Thursday, November 13, 2014

What Impact Does Increased Natural Gas from Fracking have on Plan to Reduce CO2 Emissions?

The effect of natural gas supply on US renewable energy and CO2 emissions (9 page pdf, Christine Shearer, John Bistline, Mason Inman and Steven J Davis, Environmental Research Letters, Sep. 24, 2014)

Today we review research that examines the impact of increased natural gas supplies for electrical generation in the USA as one factor among the existence of a strict or absent climate policy, the emergence of renewable energy sources and the net impact of CO2 emissions between now and 2055. Given the advantage in terms of lower carbon emissions from natural gas compared to coal (which is used for almost 50% of the energy used to generate electricity in the USA), hydraulic fracking is seen as a bridge toward a lower carbon future. However, the likelihood of increased leakage of greenhouse gases from fracking offsets this advantage, even if natural gas emissions are less dangerous in health terms than coal emissions (fine particulate matter). The paper points out that the key factor is a strict climate policy as, without it, a switch to ample natural gas may increase the cumulative emissions over the next 40 years. Also, an increase in natural gas from fracking would tend to reduce the growth of renewable energy sources with zero carbon emissions, such as solar and wind.

  fracking and co2 emissions  

Key Quotes:

 “Fossil fuels supply approximately 87% of the primary energy used worldwide, and the carbon dioxide (CO2) emissions from burning these fuels are the main cause of climate change”

 “natural gas-fired power plants emit ∼57% less CO2 per kilowatt-hour (kWh) than coal-fired plants, and are on average 20% more efficient at converting fuel energy to electricity than coal plants”

“innovations in hydraulic fracturing technology have dramatically increased domestic supplies of gas”

 “cumulative emissions increase by 5% (2.6 Gt CO2-eq) in the high gas scenario under our stringent climate policy when a leakage rate of 3% is assumed”

“ increased use of gas may not lead to substantial reductions in GHG emissions where gas competes with renewables in the energy market. On the other hand, the effect of more abundant gas supply on GHG emissions is so small that the quantity of methane leaked may ultimately determine whether the overall effect is to slightly reduce or actually increase cumulative emissions”

“The costs of wind and solar can be expected to decrease with increased deployment (e.g., 30), but more abundant natural gas may delay deployment and thereby increase the time period over which renewable energies decrease in cost.”

“coal use will continue to decline in the US electricity sector, but will decline most if natural gas is abundant and stringent climate policies are adopted. Similarly, the use of renewable technologies continues to increase in our model results, but increases least when natural gas is abundant and there is no new climate policy.”

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