Compliance with Regulations and Replacing Coal Generation with
Natural Gas and Renewables led to Massive Decreases in SO2 and NOx Power Plant
Emissions Over the Last 20 Years (1997-2017) – and Coming Reductions in Marine Fuel
Sulfur Limits
The EIA just released a 20-year analysis (1997-2017) of SO2
and NOx emissions from power plants. 1997 was the year that emissions of both
of these pollutants peaked. The two main reasons for the decrease are
compliance with environmental regulations and switching from burning coal to
burning natural gas and renewables for electric power generation. Increases in
efficiency is another factor in the redcutions. The regs responsible for the
decrease are the 1990 Clean Air Act Amendments (CAAA) and the 2005 Clean Air
Interstate Rule (CAIR). CAIR was replaced in 2015 with the similar Cross-State Air
Pollution Rule (CSAPR). These were federal regulations that required scrubbers
to remove SO2 and other pollutants. These reductions in pollutants are clear
regulatory successes that have aided human well-being and demonstrate that pollution
reduction is achievable and is a public good. In the second part of the time
period coal-fired generation dropped from a high of 2016 million MWh in 2007 to
1206 million MWh in 2017. Thus, it looks like the drop in SO2 and NOx from 2007
to 2017 is mostly a result of natural gas (and to a much lesser extent renewables)
replacing coal in power generation with some improvements still coming from pollution
abatement of coal plants. The coal-heavy Midwestern, Appalachian, and
Southeastern states have benefitted the most in improved air quality. Texas
also saw significant reductions. Burning natural gas produces very low amounts of
NOx relative to coal and fuel oil and virtually no SO2. However, some of each pollutant
is emitted in the production phase of natural gas mostly due to the use of diesel
fuel in upstream operations. Renewables are, of course, the least emitting
source of these pollutants among power production.
Soon to be Implemented Marine Fuel Sulfur Limits in Open Seas
Another issue involving the reduction of SO2 worldwide will
be coming limits to marine fuel sulfur which produces SO2. SO2 has been
problematic in acid-rain production in the U.S. Northeast, Canada, Northern
Europe, and other places. Since marine fuel is currently mostly high-sulfur
diesel this will spur changes in the oil refining sector where de-sulfurization
of fuels and utilizing lower-sulfur crude oils will occur. It will also likely increase
the use of LNG for ships as a very low-sulfur alternative. Ships will also have
the option of installing scrubbers and while that may save them money in the
short-term it may be more costly later if tighter restrictions occur in the
future. The standards are set by the International Maritime Organization (IMO),
a 171-member state UN agency. The regs for sulfur content by percent weight in
marine fuels for open seas are set to drop from the current 3.5% to 0.5% by 2020. This is a big drop. These
reductions will also reduce nitrogen oxides (NOx) and other pollutants. It is
uncertain whether they will affect shipping costs at this point, but it seems
likely they will increase costs at east for a while. However, quite a few coastal
areas deemed Emission Control Areas have already dropped emissions from 1% to
0.1% in line with previous IMO rules. This has mostly been in North American and
European coasts with a few Chinese and African coasts as well. If the new rules
cause refiners to devote more capacity to distillates for the bunker fuel (marine)
market then that could affect availability and price of distillates which are
already in high-demand for the trucking and heavy equipment markets.
References:
Changes in Coal Sector Led to Less SO2 and NOx Emissions from Electric
Power Industry – by Cara Marcy (principal contributor), in Energy Information
Administration (EIA), Today In Energy, Dec. 11, 2018
Coming Changes in Marine Fuel Sulfur Limits Will Affect Global Oil Markets
– by Mason Hamilton (principal contributor) in Energy Information Administration
(EIA), Today In Energy, Dec. 14, 2018
