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Zero Emissions from Natural Gas?


January 17th, 2012 by Armond Cohen, Executive Director

This posting originally appeared in the National Journal’s Energy and Environment Expert Blog.

photoWith the global explosion of unconventional gas production, reports of the death of the fossil fuel economy are, to paraphrase Mark Twain, greatly exaggerated. Gas may not stay at its current extraordinarily low price, but the market landscape seems to be altered for quite some time.

The explosion of low-cost shale gas reserves is a two-edged climate sword. Generating electricity with gas is 30 to 50 percent less carbon-intensive than coal when leaks and releases of methane, the main component of natural gas, are accounted for. (For other uses like vehicle fuel, we haven’t seen any evidence that gas is better than other fossil fuels, and if vehicles leak even a small amount, natural gas could be worse than gasoline). But even for electricity, gas is still a high-carbon fuel: replacing all coal-fired generation with gas would get us only part of the way to the 80 percent CO2 reduction needed by mid-century. Moreover, new gas plants are more likely to displace new zero-carbon generation sources than to displace existing cheap coal plants. Carbon dioxide emitted to the atmosphere stays there, causing warming, for many centuries. By some estimates, the amount of CO2 already emitted has committed the world to warming in excess of 2 degrees Celsius, which is well outside human experience; to hold the increase to 3-4 degrees might well require zeroing out carbon emissions by mid-century.

It would be very nice if we could supply most energy demand with wind, solar and energy efficiency. But there are a lot of real reasons to doubt that these technologies can achieve the necessary scope and scale to displace fossil fuels in the next thirty years. Serious challenges lie ahead for renewables, notably their low output, affordable energy storage, large land area requirements, and the need for back them up with fossil power such as gas when they are naturally not available. Biofuels in use and development today won’t do it because the large amount of new energy crops they require cause substantial carbon emissions (direct and indirect) and would cause other large-scale environmental problems. And, while more energy efficiency is important, it is notable that twenty-five years of the world’s most aggressive electric energy efficiency programs, in California, have reduced electric demand by only around 15 percent from business as usual – not enough to displace the 100% electric demand growth we expect to see in the world over the next two decades.

So, gas is less a “bridge to zero-carbon energy,” than it is a very long highway – gas will be used for some time. What must be done to ensure it makes more than a modest contribution to climate protection?

First, we must ensure that gas production itself does not get in the way. Gas that leaks and is released from US gas systems warms the climate about 40% as much as America’s coal plants, because methane, pound for pound, warms the climate seventy times more than CO2 (considering the warming over twenty years). Addressing this problem is not rocket science – it’s a matter of dollars and engineering. The EPA is currently considering rules that could have the co-benefit of reducing this leakage by about a quarter, but we can cost-effectively – certainly more than half – by focusing on methane directly.

Second, as a recent report of the National Petroleum Council, a petroleum industry-led organization, noted:

[I]f very deep reductions in GHG emissions are desired over the long run, fossil fuels, including natural gas, could play only a limited role in providing energy unless there is a means to capture and sequester the CO2 emissions from burning fossil fuels.

Fortunately, there is. CO2 capture technology is available now for natural gas power plants, geologic carbon sequestration is available in many areas of the country, and geologic sequestration through enhanced oil recovery has been in use for decades. Perhaps the single most important message EPA could send to the clean energy market when it sets CO2 performance standards for gas plants, would be to indicate that CCS will eventually be required on existing natural gas power plants (as well as on coal plants). Because gas is the cheapest new power option, and typically undercuts cleaner forms of energy on price, requiring CCS on gas in the next decades could level the environmental and economic playing field between zero- and near zero-emitting sources of electricity, spurring substantial incremental investment in all forms of clean energy going forward. The sooner we get started, the better.

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This entry was posted on Tuesday, January 17th, 2012 at 3:25 pmand is filed under Climate, Fossil Transition. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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