Their are big dreams among many on using solar power to have a house that is totally off the grid. I am one of those people.
The problem is that the economics usually don’t make sense, and for the surface area of your roof, it is difficult to generate enough power to satisfy your electricity needs.
The culprit is AC power.
The main advantage of AC over DC power is that it can be transmitted over long distances with little loss. This makes it a perfect match to our current electricty distribution system.
The strange thing is that most of the devices in your house run on DC power that has been converted from AC power. For example your computer has an inverter which transforms one into the other. This results in a significant decrease in power.
Now to compound this, solar cells output dc power, which is then stored in a battery. When you store power in a battery, and pull it back out you there is a loss in power. This power is in DC, which is converted to AC so the house can have normal electrical outlets, devices are plugged in which convert the energy back to their native DC power.
With all these steps, you can see when you set up solar panels and configure it to run on a normal household setup you just wasting most of the juice.
The best way to deal with this is to have DC outlets throught the house set up to pull directly from the panels when there is power, and to fall back on battery. Some AC outlets can be set up with inverters.
Since DC power for different devices varies greatly, we need a common standard that is used for all of them, and I think the most common standard is the cigeret outlet in most cars. So many devices have adapters for this type of outlet that it would be the perfect way to power your house.
This would mean moving away from the AC standard, but as power generation gets more local, this may be the way to go. Without any knowledge of how much loss you experience with power conversion, I might guess that this would mean a 50-70% reduction in power loss. But who knows. If my gut feeling is right, we won’t need more effecient solar panels, we might be able to get by on what exists in the market.
Does anyone who knows a bit about power conversion want to throw their two cents in?