Hooking up a light bulb can involve social and financial reforms as dramatic as the transition from kerosene lamps to photovoltaic cells. You also need to develop the financing, the management expertise and the market. In cash poor areas without an educated workforce, building the modest utility company needed to administer a solar project requires careful planning. And things can still go wrong. Holding on until a project breaks even is challenging even when everything else is in place.
Financial risk is high and returns are low.
Even when the projects succeed, the amount of hydrocarbon energy the save is negligible on a global scale. Usually a system of kerosene lamps is being replaced by electric lights. For a developed country to receive credit for CO2 emissions save by a CDM project abroad, the project must be evaluated under procedures to be set down in the final version of the Kyoto Protocol. These may not be known in detail, but in all likelihood they will cost more to carry out than the credit is worth. Because the cost of the evaluation exceeds the value of the credit, few investors would be interested in the project.