Is solar power viable now?
by William Papolis, Monday Mar 26, 2007 10:34AM EST
OK it sounds credible, but is it technologically feasible?
Those “hawk eyes” among you are probably asking yourself this question. Solar panels, hmm … don’t they require lots of space?
That’s a good question. Let’s consider a real world example. Looking at the USA’s energy consumption, we observe:
| Energy mix for the USA (ktoe = thousand tonnes of oil Equivalent) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Region | Coal | Oil | Gas | Nuclear | Hydro | Solar, Wind & Geo | Comb, Renew & Waste | Pop (2006) | Energy (2004) | ||
| "Superpower" | 23.4% | 40.7% | 22.1% | 9.1% | 1.0% | 0.5% | 3.0% | 298,444 | 2,325,887 | ||
Source: International Energy Agency or our previous article What forms of Energy do we consume?
Burning coal is considered our dirtiest energy source and it would help the planet a great deal if we stopped. Coal represents 23.4% of our total energy use. Let’s say the World's Superpower decides it wants to eliminate coal as an energy source. Is it possible to replace coal with solar power? Is it technologically feasible?
How much energy do we consume from coal? (using the numbers in the table above we get ...)
TURN ON MATH LESSON
Total Energy from Coal = 544,258 ktoe = (2,325,887 * 23.4%)
Using the unit converter in the left column we get ...
Converting to electricity 6,342.5 TWhrs per year = 544,258 ktoe
"The power we need" = 6,342.5 TWhrs per year
Now, how much area do we need to produce the same power from solar? Using the following assumptions ...
- 6kWhrs/day per sq meter = the amount of sunlight that strikes each day per sq meter
- 20% = solar panel efficiency (the amount of usable electricity generated)
- 1 million sq meters = 1 sq km
We can determine the amount of power generated per year (365 days) for 1 sq km.
Power from 1 sq km = 438,000,000 kWhrs/year = 6kWhrs * 20% * 1,000,000 * 365
Converting to TWhrs (divide by 1,000,000,000) we get ...
Converting to TWhrs = .438TWhrs/year = 438,000,000 kWhrs/year
"The power we can generate" = .438TWhrs/year per sq km
Now we take "the power we need" and divide by "the power we can generate" to get the total area required ...
Total Area required 14,481 sq km's = 6,342.5 TWhrs / .438 TWhrs
TURN OFF MATH LESSON
How big is 14,481 sq km's? Well, the 48th largest state, Connecticut, is 14,357 sq km. So a little bigger than that!
Let’s consider it another way … Instead of occupying the state of Connecticut, let’s put the panels in an out of the way place. How about the desert?
- The Great Basin (most of Nevada, and half of Utah) = 520,000 sq km
- Chihuahuan Desert (40% in New Mexico, and the rest in Mexico) = 362,600 sq km
- Colorado Plateau (Utah, Arizona, New Mexico and Colorado = 337,000 sq km
- Sonoran Desert (Arizona, California, and 50% in Mexico) = 311,000 sq km
- Mojave Desert (California, Nevada, Utah, and Arizona) = 57,000 sq km
TOTAL area of deserts in the US = 1,214,540 sq km
Combined this yields almost 84 times the area required to replace coal and we locate solar panels on largely unpopulated and not arable land. In fact, we could produce 20 times all the power we consume today by converting our deserts to solar power generating stations. This is technologically feasible, today!
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