Furthermore, this calculation method can be applied to estimate additional solar modules and batteries required to charge a larger number of phones. It is an interesting economic exercise to compare extra equipment investment with the expected revenue from the charging and communication fees. Then, we described the importance of a web-based information service for the cell phone charging service and presented a design for a solar-powered energy-proportional web server cluster. To utilize this system in emerging regions, we defined two requirements for our system: using low-power and inexpensive devices running on just solar power and being autonomous and scalable, starting from a very small village.