01 August, 2008

Every house to be a power plant within 10 years?

A serious problem with solar energy is that (a) solar panels only transform a fraction of the sun's energy into electricity, although the fraction is increasing regularly, and (b) solar panels can't generate electricity when the sun doesn't shine.

On the other hand, when the sun does shine, a sufficiently-sized solar array generates a lot more electricity than a house needs.* Finding a way to store this excess electricity so that it can be used once the sun ceases shining has been very difficult.

On the one hand, one could store the electricity in batteries, but batteries degrade over time, and are expensive. (One drawback of hybrid cars is the cost of the battery.)

Another method would be to use the electricity to power a fuel cell. In this case, one uses electricity to separate water into hydrogen and oxygen; when one needs the electricity, a fuel cell re-combines the two gases into water. From what I read, fuel cells last much, much longer than batteries. They are already used in many industrial applications, including spacecraft.

The difficulty with fuel cells lies in separating water into hydrogen and oxygen using efficient and inexpensive methods. The catalysts currently in use are expensive and rare, and a lot of energy is lost in the conversion.

…until now. A small team of scientists at MIT claims to have found "earth-abundant" catalysts that will do this very thing.

The new catalyst works at room temperature, in neutral pH water, and it's easy to set up, Nocera [the lead scientist] said. "That's why I know this is going to work. It's so easy to implement," he said.
He is optimistic about the future of this technology:
Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electricity-by-wire from a central source could be a thing of the past. [emphasis added]
That may be overly optimistic. It is not trivial to generate that many solar panels.

We can hope, anyway. I will.

*In some states, homeowners feed that excess electricity into the grid and, via "net metering", receive credits from power companies for that electricity by the electric company.

At least one radio talk-show host dismisses this as nonsense, and compares it to refilling your car's gas tank by driving it. I was shocked to hear him spout this nonsense on the radio, but it won him a $400 million contract.

1 comment:

Elliot said...

That's great news!

And, if it doesn't work out, Bill McKibben suggests that the net metering concept could be the way of the future. That way you have many smaller electricity-generating centers that all contribute to the grid. At the same time there could be larger wind or hydro sources for when the sun doesn't shine much, or in times of peak demand.