Customers must charge their cards with prepayment for a set amount of gas. These cards are then used to open the home valves connecting to the biogas grid - releasing exactly as much biogas as was pre-paid. In all, such novel and profitable business ideas hold great potential for renewable infrastructure. Indeed, the "development trajectory" of developing countries can be very different from that of the developed economies due to the possibility of "leapfrogging" and avoiding mistakes by learning from others' experiences. Neighbouring or similar countries share lessons with particular effectiveness.