The charging of batteries of plug-in hybrid electric vehicles at home at standard outlets has an impact
on the distribution grid which may require serious investments in grid expansion. The coordination of
the charging gives an improvement of the grid exploitation in terms of reduced power losses and voltage
deviations with respect to uncoordinated charging. The vehicles must be dispatchable to achieve the most
efficient solution. As the exact forecasting of household loads is not possible, stochastic programming
is introduced. Two main techniques are analyzed in this paper: quadratic and dynamic programming.
Both techniques are compared in results and storage requirements. The charging can be coordinated
directly or indirectly by the grid utility or an aggregator who will sell the aggregated demand of PHEVs
at the utility. PHEVs can also discharge and so inject energy in the grid to restrict voltage drops. The
amount of energy that is injected in the grid depends on the price tariffs, the charging and discharging
efficiencies and the battery energy content. The impact of a voltage controller embedded in a PHEV
charger is regarded in this paper. A day and night tariff are applied. The charging and discharging of
vehicles can respond to real-time pricing or on a price-schedule as well. Voltage control is the first step
in the utilization of distributed resources like PHEVs for ancillary services.