The Roundhouse in Brithir Mawr, Wales, is made with wood frame, cobwood, recycled window walls and a straw-insulated turf roof. Electricity is provided by three photovoltaic panels on the roof and a small (200w) wind turbine situated about 70 yards away in a field. For most of the year these provide enough electricity to power two or three 12-volt lights simultaneously, plus a radio for an hour or two per day, or a laptop computer for an hour or two. Only in the high summer do they produce a surplus of electricity; often in the deep winter of December or January the home is plunged into darkness if the laptop is used too much, so the residents often eat and read by candle-light. 

(Source: solaripedia.com)