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Water Now More Awesome Than Previously Thought
Dan writes "Wired has a great article about a guy who thinks we can provide unlimited energy , accelerate crop growth, desalinize and purify drinking water, obtain health benefits and provide air conditioning, all by pumping up water from the depths of the ocean."
Do you have any idea how much water there is in the ocean? And what the specific heat of water is? By the time we're pulling enough energy to make a difference, we'll have colonies in multiple solar systems.
Luckily it's pure grade-A horse poop.
Er, no, not really. Granted, this particular guy sounds a few gallons short of a hogshead, but deriving useable energy from cooling things off works exactly the same way as by heating them up - Namely, we can use the transfer of energy from the warmer side to the colder side to perform useful work (such as generating electricity). The absolute temperatures involves don't particularly matter.
So why do virtually all human-created energy extraction technologies use warmer than ambient going to ambient as the two sides? Simple... We humans have enjoyed, at least for the past few millenia, a really easy way to get things hot (ie, fire and a supply of fuel that literally grows on (as?) trees). We have not had a convenient way of making something colder-than-ambient, except very recently (within the past century), and even then only by using the hot-to-ambient conversion to get electricity to do the ambient-to-cold conversion - Sort of trading one for the other, with a net loss in both conversions.
Deep ocean water, however, provides exactly that - A nearly limitless supply of something colder than ambient, with a high enough specific heat that the energy we can extract from the temperature gradient FAR exceeds the energy needed to pump it in the first place.
Imagine the climactic effects, and effects on the oceans ecosystems
Now, here you make a good point. In the short term, or on a small scale, I would tend to say that we couldn't even come close to the natural processes that mix the oceans. But then, people thought the same about burning wood and later oil, until just the past few decades.
Maybe I've forgotten too much of my highschool physics, but how does this really work? I was under the impression that the "sweat" on cold pipes is the result of the chilling of the surrounding air/material, which lowers its capacity for carrying water, thus in essence extracting it into solid form.
So if the pipes sweat below ground, aren't they simply solidifying water that already is in the ground? If so, that's not what I'd call irrigation...
This is a fantastic idea, except for one flaw. This would only work for cities near the coast.
That's a goodly majority of all humanity.
C//
A 2% efficiency isn't a problem. Efficiency tells you the ratio of the energy you can sell to the energy you put in. But if the energy you put in costs zero, then efficiency is an utterly unimportant number.
What's more relevant is to compare the cost of building the plant to the money you can make by running the plant over its planned lifetime. That's the relevant figure of merit for a nuclear power plant, and I think it's the relevant one for an OTEC plant as well.
The problem is that fossil fuels are artificially subsidized. Say I increase my energy use, and use an extra megajoule of energy derived from burning coal or gasoline. Well, I don't pay anything extra for the damage I'm doing with global warming, and I also don't pay enything extra for all the wars in the Middle East that the U.S. keeps getting into.
Find free books.
There are several factors that make up for the inefficiency in power generation:
Places like Saudi Arabia and Chile, which have lots of sun and salt water, but almost no fresh water, should jump on this. Saudi Arabia in particular, which has all the power it needs, could really benefit.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
chilling the moisture out of the ground is going to dehydrate that soil, causing things to die.
Only if you're pumping that water off somewhere else. If you just use the pipes to chill the ground, then water from the air condenses on the ground. Upshot: irrigation.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
No, discharging sewage into the ocean can have unintended effects. That's the real problem.