An energy consumption controller may be communicatively coupled with a plurality of alternative energy sources and an engine. The controller may be configured to manage energy consumption from the alternative energy sources interconnected with the engine and to keep the engine within a desired temperature range. Within the desired temperature range, the engine will start and run at a full load more rapidly than if the engine cooled excessively. The controller may change the selected energy source as required, based on factors such as cost, engine maintenance and testing and/or imminent need of the engine.