About a year ago I wrote the following essay but it was never published anywhere. More or less the basic thesis is the same. I was inspired to post it after hearing Michael Bloomberg claim on Meet the Press with Chuck Todd that being on target for the Paris climate goals was due to local municipalities remaining committed to the goals even though the Trump administration had not (Transcript). Of course, local municipalities are to be applauded for continuing to implement climate action plans that move us into a low CO2 emissions world. And, of course, action by local municipalities will enable us to meet the goals. But the data continue to suggest that it’s an economically motivated transition from coal to natural gas that is the real cause of this phenomenon.
Here is the original essay with one of the graphs updated:
The Clean Power Plan (CPP) was an Obama era EPA policy published in October, 2015, to reduce CO2 emissions from fossil fuel burning electrical power plants 32% relative to 2005 emissions by 2030. The plan required states to develop and implement emissions reduction plans. The CPP was a key plank in the US emission reduction goals presented at the 2015 Paris Climate Talks. The CPP came under immediate political fire and eventually enforcement was blocked by an action of the US Supreme Court. The Trump administration ordered a review the CPP which eventually led to its proposed repeal in October, 2017.
CO2 emissions in 2005 from the electric power sector were 2.4 billion tonnes. They will be around 1.7 billion tonnes by the end of 2017. This is a 29% reduction, already close to the 32% mandated for 2030. It appears that the goals of the CPP are being met without it ever having been implemented. Interestingly, in 2016 the transportation sector exceeded the electrical power sector as the sector responsible for the most emissions.
Two factors contribute. First, these reductions in CO2 emissions for the electrical power sector are due to the transition from coal to natural gas. See the accompanying chart “Fraction of Source for US Electricity.” In 2006 50% of electricity in the US came from coal-fired power plants, 20% from nuclear, 20% from natural gas-fired power plants, and the rest from renewable forms of energy. A dramatic shift occurred during the past decade where coal dropped to just under 30% and natural gas increased to nearly 35%. Nuclear remained at 20%. The total electricity demand remained constant throughout this period. The transition to natural gas produced a significant reduction in CO2 emissions. Natural gas produces less CO2 per unit energy than coal. For each kilojoule (kJ) of heat produced, natural gas produces 0.05 g CO2, whereas sub-bituminous coal produces 0.13 g CO2 and anthracite/bituminous coal produces 0.10 g CO2. Emissions are at least cut in half when natural gas replaces coal (assuming minimal leakage of gas in the transport system). Natural gas combined cycle systems are closer to 60% efficient whereas conventional coal plants are 40% efficient. A combined cycle natural gas turbine uses the heat from the initial combustion in the gas turbine to drive a second conventional steam turbine. Gas plants also burn cleaner.
The driving force for this transition, however, is not emissions reduction, but rather simple economic factors. Due to hydraulic fracturing, natural gas has become much more abundant and less expensive. Natural gas power plants are cheaper to build (~$1 billion/GW vs. ~$3 billion/GW for coal plants). Currently, there are only four coal-fired power plants being built in the US, and it appears that three of the four may not be completed. Even apart from the low price of natural gas, the cost of non-CO2 emissions controls (SOx, NOx, O3, Hg, and particulates), the uncertain regulatory climate, and the long-term investment makes a new coal plant a risky plan.
The second factor is the growth of renewable energy, especially windand solar PV. The accompanying chart shows that the fraction of coal plus natural gas has decreased by about 7%. A 7% increase in combined wind and solar offset this decrease. Nuclear and hydroelectric have not changed. Both wind and solar have seen a 10-fold increase in actual energy production in the past decade. Both are zero-emission sources. Energy production from wind and solar that replaces coal or natural gas will reduce CO2 emissions.
Where Do We Go from Here?
- It seems that the doomsday predictions of those lamenting the repeal of the CPP are overstated. Let it die, and let the market continue to bring emissions down.
- Let the market do what it will to conventional coal. As coal is replaced by natural gas and renewables, CO2 emissions will continue to drop. Funding for the re-training of coal industry workers should be made available.
- The reaction of certain states and local municipalities to the CPP repeal and the planned withdrawal from the Paris climate agreement suggests that there is a commitment to these policies despite the Trump administration’s ambivalence. Perhaps the best solutions now are those that work with state and local regulators.