Thursday, April 2, 2009

Percentage Land Area required for 100% Replacement of 2006 Energy Demand.

The following chart represents the percentage of land for each State, and the USA as a whole (without Alaska), that would be required to replace 100% of that State's Annual Energy Demand.

Make no mistake, the numbers are huge. Then again, nobody is actually talking about 100% replacement by Solar, Ever. This is just to give an idea that it is physically possible, at all.

Assumptions and references follow.

here's the spreadsheet.


State Energy Data.
State Land Area Data.
State Insolation Estimates.
Sunpower Power/Area Claim.

Assumptions / Notes:

The percentages reflected in the Graph are based on a Stationary system, though the value for Power/Area is based on a Sunpower claim related to their tracking system. This should be irrelevant, as Power is independent of whether the system tracks or not. Since these are Sunpower numbers, the Panel's Conversion Efficiency should be around 22%.

The Demand cited is irrespective of source, and so includes existing production of renewables such as Hydropower. Here's a very interesting page from the DOE giving detailed map-based information on US Energy sources. There's a "Select a State" dropdown that will take you to a close-up of the individual State including facts and demographics.

In order to work out an the Area, I used the equation:

Annual Energy Output = 1 Year * Power/UnitArea * Insolation Ratio * TotalSolarArea * 8760.

For more info, see A Note on Units of Energy and Insolation. Solve for TotalSolarArea, and divide by the State's Total Land Area, and you will get the percentage. Most of the trouble here is just in the conversion of units. On a political note, can we just all go metric please?

The Insolation values were eyeballed from the map. If anybody's got some better data on State Average Insolations, I'd love to see!

The base data does not seem to include Transportation Energy, though it didn't specify.

Of course, this assumes nice flat areas of land, on which to set up installations, and it also assumes that each state takes care of its own needs irrespective of local conditions or capacity. It's a brief look from 1000 miles up above. It's not exhaustive, but it's fun, and maybe interesting.

By all means, if my basic math is way off, let me know.

This post is followed by Part II, which calculates the same area percentage, but only for the replacement of Electricity End Use.

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