- The 40 kilowatt DuPont solar photovoltaic (PV) array could power about 8 typical homes in the mid-Atlantic.
- The annual CO2 emissions displaced by DuPont’s solar array are equivalent to taking about 8 cars off the road every year.
- A residential energy system typically costs about $8 to10 per watt. Where government incentive programs exist, together with lower prices secured through volume purchases, installed costs are as low as $3 to 4 a watt, or 10 to 12 cents per kilowatt-hour can be achieved.
- The most frequently seen application of PV is in consumer products, which use tiny amounts of direct current (DC) power, less than 1 watt. More than 1 billion hand-held calculators, several million watches, and a couple of million portable lights and battery chargers are all powered by PV cells.
- PV-generated power correlates well with utilities' daily load patterns, because the power is available when it is needed most—during daylight hours.
- Every hour, the sun radiates more energy onto the earth than the entire human population uses in one whole year.
- Only 2% of the nation’s energy supply comes from clean sustainable sources like solar and wind energy.
- All of California's electricity can be produced from 200 square miles of sunshine; 128,000 acres of desert land.
- PV modules covering an area about 100 miles by 100 miles of the land in the United States, one-third the land occupied by roadways, could supply all the electricity consumed here.
- The cost of larger PV systems (greater than 1 kW) is measured in "levelized" costs per kWh – the costs are spread out over the system lifetime and divided by kWh output. The levelized cost is now about 30 cents/kWh. At this price, PV is cost effective for residential customers located farther than a quarter of a mile from the nearest utility line. Reliability and lifetime are steadily improving; PV manufacturers guarantee their products for up to 25 years.
- About 70% of U.S. solar cell production is exported, mostly to developing countries where 2 billion people still live without electricity.
Currently, 48 states and a U.S. territory have some type of solar or renewable incentive – including investment credits, rebates, sales tax, or property tax waivers.
Consider this:
The solar energy available in a 100 mile-square area of Nevada desert could supply the United States with 100% of its electricity needs. This area is represented by the green square. The black square represents the area of the United States that is covered with roadways…three times as much.
A more realistic scenario involves distributing these same PV systems throughout the 50 states. Currently available sites – such as vacant land, parking lots, and rooftops – could be used. The land requirement would average out to be about 17 x 17 miles per state. Alternatively, PV systems built in "brownfields" – the estimated 5 million acres of former industrial sites in our nation's cities – could supply 90% of America's current electricity.
Energy Payback
The energy payback period for today's typical solar panel is about 4 years to generate more energy than went into making the module in the first place. The next generation of silicon modules, which will employ a different grade of silicon and use thinner layers of semiconductor material, will have an energy payback of about 2 years. And thin-film modules will soon bring the payback down to one year or less. This means that these modules will produce "free" and clean energy for the remaining 29 years of their expected life.
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