic devices ..turn thermal energy into electricity by solid state means
Vapor turbines ..convert steam pressure into rotary motion then electricity
Piston vapor engines ..convert vapor pressure into rotary motion then electricity
Piston gas engines ..turn expanding gases to motion then electricity, Diesel, Otto, Brayton, Atkinson etc.
Gas turbines ..turn hot expanding gases to rotary motion then electricity
Stirling piston engines ..closed cycle engines turn thermal energy into motion then electricity
MHD ..turn moving charged fluids directly to electricity
Fuel cells ..turn chemical energy directly to electricity by the action of moving ions
Wind turbines ..turn moving air into rotary motion then electricity
Nuclear radiation cells ..solid state materials that produce electricity directly from nuclear radiation impact
Nuclear "ion" cells ..solid state materials that produce electricity directly from nuclear "ions"
Fig 1 Chart showing projected efficiencies of different future electricity generating powerplants
Panasonic lights up on Wind power
Tokyo is well known for it’s lights. Blaring ads that rival Time Square and soak up the power grid while doing it. Godzilla stomping on buildings while the Neon lights explode. But over at Panasonic Center, environmentally conscious designers are changing that high powered perception with a design that probably had a kid’s toy as it’s inspiration.
Solar Keyring Torch
The Solar Keyring Torch ensures you no longer have to fumble at the door whenever arrive home after a late night date, as it provides ample light from a trio of LEDs to keep your keyhole illuminated. Since it is solar-powered, there is no need to worry about dead batteries as well.
The best things in life are free, and sunlight is pretty well at the top of the list. The only trouble is of course, that the sun has a regular habit of shuffling off to the other side of the world leaving everything a little dark round here. Fortunately this little gizmo ensures that the sun leaves a little light behind that you can carry around with you on a key ring. It’s integral mini solar panel stores up energy from the sun and via it’s three super-bright LEDs becomes a blazing and very useful little torch when night falls. Many of these sorts of solar powered lights can have a tendency to be a tad lame, but this one is not only astonishingly bright, it also lasts for an absurdly long period of time, so long in fact that we don’t know how long it is - we got bored waiting for it to run out of power. It comes in a shock resistant rubber casing, and naturally requires no batteries, ever. Free light for life.
Torpedo Solar Spotlight
What better way to lower your monthly electricity bill than rely on good ol’ solar power that never runs out (at least until our sun decides to explode)? The Torpedo Solar Spotlight makes a good candidate to spruce up your garden long after sundown at an affordable price.
Make a walkway safer, uplight a tree or highlight garden art without the hassle of running extension cords or digging trenches for wiring. These garden spotlights are solar powered! Each 2¼” reflective lens has three bright LEDs that never need replacing, and an integrated solar panel that pivots and swivels to catch the best rays. Lights come on at dusk and shine for up to eight hours.
Keep your car fresh using solar power
Cars tend to attract odors, especially when several people are crammed in one for long trips. Add in a couple of smokers and the smell can become overbearing. Thankfully I don’t smoke, and most of the people that ride with me don’t either, so I just stick with the occasional pine tree air freshener. However, if you want something a little more hi-tech cleaning your air, you might try out this little gadget.
Solar Breeze Pool Skimmer takes some of the work out of pool maintenance
When I was a kid, I was lucky enough to have a pool. I was excited when my parents informed me that we would be getting one, and it was awesome jumping in it that first time. Of course it also meant that I had the task of keeping the pool clean. What I wouldn’t have given back then to have a couple of handy gadgets to do my work for me.
Backpack solar heater could help the planet
It looks like one of those inflatable pool loungers you use to soak up the sun. However, SolarStore panels are meant for a more practical use. Backpackers can use them to store up to 3 full tanks of water per day while heating the water at the same time. Easy to fold, easier to use, SolarStore panels are now being looked to provide not only heated water, but also solar energy to low income and third world housing.
Solar Powered Cordless Fan uses the sun to keep you cool
Until this past weekend came, the area where I live was experiencing near summer-like temperatures outside. I was even forced for a couple of days to kick on the old A/C for a little bit. Most of the time I made do with just some fans around the house, which got me thinking about how much power I must be using running those fans all the time. If I had one of these Solar Powered Cordless Fans, I wouldn’t need to wonder.
Solar powered speedboat
Solar power looks like it is here to stay, and we have so far seen solar powered cars being the Holy Grail in the fight to be independent of black gold, or rather, oil. Hybrid cars aren’t exactly catching on as fast as environmentalists prefer, and solar powered cars have not made the impact they were supposed to mainly because the technology is not yet there for a powerful, conventionally shaped vehicle that runs entirely off the sun’s rays. Never mind modes of transportation on land - here we have a solar powered speedboat that will slice through water pretty much in the same way an ordinary speedboat does, save for the fact that this one relies on the sun to power its electric engine instead.
Solar Powered Gear
Most gadgets that we report on require some sort of power source. One of the most techie and ecologically friendly ways of powering gadgets is via the power of the sun. This section of Coolest Gadgets is dedicated to gadgets that get their power from the sun’s rays, be it via solar panels or just simple heating.
