Monday April 24, 2006

What is a renewable energy source?

wind power

This is a bit off-topic, but ever since our energy conversation, I’ve been thinking about how the whole notion of “renewable energy” might be a little short-sighted and skewed. We have a “non-renewable=bad, renewable=good” mentality, which partly rests on the understanding that non-renewable energy (i.e. coal) is bad for the environment, while renewable energy (i.e. wind) causes no harm.

Well: the world currently consumes about 450 quadrillion btu’s of energy per year. The burning of fossil fuels accounts for about 85 percent of that energy, and while wind still accounts for less then one percent, it makes for a valuable example, since it is growing rapidly [MS Excel link from this page 1].

Consider the causal chain by which fossil fuels harm the environment: the burning process produces compounds which interact with 02 molecules in our atmosphere (the ozone layer), defeating their solar-power deflecting properties, causing global warning. Note that the harm to the environment happens through changing the weather.

Now think about wind energy. What would happen if our use of that resource were to increase substantially? A causal relationship to weather change seems much easier to imagine then with fossils: when tens of quadrillions of btu of energy is harvested from winds, contrary to conventional notions of ‘renewable energy’, those btu’s will not be transparently replaced by anything: the only possible result is less wind.

This may sound far-fetched, but the laws of thermodynamics dictate that if energy is generated by a turbine, the wind must move more slowly after it passes over that turbine. The effect on winds may be immeasurable or irrelevant at today’s levels of wind energy harvesting, but there is no reason for assuming that it will remain so at higher levels of harvesting. One might even argue that messing with the winds could have much more dramatic effects on weather then global warming ever will. Analogous cases could be made for solar power, tide power, geothermal power, and any other energy source you’d care to name, in proportion to that source’s potential to provide a significant source of energy.

And while creating balance is a worthwhile goal, it won’t be a solution, since any renewable energy source that begins to contribute a significant proportion to the world’s energy reveals its downside; just look at the problems the Chinese are creating by attempting to harness hydro power.

So what’s the solution? Well, I don’t know, and I’m certainly not suggesting we abandon wind power (or any other alternative), just that our thinking might be a little short-sighted. I suspect that nuclear energy should be revisited, especially fusion. And I suspect that we need to really look at everything: conservation, increased efficiency, energy alternatives, and yes: drilling the damned gulf.

[1] Very typical government move: they don’t use HTML tables for displaying data, which is what they’re intended for (they I suppose they expect readers to open every one of those dozens of Excel links), but they have no problem using them for the page layout (for which they’re not supposed to be used).

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  1. A.T.    Mon Apr 24, 08:47 AM #  

    Alesh, interesting post (never heard that argument). Even as more voices come out from the conservationist camp defend nuclear energy, some experts have pointed to the need for more diverse variety of options to deal with the challenge posed by the depletion the world’s oil reserves (See link text.) By the way you didn’t mention solar energy (which is plentiful in the tropics).



  2. Franklin    Mon Apr 24, 09:56 AM #  

    450×10^15 btu’s is a lot of energy, but you could only determine the loss by subtracting it from the total btu’s available. Individual hurricanes have enough energy in them to power the entire world for hours at a time. There’s a lot of wind out there.



  3. alesh    Mon Apr 24, 10:38 AM #  

    AT~

    The argument for solar goes something like this: The sunlight hitting the earth is the primary source of energy for everything that goes on. For example, heat energy is absorbed by the ground and radiated back out, contributing to all sorts of stuff (not the least of which is wind). Solar panels reduce the amount of that energy that goes back out into the enviroment, with unknown consequences.

    Nuclear fission (how current nuclear plants operate) has two negative consequences: danger and radioactive waste. Fusion power would at least eliminate the latter.

    Franklin~

    I’m not sure whether “Individual hurricanes have enough energy in them to power the entire world for hours at a time.” is good news or bad news – to me, that doesn’t make it sound like there’s that much energy in winds: hurricanes are some of the most massive, powerful weather phenomena we know.

    But you’re right – there’s a real equation to be done here, where a serious estimate of the power trapped in winds is compared to projected energy consumption.

    That leaves out an important variable: what percentage of wind power can we take out of the system before serious consequences arise? And will we have flat-earthers proclaiming that the results are being caused by, say, historical fluctuations in wind levels (ala global warming)?



  4. riley-o    Mon Apr 24, 11:01 AM #  

    Alesh:

    Another displacement you forgot to mention is the effect that even cleaner emissions will have on the production of wind (i.e., wind is is the movement of, better yet the interaction of, air at varying temperatures) We can assume that the same factors that cause global warming, the degradation of the ozone layer, also serve to change air temperature, and so it follows that a change in those factors can have have an effect of “usable” wind available for these more enviro-friendly pursuits. Also keep in mind that it is not so simple as saying wind energy is good (it is) and that is that. Wind generation cannot thrive just anywhere, so that puts into play both geographical constraints (where the generation is located) technical constraints (how to distribute) and the inevitable economic constraints which all these serve to drive to the consumer. Discussion of any one of these constraints would be interesting and very lengthy…

    whoever said balance is the answer is absolutely correct, though even that answer is too simple…



  5. WK    Mon Apr 24, 02:24 PM #  

    Recently, my whole take on Global Warming has been turned up-side-down with the acknowledgment that “Global Dimming” is a major force occuring at the same time. (See Wikipedia).
    It seems that an almost equal and opposite effect to global warming is now also a significant player in the state of our atmosphere. Put simply, it is the process where pollutants in the air are also causing more of the sun’s light and heat to be deflected away from us. Could this mean that SUV drivers are, in fact, our saviors?



  6. Steve (Klotz As In Blood)    Mon Apr 24, 02:52 PM #  

    Wow. Talk about wind. Is there a single scrap of evidence or even theory (other than those expressed by the learned academics here) that suggests capturing the energy produced by solar panels and wind turbines would have a deleterious effect on the environment? Please point me to it.



  7. jps    Mon Apr 24, 06:29 PM #  

    I’ve had many similar thoughts about wind turbines somehow effecting weather patterns by virtue of the basic fact that you never get energy totally for free.

    By virtue of the same basic knowledge, you do have to consider the fact however that if there is any truth to the concept of global warming, whether it’s manmade or not, reducing the load of sunlight that is being radiated into heat and trapped by the atmosphere would only slow global warming and be a GOOD thing.

    man, i’m totally sending this to straight dope.



  8. NicFitKid    Mon Apr 24, 08:19 PM #  

    Alesh, are you kidding me? The wind turbine industry is tiny, and you’re already worrying about how it might slow down global winds? We would have to build an astronomical amount of turbines to put a dent in the energy available in global winds (which orginate in the Coriolis effect caused by the Earth’s rotation, by the way), so I wouldn’t be losing any sleep over it.

    I’m sure we’ll all be cooking to death under a warmer atmosphere with increased UV radiation once the Chinese and Indian economies surpass our prodigious polluting power by mid to late 21st century or so. Relax, enjoy the rising sea levels, and don’t worry so much about the wind.