I use a few different types of solar power at Green Cottage.
Firstly, I have a solar hot water system which provides around half of my hot water for baths and showers etc. It has a flat plate collector and uses a dual coil solar cylinder to store the hot water, with the bottom coil connected to the solar collector on the roof, and the top coil connected to our wood burning stove. There is an immersion heater in the cylinder for backup, but I have never got around to wiring it up!
The second kind of solar power I use is solar photovoltaic panels. I have around half a kilowatt of PV mounted on the back wall of the house. These solar panels are not connected into the national grid, but are connected into a voltage inverter and a bank of batteries, which converts the 24V direct current from the solar panels into 240V alternating current, which runs one of the two ring mains in the house. The kitchen is on a separate ring main, which is connected to the national grid, as the kitchen appliances require too much electricity to run on solar power.
As well as getting free electricity from the sun, the battery bank means I have electricity (except for the kitchen) for a few days in the event of an extended power cut – which means lights, warmth, communications etc, which go a long way to making life in a power cut more bearable.
There is an article over at the Big Green Idea giving a full run-down on how to build this kind of system.
The third kind of solar power I use is still solar photovoltaics, but on a much smaller scale. I use two solar battery chargers to charge rechargeable batteries, which I then use in LED lights around the house and in the garden. Some of these LEDs (for example in the stairwell) have motion sensors which mean that they only come on when someone is passing, switching on and off automatically to use the solar power at maximum efficiency.