Taking into account fugitive methane emissions from the production and distribution of natural gas, the U.S. electricity-generating sector may not reduce overall climate-warming emissions at all during the foreseeable future. Nor has it in the previous decade, as claimed by the U.S. government. With Canada already generating 84% of its electricity from renewables and nuclear, it can only play a small part in reducing overall North American emissions. Especially when the U.S. produces eight times the amount of electricity. Mexico may significantly increase its share of renewable and nuclear sourced electricity, but overall growth in electricity demand will mean that this will not reduce greenhouse gas emissions.
Unless fugitive methane emissions throughout the natural gas production and distribution network can be significantly reduced, the North American electricity-generating sector may not provide any reductions in climate-warming emissions. Given that this sector has been at the forefront of emission reduction efforts, this does not bode well for any real reductions in greenhouse gas emissions – when measured on a CO2 equivalent basis (incorporating other greenhouse gases) rather than just a CO2 basis.
United States (66% fossil fuels)
As of 2015, U.S. electricity generation was provided predominantly by coal (33%), natural gas (33%), nuclear (20%), and hydroelectric power (6%). Wind provided 4.7%, and Solar 0.6%. The largest change in the U.S. electricity generation mix in the past 10 years has been the significant replacement of coal generation, which was reduced by one-third, with natural gas plants. This was driven by the low prices produced by the exploitation of shale gas resources. As the incineration of natural gas produces significantly less carbon dioxide than that of coal, the result was reduced CO2 emissions.
Over 80% of natural gas is made up of methane, a gas that has many times the climate-warming impact of CO2. Fugitive methane emissions of as little as 3% from the production and distribution networks can offset the lower levels of CO2 emissions. Independent analyses, together with an observed 30% increase in U.S. methane emissions, point to at least that level of fugitive emissions from the U.S. production and distribution sectors. Therefore, on a CO2 equivalent basis (converting all climate change gases into CO2 equivalents) the U.S. electricity sector has not reduced climate change emissions as claimed by the U.S. government. Any further move from coal to natural gas, as envisaged by the U.S. Environmental Protection Agency’s Clean Power Plan, will have little effect on CO2 equivalent level of emissions. A reality accepted by Bill McKibben, one of the founders of 350.org. As he states, “it’s even possible that America’s contribution to global warming increased during the Obama years”.
The U.S. fleets of both coal-fired and nuclear generating plants are now quite old when compared to average retirement ages and intended operating lifespan. The general age of coal-fired plants will be passing the average retirement age in the next 10 years, and many nuclear plants are having their lifespans extended well beyond 40 year assumed operating periods. As the construction costs of these plants will have been written off many years ago, their retirement will not have a detrimental impact on utilities’ balance sheets, although the nuclear plant decommissioning costs may provide some financial risk. A counterpoint is that the profitability of fully depreciated coal plants may be relatively high, and therefore any relative price and/or government policy changes may produce a swift move back to coal generation. This is possible without building new coal plants, given the amount of under-utilized coal-fired capacity available. With the most beneficial locations for hydroelectric plants already utilized, there will be little or no increase in that source. In addition, the possibility for any significant expansion in nuclear capacity has proven to be extremely limited.
In 2015, incremental new generating capacity consisted of wind (41%), natural gas (30%), and solar (26%). Taking into account the much higher possible capacity utilization of natural gas plants, which are not weather or sun dependent, the majority of incremental electricity generating capability was from new natural gas plants. This has been the trend over the past decade, reflected in the much larger increase in electricity generation from natural gas than from wind and solar. For 2016, it is forecast that new additions will be split between solar (9.5 Gigawatts), natural gas (8 GW), and wind (6.8 GW). Again, taking into account the higher utilization ability of natural gas plants, the natural gas capacity additions represent a greater increase in generating capability than the combination of wind and solar. With the next four years of a “fossil fuel friendly” Trump administration, the lack of CO2 equivalent emission reductions may turn into an actual increase as financial and policy support for renewable generation is reduced.
Canada (16% fossil fuels)
The Canadian electricity generating system is already at a low level of carbon intensity, relying predominantly on hydropower (60%) and nuclear (16%). The balance is provided by coal (9.5%), natural gas (8.5%) and new renewables – the latter being predominantly wind power (6%). With some viable sites remaining for hydropower, and extensive possibilities for wind, the country is in an excellent position to further reduce greenhouse gas emissions. Canada has committed to phase out coal usage by 2030, but has made no such commitment on the usage of natural gas. Given its low-carbon base of dispatchable power, and commitments to new hydroelectric installations, the replacement of all fossil fuel usage with renewables would be feasible within that timeframe.
Mexico (80% fossil fuels)
Unlike the U.S. and Canada, Mexico has seen significant increases in its electricity usage over the decade up to 2015; with overall generation increasing 21%, with 80% of that electricity supplied from fossil-fuel generating capacity (about three quarters from natural gas). The remaining 20% was provided by hydroelectricity (10%), a single nuclear plant (4%), wind (3%), geothermal (2%), and solar (<1%). Mexico’s wind capacity is planned to quintuple by 2022, and three new nuclear plants are planned for implementation in the 2020-2030 period. There is also some limited additional hydroelectric capacity planned. Solar is expanding, but from a very small base. Overall, Mexico has committed to generate 35% of its electricity from clean energy sources by 2024 (40% by 2035 and 50% by 2050), a doable aim given its nuclear and renewable expansion plans. With significant growth in electricity consumption forecasted, such a level of growth in clean energy would not produce a reduction in greenhouse gas emissions.
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