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A climate change solution?

Beneath the Columbia River Basin, a real-life trial of the uncertain science of carbon sequestration – Part I


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Of the world's major continental flood basalts, the Columbia group is the youngest and smallest. (The much larger Deccan traps in west-central India erupted about the time the dinosaurs disappeared 65 million years ago, and the even vaster Siberian traps surged out nearly 250 million years ago at the end of the Permian period. The Siberian traps are too remote from large sources of CO2 emissions to be widely considered a candidate for sequestration, but India is intensely interested in the potential of the Deccan traps.) The Columbia basalt's surface landscape is classic Western sagebrush desert, which, unmodified by paved roads, irrigation or air conditioning, appears to be a trackless, inhospitable and worthless wasteland, good for nothing but possibly grazing sheep. The federal government viewed it as a handy spot to conduct dangerous experiments and dispose of nasty wastes, building the Hanford Nuclear Reservation just northwest of Richland to manufacture plutonium during World War II.

Today, Hanford is considered the most contaminated spot in North America, storing a variety of "legacy" nuclear wastes that are far from being completely contained and immobilized. And just across the Columbia River in Oregon lies the 20,000-acre Umatilla Army Depot, where the Defense Department is destroying millions of pounds of chemical weapons at a snail's pace.

For 60 years, these two blights have brooded over the region even as more life-affirming activities like farming and recreation have expanded. Today, the area's population centres on the Tri-Cities — Richland, Pasco and Kennewick — which cluster where the Columbia River, flowing down from the north and skirting nuclear wasteland, swallows the Snake and Yakima rivers before taking a sharp westward turn to become the border between Washington and Oregon.

Giant storage site

At one point, the Department of Energy considered injecting its millions of gallons of liquid nuclear waste deep into the Columbia basalt. During the search for an appropriate injection site, hundreds of core samples were drilled and archived. Those core samples have come in very handy for Pete McGrail as he conducts studies that may lead to another industrial use for an already hard-used land.

Regardless of geology, proper carbon sequestration requires a chamber or system of interconnected pores to accept an infusion of carbon dioxide, as well as a competent caprock above it, to keep the CO2 from escaping. Spent oil and gas formations and saline aquifers contained in sedimentary rock have usually been considered the most likely candidates for geosequestration; experts frequently point out that oil and gas have been safely held for millions of years in such formations.