Today I was driving past a 1 Megawatt solar power installation and got thinking about power distribution. One of the troubles with solar is that solar panels put out DC, while our homes use AC. The whole AC/DC fight goes back to Edison/Westinghouse/Tesla/Steinmetz, etc and is a longer story than I can go into here. Edison wanted to run homes on DC, everybody else knew the only way to conduct electricity over long distances was AC, so our homes run on AC. All well and good until rooftop solar power shows up, generating DC. The traditional solar setup then stores the energy in batteries, runs an DC-to-AC converter, synchronize it to the grid, and use it.
But let's look at how we use it once it comes out of the receptacle. My computer changes that AC wall power to DC for the machine. So does my cell phone charger, battery charger, TV, amp, PS3. In short, everything in my house except lights and things with motors changes the AC to DC before it can use it. When LED lighting comes about in the next few years, move the lights to the DC column as well. So here's my radical notion: start transitioning house current to DC. Initially this would be a separate 12 volt distribution system in the house. Once standards are set, then electronics manufacturers could start making alternative DC adapters in addition to the AC adapters (power bricks) we now use. There's already lots of manufacturing capacity and engineering knowledge built around 12 volt DC systems, since that's what cars run on.
The advantages of this system are numerous: solar power would be much more efficient and economical since you don't have to convert their output to AC, power supplies (and power bricks) would be smaller, cheaper and more efficient. And best of all, we start to truly get the benefits of the long-touted 'smart-grid' systems because storing DC in batteries without having to convert it back to AC reduces complexity and loss. Did I mention that 12 volts DC is much safer than 120 volts AC? All in all, when we convert to LED lighting a few years hence, I think it's time to take a serious look at wiring homes with DC.
I'm sure hundreds of people have thought of this before, but I don't have a link into their fountain of knowledge. If anybody knows of a reference, drop me a note or post a comment to this blog entry.