Green energy and nuclear power

In discussions of wind and solar power, sensible centrists always pop up with, “We must build new nuclear power plants too!”. And then mumble on about how nuclear power isn’t really dangerous, especially new designs, and talk about how nuclear power provides steady base load power which is necessary because wind and solar are intermittent.

For example, see this Freakonomics Radio podcast hosted by Stephen Dubner, which is noteworthy for never meationing the cost or relative cost of nuclear power. No economics in Freakonomics! And in a more reasonable discussion between host Ezra Klein and Jesse Jenkins covering a host of energy / decarbonization topics, nuclear power is boosted as a necessary component, again without a discussion of costs.

But this idea that nuclear power is necessary and complementary is mostly nonsense. Yes, nuclear power has killed very few people, and compares favorably in overall safety to coal power plants which cause plenty of deaths due to air pollution. But this argument is almost entirely off target.

The intermittency of wind and solar power is a big issue. Working out solutions for providing steady power in a grid powered mostly by wind and solar is the challenge for the next generation or two.

The thing is, nuclear power doesn’t help with that. Nuclear power plants are run full out except for maintenance (a capacity factor of 92%). What’s needed to complement solar and wind are power sources that are dispatchable and can be ramped up and down quickly. Hydroelectric power provides that in places like the US’s northwest that have lots of dams. And today gas peaker plants and coal plants provide fast and slow power that can be ramped up and down as needed.

And nuclear power is expensive, very, very, expensive. Today nuclear power costs 3-4X as much as solar and wind power. And that is market cost, excluding the subsidies provided by the federal government for nuclear power. Nuclear plants are insured by the US government. The costs of a meltdown are immense, from billions to hundreds of billions, and with a chance of a nuclear plant disaster of at least 1 in 165 over the life of a plant, the risk is substantial. Long term high level nuclear waste disposal has not been paid for or figured into costs–US nuclear plants store high level waste on site, along rivers and coasts, with the US government expected to handle final storage. And nuclear plant decommissioning will likely cost more than the collected funds account for.

So nuclear plants don’t make economic sense on their own and they do not complement wind and solar power generation.

What is needed to make a power grid with wind and solar the primary power sources able to provide reliable power? There needs to be ways of meeting short term (minute to minute), medium term (hourly and daily), and long term (days and weeks) interruptions in wind and solar power production. Short term irregularity can be met today with small grid storage and hydropower.

Dealing with the daily cycle of solar power production requires much larger grid storage, generally not available today, and/or large scale demand shifting not done today. Short periods of low wind are fairly common, and week- or month-long regional low wind is known to occur. Solar power production is lower on cloudy days, and varies seasonally.

It is not clear today what solutions will be used. Grid scale power storage is an active and promising R&D area. Over-capacity–having more solar and wind capacity than is needed will help, and solar and wind are already cheap enough for it to be economic, but this creates a new problem–what to do with the excess power generated during high periods.

Demand-shifting has a lot of promise, and will help with hourly and daily power demand balancing. Residential and industrial power use modulated by utilities is already in widespread use, mainly used to shave off peak demand and do modest demand shifting today, but there is much more potential, especially as electricity gets used more widely for heating water, cars, and homes.

For long periods with low wind and solar power production, other strategies are needed. Today, fossil fuel plants are used. Grid interconnects able to transfer substantial power between regions can be part of the solution–areas with low wind and heavy cloud cover are typically regional. Long-term, there is also potential for storage of energy in other forms–compressed air, hydrogen, or hydrocarbons. A round trip efficiency of ~25% is enough to make this practical.

So there are challenges to powering the grid mainly with wind and solar power, but nuclear power doesn’t help with solve them. If nuclear power with lower, competitive costs can be developed, then it is safe enough to use.

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