Deep beneath much of the United States lie rock formations containing waters far too salty for human consumption. Long overlooked, these brine-filled reservoirs are now attracting new interest as possible ‘storage sites’ for greenhouse gases emitted from power plants.
With this in mind, the US Department of Energy has given the go-ahead to a research team headed by American Electric Power (AEP) and Battelle to begin studying potential carbon sequestration sites – where carbon gasses can be captured and permanently stored – in the Ohio River Valley.
AEP has volunteered its Mountaineer Plant in New Haven, along the Ohio-West Virginia border as the test site for investigating the concept.
If the approach proves feasible, it could offer a way for many electric and industrial plants to reduce emissions believed to contribute to global climate change. The AEP/Battelle project will be especially important because it will take place in the heart of the largest concentration of fossil fuel power plants in the US.
Energy Secretary Spencer Abraham announced the new ‘carbon sequestration’ effort at a speech delivered to the National Coal Council, an advisory panel to the Department of Energy.
‘Our goal is to develop a suite of carbon management options that we know are safe, affordable, and effective. We want to have these options ready should the science tell us that large-scale carbon reductions are necessary in the future,’ Abraham said.
Abraham said that if carbon sequestration proves practical, it could help mitigate environmental concerns regarding the use of coal. Coal supplies more than half of America’s electricity and is one of the reasons why Americans benefit from some of the lowest cost electricity in the world.
Theoretically, deep saline reservoirs, which underlie all or part of 35 states, could hold all of the carbon dioxide emitted from the nation’s coal-burning power plants over the next 100 years.
Beneath the Ohio-West Virginia border lies the massive Mount Simon Sandstone saline formation. Ranging from 3,000 to 12,000 feet deep, this huge formation extends as far as Illinois and Wisconsin. Several other potential host reservoirs for carbon dioxide storage are also in the area.
The project’s current phase is expected to last 18 months. During this time, researchers will conduct a seismic survey within a 5- to 10-mile radius of the Mountaineer Plant to study the characteristics of the underground rock formations. Early next year, a 10,000-foot well will be drilled on the plant property to study the target area and overlying sediment layers in detail.
Data will be used for simulations, risk assessments, permit applications, and to design the monitoring plans for future stages of the effort if the site proves geologically sound. No decision will be made on proceeding beyond the current study phase until the subsurface geology is deemed suitable for permanently entrapping large quantities of carbon dioxide and cost estimates are developed.
Using deep saline reservoirs for carbon dioxide storage is attractive not only because the reservoirs are common but because they are well below drinking water aquifers. In the Ohio River Valley, drinking water is typically produced from formations only 10 to 200 feet below ground, compared to the 3,000- to 12,000-foot depths of the saline formations.
Geologists believe the distance between fresh water and possible injection zones is so great and the intervening rock layers so impervious to the upward movement of carbon dioxide that the approach will pose no hazard to drinking water. Indeed, a major question the AEP/Battelle project hopes to answer is whether rocks above possible ‘storage’ areas are sturdy enough and sufficiently free of interconnected fractures to assure that the carbon dioxide cannot gradually escape.