# Physical Insights

An independent scientist’s observations on society, technology, energy, science and the environment. “Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.” – Carl Sagan

## The real potential for nuclear energy in GHG abatement

We often hear from the anti-nuclear crowd that nuclear energy just isn’t practically able to put a significant dent in worldwide GHG emissions fast enough over the immediate future, and this excuse for interest in nuclear energy is worthless.

Let’s see if we can quantitatively find out if this is true.

The basic outline of these numbers is taken from here, but I’ve reworked it.

The Carbon dioxide emissions profile from coal ranges from 0.97 kg to 1.3 kg CO2e/kWhe, Nuclear power ranges from 9 to 21 g/kWh.

How many nuclear power plants are needed to reduce ultimate atmospheric levels of greenhouse gases by 1 part per million?

If there is a positive feedback loop – warming soils releasing carbon dioxide and methane, plants growing in dryer soils and warmer oceans holding less carbon – then GHG we add today will produce more tomorrow. But for now, assume no feedback loop exists. Pouring 2.1 billion tons of Carbon Dioxide into the atmosphere raises GHG concentrations by 1 ppm.

At this point, we can assume every ppm saved counts, as it reduces the amount of damage we do the Earth.

Considering a 1GW nuclear plant, the plant lasts 60 years, and has a 90% capacity factor, then the plant will produce 1GW * 24 hours/day * 365 day/year * 60 years * 90% = 526 billion kWh, and produce 7.89 million tons of CO2, assuming 15g/kWh.

Each kWh from coal puts 1 kg of CO2e into the atmosphere.

526 billion kWh * 1 kg CO2e/kWh * 3/11 = 140 million tonnes Ce.

The factor of 3/11 gives the mass in tonnes Ce.
2.1 billion tonnes Ce/(140 million tonnes Ce/plant – 2.15 million tonnes Ce/plant) = 15,234 MW of nuclear power, to get a 1 ppm abatement.Building 10 large 1500MW nuclear power plants will give us a 1 ppm reduction in CO2 emissions versus burning coal.

And, like it or not, that’s what the alternative has always been in the past, and that’s what the alternative will continue to be in the foreseeable future. Burning coal. That’s what we’re doing right now, and that’s what has got to be stopped.
If we start 15,000 MW in nuclear power every year for the next 20 years, these power plants will potentially reduce atmospheric GHG concentrations by 20 ppm. If these take an average of 4 – 5 years to build, at least 60 GW will be under construction every year.
In the late 1970s and early 80s, 150 GW was under construction. This was the peak of the earlier construction period, when plant construction was much slower than it would be today.

Not only were new designs being worked out, but a new regulatory system as well. Add in a few nuisance lawsuits here and there. Nevertheless, the construction rate was 4 – 5 times what it would need to be to reduce GHG concentrations by 20 ppm through projects started over the next 20 years.

Perhaps in 25 years it will become obvious that solar, etc will be able to supply electricity needs and no more nuclear power plants need be built. But it’s not bloody obvious today. What is clear is that building nuclear power plants decreases atmospheric GHG concentrations.