SOURCES OF ENERGY
There are many sources of energy on earth. The original source of all this energy is nuclear energy in the universe. All other forms of energy are the result of nuclear energy trickling down into lower forms. The following are common sources of energy on earth:
Geothermal ..taking thermal energy from the earth's core
Falling water ..rivers, ocean tides
Wave motion ..in ocean
Thermal cycles ..in water and air
Wind motion ..of air
Pressure changes ..in atmosphere
Solar radiation ..from the sun
Fossil fuels ..coal, oil, natural gas
Biomass ..trees, plants
Fission nuclear energy ..splitting atoms
Fusion nuclear energy ..combining atoms
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Solar Photovoltaic (SPV) cells
Solar energy can also be used to meet our electricity requirements. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly. This electricity can either be used as it is or can be stored in the battery. This stored electrical energy then can be used at night.
SPV can be used for a number of applications such as:
a. domestic lighting
b. street lighting
c. village electrification
d. water pumping
e. desalination of salty water
f. powering of remote telecommunication repeater stations and
g. railway signals.
If the means to make efficient use of solar energy could be found, it would reduce our dependence on non-renewable sources of energy and make our environment cleaner.
Uses of Solar Energy
Solar Energy Uses
We have always used solar energy as far back as humans have existed on this planet. We know today, that there are multiple uses of solar energy. We use the solar energy every day in many different ways. When we hang laundry outside to dry in the sun, we are using the solar heat to do work, drying our clothes. Plants use the solar light to make food. Animals eat plants for food. And as we learned, decaying plants hundreds of millions of years ago produced the coal, oil and natural gas that we use today.History of Solar Energy
Solar Hot Water
Solar Thermal Electricity
Solar Cells or Photovoltaic Energy
Very often there is confusion about the various methods used to harness solar energy. Energy from the sun can be categorized in two ways: (1) in the form of heat (or thermal energy), and (2) in the form of light energy. Solar thermal technologies uses the solar heat energy to heat substances (such as water or air) for applications such as space heating, pool heating and water heating for homes and businesses. There are a variety of products on the market that uses solar thermal energy. Often the products used for this application are called solar thermal collectors and can be mounted on the roof of a building or in some other sunny location. The solar heat can also be used to produce electricity on a large utility-scale by converting the solar energy into mechanical energy.
So, fossil fuels is actually solar energy stored millions and millions of years ago. Indirectly, the sun or other are responsible for all our energy. Even nuclear energy comes from a star because the uranium atomsused in nuclear energy were created in the fury of a nova - a star exploding. Let's look at ways in which we can use the solar energy.
The Future of Alternative Energy
"The future belongs to renewable energy," said Brad Colllins, the executive director of the American Solar Energy Society, a Boulder, Colorado-based nonprofit. Scientists and industry experts may disagree over how long the world's supply of oil and natural gas will last, but it will end, Collins said.
While renewable energy is generally more expensive than conventionally produced supplies, alternative power helps to reduce pollution and to conserve fossil fuels.
"People sometimes get caught up in cost-effectiveness," said Paul Torcellini, a senior engineer at the DOE's National Renewable Energy Laboratory (NREL) in Golden, Colorado. "But it can be a question of values and what we spend our money on."
ENERGY FOR THE FUTURE: RENEWABLE SOURCES OF ENERGY
The need for Community support for Renewable Energy is clear. Several of the technologies, especially wind energy, but also small-scale hydro power, energy from biomass, and solar thermal applications, are economically viable and competitive. The others, especially photovoltaic (silicon module panels directly generating electricity from the sun’s light raher than heat), depend only on (how rapidly) increasing demand and thus production volume to achieve the economy of scale necessary for competitiveness with central generation. In fact, looking at the various sector markets in early 2003, it is probably not over-optimistic to conclude that the lion’s share of remaining market resistance to Renewables penetration relates to factors other than economic viability. This should be seen against the rapidly improving fiscal and economic environment being created in the EU both by European legislation itself swinging into full implementation and the Member States’ own programmes and support measures, which despite the short-term macro-economic background, are accelerating rapidly at the time of publication.
The European Commission's White Paper for a Community Strategy sets out a strategy to double the share of renewable energies in gross domestic energy consumption in the European Union by 2010 (from the present 6% to 12%) including a timetable of actions to achieve this objective in the form of an Action Plan.The main features of the Action Plan include internal market measures in the regulatory and fiscal spheres; reinforcement of those Community policies which have a bearing on increased penetration by renewable energies; proposals for strengthening co-operation between Member States; and support measures to facilitate investment and enhance dissemination and information in the renewables field.
About Renewable Energy
Renewable energy effectively uses natural resources such as sunlight, wind, rain, tides and geothermal heat, which may be naturally replenished. Renewable energy technologies range from solar power, wind power, hydroelectricity/micro hydro, biomass and biofuels for transportation.
RET: RENEWABLE ENERGY TECHNOLOGIES, THE SOLUTION
Renewable Energy Technologies bridge the gap between mounting global energy demand and diminishing supply of conventional source of energy. Popular awareness on the need of a cleaner environment and the increasing demand for more healthy and hygienic products encourages the use of RET in agro-industrial production processes. International efforts for maximizing the efficiency and minimizing the cost of RET is slowly enabling this technology to compete with conventional energy technologies. As conventional energy is exhaustible, polluting and responsible for environmental hazards like global warming, the renewable energy technologies are becoming more popular.
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