Energy efficiency is a key factor in developing mobile sensing applications. Despite its importance, such laborious and time-consuming energy evaluation process makes developers reluctant to perform the measurement during the development. To this end, we propose a novel context-driven energy assessment system, which utilizes the unique characteristic of MSA's energy consumption pattern. We implemented the energy emulation environment, which supports accurate energy estimation in the development environment and repetitive evaluations for the same real-life situations. The evaluation shows that our environment achieves a reasonable energy estimation accuracy of 95.9%.