What is Renewable Energy?
Most of the renewable energies can be said to be both solar and renewable. Most of our "renewable energies" get their basic energy from solar radiation. Wind is caused by the heating action of the sun; hydro relies on the hydrologic cycle (which relies on the sun); and geothermal is technically "stored solar energy."
In a more general sense, "renewable energy" is any energy that is self-replenishing. For example, we do not need to find new 'reservoirs' of wind, solar or geothermal energy. The energy is always there, though critics note that these are usually "limited flow."

What does "energy conversion efficiency" mean?
Energy conversion efficiency is an expression of the amount of energy produced in proportion to the amount of energy consumed, or available to a device. The sun produces a lot of energy in a wide light spectrum, but we have so far learned to capture only small portions of that spectrum and convert them to electricity using photovoltaics. So, today's commercial PV systems are about 7% to 17% efficient, which might seem low. And many PV systems degrade a little bit (lose efficiency) each year upon prolonged exposure to sunlight. For comparison, a typical fossil fuel generator has an efficiency of about 28%. (from EERE.gov)

Can I really use renewable energy to power my home or business?
Many renewable energy systems can be compatibly blended with the regular electricity provided by your local utility. This is called grid integration and it is increasingly popular around the world and in the USA. Today the U.A.E are working on it.

Can I install it myself?
Maybe — if you are a pretty good electrician. You would be better off seeking out a licensed installer who knows all the ins and outs of electricity, codes and regulations in your area.
You are also likely to void warranties if you self-install. And don't forget that electricity can be very dangerous.

What are the environmental benefits of renewable energy?
Every kilowatt-hour of electricity produced by a renewable energy system displaces the same amount of electricity produced by conventional power generation stations that are using fossil fuels that contribute to CO2, SO2, NOx and smog. Clean renewable energy production reduces suspended particulates we usually call smog, which are a significant health problem on the same hot sunny days when (for example) a solar energy system can produce electricity at its peak level.

What are the disadvantages to using solar and renewable energy?
The biggest disadvantage and the only truly significant one remains the cost. For example, solar energy technologies require a significant initial outlay. Still, in nearly all cases, this high initial cost is recovered through substantial fuel savings over the life of the product (15-30 years), and solar energy systems can last much longer than this. But in areas where there are no hydro wires, choosing solar is as obvious as the sun in the sky.

Is there a difference between solar thermal and solar water heating?
Yes. The Solar Guide uses solar thermal as a catch-all term, but it is important to note that solar thermal and solar water heating fall into three or more very different types of systems:
Solar thermal water heating systems heat water for your home. They do this using heat exchange or by directly heating the water. For more information, see The Solar Guide's section on solar thermal.
Solar thermal also applies to solar floor heating and space heating.

Why would I choose solar thermal or solar water heating?
Solar thermal and other solar water heating systems (solar pool heating) are easy to install and can work year round to heat water for your home. These systems pre-heat your water before it enters your hot water tank. Free heat of the sun (year round) gives you significant savings on your energy bill.
Solar water heating systems cost is depending on the type of system you choose. These can reduce your hot water heating bill depending on how much you use and where you live. The payback period for an investment in a solar thermal water heating system is three to five years in European countries. After that, the savings are all yours and systems have been known to last longer than twenty years.

What is the best solar thermal system?
"Best" is a relative term. We'll answer your question in terms of most practical, most reliable or most energy efficient, but these all depend on where you live.
For any climate where it freezes, the use of a closed loop thermal glycol based solar system might be the only practical choice. Drainback systems are also used under these conditions, but these are not as popular because they are not quite as reliable.
For warmer climates, another collector that are the most energy-efficient is thermosiphon. It requires no electric pumps to operate (in technical terms, this makes it a passive solar thermal system). The sun heats the fluid until it rises to the top of the panels, where it flows into a tank or heat exchanger. From the heat exchanger, only the hottest water is skimmed off from the top of the tank as you draw down the hot water.

How many solar thermal panels would I need to heat water for my home?
You can get the best answer to this by contacting us. This will depend on how many people in your household, on how much hot water you use and how much sunlight you receive.
However: a typical family of four might require four square meters, and we can roughly guess that a square meter per person is a fairly accurate estimate. But don't hold us to that!

What is the difference between solar thermal and photovoltaics?
Solar thermal systems generate heat (for water or air) with the radiation of the sun.
A solar photovoltaic system uses solar radiation to generate electricity
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How does the conversion of solar energy to heat in a glycol-based system work?
Solar radiation hits the absorber (solar thermal panel) and is then transmitted to the heat transfer medium (glycol, usually) and converted to heat. The vacuum plus the insulation provided by layers of the absorber assure that heat remains in the solar thermal system.
Solar thermal systems with glycol use a composite tube that is made up of a jacket tube and absorber tube. Since these are made completely of glass, they are well-protected against degradation.

Do you really think solar and renewable energies are a good investment?
Yes. Solar energy and other forms of renewable energy (such as geothermal) will become cheaper as people continue to invest in them. When people invest in them, this will drive down the cost-- as it already has over the last few decades. This has a snowball effect: the technology becomes increasingly usable, cheaper and convenient.
Look at changes in satellite dish technology: twenty years ago, they were gigantic wieldy things only people in the country bought. As more people invested in these, though, the cost went down, the technology got more compact and now they are everywhere-hardly noticeable. Recent developments indicate that this is becoming true of solar energy, too. For example, see our page on building integrated photovoltaics.

How much do any of these renewable energy systems cost, and how much will I save on utility bills?
There is no single or simple answer, even if you are only talking about one kind of energy, such as solar. Some short answers we can give here:
They are all definitely in the thousands.
Solar and renewable energy rebates as well as other incentives can reduce the cost of any RE system.
The size of the system is of course a factor.
For solar thermal, you have to consider the price of the fuel used to back up the system.
The price of other sources of energy will continue to rise, so who knows how much money you will save in the future?
It also depends on how much you pay your utility for electricity or natural gas, and how much your utility will pay you for any excess power (with net metering) that you generate with your solar system (sadly no regulation yet in U.A.E).
You can ask your renewable energy system provider how much your new system will produce on an annual basis and compare that number to your current annual electricity or hot water demand to get an idea of how much you will save.