Multiple Elements - Solar & Wind Power Supplies

Nature shows us that every need should be supplied by more than one source if we wish to have a stable & reliable system. In permaculture we call these sources 'elements' & we design so that more than one element can fulfill each important function. This way if one element 'fails', there should still be one or more alternative supplies instead. Here we have a good example of designing an off-mains electricity supply. The photograph was taken in Portugal, which is why there is such a large solar array, but should the daylight be poor for a period, the wind generator can provide power instead & those winds are most likely to occur when the sun isn't shining.