Replacing “dirty” power plants

Power plants are becoming slightly cleaner by switching from coal to natural gas—without increasing electricity prices.

Cheaper natural-gas plants are being built to replace aging coal plants, but both remain competitive until the end of their lifespan.

In the US, a large share of GHG reductions comes from switching from coal to natural gas in power plants.[1] Yet globally, the number of “dirty” coal power plants has remained relatively stable, with some increases observed in countries such as China.[2][3]

Achieving a large share of renewable electricity would be costly when accounting for dilution and intermittency.

The share of solar and wind in electricity generation is growing as complementary energy sources, but natural gas and coal remain indispensable baseload energy sources, capable of ramping up when the sun does not shine or the wind does not blow. Solar and wind are approaching 20% of electricity production in the US[1] and 30% in the EU[2]. Yet, these figures represent only about 5% of total US or EU energy consumption.[3][4] They have nonetheless contributed to the decline in emissions.

Any further expansion of renewable energy would face two major challenges[5]:
• The dispersed nature of solar and wind power requires extensive land. Remote sunny deserts or plains offer potential sites, but they necessitate costly power transmission back to the urban centers.
• The intermittent availability of solar and wind energy, due to nightfall, calm weather, or seasonal changes, leads to expensive backup systems to maintain a consistent energy supply.

The workarounds would imply an impractically high cost to achieve a large share of renewable energy:
• A costly interstate electrical super-grid is required to deliver electricity to regions with limited wind or sunlight for electricity generation. The current grid is insufficient.[6][7].
• Electricity-storage systems, using batteries or gravity[8], would need to exist at sufficient scale to guarantee continuous power generation.

Nuclear power plants have the potential to provide base-load electricity without CO2 emissions.

There is growing optimism that Generation IV nuclear power plants, expected to become operational around 2030, will offer a solution by generating clean electricity with reduced uranium consumption and lower radioactive-waste production, while hydrogen-based nuclear-fusion experiments are not expected to succeed until much later in the century.

This Generation IV technology could address several major challenges:
• Reduced uranium (or thorium) requirements: Known uranium reserves have historically constrained the large-scale deployment of previous generations of nuclear facilities.[1]
• Reduced volume and longevity of radioactive waste: This could weaken the case for fully phasing out nuclear power based on waste-management concerns.[2]
• Reprocessing accumulated waste from earlier nuclear plants: Re-burning this waste could produce energy and byproducts with very low residual radioactivity, eliminating the need to mine new uranium and reducing the requirement for long-term storage.[3]
• Reducing reliance on massive renewable expansion: This would alleviate the need for an unrealistic expansion of solar and wind power and the associated impractical energy-storage requirements.