Tuesday, October 28, 2014

Where Wind Outpaces Nuclear: Carbon Emissions

Forbes provides a pretty good primer on why the Environmental Protection Agency’s plan for limiting carbon emissions can make a nuclear advocate a little grumbly – maybe a lot:

The Clean Power Plan calls for a near 20% reduction in U.S. carbon emissions from 2012 baseline levels by 2030. But here’s how the Clean Power Plan works—or doesn’t work, in the case of nuclear power. The draft rule sets forth an emissions rate baseline of CO2 emitted per megawatt-hour of fossil fuel generation … The draft rule allows for a 100% credit for all existing wind, solar, and geothermal sources, but only a 6% credit for nuclear. There’s no room at the inn for the other 94% of nuclear.

Remember, these are proposals, so they will change. Still, the issue of relative valuation in the proposed rule is at the root of discussions about properly valuing nuclear energy. Natural gas is currently priced very low due to its ubiquity. The problem is that natural gas only works as a replacement for coal because it produces about half the black rock’s carbon emissions. That’s still a fair amount of carbon, though, and on its own won’t get the country where it wants to go.

And it could get worse: what if natural gas prices prove enough to drive a nuclear facility out of the marketplace? That’s a lot of emission free energy taken off the table that can’t be easily replaced.

Why not renewables? Forbes writer Michael Krancer explains that because wind and solar are intermittent in nature, they need baseload energy to back them up. That requires natural gas (or coal or nuclear) to backstop them. Nuclear isn’t the best choice because it runs full tilt virtually all the time and it’s tough to ramp it down to allow renewable energy onto the grid – the same is true of hydro, plus the difficulty of building new dams. Coal and natural gas are more natural partners in this scenario, but they produce carbon emissions. The result: renewable energy plus natural gas or coal produces far more emissions than nuclear energy alone.

So the virtues of nuclear energy – baseload, non-carbon-emitting – has a decided value that the EPA’s proposed rule barely acknowledges. It’s hard to say for sure – there are a lot of factors – but the rules as they stands have the capacity to do a lot more harm than good. They could roil energy markets such that more not fewer carbon emissions are produced.

Lots of “coulds” there, an invitation to overstating the case. There are potential market forces, but also plenty of unpredictable human agency. Krancer does offer examples to suggest the case cannot be overstated:

Bentek, a Colorado energy analytics firm, found that 1,327 such cycling events [that is, a natural gas plant ramping up and down to accommodate wind) happened in Colorado in 2009, which released up to 6.8 million pounds of extra sulfur dioxide (“SO2”), 3.1 million pounds of nitrogen oxide (“NOX”), and 147,000 pounds of carbon dioxide (“CO2”).

That’s – awful.

Krancer provides the bottom line on nuclear energy:

Nuclear power is the work-horse of power supply and of zero-carbon generation.  Nuclear plants operate around the clock in all weather, providing nearly 20% of the nation’s electricity supply and comprising about 63.3% of all clean (zero carbon emissions) energy, which is more than all other clean energy sources put together.

It’s a great article on a complex topic. Well worth a full read.

1 comment:

Engineer-Poet said...

The article certainly has its thousands and millions of pounds reversed.  There is no way that a gas turbine would emit mere thousands of pounds of CO2 while generating over a million pounds of NOx.