PV Gap

Todd Said:

Solar/wind electrical generation?

We Answered:

You are absolutely correct! Your question pretty much answers itself!


Just to clarify further 2500 watts is 2500 joules every second. Theoretically this means in one hour the total amount of energy produced would be 2500 (joules/second) * 3600 (seconds in an hour).

But You and I know circumstances will change! Sun light will vary throughout the day. Therefore, the companies boast off by saying stuff like maximum power possible. In fact in my experience the maximum power is seldom possible depending on where you are located.

Luis Said:

Does anyone know a good website with a electrical-to-boiler schematic of a 3.6kW Element powered by solar?

We Answered:

Some wind turbines connect to a water heater, but that's called a dump load, to prevent the turbine from turning too fast. If the water is heated, that's incidental.

Running an electrical heater by solar is horribly wasteful. When water is to be heated, typically it is heated directly by the solar. This takes a fraction of the area (maybe 1/5 the size), and is much cheaper (maybe 1/6 the price).

Curtis Said:

How many wind turbines & solar panel farms (1 acre sized) would it take to power half of US electrical needs?

We Answered:

In 2004, the total energy consumption of the US was 90.94 Quadrillion BTU's or 3.2 TWh. This is from all energy sources not just electrical.

With 10% efficient Solar panels we can produce 0.5 KWh per day from 1 meter squared. So to provide for half the US energy needs from all sources never mind just electrical would require 2,179.45 acres

However the current record for solar photo-voltaic is now 42.8% efficiency not 10% with 65% just around the corner hence we should really only need 335.3 acres if we used the quantum dot 65% efficient solar panels.

Timothy Said:

Could solar panels be charged by a 90w LED UFO light?

We Answered:

Yes, but it would be inefficient.

Energy loss occurs every time you change the form of the energy. Some energy would be loss changing the energy from battery or A/C to light. Additional power would be lost changing the light energy to power from the solar cells.

So yes, you can. But why would you want to?

Ida Said:

how many solar panels do i need to power up my house?

We Answered:

Hey Martin, Shane may be close on the numbers, but it is all just a guess without knowing more about your house and your weather. You see, asking a question like yours is no different than asking, "How much gas does it take to run a car?" It depends on the car, the miles it is driven, driving habits, and so on. We have a home in the Northern Great Lakes that is completely powered by the wind and sun. The solar array is our primary power source, probably providing about 80% of our needs, more in the summer. Although our house is small, about 1200 square feet, and fairly efficient, our array fits nicely on the roof of our single car carport, maybe taking up 180 square feet, nothing nearly the size of a football field. All of our equipment cost just under $15,000, including the batteries. Today, if you can take advantage of net metering in your area, you don't need batteries or charge controllers, but you do need utility power. The grid becomes your battery in this arrangement. The only drawback is if the power grid goes down for any reason, you solar array goes with it. So you might find yourself in a situation where the sun is out, and you do not have access to the power in your own solar array. This can be frustrating to new owners.

My best suggestion is you get a subscription to Home Power Magazine, they are the only periodical that get into the nuts and bolts of what you are asking about. There are some good websites as well, I will list a few below. Don't waste your time asking hacks like me online for information, you get answers like football fields and barrels of money which distort the real facts. You can read about people who have done exactly what you are trying to do in the magazine articles, check out suppliers websites that advertise there and learn a great deal. In the end, you might decide not to get involved, and that's fine, but at least you will be well informed.

If you're a handy type and can do some basic wiring, I would suggest you start by getting one panel, a couple golf cart batteries and some DC breakers and switches and set up your own 12 volt power system. We did 12 years ago, even put 12 volt outlets in all the rooms. They still work today and continue to be handy for small electronics and lights. If you subscribe to Home Power, you can go online to their website and look up archived articles from years past. Our home was even featured in one some time ago. Use their search engine to look up, "Starting Small First," if you want to see it. I would also suggest going to an energy fair if you're really interested after looking all this up, they are listed in the magazine as well.

For comparison purposes, I will give you the specs on our homes system you were asking about above. This is the equipment necessary to run our home, with a little help from the utility company. Our electric bills average just under $5 per month.

Solar: 14 Kyocera KC-120 panels, total solar power 1.6 KW
Wind: Southwest Windpower H-40,. peak power 900 watts
Inverter: Trace Engineering SW-4024 4000 watts continuous, 10,000 watts surge limit
Batteries: Trojan L-16 model 360's, 20 total storing 1800 amp hours at 24 volts DC

Take care, and good luck, Rudydoo