A New Way to Harness Wasted Methane

Approach developed at MIT could help curb needless 'flaring' of potent greenhouse gas.

MIT chemistry professor Yogesh Surendranath and three colleagues have found a way to use electricity, which could potentially come from renewable sources, to convert methane into derivatives of methanol, a liquid that can be made into automotive fuel or used as a precursor to a variety of chemical products.  This new method may allow for lower-cost methane conversion at remote sites.  The findings, described in the journal ACS Central Science, could pave the way to making use of a significant methane supply that is otherwise totally wasted.

Existing industrial processes for converting methane to liquid intermediate chemical forms requires very high operating temperatures and large, capital-intensive equipment. Instead, the researchers have developed a low-temperature electrochemical process that would continuously replenish a catalyst material that can rapidly carry out the conversion.  This technology could potentially lead to "a relatively low-cost, on-site addition to existing wellhead operations," says Surendranath, who is the Paul M. Cook Career Development Assistant Professor in MIT's Department of Chemistry.

The electricity to power such systems could come from wind turbines or solar panels close to the site, he says.  This electrochemical process, he says, could provide a way to do the methane conversion -- a process also known as functionalizing -- "remotely, where a lot of the 'stranded' methane reserves are."

Already, he says, "methane is playing a key role as a transition fuel."  But the amount of this valuable fuel that is now just flared away, he says, "is pretty staggering."  That vast amount of wasted natural gas can even be seen in satellite images of the Earth at night, in areas such as the Bakken oil fields in North Dakota that light up as brightly as big metropolitan areas due to flaring.  Based on World Bank estimates, global flaring of methane wastes an amount equivalent to approximately one-fifth of U.S. natural gas consumption.

When that gas gets flared off rather than directly released, Surendranath says, "you're reducing the environmental harm, but you're also wasting the energy."  Finding a way to do methane conversion at sufficiently low cost to make it practical for remote sites "has been a grand challenge in chemistry for decades," he says.  What makes methane conversion so tough is that the carbon-hydrogen bonds in the methane molecule resist being broken, and at the same time there's a risk of overdoing the reaction and ending up with a runaway process that destroys the desired end-product.

Catalysts that could do the job have been studied for many years, but they typically require harsh chemical agents that limit the speed of the reaction, he says.  The key new advance was adding an electrical driving force that could be tuned precisely to generate more potent catalysts with very high reaction rates.  "Since we're using electricity to drive the process, this opens up new opportunities for making the process more rapid, selective, and portable than existing methods," Surendranath says.  And in addition, "we can access catalysts that no one has observed before, because we're generating them in a new way."

Read more at A New Way to Harness Wasted Methane