Abstract—Renewable energy and Electric Vehicles (EV) show
potential to be promising solutions for energy cost saving and
emission reduction. However, the integration of renewable energy
generation into the electric grid can be difficult, because of
the source intermittency and inconsistency with energy usage.
In this paper, we study the problem of allocating energy from
renewable sources to EVs in an energy efficient manner. We
assume that the renewable energy supply is time variant and
possibly unpredictable. EVs’ charging requests should be satisfied
within a specified time frame, which may incur a cost of drawing
extra energy (possibly non-renewable energy) if the renewable
energy supply is not sufficent to meet the deadlines and may also
reduce energy efficiency. We formulate a stochastic optimization
problem based on queueing model to minimize the time average
cost of using other energy sources (and hence make most usage
of the renewable energy source). The proposed approach fully
considers the individual charging rate limit and deadline of each
EV. The Lyapunov optimization technique is used to solve the
problem. The developed dynamic control algorithm does not
require knowledge of the statistics of the time-varying renewable
energy generation, EV charging demand process, or extra energy
pricing.