Slashdot Mirror

I have not done in myself so I can't make a list of don't do's. I found this site which talks about things I've heard are important. http://www.solarexpert.com/instroof5.html I'd suggest getting several estimates now. Pick the lowest one, take 30% off and then let each contractor know that you would be ready to go forward when the price falls that far. Here are your incentives: http://www.dsireusa.org/incentives/index.cfm?getRE=1?re=undefined&ee=1&spv=0&st=0&srp=1&state=IA Doesn't look like anything important is expiring but check yourself.

I just did a few quick calculations. Assuming humans have 2 square meters of skin, and stood naked in direct sunlight in the best conditions for 8 hours per day, and assuming 5% efficiency for photosynthesis, we would only get enough energy to provide for 11 hours of sleep (250 BTU/hr), 7 hours of sitting still (400 BTU), 4 hours of light work (650 BTU) or 1 hour of heavy work (2400 BTU). We'd still probably need to consume 2/3 or so of our normal caloric intake from food.

Sources:
http://www.solarexpert.com/Heat-theory.html
http://hypertextbook.com/facts/2001/IgorFridman.shtml
http://www.answerbag.com/q_view/514275
http://www.ccmr.cornell.edu/education/ask/index.html?quid=1021

http://www.solarexpert.com/pvbasics2.html
http://en.wikipedia.org/wiki/Solar_cell

12 percent efficiency isn't very high, and cells are expensive.

What other data would you like to see? Seriously. How comprehensive do you want on slashdot?

Solar is good for isolated installations where grid power isn't going to be able to get to. It isn't mass production ready.

No I'm not an expert but I have talked with people who are.

Wind is far cheaper and more efficient. Still with solar and wind storage potential and efficiency also comes into play. Until that is improved a nuclear backbone or some CO2 backbone supply will be necessary as hydro power is fairly well tapped. That is unless people get hot-rock geothermal going which has yet to be tried.

Solar panels have a finite lifetime. Last I checked a few years ago that was about 20 years, may have improved since then. Also, the sun only shines a certain amount each day...for LA, you get an average of 5.6 sun hours per day (per http://www.solarexpert.com/Pvinsolation.html). So, let's do some math, assuming a 100-watt panel that costs $100.
100 watts * 5.6 = 560 watt-hours per day.
560 watt-hours * 365 = 204 kWh/year.
204 kWh/year * 20 years = 4080kWh over the lifetime of the panel.
$100/4080 kWh = $.0245/kWh.

Add in the cost of inverters, if you want power 24 hours a day you'd need batteries (which have about a 5-year life before needing replacement), and the costs do add up (I don't have inverter/battery prices in front of me, nor do I have the time to work up a full PV system plan right now, but the info is out there and just takes some basic math to figure out the total cost per kWh of a system over its expected lifetime).

But it doesn't matter because after Natural Gas is the most commonly used source of electricity generation on the California Power Grid. In addition a wopping 10% is already from renewable sources. http://www.energy.ca.gov/html/energysources.html It should be assumed that even if there was a need for new generation (a big possibility) that Natural Gas and Renewable sources would be the source of that generation. In addition people could install solor panels on thier roofs to add electricity to the grid during peak times. Currently if you do this you will recoup your ivestment in about 15 years.

The simple fact that it produces that much more engergy than traditional methods is a sure sign that we will never see it used.

The sun has existed for a very long time, and solar energy is still greatly lacking both in r&d (we only have about 12% to 60% efficiency on average depending who you ask, when higher should be possible) and implementation (e.g. as a replacement for fossile fule and/or nuclear).

A good implementation could requier relativly little or no maintenance and relativly little attention by employees while making a hell of a lot more energy. And the sun is FREE and READY NOW.

• Started an incentive program that grants a one-time payment of $4.50-$6.50/watt generated by homes or businesses connected ot the LA DWP power grid, starting 2000/9/1 and ending five years later.
• The State of California provides an income tax deduction of 15% towards the net cost of installed grid-connected solar electric systems. This new tax credit is retroactive to January 2001.