PV Gap

Bruce Said:

How/where can you get data with solar cells(solar energy) ?

We Answered:

"with...?" Do you mean where to find data *about* solar cells?

Here's an excellent article about solar cells:
http://en.wikipedia.org/wiki/Solar_cells

If you mean technical data, as in a manufacturer's data sheet, here's a fairly typical one:
http://www.jameco.com/Jameco/Products/Pr…

If you truly mean "how do you transfer data from one location to another using photocells", I'm not aware of any reliable way to do this. Photocells would make a poor choice for data transfer. I do not think they would react fast enough to keep up with a realistic data stream.

Timothy Said:

With solar energy so abundant, why don't certain states that have plenty of sunshine, create super solar cells?

We Answered:

It might be less expensive to fit all new construction with solar panels to capture solar energy on a small scale but ultimately on a large scale. As new communities spring up, each house would be like a cell in a plant but the total community would be a mega generator. In sunny climates there might even be surplus electricity to sell to the power company and so to the electrical grid, thus reducing the amount of fuel (oil, gas, coal) needed to provide electricity.

Andre Said:

What are solar cells ideal energy sources for satellites?

We Answered:

No moving parts. Unlimited supply of energy unless the sun is blocked. Lightweight compared to other energy sources. The lack of clouds and atmosphere allow the solar cells to function at their optimal efficiency. They only lose about 1-2% a year of their efficiency as long as they are orbiting in lower radiation zone (above 2000 km they can lose 50% per year).

Batteries don't last long without recharging. Fuel cells eventually run out of fuel. Nuclear power sources in space freak out everyone so they don't attempt to send them into space. There aren't many other sources to choose from.

See:
http://www.solarnavigator.net/solar_pane…

Glen Said:

What elements are the best choices for storing solar energy captured by solar cells? Why?

We Answered:

There is nothing in the periodic table of elements that is a good choice for storing solar energy. For that matter, solar cells produce electrons, which can only be stored in a rechargeable battery of some kind or a capacitor of some kind. Alternating currents cannot be stored at all. A capacitor capable of storing enough electrons to be commercially useful for grid power would be extremely large and extremely dangerous. Even the best of rechargeable batteries today have limited energy densities, too small for commercial grid power. Photoelectric elements lie along the semi-metal line in the periodic table - arsenic, silicon, gallium, etc.
Silicon dioxide and gallium arsenide are the present industry leading materials in photoelectric devices. The molecular key is that the bond energies of electrons in these substances are equal, approximately, to the energy levels of certain photons, so capturing such a photon knocks loose an electron, which can be collected with others into an electric current. Better capture rates require a mixture of materials such that photons of any wavelength can be captured and used to liberate electrons.

Walter Said:

Where can I get wires to connect to commercial solar cells to get the energy ?

We Answered:

Wire is wire. Use wire heavy enough to handle the current and good enough insulation to handle the outdoors conditions.

Sherry Said:

renewable energy: solar, cells, or biomass?

We Answered:

biomass is a small fraction of solar energy, indeed it is solar energy converted to chemically stored energy via photosynthesis. The maximum theoretical efficiency of photosynthesis is only 6.6%, when you take into consideration that first generation bio-fuels only use the food grade part of the plant then you can see that it's only a fraction of a fraction of 1% efficiency that you get. Compare this with the current photovoltaic record efficiency of 42.8% Fuel cells are a matter of storing energy chemically as hydrogen, the energy can be generated through solar photovoltaics, solar thermal, wind, hydro, tidal, geothermal, nuclear or even ancient stored solar (fossil fuels). Unfortunately hydrogen is a terrible way to store energy as it's volumetric energy density is extremely low (405 WH/l for compressed hydrogen compared to gasoline's 9,000 WH/l). It's an irony of nature that a gallon of gasoline contains more hydrogen then a gallon of liquid hydrogen. Hydrogen is also difficult to contain for any period of time as it's the second smallest gas molecule possible and will diffuse through any material you wish to make the pressure vessel out of. When Sandia Labs investigated more efficient ways of obtaining hydrogen from water, they concluded that it would be better to use the methods found to synthesize liquid hydrocarbon fuels such as gasoline and diesel instead of just producing hydrogen. The liquid fuels could be distributed by existing infrastructure and used in existing vehicles and avoid all the containment and density problems of hydrogen.

Ultimately solar is the future but 1 MW of solar photovoltaic panels can cost 5 million to 10 million dollars US. Megawatts is a unit of power which is energy per unit time so there is no MW per hour with it, however a MWh is a unit of energy ie.: power multiplied by time.

You could reduce this cost by going with solar thermal which should be one tenth the cost of solar photovoltaics but then you are producing steam to drive a steam turbine hence have the added cost of the turbine generator and it's maintenance.

Wind power turbines are typically available in 3 MW turbines so that may be an option, but these costs millions of dollars as well plus they have a high maintenance cost.

You could use gasifers to burn biomass in the form of woody matter, trash, old tires, and dried sewage to form syngas which can then be used to run gas turbines. You would have the option of using natural gas for the gas turbines should there be a problem with the logistics of getting the biomass but that is the achilles heel of this method, collecting and handling the biomass.

Small portable gasifiers could be brought out to the biomass sources and portable Fischer Tropsch reactors could then convert the syngas to liquid hydrocarbons like diesel for transport to where you need to generate the power or sold to the nearest refinery to avoid transportation costs and power then purchased as needed with the proceeds. The portable solution will allow you to take advantage of storm debris cleanups. This technique has been proposed for recovering stranded natural gas from remote wells.

Now if it's 1 MWh of energy that you need over a month not 1 MW of power then since there's about 700 hours in a month of which you can expect a third to be useful solar power, you would only need 4.5 KW of generation capability and that would only be 25 thousand to 45 thousand dollars.

As this is a business, and hence not as likely to be subject to home owners associations or deed restrictions then wind power will be the most cost effective, again only expect a third of the time to be useful for generation as the steadiest winds blow at night.

Microhydro is very cost effective provided that you have access to a water resource (stream or river) and that you actually have water rights to tap that energy. Hydro is also more consistently available so the generation capacity can be a third that of solar or wind to achieve the same total monthly energy generated ( i.e.: 1.5 KW instead of 4.5 KW ). The water rights can be very complicated and could result in you having to pay anyone upstream who has the capability of retaining water since their reserves act as reserves for your flow as well.

First, you need to determine if it's 1 MW of power that you need or 1 MWh of energy per month that you need. Some details as to what you intend to do with the power would help us comment on what's suitable.

Tara Said:

What are the environmental factors when using solar cells as an energy source ?

We Answered:

Light