Thursday, April 14, 2016

Lessons from the Coal Bust

Yesterday's Chapter 11 filing by the largest US coal mining company is the latest in a series of coal bankruptcies. While factors such as regulations and poorly timed acquisitions have played a role, this trend reflects the parallel technology revolutions playing out across the energy sector. Here are a few key lessons from the ongoing coal bust:
  • There are many other ways to make electricity, and coal brings nothing unique to the party. In a growing number of markets it is no longer the cheapest form of generation, and it is certainly the one with the most environmental baggage, from source to combustion.
  • Coal-fired power generation is in competition with alternatives that are already producing at scale, like nuclear and natural gas generation, or growing rapidly from a smaller base, like renewables. It may not compete with all of these in every market, but few markets lack at least one of these challengers.
  • The costs of renewables and gas have fallen significantly in recent years, due to major technology gains. Coal has also benefited from some improvements in scale and end-use technology. Today's ultra supercritical coal plants are more efficient than coal plants of a generation ago, but they are more expensive to build, even without carbon capture (CCS). However, wind and solar power continue to grow cheaper and more efficient, while gas has benefited from resource-multiplying production technologies and advanced gas turbines that can exceed 60% efficiency and ramp up and down rapidly to accommodate the swings of intermittent renewables.
  • Despite all of these threats, coal is not on the verge of being forced out of power generation, even in developed countries where all the above factors are at work. Replacing its enormous contribution to primary energy supply and electricity generation will be a very heavy lift, particularly where another major energy source like nuclear power is being phased out. Germany is the prime example of that.
Consider what it would take to replace the remainder of coal in the US power sector. Last year coal generated 33% of US electricity, down from nearly 45% in 2010. Gas picked up 70% of the drop in coal's power output, but that still left coal's contribution at 1,356 Terawatt-hours (TWh) or about 6x the grid contribution of all US wind and solar power last year. (A Terawatt is a billion kilowatts.)

Displacing coal completely from US electricity would require doubling the 2015 output of US gas-fired power generation and a roughly 36% increase in US natural gas production. By comparison, the US nuclear power fleet would have to more than double. If coal were to be replaced entirely by renewables, which in practice probably means gas pushing coal out of baseload power and renewables reducing gas-fired peak generation, the hill looks steep.

Last year the US added 7.3 GW of new solar installations and 8.6 GW of new wind turbines. Assuming they were mostly sited in locations with reasonable solar or wind resources, their combined annual output should be around 35 TWh. At that pace it would take another 36 years to make up what coal now generates. It's true that net annual wind and solar additions continue to grow at double-digit rates, but keeping that up may get harder as the best sites become saturated and earlier wind turbines and PV arrays reach the end of their useful lives in the meantime.

In other words, driving coal from here to zero seems possible but very difficult, even with an all-of-the-above strategy in a market without demand growth. And if electricity demand continues to grow, as it is globally, or resumed growing in the US and other developed countries to enable a big shift to electric vehicles, the prospect of retiring coal entirely recedes into the future.

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