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Let's figure out just how much area we need for solar panels. The US consumes about 19.05M barrels of oil per day. Each barrel of oil is about 1.6 MWh of powe

Let's figure out just how much area we need for solar panels. The US consumes about 19.05M barrels of oil per day. Each barrel of oil is about 1.6 MWh of power. So this is 31017210 MWh (3.1 x 10^10 kWh) of power just in oil every day.. The solar constant is 1.36kW/m^2 on average. Solar panels convert solar energy into power with roughly a 14% efficiency or about 190W/m^2 or about 2.2kWh/m^2 in 12hrs. Taking 3.1 x 10^10 kWh/(2.2kWh/m^2) I get 13 x 10^9 m^2. Converting this to miles gives us about 5240sq miles of solar panels just to get the same amount of energy we consume in oil. Hopefully I did everything right above.

toomuchtodo 11y ago
You're comparing a barrel of oil directly to electricity, a fallacy. Electric vehicles are extremely efficient photon to road compared to combustion vehicles. "Tank-to-wheel efficiency of conventional Otto cycle car is only 16% as illustrated fellow. Here, Otto cycle engine loss is 72%, standby /idle loss is 10% and drive line loss is 2%. Accessories loss, such as air conditioning unit consumes 2% but for comparison purposes, it was assumed 0%." That's right. You're losing almost 90% of your available energy to heat. In all practicalities, you use less than 1% of energy available in a barrel of oil to move a car forward. http://www.asahi-net.or.jp/~pu4i-aok/cooldata2/hybridcar/hybridcare.htm http://www.asahi-net.or.jp/~pu4i-aok/cooldata2/hybridcar/hyb... "That’s right, an electric car is over four times as efficient at turning energy into motion." https://matter2energy.wordpress.com/2013/02/22/wells-to-wheels-electric-car-efficiency/ https://matter2energy.wordpress.com/2013/02/22/wells-to-whee... Please see /u/Brackenshire's post (https://news.ycombinator.com/item?id=9676675 https://news.ycombinator.com/item?id=9676675) regarding land required.
Brakenshire 11y ago
The NREL have done this calculation, it comes out with a total figure of about 0.6% of the US landmass, 50 times less than the land allocated to growing crops. Although that figure includes Alaska, it gives a pretty good idea, and the state by state percentage areas to generate their share of US national electricity demand are also given: http://www.nrel.gov/docs/fy08osti/42463.pdf http://www.nrel.gov/docs/fy08osti/42463.pdf

toomuchtodo 11y ago

You're comparing a barrel of oil directly to electricity, a fallacy. Electric vehicles are extremely efficient photon to road compared to combustion vehicles. "Tank-to-wheel efficiency of conventional Otto cycle car is only 16% as illustrated fellow. Here, Otto cycle engine loss is 72%, standby /idle loss is 10% and drive line loss is 2%. Accessories loss, such as air conditioning unit consumes 2% but for comparison purposes, it was assumed 0%." That's right. You're losing almost 90% of your available energy to heat. In all practicalities, you use less than 1% of energy available in a barrel of oil to move a car forward. http://www.asahi-net.or.jp/~pu4i-aok/cooldata2/hybridcar/hybridcare.htm http://www.asahi-net.or.jp/~pu4i-aok/cooldata2/hybridcar/hyb... "That’s right, an electric car is over four times as efficient at turning energy into motion." https://matter2energy.wordpress.com/2013/02/22/wells-to-wheels-electric-car-efficiency/ https://matter2energy.wordpress.com/2013/02/22/wells-to-whee... Please see /u/Brackenshire's post (https://news.ycombinator.com/item?id=9676675 https://news.ycombinator.com/item?id=9676675) regarding land required.

Brakenshire 11y ago

The NREL have done this calculation, it comes out with a total figure of about 0.6% of the US landmass, 50 times less than the land allocated to growing crops. Although that figure includes Alaska, it gives a pretty good idea, and the state by state percentage areas to generate their share of US national electricity demand are also given: http://www.nrel.gov/docs/fy08osti/42463.pdf http://www.nrel.gov/docs/fy08osti/42463.pdf