In 2012, there remain 1.4 billion people without access to energy and 783 million without access to improved water resources. Mobile penetration in Africa is estimated to reach 76 per cent by 2014 and more people have access to a mobile phone than to energy and water. Mobile technologies have been identified as one potential area of innovation in support of improved water and energy services for the poor. This cost benefit analysis provides a useful example of how to approach undertaking an appraisal of a development programme to provide seed funding for entrepreneurs and researchers to develop new mobile applications or business models in the water and energy service provision space. It looks at different ways to provide that funding but importantly estimates impacts on carbon emissions, health benefits of clean water and so on. It was used to inform the design of a DFID funded programme to support mobile technology development.