As a matter of fact, WHO estimates that meeting that goal would yield annual average benefits of $91 billion worldwide (cited in IEA, 2006: 440, table 15.6). However, these costs concern exclusively biomass and cooking fuels, and not the costs of providing other types of energy (e.g. electricity). In fact, other than project-specific information, there seems to be little information available on the costs of RETs as a source of household energy relative to fossil fuels. Moreover, the training, technical assistance and capacity-building that are needed to support rural electrification schemes add to capital costs. Given large capital costs and high associated risks, service providers would need to charge high connection fees and monthly rates to recover their investments, which would undermine the affordability of electrification for poor consumers.