By decreasing nonrenewable resources, efficiently using of energy have become more important. So, reducing energy consumption in production sectors, as one of the largest energy consumers in the world, has attracted many researchers. Energy tariffs are a good approach that governments assigned to control energy consumption in factories. These tariffs can balance energy consumption. In this research the objective is minimizing energy cost in a production sector with unrelated parallel machines. Each machine can process each job with various speeds, that it causes machines have different energy consumption rate
