India need the other kind of solar power..

our country is very reach in the source of sun light.And this is one of the most positive and golden opportunity for we all Indians to use it.In our country there is a lot solar power plant but we haven’t solar thermal plant.This time we are using solar thermal is only as a solar water heater,but it is a also great scope in to use it as a solar thermal power station for generating power.

https://mydreamismypower.wordpress.com

Solar-thermal power stations have several advantages over solar-photovoltaic projects. They are typically built on a much larger scale, and historically their costs have been much lower. Compared with other renewable sources of energy, they are probably best able to match a utility’s electrical load, says Nathaniel Bullard of New Energy Finance, a research firm. They work best when it is hottest and demand is greatest. And the heat they generate can be stored, so the output of a solar-thermal plant does not fluctuate as wildly as that of a photovoltaic system. Moreover, since they use a turbine to generate electricity from heat, most solar-thermal plants can be easily and inexpensively supplemented with natural-gas boilers, enabling them to perform as reliably as a fossil-fuel power plant

Storage and hybrids

Both power-tower and parabolic-trough systems can store thermal energy in the form of hot, molten salt. It is then possible to generate steam, and thus electricity, even when the sun is not shining. Solar-thermal plants without storage can operate about 30% of the year; but with storage that number could climb to 70% or higher. Unfortunately storage is expensive, and is only economical when regulators provide incentives. In Spain, for example, producers of solar-thermal power receive a guaranteed feed-in tariff. That makes it particularly appealing for Spanish plants to have storage capabilities, to maximise their ability to sell electricity to utilities. In America the main incentives for solar-thermal projects are a 30% investment-tax credit or an equivalent cash grant. As a result, American plants have to be built more cheaply in order to make a profit, and thus typically do not include storage.

Power from a parabola

A cheaper alternative to storage is hybridisation. All the original Luz plants also have natural-gas boilers that can generate steam when the sun is not shining. Because solar-thermal plants have a power block and turbine already in place, the extra cost is marginal. Hybridisation could also be done the other way around, by using steam generated from solar-thermal collectors to help drive the turbines at existing coal or gas plants. The Electric Power Research Institute, based in Palo Alto, is studying the feasibility of this approach as a means of reducing fuel costs and emissions at existing power stations.

In addition to parabolic troughs and power-towers there is also a third solar-thermal technology, which combines curved, dish-shaped mirrors with heat engines. In a dish-engine design, the mirrors concentrate sunlight to generate heat, which then typically powers a Stirling engine—a machine that converts heat into mechanical energy by compressing and expanding a fixed quantity of gas. The change in pressure drives the engine’s pistons, which drive a shaft that turns a generator to produce electricity.

Although they are highly efficient, Stirling engines have seen little practical use since their invention nearly two centuries ago, and so far there are no commercial solar-thermal systems that use this approach. Critics of the technology say it involves too many moving parts, making it more complex and expensive to operate and maintain than competing technologies. Stirling Energy Systems, based in Phoenix, Arizona, hopes to prove the doubters wrong. It has signed two large power-purchase agreements, for up to 1,750MW, and plans to fulfil them using dish-engine systems built in conjunction with its sister company, Tessera Solar. Both projects are due to start construction as early as 2010.

–  thankyou ambuj

Longing for Gravity – in the clouds

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You are on a mission to Mars. Because of the length of the journey, you will never be able to return to Earth. What about our blue planet will you miss the most?

The only reason that I am leaving the planet earth is because a terrible disaster has occurred. It is not because mankind can not get along, so the wars that were happening across the globe were not a factor. It’s not because of global warming, in fact the opposite has occurred the temperature on the planet has risen and in the desserts there is snow. How could this happen? I lived in Florida and the average temperature for the last several years has been 40 degrees Fahrenheit. Florida along with Texas is the warmest spot in the U.S. and everyone is moving here. That’s the disaster!! Too many people, housing is impossible and it’s become so expensive.my dream is my power

So I am standing here in line to board a spaceship to Mars, where it’s hot and there is lots of space. What I will miss most about this beautiful blue planet known as Earth are the clouds; fluffy white clouds and on some days the clouds are grey and dark and deep and eerie. I will miss them both, the friendly white billowing clouds that can look like anything in your imagination and the large ominous clouds that blow in on a large cold front which will bring in a storm.

So sorry to be leaving! But I have lots of pictures. So although I will not see the clouds again I will remember them and the joy I got from watching them in the sky.

ambuz