There is a huge amount of energy wasted by major industrial processes at the moment, with fossil fuel burning in power plants being a prime example. In particular a lot of heat is dumped straight into the atmosphere with flue gases. Temperatures are typically tens of degrees warmer than ambient but less than 100C - heat exchangers are normally used to cool hotter exhaust gases by raising steam (boiling water) which can then be used to generate electricity. Further cooling below 100C with energy recovery is difficult but there is research being done on new heat exchange processes to help.
I remember an article in New Scientist last year about a new idea for recovering energy from such gases, and a related one in the UK national press a little later on work done at MIT. I think the talk was of cooling gases to around 50C which would often be a big improvement.
Oil wells do flares to burn off gas because oil producers find that they can not afford the cost of a pipeline or a way to store it. Makes you wonder why other companies or governments don’t attempt to find a use or a way to convert all that wasted energy.
Burn-off from gas and oil fields is certainly a real waste of energy. Flaring is different though.
A industrial process has inputs and outputs. The product stream from a process contains the desired product at a higher purity than the inputs. As what goes in must come out (lets not go into reactions here), if there were no other output, the undesired components would build up in the process, quickly causing problems. Hence, there are always by-product or waste streams.
Oil and gas are separated into different desired components (to a certain degree of purity) when they are extracted. They initially also contain undesired and often dangerous chemicals, and these are concentrated into a waste stream. However, some gas/oil will always be mixed with the waste. Burning it as a flare breaks down the harmful chemicals into less harmful ones (though they are still greenhouse gases).
It is in the interest of the company operating the process to flare as little as possible, as flared oil/gas is wasted money. Therefore you can be pretty certain that the process is optimised to minimise flaring. It will not be possible to gain any significant amount of energy by reducing flaring.
Summary: A Southj African researcher, Prof. Vivian Alberts, has refined the CIGSS photovoltaic cell (as opposed to the Silicon one) to the point where it should be ready for industrial scale production . Two German PV manufacturers (one is Europe’s largest, IFE Thin Film Tech) have already licenced the process.
Advantages:
the active layer is 70 times thinner, can be applied as a coating to ordinary window glass, amongst other surfaces (polymers, flexible surfaces).
Cost should be around 20%-25% of current systems for the same output.
Not sure what the disadvantages are, other than the unproven nature of the process.
There’s also Ocean Thermal Energy Conversion, which uses the temperature gradient between the surface of the ocean and the deep ocean to generate power. It has the added benefit of pulling nutrient-rich cold water from below and bringing it to the surface, creating blooms of plant and animal life which can also be harvested.
It’s too expensive to replace any current major energy sources, but assuming energy costs continue to climb, at some point it might become a significant source of power, at least for islands.
Magnetic field? Isn’t a magnetic field just a way to turn kinetic energy into electricity (or vice versa)? You still need your prime mover from somewhere. And the local density of the geomagnetic field is kinda weak surely - barely enough to orient a really light, well-balanced magnetised pointer.
Rather impractical. 90% of a ship’s power generation capability isn’t actually converted to electicity, but to motive power. Forex: I was on the USS Virginia, a ship with two 150 MW reactors. So, nominally it could generate 300 MW total power. Now, naval reactors are rather inefficient, compared to civilian plants, so about 10% of that total is needed to run the plant and ship. The other 270 MW is available only as shaft horsepower.
So you’d actually be putting about 150 people (less for a tuber, more for a birdfarm) on restricted liberty for anywhere from 1-5 MW of power. Total. Morale would plummet to the abyssal plains. We’re talking about a job you literally couldn’t leave for months on end. I really don’t think the benefits would be worth it.
I’m still hoping that some of the plans to use the tidal energy in the Bay of Fundy will come to something.
During my more ruminative moments on the subway, I watch the subway cars sway and jiggle and imagine being able to put something between the cars to somehow capture the shearing forces (?) of one 70,000 lb car moving back and forth in relation to another 70,000 lb car.
It’s not like there’s anything that can do that that we’re not using, to my knowledge, but it seems like there’s a lot of energy there. Maybe at least enough to charge up everybody’s iPods.
Let me expand on that: There are a lot of places where waste heat can be used advantageously. Regenerative heat exchangers, for example, often preheat incoming fluids using the outgoing wastes and waste heat, making for a more efficient cycle, overall. It’s not that waste heat can’t be used, it’s just that you can’t beat entropy. You can find ways to use the entropy being generated, though.
I can’t imagine how one would be able to use the chaotic energy of swaying subway cars, myself. But a lot of engineering, from my point of view, is a matter of looking at someone else’s mechanism, and going :smack: .
Simply because something is waste energy doesn’t mean that it’s ipso facto unuseable.
It uses a lot of energy to refine the silicon. You do know from your post about how much it costs to refine it. somewhat less than $4 for the amount of silicon that will produce a watt. Otherwise the $4 is meaningless.
This silicon in photovoltaic cells is pretty much the same as the silicon used for computer chips. If there is to bee a big increase in use of photovoltaic cells the amount of silicon produced will have to go up a lot. I would guess the total area of all the silicon chips I have in all my electronic crap. Is less than a square foot. If I wanted to power my house I would need many square feet of solar panels I think in the hundreds but I have not done the calculations. My point is that an aggressive photovoltaic program will need to greatly increase the amount of silicon being produced.
I was talking to my uncle who has installed solar power on his winery. He said that it made sense from a business point of view. But that putting them on his house did not. Capitol improvements to the business are expenses against income. But capitol improvements to your house are just expenses until you sell the house.
[post=6435667]It’s more complex than you think.[/post]
As people have noted, there’s plenty of “free” energy that could be utilized. The problem isn’t really recovering the energy–it’s easy enough to make a battery out of uric acid or a pendulum generator to recover wasted motion–but storing and distributing small amounts of energy is neither cost-effective nor efficient; often less efficient than the amount of energy to be had. Small, localized systems require a high degree of maintenance, and large networked systems require an infrastructure to connect to your distirbution grid. Compared to our current means of producing energy (coal, oil, and nuke plants connected to a progressively built power grid) and transporting it in portable form (gasoline, kerosene, diesel oil), there really aren’t any currently technologically viable solutions that can compete economically or practically. remember, though, that thermodynamic models have theoretical limits on efficiency based fundamentally upon temperature difference; if you aren’t able to access a low temperature reservoir (relative to your thermal source or temperature of waste heat) then you’ll have very poor efficacy regardless.
As better energy storage capability (power cells, batteries) becomes available and environmental energy recovery MEMs technology is developed we can create distributed systems–perhaps even coatings that can be sprayed on, or shock absorbers and brakes that regenerate most of the energy they absorb rather than rejecting it as heat–which can recover a high percentage of power. But at this point revolutionary development in those technologies is still speculative; incremental improvements in storage technology don’t allow for generational leaps in effectively accessing “waste” energy.
