SOLAR POWER

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.

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.