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Monday, April 2, 2012

Does fracking preclude underground carbon storage?

The US EPA has proposed a carbon pollution standard for new power plants that marks a significant advance in the battle against global climate disruption and for improved public health. EPA is proposing that new fossil-fuel-fired power plants emit no more than 1,000 pounds of CO2 per megawatt-hour (MWh).

What’s the impact of the proposal?

New natural gas power plants (which emit about 800 pounds or less of CO2/MWh) - and according to EPA, perhaps as many as 95% of gas units built since 2005 - should be able to easily meet the proposed standard without add-on controls. New coal-fired power plants would have to incorporate technology to reduce CO2 emissions to meet the standard, such as carbon capture and storage (CCS) - capturing the CO2 emissions and storing them in geological formations deep underground.

In an excellent overview of the new standard, NRDC’s George Peridas writes that CCS technology is being deployed at power-plant scale worldwide; that the new standard would require CO2 capture at only “moderate” rates; and that, from a Federal regulatory standpoint, all the pieces are in place to permit a CCS project today. So the new standard is not necessarily an obstacle to the continued use of coal to generate electricity.

But finding a safe place to store CO2 on-shore in the continental US may prove to be an insurmountable obstacle.

During my tenure at the Pennsylvania Department of Conservation and Natural Resources (DCNR), I led some of the nation’s most advanced planning work on CCS. The DCNR studies highlighted 3 issues that are relevant to the future of CCS in the Keystone State, and nationwide.

First, cost issues aside, you need the right kind of geologic formation - one that is “capped” with an impermeable layer of rock that will not allow the stored CO2 to leak out into the atmosphere – and lots of it. A rule of thumb used by the US Department of Energy: one 500 MW coal-fired power plant that captures 90% of its CO2 emissions over a 40-year operational life and that is injecting captured CO2 emissions into a 300-foot thick geologic storage formation will require 100 square miles of storage space. Still, the resource is vast; DCNR found that Pennsylvania has the geologic capacity to store hundreds of years’ worth of the state’s CO2 emissions.

The second issue identified by DCNR was practical: amassing the storage rights through purchase or lease would be challenging. That’s because in Pennsylvania, the owner of the surface of the land might not own the subsurface mineral- and hence storage - rights. And figuring out who owns the subsurface can be a challenge because the rights could have been severed over a century ago, in the early days of oil, gas, and coal exploration.

But DCNR pointed out that the then-emerging shale gas industry was assembling mineral rights and could one day possibly get into the CO2 storage business. The industry has leased mineral rights on a massive scale in Pennsylvania. So the storage space ownership challenge may have been solved by the shale gas industry.

But the third issue identified by DCNR may prove to be the insurmountable obstacle to CCS: the shale gas boom is drilling holes in or fracking the essential seals that would hold stored CO2 underground. This issue has emerged nationally; indeed, as much as 80% of the US's potential on-shore CO2 storage volume overlaps with shale gas fields.

Off-shore storage potential may be vast, so CCS may still provide a climate protection tool to allow the continued use of coal for electricity generation. But the apparent fundamental conflict between on-shore CCS and shale gas development will need lots of further study.

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