PV Gap

Joy Said:

what is the best solar panels to use on my new house(tube or flat)?

We Answered:

My solar thermal installation uses a 30-tube NAVITRON panel. This has an effective area of 2m2 and produces enough hot water in summer for 3 showers and plenty of washing up! I estimate that, in it's first year, it has saved me about £60 in gas.

The panels and prices are shown in the attached link. Mine was fitted by a professional installer for £2500, including a huge, new cylinder (dual coil) to store the extra hot water.

Flat panels are much less efficient than vacuum tube collectors. While flat panels are frequently cheaper, these Navitron panels are such good value that I think buying inferior, flat panels would be a false economy.

Cecil Said:

What is the best solar panel?

We Answered:

You have to decide which is more important to you, cost or efficiency.

The most efficient solar panels that are commercially available cost more than twice as much per square foot than the cheapest ones. Ultimately, I believe that the cost per watt was actually better on the cheaper, least efficient panels, but then you need a lot of square footage in order to generate any substantial power.

So it comes down to what you have more of, space or money.

The new panels that collect a wider range of light are not currently available commercially, and when they are I am sure that they will be expensive. I have read the research but have not heard of anyone mass producing them yet.

Daniel Said:

What is best value solar panels which are small and low maintenance or wind farms which are big and high?

We Answered:

For individual benefit, the solar panels are all that will work for most households.

As for wind farms, I don't know if it would be profitable to build one and sell the electricity at wholesale, unless there was a government incentive. If someone is trying to court you as an investor in a wind farm, I'd stay away.

Victor Said:

What percentage of rooftops in major cities have solar panels installed? Best estimate?

We Answered:

It varies substantiallyh by country. Germany and Spain do have 5%, and China is catching up.
The American South west is catching up, otherwise way below 5%.

One of the world's best purchase offers for solar generated power is in Ontario, Canada, and yet installations are proceeding very slowly because of very long wait times for solar equipment.

Yolanda Said:

What kind of solar panels are best and what method of storing power is the best?

We Answered:

The solar panels that are "best" are going to be the ones that fit your needs. Since you havn't explained them it is a bit difficult. Solar photovoltaic panels make electricity. There are many different types. (I recently saw information about tube photovoltaic collectors being installed over a greenhouse.)

Solar thermal panels make heat from sunlight but come in 3 major flavors: Solar air panels, solar thermal (water based medium) panels and vacuum tube collectors (often based upon phase change materials) Sometimes a distinction is made between vacuum tube collectors and "flat panel collectors" The cheapest collector will be the one you make yourself, but depending upon your skill level it may not be as effective.

The solar alternative to photovoltaic panels for home electricity is probably the parabolic dish collector with a stirling engine at less convience. There are few solar air panels made commercially as they are easy to make, have what might be the best payback for heating augmentation but need to be adapted to the situation so are often made in place. Solar hot water is probably the next best payback. Solar heat is easier to store with phase change materials than solar electricity is to store with batteries. For solar electric most would use a grid connection for backup.