The fractal dimension, chemical distance, and finally the effect of an applied electric field on the transport within the interpenetrating network of poly (3-hexylthiophene)/fullerene bulk heterojunction materials are calculated. According to simulations, charge carriers travel along a pathway similar to 4 times longer than the regular Euclidean distance. In an applied electric field, the drift speed of charged carriers is reduced because of field-induced trapping on the tortuous network.