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ECONOMIC REPORT OF THE PRESIDENT

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in the United States where new wind and solar can come online at a similar<br />

or lower cost than new coal.30 Note that EIA projections suggest that the<br />

unsubsidized LCOE for wind and solar will continue to be above that for<br />

natural gas (conventional combined cycle), on average across the United<br />

States, in 2018 and 2022 (EIA 2016a).<br />

To better understand what is driving the declining carbon intensity,<br />

CEA estimates the portion of carbon intensity in electricity generation<br />

decline due to two factors: a reduced carbon intensity of fossil-fuel generation<br />

driven by a shift toward natural gas resources, and an increase in electric<br />

generation from renewable resources. To do so, CEA uses an analytical<br />

approach that develops estimates of counterfactual emissions holding constant<br />

the carbon intensities of the electric generating portfolio in 2008.<br />

In particular, CEA first considers the case where the emissions factor<br />

associated with the portfolio of fossil-fuel electric generation; that is, the<br />

emissions per unit of energy generated from a fossil-fuel resource, in 2008<br />

is held constant through 2015. As the emissions factor reflects the mix of<br />

resources in the fossil-fuel electric generating portfolio in 2008, this factor<br />

reflects the composition and efficiency of coal, natural gas, and petroleum<br />

generation resources in 2008. Applying this factor to the total electricity<br />

generated from fossil-fuel resources from 2009 to 2015 develops a counterfactual<br />

level of emissions had the portfolio of fossil-fuel resources remained<br />

constant in mix and efficiency over this time. Then, the difference between<br />

the quantity of emissions in the counterfactual and the observed emissions<br />

from electricity generated by fossil fuels during this time provides an<br />

estimate of emissions saved as a result of the reduction in carbon intensity<br />

of fossil-fuel electricity generation.31 This reduction in carbon intensity is<br />

expected to stem primarily from increased natural gas generation, though<br />

would also include improvements in technical efficiency from fossil fuel<br />

resources. Much of the shift toward natural gas comes from rising supplies<br />

and falling prices of natural gas in the United States, though some may stem<br />

from policies that have aimed to account for and internalize some of the<br />

externalities of coal combustion.<br />

Next, in a similar fashion, the analysis considers the emissions outcomes<br />

if the emissions factor from the entire portfolio of electricity generating<br />

resources in 2008 were held constant through 2015. The difference<br />

between these counterfactual emissions and total actual emissions from<br />

30 Wind: DOE (2015), Wiser and Bolinger (2014); Solar: Galen and Darghouth (2015), Bolinger<br />

and Seel (2015).<br />

31 This analytical approach holds fixed the observed kWh demand from fossil fuels and total<br />

power when estimating counterfactual emissions. To the extent that the shift to natural gas led<br />

to an increase in electricity demand, this approach would overstate the impact of coal-to-gas<br />

switching on reducing emissions.<br />

Addressing Climate Change | 465

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