U.S. Department of Energy - Energy Efficiency and Renewable Energy
Tribal Energy Program
All energy planning starts with an assessment of present and future energy needs. These energy needs are essentially the loads, or energy services, that define the need for energy supply, and they can be grouped into residential, commercial, and industrial loads.
Residential loads can be further broken down into space heating and cooling (defined primarily by the home design, including orientation, method of construction, insulation, and occupancy comfort levels), and the appliance loads that include everything from lighting and cooking to the HVAC (heating, ventilating, and air conditioning) system.
Commercial loads (including everything from office buildings to restaurants, hospitals, hotels, and casinos) also can be divided into building envelope loads (defined by the building design and construction), and appliance loads (lighting, computers, cookers, laundry, slot machines, etc.). Unlike residential structures, where the building envelope is the primary determinant of energy needs, commercial buildings are usually dominated by their appliance load, also called plug loads. In general, as the size of the building grows, the plug loads become a larger and larger fraction of the building's energy needs. In large commercial buildings like skyscrapers, the building envelope defines less than 10% of the energy requirement, and the HVAC system's job is primarily to reject the heat generated by all the appliances and the people.
Industrial electric and thermal loads are nearly entirely defined by the industrial process with building envelope loads being, in many instances, insignificant. Cement factories, power plants, semiconductor fabrication lines, auto assembly lines, and food processing are all good examples.
In energy planning, it is critical to start with a good understanding of the energy loads that are driving the need for new supplies. This should start with the design of new residential, commercial, and industrial facilities, because once they are built, the energy requirements and bills will be determined for a very long time into the future. Energy-efficiency retrofits are often possible, but it is always cheaper in the long run to include building envelope and appliance efficiency measures during initial construction.
For existing facilities, it is important to get accurate records of monthly energy bills and assess the range of energy efficiency and conservation improvements that could be made to the building structure and appliance loads before committing to new energy supplies. When considering the total cost over the life of a project, it is nearly always cheaper to save energy than buy new energy. For more information, see the section on costs.
By combining the residential, commercial, and industrial loads throughout the tribe's lands; and assessing the need for growth in these loads (population growth and new housing, as well as commercial or new industrial growth), the tribe will be in a good position to balance the opportunities for improved energy efficiency and conservation with the opportunities for new energy supply.