By the time it reaches Earth's surface, the energy in sunlight has fallen to about 1,000 watts per square meter at noon on a cloudless day. Averaged over the entire surface of the planet, 24 hours per day for a year, each square meter collects the approximate energy equivalent of almost a barrel of oil each year, or 4.2 kilowatt-hours of energy every day. Deserts, with very dry air and little cloud cover, receive the most sun—more than six kilowatt-hours per day per square meter. Northern climates, such as Boston, get closer to 3.6 kilowatt-hours. Sunlight varies by season as well, with some areas receiving very little sunshine in the winter. Seattle in December, for example, gets only about 0.7 kilowatt-hours per day. It should also be noted that these figures represent the maximum available solar energy that can be captured and used, but solar collectors capture only a portion of this, depending on their efficiency. For example, a one square meter solar electric panel with an efficiency of 15 percent would produce about one kilowatt-hour of electricity per day in Arizona.
Group items matching
in title, tags, annotations or urlMaking Biodiesel - 1 views
2More
New Platinum Could Mean Cheaper, More Efficient Fuel Cells - 0 views
Biodiesel Performance, Costs, and Use - 0 views
« First
‹ Previous
301 - 320 of 368
Next ›
Last »
Showing 20▼ items per page