PV Gap

Anita Said:

My electrical usage is about 312kw/month.How many solar panels would I need to generate that myself?

We Answered:

Er, my figures are quite a bit different to that.

Okay, you use around 10kw/h per day. That's pretty good, as most households use over 15kWh. Well done there.

I'm going to assume you're in an average area (as far as solar irradiation is concerned, so get an average of four solar hours per day.

To generate 10kw/h you'd therefore need a 2.5kw solar system (4 hours x 2.5kw = 10kw/hs)

So assuming you're buying an 'average' solar panel of about 175 watts, you'd need about 14 of them. But something very important to remember is that people become an average of 30% more efficient once they're producing their own power, which should bring your usage down to 7kw/h per day and would mean you'd need 10 panels.

By the way I've just purchased and installed a 7-panel 205 watt Sanyo system, which will power everything I need (My house uses about 5kw/h per day).

Hope that helps

You don't HAVE to have batteries by the way. Most solar systems these days have interactive grid connections. Much easier.

Vernon Said:

Storing Electrical Energy Collected through Solar Panels ?

We Answered:

Store the electricity from the solar panels in batteries.

Beverly Said:

Would you pay for electricity if you had solar panels?

We Answered:

Yes. At night or in cloudy conditions a computer will sense drop in available electric current and the Electrical company supply makes up for the shortfall.

The solar panels are coming down in price and eventually they will pay for themselves. Maintenance is low too. Also you have the good feeling and ability to crow about being a non-polluter.
The Electrical company will only ask money for what you use when it is cloudy or at night. Some use battery storage to get around or reduce this. If you have a surplus of electricity during a very sunny day for example, the electrical company will even buy the electricity back from you if you have this set up to do so.

Hector Said:

How much electrical energy is generated from one acre of solar panels?

We Answered:

In addition to what has been previously mentioned, keep in mind that solar panel production in kilowatt hours (kWh) depends upon the geographical location and the time of year. A solar array in Boulder, Colorado will produce more in a given day and in a given year than an array of the same size in Portland, Maine. That being said you can ballpark the kWh output of an array based on its size in kW. A more refined estimate can be made if you know the location.

For example, in New England, in ideal conditions - no shading - every 1 kilowatt (kW) of solar PV will produce about 1000-1200 kWh in a year. And every 1 kW takes up about 100 square feet of space. You can extrapolate from those numbers to your acre of panels. Identify about how many kW will fit in an acre and then multiply that times the annual production.

A great source is PV Watts from the National Renewable Energy Lab:
http://rredc.nrel.gov/solar/codes_algs/P…

Select the array location. Enter the array size in kW, and the program will output the annual kWh generation.
I hope that helps!
Kristen
http://newenglandbreeze.com/