Apparently the idea of hydrogen fuel cells as home-electricity suppliers in Japan is catching on.

The Japanese government is so bullish on the technology it has earmarked $309 million a year for fuel cell development and plans for 10 million homes - about one-fourth of Japanese households - to be powered by fuel cells by 2020.

Whether their plan is practical depends on the answers to the following:

• Does it make sense to use a fossil fuel (natural gas) that will only get more and more expensive (as demand increases, which it will as developing nations continue to develop) and less and less available?
• Is the decrease in carbon dioxide (assuming there really is one) worth all the manufacturing and transportation that needs to occur to supply homes with the devices?
• Will it make a permanent transition away from fossil fuels easier?

If the answers to these questions are favorable to sustainability, then it's great, but I think hydrogen fuel cells are overhyped in general because there's nothing on the horizon that will give us a renewable yet cost-effective source of hydrogen.