Algae to crude oil: Million-year natural process takes minutes in the lab

Dale Hodgins wrote:The total stored energy in all fossil fuel reserves combined, is equal to approximately 20 days worth of sunshine. Although the processes of storing it took millions of years, some tiny fraction of 1% of the available energy was actually stored.

tel jetson wrote:

Dale Hodgins wrote:The total stored energy in all fossil fuel reserves combined, is equal to approximately 20 days worth of sunshine. Although the processes of storing it took millions of years, some tiny fraction of 1% of the available energy was actually stored.

tel --- "and in turn, some much tinier fraction of energy arriving from the sun could be converted into fuel, using algae or some other method. still, if the technology pans out, this will be pretty excellent."
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I guess there's no use in dropping in those links. -------- I don't see how we're locked into some incredibly small percentage recoverable whether we go solar, algae, wind... One tenth of 1% seems small, yet I'm guessing that it would put a big dent in our energy needs. Time to visit Mr. Google.
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I got this from "How Stuff Works" Currently, the world’s population consumes 15 terawatts of power from a combination of these energy sources (all of them) [source: The Economist]. Just how much power is 15 terawatts? Let's think of it in smaller and more familiar terms: watts. Many of the light bulbs in our homes consume 100 watts of energy. One terawatt could power about 10 billion 100-watt lightbulbs at the same time. (Dale --- They aren't counting barrels of oil etc. Think of it as a big electric meter that is spinning at 15 terawatts per hour)

Dale again --- The human race is currently consuming enough power to light 150 billion 100 watt bulbs. Divide that by 7 billion people and we get an average consumption of 21.43 bulbs per person. That's 2143 watts. That's like running a big electric heater full time. If this were all electricity, it would represent about 20 cents per hour and $4.80 per day where I live. That's the average. Most North Americans and Europeans use quite a bit more.
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So, how big is this number as compared to the solar energy that strikes the Earth. As we've learned, a terawatt is a huge amount of power. A petawatt is a much larger measure of power. 1 petawatt = 1000 terawats. Numerous scientific sites agree that the incoming light from the sun is 174 petawatts and that it is quite constant, varying with solar flares and such but only by a tiny amount. About half of that energy reaches the surface. The other half is reflected away or absorbed by the atmosphere. So, we're working with the 87 petawatts that make it to the surface. Let's look at how many times more than our current usage is available. 1000 divided by 15 is 66.66... Therefore --- One petawatt is 66.66 times more power than humans currently use. Now we multiply that by the total petawatts 87x66.66...= 5800 The sun delivers 5800 times more energy than we are currently using. ------------ Now for some division. Lets say we're willing to use 1% of the Earth's surface for whatever solar energy scheme. That's going to be about 3% of the land. I say we use deserts. They do much better than the average 50% of light to the ground that was stated earlier. Dividing our 5800 by 100 we get 58. This much real estate receives 58 times more energy than we currently consume. Let's say that we're only able to recover and transmit 10% of that to the consumer. That much land could produce 5.8 times our current usage. I guess we can go a little smaller, to say half of 1% of all of the Earth's land area to replace our current usage of all energy sources. Much of this could be put on rooftops and in other areas near the end user.
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edit --- It's morning and I'm back. This thought experiment utilizes 1/100th of the Earth's surface. It turns out that we would really need to use 1/600th to meet current needs. At 10% efficiency, that means that we'd be harvesting 1/6,000th of the planet's incoming solar energy.

Back to the 20 days of fossil fuel. 6000x20=120,000 We have enough fossil fuel (mostly coal, the gas and oil would run out much sooner) left to continue burning at the current rate for another 120,000 days. That's 329 years. This assumes that we aren't smothered out of existence by coal smoke. Assuming that humanity were to choose solar and do it as stated, it would take us 329 years of utilizing 1/6000th of the available energy to use the equivalent amount of energy that is stored in all of the world's fossil fuels.

Just for fun, let's compare that to nature's efficiency in storing fossil fuel. Estimates on how long it all took vary widely from 100 million to several hundred million years. I'm going to give mother nature the benefit of the doubt and say that the accumulation all occurred within 100 million years. We'll assume that humanity is capable of harnessing 10% of the energy from 1/6 of 1% of the planet for our 329 year figure to be used. 100,000,000 divided by 329=303,951 In this scenerio, man's efforts would be 303,951 times as efficient at storing energy as were the processes that led to coal, oil and gas. To match natures efficiency during the laying down of those fuels, we would need to use 1/1,823,706 of the Earth's surface. That surface comprises about 196,940,000 sq miles. Divide that by 1,823,706=107.9888 108 square miles of solar collection at 10% efficiency matches the efficiency of nature in laying down those fossil fuels. In this case, I believe that we have a good chance of winning.
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That was a fun little exercise. I've always wondered how much we use as compared to the total available. I looked for it all over internet land and couldn't find it, so I did it myself.