What's the best mode of energy production?

Factual Questions
1

So, I was wondering, what’s the best mode of energy production? Not necessarily something clean, but something that is sustainable. It would have to produce more energy than it takes to create the device, and in sufficient quantity to power the world. Here are some options, but I don’t really how viable and efficient they are:

Tidal (I heard that this is the best, but the technology isn’t quite there, and it only really works in countries with a lot of coastline. Also, this would work for practically forever, as gravity doesn’t really run out.)

Solar (They say that you would have to cover a prohibitively large amount of the world (like say, a majority of the land area) in order to produce enough power.)

Geothermal (It seems that this would be just as sustianable as Tidal, but is it very efficient.)

Bio-mass (Some say that this isn’t really efficient for the same reasons as solar, it would take far too much bio-mass power to power the country.)

Hydroelectric (I heard this is a little less efficient than tidal, but you don’t need the ocean, only rivers, for it to work. Plus, we obviously have had the technology for a long time, as evidenced by the Hoover Dam.)

Fossil Fuels (These are prohibitively dirty, and according to the Hubbert Peak Theory we’re going to run out (people disagree on when, but definitely by the end of the 21st century).)

Nuclear Fission (This would be the best option for the short term, they say. They can make reactors that automatically shut themselves down in case of a problem, even loss of all control and electrical power, so they can be very safe. Plus, the director of a huge government nuclear research facility/think tank gave a talk to my class, saying that we only use a small % of the material in fissionable material. If they reacted the uranium/plutonium/etc. fully, then we would get much more energy. However, there is only a limited amount of fissionable material on earth.)

Nuclear Fusion (This technology is decades away from being practical, and no one really knows how energy efficient we could make it anyway.)

There are also esoteric ideas like Matter Conversion (i.e. since e=mc^2, we can get a lot of energy out of converting matter to energy.) however, most of these ideas are just sci-fi, because they are centuries away from anyone even knowing how to harness them.

So, does anyone have the numbers on which of these would be good for long term energy production?

2

This is actually how nuclear fission & fusion work. Matter is converted into energy.

Nuclear fusion is probably our best bet, if it’s really a feasible project (and that’s quite a big if). As I understand it, the problem isn’t so much sustaining the reaction, as removing the energy from the reactor to generate electricity. You can’t just stick a water pipe through it like a fission reactor, you need to transport a vast amount of energy.

Another possible energy source is using GM bacteria to break down waste matter into alcohol and methane. Don’t know how practical this is though.

3

Your question is too vague to have a single answer. The only attributes you mention specifically are sustainability and plentiful supply. For these purposes your best bet is probably nuclear fission, which produces vast amounts of electricity from small amounts of uranium. It is also sustainable in the wider environmental sense, as it does not result in harmful atmospheric emissions or emissions of climate-change gases.

4

“Best” is hard to define, especially given only very high-level requirements. Since it is relatively inefficient to transport power, you’re looking for a solution that can be used in a wide variety of situations. Solar might be the “best” solution for developing nations in the tropics, but a lousy solution for the north coast of Scotland. Vice versa for tidal and wave power generators.

I’m not sure I even agree philosophically with the search for a “best” solution. If we had a “Mr. Fusion” device that generated power with almost zero overhead, maintenance, etc. then maybe we’d settle on using it alone, but given the currently realistic solutions, I think diversity is a benefit. Any given region could have a mix of different power generation techniques and, while some might be slightly less efficient than others, there is a certain amount of security in diversity.

5

Except you have to store all the barrels somewhere, not to mention the damage even one reactor going critical and then boom would do.

6

Given the state of technology all of the methods that you stated have their drawbacks. Some pollute, some are difficult and expensive to build, some are very innefficient.

The best technologies are the ones being built right now. Unfortunately those technologies too have drawbacks. Fossil fuel technologies will still pollute, geo technologies like wind, tidal, hydro etc will kill wildlife, and photo / new tech technologies are not cost effective.

Contrary to what many people believe, electric utilities build coal, gas and oil plants because those are the technologies which are the most reliable and cost effective. They would rather not rape the environment, defile the landscape, and pollute but when the customer needs energy they work to deliver it. They will still build alternatives to fossil technologies but the costs and operational aspects of new technologies the will not justify quickly replacing current technologies.

Bubbadog
Bubbadog pauses his normal work to provide a way too short answer to this question and then quietly resumes his day job of power plant analysis

7

Reactors don’t go “boom”. You yourself may not be confusing nuclear reactors with nuclear bombs, but you run the serious risk of creating such confusion among those who don’t know.

A nuclear reactor can not explode. The worst that can happen is a release of radioactive material into the biosphere. This happens rarely enough that, per kilowatt-hour generated, nuclear power is by far the safest and cleanest mode of power generation available.

For more detailed information, see the ExternE study, which quantified the external costs of a large number of fuel cycles (I carried out the coal and peat studies in the Irish national implementation).

One more thing: before anyone mentions Chernobyl, do some checking for published studies online and find out for yourself how many people died, how many illnesses, birth defects, etc., resulted from this accident. You may be surprised.

8

A note that the Hubbert Peak really only applies to petroleum, not fossil fuels in general or any other specific fossil fuel (although some argue it works for natural gas wells; I personally don’t know if it does or not). Some people do try to erroneously apply a Hubbert Peak to coal, and it doesn’t work at all due to numerous differences in the way that coal resources can be developed and utilized, fuel switching considerations, and the huge range of variability in coal quality.

9

Critical means that the fission reaction is self-sustaining, i.e. on average one fission leads to one neutron inducing another fission. All reactors that produce macroscopic amounts of power go critical. Supercritical, even.

10

A few people have mentioned uranium while discussing nuclear fusion; I was under the impression that a fusion reactor would, er, fuse light elements like hydrogen and create energy (and heavier elements) in the process. Am I way off on this one? If not, what sort of elements do we get as the product of fusion?

11

Yes, to release energy you need to fuse light nuclei. The products you get depend on what you try to fuse - you will still have the same number of neutrons and protons after the interaction. He-4 is often a target, as it is very tightly bound and would tend to release more energy (per unit mass).

12

Just a note, The ITER* Group is planning to build the first fusion reactor to test commercial viability of fusion power. Clarington, Ontario, near my hometown, was a leading build site. For some stupid reason, Canada has withdrawn from the project altogether. Anyway, the goal is to determine if a fusion reactor could be made commercially viable. Its slated for completion in 2006.

13

Since we are not gods and can’t know the long term effect on any one, I would like to propose that making multiple energy sources about equal in terms of efficency (and price) is a worthy goal. If we find a way to make power out of water for pennies, convert all energy plants to do this then find out that this form of energy is killing the dolphins and we have to stop today to save them we will have no alternatives to fall back on.