welly asked:


Every day, the Earth receives more energy from the sun than mankind uses in a year. Still, solar energy remains a tiny sliver in the global energy mix. Falling prices and better efficiency could change this, but can it happen fast enough?

When it comes to meeting energy needs, humanity has not been able to eliminate the middle man. The energy we use today comes from the sun, but we get it indirectly. Sunrays fed countless generations of plants and organisms millions of years ago, which we now use to burn to produce electricity, heat our homes, and run our cars. Its heat also strikes up the winds that we use to sail ships and run turbines. Despite our dependence on the sun, mankind has still not fully realized the potential of harnessing the sun’s vast energy directly.

Worldwide Importance and Future Trends

Even with steady annual growth, the International Energy Agency says solar energy – combined with wind and geothermal power – still only supplies less than one percent of the world’s energy. In Germany, the global solar market leader, solar supplies around 0.3 percent of national electricity demand; in the United States, it supplies less than 0.1 percent.

The UN’s annual “Global Trends in Sustainable Development” report said that the solar sector attracted 16 percent of the 70 billion U.S. dollars invested in renewable technology in 2006 – behind wind (38 percent) and biofuels (26 percent). According to the World Energy Council, solar water heating market is growing at a rate of around 20 percent a year, and solar PV at 35 percent.

If the costs of solar technology continue to drop, it has a chance to compete with other forms of energy production. In places like sunny California, solar has already reached “grid parity,” which means the costs of producing solar power are now competitive with conventional energy production even without government subsidies. Sinking production costs would allow solar power to eventually join or even replace coal, gas, and oil as a primary energy source by the end of the century, which some experts say is possible.

Global Resources and Producers

The amount of solar energy that reaches the Earth’s surface every 20 days exceeds the energy trapped up in all of the planet’s coal, oil, and natural gas reserves. The trick is finding cost-effective and efficient ways of converting this abundant resource into usable energy.

Currently, there are two main ways of doing so. Photovoltaic (PV) panels, thin pieces of crystalline silicon, transfer sunlight directly into electricity. Solar thermal collectors, on the other hand, are used to heat water for domestic or industrial use and to run steam power plants.

Germany is the world’s leading producer of PV and solar heating technology and energy. In 2006 alone, 968 Megawatts (MW) of PV was installed in Germany. Japan, which added 292 MW last year, is also an important market and exporter of PV technology. China is aggressively adding solar systems to its energy mix. The country already consumes half of all solar-heated water in the world, and aims to increase solar water heater coverage by 50 percent by 2010. China is also emerging as an important producer and consumer of PV cells, which the government is integrating in remote and urban area.

Energy Output

The energy output of photovoltaic and solar heating depends on the size location of the system. Most areas receive ample sunlight, but deserts that seldom get cloud cover are better suited for solar energy production.

Standard PV cells have an energy conversion rate of 6 to 8 percent, meaning that 6 to 8 percent of all solar power absorbed is turned into energy. Some prototypes have already achieved conversion rates of more than 40 percent, but are still too expensive for mass-market production. Solar heaters utilize solar collectors that are significantly more efficient. Current collectors turn between 60 to 70 percent of absorbed sunlight into heat.

Concentrated solar thermal systems use mirrors to reflect sunlight onto a tower, producing extremely hot temperatures to boil water or other fluids and produce steam to drive a thermal power plant. An 11 MW concentrating solar power plant was completed near Seville, Spain in March 2007. A 154 MW facility is planned in Australia, and a 500 MW system in California’s Mojave Desert.

Environmental Impact and Drawbacks

Manufacturing and installing solar systems requires energy, and as with almost any industrial activity, involves handling hazardous materials, such as arsenic and cadmium. Mass production of PV cells is sometimes marred by shortages of quality silicon. Large-scale solar power plants also take up lots of land.

Overall, however, the environmental impacts of switching to solar energy are positive. Solar heaters require significantly less fossil energy input than natural gas and electric systems. PV systems are cleaner energy producers compared to coal and oil. Greenhouse gas emissions of solar PV plant including production and installation are eight times less than that of a coal-fired plant.

The initial costs of solar heating and PV systems, however, prevent many homeowners from installing them. But falling costs and subsidies have helped sustain market growth in some countries. Like with wind turbines, another technical problem is effectively storing solar energy to provide power throughout nights and cloudy days.

Bob Lindner asked:


Solar energy can be used to create electricity, central heating, heated water, cooking, and even for producing salt desalination. Solar energy comes from the suns rays. Solar energy is known to be very environmentally friendly. However, when the suns rays move into the earths atmosphere it is quite dilute.

Although solar energy is known to be very environmentally favorable it does not only have advantages, but some disadvantages, as well. Lets hash out some of the advantages and disadvantages of solar energy.

Why don’t we start with the main advantage of solar energy. Solar energy is clean. To develop electricity or heat with solar energy you need only the sun rays. There is no need for fossil fuel in conjunction with sun rays to produce electricity or heating. You simply need a solar energy collector or solar power panels in order to collect the suns solar energy.

Solar energy is less expensive than traditional electric heating. That’s another prime reward of solar energy. Just by utilizing solar energy you can save a lot of money on heating. In return you will realize smaller electric bills and it also means that you dont have to maintain heaters or furnaces.

If you live in a rural area where there are no power-lines solar energy can be your solution. There are rural areas where power companies have no means to access your home. Solar energy is a great alternative because it provides you with everything from heating water, a supply of electricity, and even cooking, and that pretty well covers all of the bases.

Another great use of solar energy is for desalination in regions where fresh, potable water is scarce. Solar energy evaporates brine and leaves the salt crystals in the bottom of the basin. The water in turn condenses into another basin where it is now potable.

While all of the above-mentioned is very useful, solar energy does have some disadvantages. These disadvantages also need to be talked over to paint a complete picture.

The main disadvantage of solar energy is that its dilute. Which means that you need to have a bunch of solar collectors installed around your house. Solar energy may be very cheap but the solar collectors are relatively expensive and require regular upkeep in order to work properly and efficiently. If you decide to go with solar energy you will need to calculat your return on invested capital in order to know if the investment makes sense.

One big disadvantage is that you need the suns rays to make use of solar energy. If you are situated in a part of the world where there is not much sun light then you could have a bit of a problem. In other parts of the world, the suns rays are almost always covered in clouds making solar energy collectors less efficient. You should first know if the sunshine in your area is abundant for the most part of the year. Of course if you live in desert areas like in Arizona or New Mexico the sun produces a lot of sunshine for the majority of the year and is ideal for solar energy collecting.

Finally the sun only shines during the day. Therefore if you need electricity or hot water during the nighttime, like many of us do, it can be a problem. You will need a backup system like the local electric company or you will need to store the electric for later use. There are battery systems available, that can store electric for later use.

Solar energy is very clean and an substitute to conventional heating and electrical systems. this is true it is also good to mention the disadvantages of solar energy. If you are thinking about applying solar energy you should read this first to make a informed decision.

The advantages of renewable energy definitely outweigh any disadvantages. If you’re like me, and sick and tired of paying electric bills, that just keep doing through the roof, visit us at www.energymoneysavings.com

Grace asked:


Please tell me some disadvantages and advantages of using solar energy. Also need to know because it is a renewable resource. You can also tell me how solar energy is left and how long you last. Thanks so much. [Tell me some websites to vist about this information