The Next Green Fuel Might Be Growing in Your Yard

Our society has reached a kind of in-between stage in history. We now know that things like plastic containers and fossil fuels are harmful to our bodies and our planet, but we're far from replacing them with the alternatives, and we’re not about to stop buying bottles or driving cars. On the fuel front, at least, we may have made some progress: Scientists say they’ve found a simple, cheap way to get energy out of common lawn grass. They published their findings in the Proceedings of the Royal Society A.

It’s not like we haven’t been trying to come up with other options. Scientists are working hard to find viable ways to turn things like corn, used deep-fryer oil, and algae into energy, but we’re still not there yet.

One of renewable energy’s rising stars is hydrogen, which has a lot to offer as a form of fuel. For one thing, it’s the most abundant element in the universe, appearing in our water, our air, and our plants. It burns efficiently and cleanly without letting off any toxic or greenhouse gases.

The trouble is that while hydrogen may be in lots of things, it can be hard to get it out. Scientists all over the world are attacking the problem from different angles. At the Cardiff Catalysis Institute and Queens University Belfast, chemical engineers began wondering how hard it would be to get the super-fuel out of common plants like lawn grass (which is itself environmentally problematic—one NASA research scientist estimated that our much-watered lawns constitute the largest irrigated crop in the U.S.). 

They used a technique called photocatalysis, which uses sunlight and a chemical catalyst to squeeze hydrogen out of cellulose (a polymer that gives plants their shape and rigidity). The experimental design was relatively simple: The team put samples of cellulose into large flasks and added one of three catalysts—palladium, nickel, or gold—to each. Then they set the flasks under a lamp and measured how much gas each cellulose/catalyst combination produced.

The results were encouraging. All three catalyst-plant combinations responded to the light. The team was glad to see gold and palladium respond, but it was nickel—which is both cheap and abundant—that really got them excited.

To confirm their findings, the researchers repeated the experiment, this time using real lawn grass, which is easier to acquire than pure cellulose. The results held: Lawn grass and nickel really were a good, cheap match.

"This really is a green source of energy,” said co-author Michael Bowker of the Cardiff Catalysis Institute in a press release.

These are, of course, early findings, so don’t start mailing your lawn clippings to the lab just yet. But Bowker is hopeful. "Hydrogen is seen as an important future energy carrier as the world moves from fossil fuels to renewable feedstocks,” he said, “and our research has shown that even garden grass could be a good way of getting hold of it."

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