PV Gap

Joel Said:

Solar Panels? 10 points?

We Answered:

you have energy and power confused.

15 watts is a RATE. It will deliver 15 watts of power as long as the sun is shining.

not 15 watts/hour, which is a meaningless term.

look at watts as miles per hour, a rate.

15 watts for 1 hour delivers 15 watt-hours of energy. for 24 hours it delivers 360 watt hours of energy. All at a rate of 15 watts.




In case I'm confusing you:

watts; power, rate of delivery of energy. Other units: BTU/hour, HP, joule/second

joules: energy, or work. Other units: watt-hour, kW-hour, BTU, foot-pound, watt-second

watts/hour: meaningless term. like miles per hour per hour.


.

Derrick Said:

It's all about Solar Panels?

We Answered:

Solar panels are still very expensive. You will typically spend something around $20,000 to get a 4kWp system which will, over a year, produce about 8,000kWh in sunny California, or 3,500kWh in cloudy Britain.

3,500kWh would have powered my house of 5 people comfortably for the past few years, but you make far more power in summer than in winter; so you have to still be on the grid and sell it in summer, buy it in winter.



In most cases, solar panels are not economically viable. Prices are falling a lot - from 1990->2000 they dropped about 75%:
http://www.solarbuzz.com/StatsCosts.htm
And thin film solar panel power stations are about 50-60% cheaper now than solar power was in 2000. But they're still not economic in most places.



Mike K's claim that solar panels produce more pollution than 'traditional' power is wrong. Coal is over 900g CO2/kWh, plus loads of pollution. Gas is ~400g CO2/kWh.

Solar is 60-150g CO2/kWh:
http://igitur-archive.library.uu.nl/cope…
Future technologies, like thin film printing, are 20-30g CO2/kWh:
http://igitur-archive.library.uu.nl/cope…

The wide range comes from how sunny it is in your area.



I've done some work with CdTe solar panels and all of the materials are recyclable; the biggest company puts money by to recycle every panel they sell. The energy use is also much smaller than that needed for pure silicon wafer cells.

Brad Said:

When electric cars go mainstream, what do you suppose will happen to your electric bill?

We Answered:

As it stands now, it is cheaper to maintain and operate an electric car. I recently converted a small pickup to full electric and it costs me around $2.15 per charge, with a range of 42 miles per charge. I charge it 3 times a week. That is cheaper than operating the gasoline powered car I was driving. See it at www.evalbum.com/2340