Energy Musings.
Dec. 6th, 2006 08:20 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
swestrupCurrently the United States consumes roughly 4e9 (4 billion) kilowatt-hours of energy per year, counting all energy sources (coal, oil, gasoline, etc). There are also about 3.9e7 (37 million) acres of paved land in the US (roads, highways and parking lots).
I've often wondered how much energy could be generated if some way of making roads out of solar cells could be found. After all, most of that pavement is bare, most of the time. A bit of Googling shows that the average square meter of land in the US receives 7.5 kilowatt-hours/day of radiant energy. A 15% efficient solar cell would therefor produce .9 kw-h/day of energy per m^2.
Well, 3.9e7 acres is roughly 1.58e11 m^2 for a total yearly energy output (assuming no distribution losses) of 5.17e13 (51 trillion) kw-h. This is something like 13,000 times the total power consumption of the US. Even with really bad distribution efficiency, its clearly a win.
And here I thought we might have to roof our buldings with solar cells too, to get enough power. Aparently not.
Oh, and that 15% efficiency? Thats typical of todays solar cells. The US Department of energy recently announced a 40.7% efficient solar cell had been developed. That would give more like 35,000 times the needed power, rather than a paultry 13,000 times...
I've often wondered how much energy could be generated if some way of making roads out of solar cells could be found. After all, most of that pavement is bare, most of the time. A bit of Googling shows that the average square meter of land in the US receives 7.5 kilowatt-hours/day of radiant energy. A 15% efficient solar cell would therefor produce .9 kw-h/day of energy per m^2.
Well, 3.9e7 acres is roughly 1.58e11 m^2 for a total yearly energy output (assuming no distribution losses) of 5.17e13 (51 trillion) kw-h. This is something like 13,000 times the total power consumption of the US. Even with really bad distribution efficiency, its clearly a win.
And here I thought we might have to roof our buldings with solar cells too, to get enough power. Aparently not.
Oh, and that 15% efficiency? Thats typical of todays solar cells. The US Department of energy recently announced a 40.7% efficient solar cell had been developed. That would give more like 35,000 times the needed power, rather than a paultry 13,000 times...
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no subject
Date: 2006-12-06 08:39 pm (UTC)1. One wonders how much energy would be saved if people didn't drive so much, and we didn't need so many bloody roads. :)
2. I'd be interested in knowing how much energy went into making that 40.7% efficient solar cell (or how much energy we can expect to go into the production process if it's mass produced).
no subject
Date: 2006-12-07 03:54 am (UTC)The high-efficiency solar cell is brand new so its probably quite expensive it terms of time, resources and energy to make. Its also, most likely, not the kind of design one would decide to pave with.
Still, I think as we improve our molecular manufacturing processes, this sort of 'active road surface' becomes more practical.
With a bit more work, one wonders if they couldn't also be made self-clearing and self-repairing.