how many solar cells do we need to power the entire united states?

Answer 1

Let's see. A "big" solar cell turns out 300watts. Figure you get an average of 7 hours a day of sun (that's a lot), you have 2.1kwhrs per cell. Figure that a house requires about 35kwhrs per day. That means you would require 16 solar panels per house, without allowing for storage and inversion losses. Say 20 panels all in. Say there are 100,000,000 households in the US. That works out to 2,000,000,000 solar panels, not counting industrial and governmental usage. Don't hold your breath for this to happen.

Answer 2

In 2003, the total electrical energy production in the USA was 3.892 trillion kWh.
The energy that comes from the Sun is estimated at about 1000 w per square metre, high noon, equator, no cloud. The best solar cells have a 20% conversion efficiency.
In the USA, the average power received (thus taking into account clouds and so on) is between 4 and 6.5 kWh/day per square metre.
Taking all the "best" hypothesis, and assuming that batteries or some other lossless storage system allows to load up energy during the day to answer night demand and peak demands that vary during the year, we can see that there is thus a need for 32.8 billion square metre of photovoltaic cells, or 32800 square kilometre. That is a square 181 km in size (113 miles) entirely covered by solar panels.

Answer 3

Considering the efficiency of solar panels, you would probably need to cover the entire United States with solar panels to create enough electricity, and that might not even be enough, but don't forget that when the sun goes down, the power goes out. So don't count on being warm during a snow storm or anything like that. For reliable electricity to cover the necessities of life we need energy sources that we can control- like oil, nuclear, and coal. We know how much we have of these sources and how much electricity they can produce at a certain time. This covers what is called the base load. Then there are peak times when electricity is on high demand. Each region of the world and country can use the renewable resources they have in the area to cover these peak loads. For example, more people use electricity in the late afternoon and early evening for things like cooking, air conditioning, etc. In coastal regions, the wind starts to blow at this same time because the land is warmer than the ocean, warm air rises and cool air from the sea blows in. Windmills may be efficient ways to cover peak load demands in energy in these areas and reduce the demand for fossil fuels. However, when the wind isn't blowing, there won't be power, so you can't totally rule out fossil fuels. Just the same for areas that don't have sun or when you need to turn the light on in the middle of the night to go to the bathroom or you want your refrigerator to keep working so your food stays fresh. You can't rely on solar power for everything because it doesn't work continuously.

Answer 4

The amount of sun sent to earth in one hour can take care of humanity's electric needs for one year! We just need to get on the ball and put solar panels all over. It is so amazing that in the oil cartel nations that the people are without electricity during these oil wars! It is ridiculous that these oil nations have not used their wealth and fossil fuels to produce solar panels and solar power plants for their desert countries-citizens. Peak oil arrived to the US in mid 70s. We are very close to peak oil globally, so we are on the verge of the solar revolution, esp in CA which has legal mandates now for the next decade. One million bldgs must be solarized in the next decade in CA. We are renting solar panels this fall for our home. Company will have 100K homes solarized in first year of business. We could feasably go 25% solar in 25 years, 40% in 40 years, whereas now we use less than 1%. Ridiculus, isn't it? I have been trying to go solar since 1981 and it has been too expensive. Renting is the only thing I can afford, but at least I can now be part of the solution and not the problem. I look forward to renting solar and plugging in an electric car and not buying toxic fossil fuels. We can all do our part now. Rethink solar and join the solar revolution.

Answer 5

to practically power a large house with the usual electrical appliances running 24/7, u'd need to cover the whole darn roof and install a power storage system in the form of a roomful of batteries for nighttime. to power the country u'd need to cover every roof in the country, and to balance out usage variations and industry requirements with things like snow, rain, just cloudy weather and other things like leaves on the roof that'd reduce output u'd need to connect every building to a national or at the least a state grid anyway.
so how much roof has the nation got? than divide by the sizes of panels to use, which vary.

Answer 6

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