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Deep Dive

Fueled – The Power Sector

Decarbonization too often is reduced to electrification (ban all gas stoves). Obviously it matters how power is generated, and a lot has been happening on that front.

For the electricity sector, let’s start with the obvious insights:

  • Net power generation increased by about 5% between 2000 and 2020. The 2020 figure was lower because of the pandemic, but overall, electricity generation in the US has been growing modestly year over year.
  • During this same period, toxic chemical pollution from the sector declined by 83%.
  • Coal-fired generation this century dropped by 61%, while gas grew 1.7 times and renewable energy, excluding hydro, grew 70 times.
  • The correlation between the drop in pollution and coal-fired generation is a positive 0.91 (less coal, fewer pollutants). The correlation for gas-fired generation is a negative 0.96, and for renewables it is 0.93 (more gas and renewables, less pollution).
  • In the last decade, the negative correlation between renewable energy use and toxic chemical release has edged that of gas by one point (0.95 to 0.94) showing the increased contribution of solar and wind to reducing harmful emissions beyond greenhouse gases.
  • The cost of electricity this century has increased on average by 2.1% annually, exactly in line with inflation. While the shift away from coal devastated mining communities and companies, it was a non-event for the rest of the economy.
    Chart 1: Power Generation from coal and gas (TWh) against total releases (bn pounds).
    Chart2: Power generation from selected sources (TWh).

    The positive effect on environmental quality from abandoning coal is generally well understood, but it gets sometimes obscured by the focus on carbon dioxide, so it bears repeating. Measured in the effects on health, the drop in pollution from power plants is even more impressive given that the steepest decline has been in metals.

    Total releases of metals and toxic organic chemicals in millions of pounds from US power plants in the 21st century

    Moving on to the less obvious, and drilling deeper into the data, we discover that while total metal pollution has dropped by a lot, not all companies are moving in the same direction or at the same pace. We compared the top 20 companies, using the year 2000 as a baseline and calculating the percentage of the baseline for each year by company.

    Some large publicly traded companies – Vistra and Duke Energy – did not reduce their metals emissions as sharply as others. Also, the average for the second decade of the century is flattered by the exceptionally low 2020 emission level.

    Generators with a presence in the upper Midwest either stayed put or increased their metals emissions. Allete, which operates four plants that burn coal and owns Minnesota Power, is in that group. The company is adding biomass to its fuel, and “renewable energy” to its plant names, but there is no impact on metal pollution. Basin Electric, in the same region of the country, also operates four coal-fired plants.

    The late 1990s and early 2000s saw a massive increase in the installation of pollution control technologies such as bag houses, scrubbers, and selective catalytic reduction reactors. The impetus for that push was the Clean Air Act, and the price it put on emissions of the oxides of sulfur and nitrogen. Now, the determining factor for a company’s environmental impact is the fuel it uses.

    Top 20 electric utility companies by volume of metals emitted in the 21st century in ascending order