Backfeeding is when electric power flows in the opposite direction that it typically flows. An alternating current power station typically delivers power to the power grid by inducing a current to flow into the power grid when the voltage is positive, and inducing it to flow out of the power grid when the voltage is negative, and a typical power grid load (e.g. factory or home) induces current to flow out of the power grid when the voltage is positive and into the power grid when the voltage is negative. If either of these types of facilities starts inducing current flow like the other, then backfeeding is occurring.