NOTE: a Forbes reader pointed out that the figure I used was for MAXIMUM capacity of wind (the figure used in my source article). So I've adjusted below for an AVERAGE annual wind capacity which is significantly lower.

In my fact-digging on the now sunken Deepwater Horizon oil rig, I came across a stat about the construction and operational costs of BP's failed rig which was to tap an estimated 7 billion barrels of oil from two recent oil discoveries (the Kaskida and the Tiber) over a 25-year period. According to Morningstar analysts (who published a study back in March), the projected investment for both wells was between \$8 billion and \$12 billion U.S.

So that got me thinking, just how much offshore wind could be bought for the equivalent \$12 billion investment? My back of the envelope calculations were enlightening. Here we go ...

1. What is the cost of offshore wind power?

We have a good comp in the form of Alpha Ventus, a 12-turbine project off the shores of Germany which was recently completed. The project was the first of its kind and as might be expected, it ran over budget. According to Spiegel, the total project cost \$282 million (it was estimated at just under \$200 million) which includes upkeep costs over 25 years. Alpha Ventus is a 60 megawatt array, enough to power about 50,000 U.S. homes at peak generation or 550 216 million kWh's of electricity per year (a typical U.S. home uses 11,000 kilowatts).

2. How many turbines can \$10 billion buy?

Projecting that the next few big offshore projects will drop in price as manufacturing and grid infrastructure improves, let's say a 60 megawatt project will go for \$200 million. Divide that by \$12 billion and you get sixty 60-megawatt wind projects, or about 33 13 billion kWh's of power capacity per year.

3. How many electric cars does that power?

A typical American drives 12,000 miles per year. The latest plug-in electric vehicles (like the much-anticipated Tesla Sedan) use about 370 wH's per mile. The typical U.S. driver would need 12,000 x .37 = 4,440 kilowatts per year. Divide 33 billion by 4,440 kilowatts and you get about 7.4 3 million electric vehicles that could be powered each year by a \$10 billion wind investment.

4. How many cars could Deepwater Horizon have fueled?

44 gallons of gasoline petroleum products are made from each barrel of crude -- approximately 30 gallons of fuel for cars and trucks (including 19.7 gallons of petroleum and 10 gallons of diesel). Deepwater Horizon was to produce 7 billion barrels of crude over its 25 year life span. 7 billion x 30 = 210 billion gallons of gas divided by 25 years = 8.4 billions gallons of fuel per year. Let's say as cars and trucks become more efficient the average U.S. vehicle goes up to a 26 mpg average. 26 mpg x 8.4 billion = 218 billion miles. Divide that by our 12,000 mile national average and you get 18.2 million gas cars vehicles (cars & trucks) per year from the \$10 billion offshore drilling investment.

NOTE: this is a tricky equivalency because crude produces a variety of fuels and other petroleum products including jet fuel (4 gallons per barrel). For the sake of this comparison I included only diesel and gasoline products. which makes up 68% of the net products from a barrel of crude.

5. What's the end cost for the consumer?

You can see why as a nation we like oil so much ... it yields about 2-3 times more transportation power per dollar invested. But it's important to note that the cost of gasoline for the end-user is considerably higher than electricity. The consumer pays dearly for all that convenient fossil fuel. Right now gasoline is about \$3 per gallon and the typical car gets 22 mpg. So the typical gasoline mile costs us about 13.6 cents or \$1,632 per year (oil). Grid electricity is about 10 cents per kilowatt, so one mile on electricity costs only 3.7 cents, or \$444 per year (wind). If you figure that 7.4 million Americans would be saving \$1,188 per year, that is about \$8.8 billion going back into the U.S. economy rather than into the grubby hands of foreign oil companies like BP.

6. What if you factor in environmental costs?

Now if we start factoring in the massive cleanup costs, it changes the game significantly. Current estimates are putting the BP cleanup bill at \$22.6 billion. This figure will be matched (at least) by U.S. taxpayers in the form of government assistance programs. So that puts the total estimated Deepwater Horizon price tag at \$55 billion (\$10B + \$22.5B + \$22.5B), assuming it's even possible to clean up the spill completely.

7. Comparing apples and lemons ...

As a comparison exercise, let's say that instead of sinking on Day 1, the Deepwater Horizon sunk halfway though its lifespan. It would have powered 13.4 million cars 9.1 million vehicles at a cost of \$55 billion ... about \$6,000 per vehicle (oil). Our wind turbines would have powered 3.7 million cars at \$10 billion or about \$5,400 per vehicle (wind). Since "windspills" have never been known to cause any impact whatsoever and oil spills are quite frequent (according to NOAA in one sample year alone there were 257 oil spills) this seems more than a fair comparison and puts wind in the lead, both from the perspective of investment and consumer spending.

Of course, this sad little number game will never make up for the incalculable losses to the fishing industry, the tourist industry, the health of wetlands, the survival of wildlife, the carcinogens that are now leaking into the water systems of Gulf residents — all things for which BP will never pay. We, the American people however, will pay those prices for a very, very long time to come.

You get my drift ... it is time to change the way we think about offshore energy resources and start switching to safe, clean wind power.

Please note: Offshore wind costs 2 times more than wind installed on land. Though it takes away hurdles in terms of permitting and land claims, many wind experts are hoping that we will focus instead on land-based wind power. If the above scenario had compared Deepwater with a comparable land array, the cost per vehicle in #7 would have been half or \$2,700 per vehicle.

Read more about the real costs of offshore drilling - MNN exclusive.