There are many different forms in which alternative energy is available.

One of these is solar power. Solar power is driven by photovoltaic cells, and these are progressively getting less expensive and more advanced. Solar energy power can be used for electricity, heating, and making hot water. Solar energy produces no pollution, as its input comes completely from the sun's rays. However, much more work still needs to be done in order for us to economically harness the sun's energy. For the time being, the resource is a little too conditional—storage batteries are needed to be used as backups in the evenings and on inclement days.

Wind energy has become the most-invested-in (by private investors and governments together) alternative energy source for the time being. The great arrays of triple-bladed windmills are being placed all over as “wind farms”, to capture the motion of the wind and use its kinetic energy for conversion to mechanical or electrical energy. Of course, there is nothing new about the concept of a windmill for harnessing energy. Modern wind turbines are simply are more advanced variations on the old theme. Of course, the drawback to wind energy is...what do you do when there is a calm, still day? Needless to say, during these times the electric company kicks in for powering your home or office. Wind energy is not altogether independent.

Hydroelectric energy is available as a source of alternative energy, and it can generate a substantial amount of power. Simply put, hydroelectric energy uses the motion of water—its flow in response to gravity, which means downhill—to turn turbines which then generate electrical energy. Needless to say, water is ubiquitous; finding sources for driving hydroelectric turbines is, therefore, not much of a problem. However, hydroelectricity as a source of alternative energy can be complicated and expensive to produce. Dams are often built in order to be able to control the flow of the water sufficiently to generate the needed power. Building a dam to store and control water's potential and kinetic energy takes quite a lot of work, and operating one is complex as well,and conservationists grow concerned that it. Of course, a dam is not always needed if one is not trying to supply the electrical needs of a city or other very densely populated area. There are small run-of-river hydroelectric converters which are good for supplying neighborhoods or an individual office or home.

Probably the most underrated and under-appreciated form of alternative energy is geothermal energy, which is simply the naturally-occurring energy produced by the heating of artesian waters that are just below the earth's crust. This heat is transferred into the water from the earth's inner molten core. The water is drawn up by various different methods—there are “dry steam” power plants, “flash” power plants, and “binary” power plants for harnessing geothermal energy. The purpose of drawing up the hot water is for the gathering of the steam. The Geysers, approximately 100 miles north of San Francisco, is probably the best-known of all geothermal power fields; it's an example of a dry stream plant.

 

Photovoltaic cells—those black squares an array of which comprises a solar panel—are getting more efficient, and gradually less expensive, all the time, thanks to ever-better designs which all them to focus the gathered sunlight on a more and more concentrated point. The size of the cells is decreasing as their efficiency rises, meaning that each cell becomes cheaper to produce and at once more productive. As far as the aforementioned cost, the price of producing solar-generated energy per watt hour has come down to $4.00 at the time of this writing. Just 17 years ago, it was nearly double that cost.

Solar powered electricity generation is certainly good for the environment, as this alternative form of producing energy gives off absolutely zero emissions into the atmosphere and is merely utilizing one of the most naturally occurring of all things as its driver. Solar collection cells are becoming slowly but surely ever more practical for placing upon the rooftops of people's homes, and they are not a difficult system to use for heating one's home, creating hot water, or producing electricity. In the case of using the photovoltaic cells for hot water generation, the system works by having the water encased in the cells, where it is heated and then sent through your pipes.

Photovoltaic cells are becoming increasingly better at collecting sufficient radiation from the sun even on overcast or stormy days. One company in particular, Uni-Solar, has developed solar collection arrays for the home that work well on inclement days, by way of a technologically more advanced system that stores more energy at one time during sunlit days than previous or other arrays.

There is actually another solar power system available for use called the PV System. The PV System is connected to the nearest electrical grid; whenever there is an excess of solar energy being collected at a particular home, it is transferred to the grid for shared use and as a means of lowering the grid's dependence on the hydroelectrically-driven electricity production. Being connected to the PV System can keep your costs down as compared to full-fledged solar energy, while at once reducing pollution and taking pressure off the grid system. Some areas are designing centralized solar collection arrays for small towns or suburban communities.

Some big-name corporations have made it clear that they are also getting into the act of using solar power (a further indication that solar generated energy is becoming an economically viable alternative energy source). Google is putting in a 1.6 megawatt solar power generation plant on the roof of its corporate headquarters, while Wal Mart wants to put in an enormous 100 megawatt system of its own.

Nations such as Japan, Germany, the United States, and Switzerland have been furthering the cause of solar energy production by providing government subsidies or by giving tax breaks to companies and individuals who agree to utilize solar power for generating their heat or electrical power. As technology advances and a greater storage of solar collection materials is made available, more and more private investors will see the value of investing in this “green” technology and further its implementation much more.