Revised – 2 May 2018
My previous blog posting was based on a report that carbon dioxide (CO2) produced by electric plants in Ohio was reduced by 38 percent between 2005 and 2015 (1). To bring the data up to date, I shifted the time frame to 2008-2017 (a) and showed that Ohio’s production and consumption were about the same in 2008. Since then production has fallen faster than consumption and Ohio has become a net importer of electricity. It is not surprising that CO2 production has fallen in view of our heavy dependence on fossil fuels.
The decrease in electricity generation starts with coal. Plant retirement in the past nine years has reduced coal capacity by about thirty percent (2) and the remaining plants are running only about half time (2,3). As sown below, the shortfall has been replaced by natural gas, imports from other states, and a decrease in demand (4).
Since 2008 CO2emissions in Ohio have decreased by about 49 million metric tons, or about 39 percent (b)(5). This decrease has the following components in million metric tons (mmt):
Coal = -59 mmt
Natural Gas = +10 mmt
it is also possible to see what has replaced the 48 mmt emissions due to coal.
- Since natural gas only produces 40% of the CO2 as coal, the 10 mmt from natural gas are replacing 25 mmt from coal, for an net reduction of 15 mmt.
- Decreased demand saves 8 mmt of CO2 (c)
- Using imports save the balance, 25 mmt of CO2
The biggest driver in greenhouse gas reduction is less use of coal. Ohio’s situation is improved considerably by importing electricity from out of state, which is approaching 20 percent of demand (4).
(a) Dating from passage of electric deregulation in 2008 (127-SB221)
(b) Actual 2015 CO2 data have been extrapolated to provide 2017 estimates.
(c) Regression analysis of data from Ref. (4) shows that Ohioans are reducing usage by about 0.9 million kWh per year or a total of about 8 million kWh over the nine year period. Comparison of Refs. (4) and (5) shows that coal produces one metric ton of CO2 for each kWh of electricity generated while natural gas produces about 0.4 metric tons..
(1) EDF This Midwestern state is the surprising standout on cutting carbon pollution, Jan 4,2018, http://blogs.edf.org/energyexchange/2018/01/04/this-midwestern-state-is-the-surprising-standout-on-cutting-carbon-pollution/
(2) EIA Electric Power Industry Capability by Primary Energy Source, 1990 through 2016, https://www.eia.gov/electricity/state/Ohio/
(3) EIA, Electric Power Monthly, Jan. 2017, https://www.eia.gov/electricity/monthly/
(4) EIA, Electricity Data Browser, https://www.eia.gov/electricity/data/browser
(5) EIA, State Carbon Dioxide Emissions Data https://www.eia.gov/environment/emissions/state/