Monday, May 08, 2006

Renewables vs Nuclear

There is a great discussion over at EnergyPulse. The article suggests renewables can replace nuclear. A number of good comments that follow show the claim to be wrongheaded, but perhaps not entirely wrong.

The claim that renewables (primarily windpower) can replace nuclear is not entirely off base. We are building windpower right now faster than we are building nuclear, and the EIA predicts this will continue to be true for 30 years, even with the new subsidies. The existing U.S. nuclear plant fleet is huge, however, and renewables are not forecast to challenge the capacity of the existing nuclear base.

I think the debate between renewables and nuclear is pointless. Both are domestic supplies. I think the more interesting comparison is between domestic and foreign energy supplies, and what we can do to move to more domestic energy. Secondarily, I think there is an interesting comparison between the amounts of CO2 produced by various energy supplies.

We use oil and gas-fired turbines and hydro to follow variations in electricity demand. Our dependence on foreign oil and gas supplies is a major threat to our national security. In the U.S., hydro is all built out. I see two strategies that will help move the U.S. from foreign energy sources to domestic sources. Both could use some legislation.

  • Dynamic pricing. If the price of electricity varies minute-by- minute, many customers can time-shift their loads. This reduces variations in electrical demand and allows domestic sources (coal, nuclear, renewables) to replace foreign sources (oil, gas). Examples are ice-storing commercial cooling plants and aluminum smelters.

  • Plug-in hybrids. These gasoline and battery powered cars can charge up at night. They actually help twice: they directly shift their energy source from a foreign one (crude oil) to a domestic one (coal, nuclear, renewables). But also, the extra demand at night makes it economic to build more domestic-source generation instead of foreign-source generation.

  • As for the CO2 problem, natural gas was once sold as a cleaner, greener substitute for coal. The cost in blood and money is now clear. We should use all the windpower we can get, and conservation can help too. But I think the big answer here is hundreds of gigawatts of new nuclear generation over the next 30 years.

    I foresee the costs of coal going up in the future, from the additional costs of CO2 sequestration. I foresee the costs of nuclear coming down in the future, if many similar plants are built and regulation and operation become more standardized. So I see a second benefit to a massive nuclear buildout: a drop in the price of energy here in the U.S. I think that drop, along with a change to domestic energy supplies, could make a big difference to our balance of trade and national security.


    1. Hi Ian:

      I think that the most important phrase in your post is "natural gas was sold. . .".

      Unfortunately many people, even engineers, do not fully realize how many of our technical choices are made because of marketing efforts.

      I believe that same thing is happening today with wind power. Americans are "being sold" huge, expensive, turbines with fundamental reliability problems. The beneficiaries of the choice are numerous, but not obvious. They are certainly not the customers.

      Beneficiaries include wind turbine companies (like Siemens and GE), turbine construction companies, agricultural conglomerates, western ranchers, and numerous electrical equipment manufacturers. The less obvious ones include back up generator manufacturers, fossil fuel producers, and fossil fuel transportation companies.

      The fact is that the average windmill in the US produces about 20% of its nameplate capacity over the course of a year, and it provides that capacity whenever the hell it wants to. As an engineer, you have to realize that there is an order of magnitude difference in value between energy that comes at its own schedule and energy that is there when and where you need it.

    2. Hi Rod,

      Are you sure about that 20% number? My understanding is that (a) windmills built in, say, the last 5 years are better than that, and (b) the windpower base is growing fast enough that the average should be dominated by newer windmills. I suppose there was a big pulse of building in the 1980s, and perhaps the holdovers from then are bringing the average down.

      Futhermore, I've read that windpower is near $1/watt (nameplate). Even with a 20% average delivery, that's $5/watt continuous or 4.5 cents/kw-hr at 8% yearly depreciation, which is almost competitive with new coal-fired production. The availability numbers I've read were more like 25% and up, so that wind power was actually marginally less than coal. I think the monetary case for wind is reasonably good. And like I said, I like the idea of domestic production and the lack of CO2 output is agreeable.

      The AWEA is selling Americans as best they can on windpower, and like most marketing it's distorts the facts to mislead consumers. Frankly, though, I'm happy if they manage to build more of the things. It's just too bad they'll never build enough to really matter, and that they'll screw up the landscape in the process. The only real danger I see from AWEA's efforts is that Americans may think that (a) being green is more important than reducing our trade imbalance, and (b) we're doing our part to be green by subsidizing a few GW of wind, so we can relax.

      I disagree that intermittent wind energy is an order of magnitude less valuable. The existing U.S. electrical system already has to deal with a large swing between daytime and nighttime loads. Wind varies faster than that, so some spinning reserve is necessary, but it's an understood problem. Spinning reserve to deal with wind variation costs money, and they probably need something like 5-10% of nameplate power for spinning reserve. If that comes from newly built GT/CC plants at $4/watt, then it's going to jack the effective price of the windpower. If wind is $1/watt, delivering 25%, then it would add 20 to 40% to the cost of windpower. It's not clear to me that prices wind higher than newly built coal power.

      I'll add that large sales of plug-in hybrids would really change this picture. 2 million plug-in hybrids a year would add about 50 GW-hr/day to the nighttime load, increasing the nighttime load floor by 10 GW or so, each year.

      The EIA predicts that electrical generation will increase at about 7.7 gigawatts a year for the forseeable future. If the nighttime load floor rises faster than this, the extra capacity can be base load and we can actually free up a few GW a year of variable sources like hydro and gas turbines to handle the variation from tens of GW of nameplate windpower each year.

      Basically, I just don't think variability is going to limit the windpower build out, and neither is cost. And neither, BTW, is the sheer acreage with good wind, since modern turbines appear to operate in more marginal conditions. I think negative reaction to tens of thousands of really gigantic turbines will stop things cold, once people realize the scope of what is needed. But hopefully I'm wrong about that. Maybe everyone will think that turbines thumping away over hardscrabble grazing fields, and massive long-distance power lines, are somehow romantic or at least preferrable to boys and girls coming back to Dover AFB in caskets.

    3. Not all of the nuclear fuel we use here is domestic. A lot comes from Canada, Australia, and Russia. We even used some of the fuel from Russia's old nuclear stockpile in our plants today.

    4. Anonymous,

      Oh it's even better than that: about half of domestic nuclear power comes from ex-Russian warhead material. I actually don't think that's all or even mostly from warheads, but as long as it's from HEU, I'm not feeling picky. I hope we can start burning ex-Russian weapons-grade Plutonium as soon as possible, too. And, if I were in charge of the program, I would find a way to increase the rate of imports significantly.

      I am okay with importing Uranium but not natural gas. The difference is that (a) we have plenty of Uranium, and (b) the cost of the Uranium used to make electricity is small enough, and the volumes are low enough, that it is entirely practical to stockpile a couple of decades worth of the stuff inside the U.S. Overseas Uranium suppliers have essentially no ability to affect our domestic supplies of electricity or electric prices.