Wednesday, September 26, 2012

Another Analysis Of The Role Of Gas In Plummeting US Carbon Emissions

Michael Levi of the Council on Foreign Relations weighs in on the role of gas in reducing US carbon emissions.

Michael's analysis discusses at length my September 17, 2012 posting on the same topic. See  I have also commented twice on Michael's analysis at his blog.

The role of gas in reducing carbon emissions differs in different time periods.  It was significant in 2011 but even bigger in 2012, for a number of reasons, including gas is displacing even more coal generation in 2012 than in 2011, and renewable electric production is down in 2012 compared to 2011.

The plummeting of carbon emissions in the US is real and not a result of magic.  Gas is at the heart of the good news, and it is sad to see some deny that fact, as others deny the reality of climate change.


  1. Why are you overstating the case?

    This analysis is as shoddy as your position that vehicle miles driven (VMT) played no role in the decline in petroleum emissions since 2007. You blogged thousands of words on the subject without mentioning VMT once.

    The EIA estimates that 2012 emissions will decline 2.4% and 2013 emissions rise by 2.8%. So assuming the economy continues to expand and the weather is normal, the only issue is whether 2013 will exceed 2011 emissions.

    WEATHER is just as responsible for the decline YTD through May 2012 in emissions as gas substitution in the electric power sector. Heating degree days were down 21% in the 6 month period ending May 2012. The residential, commercial and industrial sectors used less direct gas and indirect gas via electricity for space heating.

    The EIA is now projecting that 2013 emissions will be higher than 2011.

  2. The reduction in demand in 2012, for whatever reasons, including weather, is captured in my analysis. Reduced demand is one reason emissions went down in 2012 compared to 2011. The posting quantifies it. Michael Levi also reaches the same quantification of the carbon reduction attributable to demand changes in the two periods.

    EIA does project that emissions will rise in 2013 and almost exclusively because they predict higher natural gas prices will mean more coal is consumed. It is just silly to pretend that gas for coal or coal for gas substitution is not a main reason for the decline or possible increase next year in carbon emissions.

  3. It is just silly to pretend that gas for coal or coal for gas substitution is not a main reason for the decline or possible increase next year in carbon emissions.

    You have overstated the case because weather and substitution are equal as explanatory variables for the decline in emissions.

    For purposes of analysis, let's ignore lower electrical demand due to lower heating degree days (hdd). [You are aware that ratio between gas heated and electrically homes in the U.S. are about equal, even though baseboard heating predominates in the south and west where hdd are lower].

    So if coal emissions declined by 132 units, gas must have increased by 61 units (2:1 emission ratio), ceteris paribus. Yet gas declined by 5 units. You are missing 66 units out of the 145 unit total decline.

    It's the 21% decline in hdd (weather) that you fail to acknowledge which is roughly equal to the gas substitution effect.

    In summary, the decline in emissions is 10% petroleum, 45% gas substitution and 45% weather. You have overstated the case.

  4. to repeat again, the post does capture the change in heating degree days and any other factor that influenced demand/consumption. I calculate that the drop in the 2012 demand accounts for about 20 million tons of the 2012 decrease. Michael Levi essentially agrees with that number.

    You are incorrect on the gas increase. EIA data shows gas emissions increased 6 million tons in 2012 compared to 2011. Part of the reason is that very efficient new gas plants are running much more that emit even less than 50% of the coal emissions. And old inefficient gas plants are being retired.

    My estimate of the role of gas in cutting 2012 emissions is probably an underestimate because I credited zero of the oil emission decline to gas. That is wrong. Gas has displaced oil at power plants, homes, buildings, factories, and in vehicles.

    So the better question to me, is why are you under-estimating the role of gas in cutting 2012 emissions?

  5. 45% or 77% is a lot of substitution and worth celebrating. I am not quite sure how to calculate it (and the varying conclusions show that difficulty) but either way its a major accomplishment.

    John, what do you think about exporting LNG? I am opposed for climate, environmental and economic reasons. I think that the gas price needs to stay below $5.00 to keep the gains we have made switching from coal to gas. If the price shoots right back up I think that we will just switch right back to coal. I'd much rather see us switch more power generation from coal to gas and vehicles from gasoline to natural gas and find more uses for the gas here.