Comparison of Time-Based Probability Methods for Estimating Energy Storage Requirements for an Off-Grid Residence

The use of energy storage in conjunction with renewable energy sources such as wind and solar is receiving more attention to help mitigate the effects of the intermittent nature of these sources. When considering energy storage, one wishes to maximize the probability that there will be enough energy available to meet the residential load demand while minimizing the cost of both the renewable energy sources as well as the energy storage device(s). In this paper, an off-grid residence with wind energy supply and energy storage is studied. Two different methods of estimating the number of hours the load is unable to be supplied are compared. Both involve Monte Carlo simulations, with one being based on a first order Markov Chain of the wind distribution at a particular site. Simulations indicate that the two methods yield vastly different results for the number of hours the residential load cannot be supplied.