PV Gap

Lewis Said:

How much energy does a 1 KW Solar PV system produce?

We Answered:

It's easy to mix the terms "kWh" and "kW" but it can confuse listeners. kW is power. If you expend a certain power, say 2000 watts (= 2kW) for an hour, you've spent 2kWh in energy. (You probably understand this; apologies as needed...)

The solar industry around me, 25 miles east of San Francisco, says that a mounted solar panel (which doesn't track the sun) will get the equivalent of 4.3 hours of sunlight on an average day. I had a company quote a small 1.5 kW system (4 panels I recall) and they wanted $11,000 for it. I understand there are some best-of-all-time rebates right now so the cost ought to be a lot lower than 11k.

So you can expect 4.3 kWh / day. That isn't much energy. My electric bill showed over 500 kWh for the month and it was so cool this past month that we didn't need air conditioning - so 500 kWh is a low figure for us (1140 sq ft, single story house, walnut creek, calif).

The posted comment about "tiered electric rates" is worth tracking down. A typical residence around us has a rate starting at 11.5 cents / kWh for the 1st 180 ish kWh, then the rate jumps to 13 cents, then to 22, then to 41 cents. If your setup can put a dent in the 41 cent usage, you may have a winner.

Also ask your power company if the panels don't qualify you for a tamer electric rate. Around here, having professionally installed panels does qualify you for such a rate. Just having some panels may qualify you for a rate which ends up saving you some money.

Wesley Said:

Solar Energy to Electricity without PV cells?

We Answered:

I'm very interested in your ideas on this. You might want to try http://www.builditsolar.com and http://www.homepower.com for ideas. Both these sites are loaded with information. Another source would be to check out the back issues of Mother Earth News. They have the info online and you can purchase all back issues on CD.

Jack Said:

What are some uses of Solar energy other than solar panels?

We Answered:

There is Solar Thermal Systems and Pool Heating Solar System, Solar Lighting, Solar Attic Fans... There is a lot of solar energy being used out there if you want more information about them all you can go to http://www.arosaenergy.com/residential.html!
Good Luck hope you get a good mark!

Marlene Said:

What is the way of calculation output energy of a solar PV system for a given Global radiation value?

We Answered:

Um I am not quite sure as to what you are asking but I will guess. If you know how much average power is incident on the surface of a particular place on earth then multiply that by the average efficiency of the solar cells.

Gina Said:

How do I calculate the number of watts of PV solar panels needed to get 1 Kwh of energy/month?

We Answered:

The 100w rating means it will generate 100watts in full sunlight.

1000 watts (W) = 1 kilowatt (kW) = 10 x 100 watts

Thus, in ten hours, you will have generated 1kWh with a 100w solar panel.

In one month, 8 hours/day x 30 days = 240 hours, 240 hours x 100w = 24000 watt-hours or 24 kilowatts (kWH).

Assumes you can get full sun 8 hours per day (dawn and dusk is not full sun), and no rainy days.

If you really want the sunlight info, you can start with a site like weather.com. Your local power utility may have some data, as well as some agriculture links.

For panel output info, check with the manufacturers directly (probably via email, not look up on site). They usually will have testing and performance data of their own stuff.

Good luck!