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Gaining Energy from Splitting Water

Posted by | February 14, 2009

On Saturdays, when the snow isn’t too deep in my backyard, I split a bit of wood for my woodstove. It’s hard work, made doubly challenging by my arthritis. But as I address the woodpile, I like to dream of the day we may be able to set aside our axes and mauls and get energy from splitting water, rather than wood.

If I live to be an old lady, my dream may well become concrete reality. It depends simply on some clever work by chemists and on the abundant energy we get from the sun each day.

The sun bathes the Earth with more power than we humans will ever need. The challenge about solar power isn’t that we don’t have enough, it’s just how to fully use what we are given.

One route for throwing a harness over sunbeams is to learn to produce hydrogen fuel by “breaking apart” water. Splitting wood is hard work. Splitting water could be easy.

Water is made of hydrogen and oxygen. If we can split apart those two ingredients, we’d have a lot of hydrogen on our hands. Hydrogen gas burns well. We could use hydrogen as our basic fuel to accomplish everyday tasks ranging from heating the house to driving to work. And burning hydrogen rather than traditional fuels means we wouldn’t be creating carbon dioxide – a real positive for climate concerns.

Scientific investigations into splitting water molecules and making hydrogen fuel are known under the phrase “artificial photosynthesis.” That’s not so formidable as it sounds. Indeed, it’s mostly a matter of being as smart as vegetation.

When plants do their work of converting sunlight into chemical energy – the process of natural photosynthesis – part of what they accomplish involves taking water and breaking it apart. In plants, the hydrogen bits end up in sugars. Plants perform this trick via a complex organic molecule that contains manganese in its center.

It may be possible to create a man-made molecule that will do something similar. Research chemists like Jim Hurst at Washington State University are looking for ways to use sunlight to split water into hydrogen and oxygen in the presence of the special molecule.

Chemists have been able to create molecules that basically do what we’re hoping for – but the molecules so far discovered in this arena are built around rare trace metals with names like ruthenium. The hope is to build molecules that can do all the work required and that will be created around common and cheap metals, like iron.

If chemists are successful, our world would change. We would have a source of hydrogen gas made directly by sunlight. We could use that hydrogen as a fuel, burning it in a flame or in a fuel-cell – a device that creates electricity by combining hydrogen and oxygen gas in a controlled reaction.

Energy might become cheaper than dirt.

There are some practical challenges, like storing hydrogen and shipping it. Because it’s so flammable, we’d need a lot of safety systems around our hydrogen tanks and pipelines. But if we can address those concerns, and if Professor Hurst and his colleagues around the world are successful, we could run the machinery of our lives on hydrogen.

We could heat our homes, power our vehicles, and do everything else to which we’ve become accustomed, all with the energy we would harvest from hydrogen, created for us by sunlight. And because we’d be producing only pure water as the output from our tailpipes or chimneys, air quality would improve tremendously over what we’ve known burning fossil fuels.

In short, there’s a lot to like about the possibility of abundant and economical hydrogen.

Some cautious souls will say that the chance of harnessing sunbeams by splitting water is only that – a chance. That’s true, but it’s also true that chemists require only a tiny amount of funding to work in their labs, looking for possible molecules that could transform water and sunlight into hydrogen fuel.

And the payoff could transform our world.

Perhaps I’d miss heavy labor in the backyard with my ax and maul. But splitting water rather than wood looks better and better as I grow older.