Renewable energy sources becoming more widespread in decentralized power supply systems. However their functioning depends on the natural resources potential having variable character. This dependence influences reliable work of autonomous power supply system.   Reliability analysis of a renewable energy based autonomous generating system is the actual practical task requiring the solution. For the reliability assessment of autonomous wind-diesel installation it is offered to use the method of dynamic fault tree with Markov models for representation of dynamic operators. The offered method is applied for reliability calculation of the wind-diesel installation functioning in the autonomous power supply system in the north of Krasnoyarsk region.