Stardate 20040606.1631

(Captain's log): So I spend my afternoon responding to letters from people who think they see easy answers after all, despite everything I've written about the problems of energy generation, or who have other kinds of questions about energy. Care to see some of them?

John wrote:

I read your vaccinating and informed viewpoints on energy solutions and am wondering, since you expertly trashed all the other solutions, what do you think is the near and long term solution for our energy needs? How much longer do you think we have doing things the way we are know?

One thing I've learned as an engineer is that it's a pointless waste of time to try to speculate too far into the future, or to try to design for far future problems.

We can't know what problems the next generation of engineers will face, and we also can't predict what new tools and approaches will be available to them which might be part of the solution.

Engineers working for the telephone company in 1950 could not possible have foreseen the kinds of things we use the telephone system for now, and they equally had no chance of predicting the way modern switches work.

State of the art in 1950 was mechanical switches in crossbars. How could they have predicted that in the year 2000 there would be no moving parts in the modern equivalent (ignoring cooling fans and hard disk spindles)?

It would have been utter futility for such an engineer in 1950 to try to design something he expected would still be in use in the year 2000.

What new energy uses will there be in 2050? What will be the equivalent for energy in 2050 to computer data in 2000 for the phone system?

And what new tools and techniques will be available? What will be the equivalent for energy in 2050 to semiconductors in 2000 for the phone system?

There is absolutely no way to answer either of those questions. So since we can't characterize the problem of energy in 2050 and don't have any idea what kinds of tools would be available to solve that problem, then there ain't really a damned lot we actually can talk about intelligently – except for admitting that it's a waste of time to even try.

Rob wrote:

I think you've proved quite well that there isn't any simple solution to the creation of a lot of new energy from new sources. The market has seen to this, of course. If there was a good alternative, we'd be using it.

There is an answer, however: use less energy. I'm not talking about crippling the economy or making people ride bikes, I'm talking about increasing the efficiency of our most energy-consuming practices. We've done a lot for the average gas mileage of cars over the last twenty years and we obviously could do more. It would be hard to insulate our existing buildings, but new ones could be far, far more insulated than they are now (I wonder if anyone is working on commercializing aerogel for use as an insulator for buildings? Ah, turns out they already have). LED's are already starting to replace incandescent lighting and that will no doubt continue. Flat panel displays are nice and they use a lot less electricity than CRT's.

If we went all-out, I imagine that we could (over twenty years or so) cut our energy needs by at least 25% and 50% isn't out of the question. In the long run it would save us money and it wouldn't hurt the environment any, either.

I'm afraid not. It is impossible to achieve that much gain solely through technological changes like that.

I don't mean "infeasible" or "impractical", I mean it is physically impossible. To get a 50% gain solely through technology improvements we'd have to revoke the laws of thermodynamics and figure out how to change the universal electrical constant. I don't expect to see that happen in my lifetime.

The second law of thermodynamics imposes an absolute limit on how efficient energy usage can be, but that level is an asymptote, a level you can never actually achieve. Each successive step towards that level is harder than the step before it. There comes a point of diminishing returns where the curve becomes ferociously steep, and any additional significant gains are extremely difficult and expensive. In most of our current energy use, we're already near that level.

There are some specific areas where major gains are possible. We can still make small overall gains. But we cannot improve 25%.

There are some areas where new technologies may come along to replace older ones yielding substantial increases in efficiency, such as Rob's example of replacing incandescent lights with LEDs. But in most of our energy usage, existing technologies are already about as good as they'll get. We may develop new approaches which might have substantial advantages in other ways, but they won't be significantly more efficient in terms of energy usage.

Improvement in efficiency is not an infinitely deep well.

This is like file compression. Putting a BMP file inside a ZIP usually results in huge compression, but if that ZIP file is placed inside another ZIP file, it doesn't compress any further. There are limits to co