To remain economically viable, combined heat and power (CHP) systems and other distributed generation (DG) technologies rely on the ability to purchase backup power from the electric grid, and to sell excess electricity they generate back to it. The lack of a consistent standard that explicitly establishes parameters and procedures for connecting to the grid drives up both monetary and transaction costs for technology manufacturers and owners, discouraging CHP deployment.
States need not start from scratch when adopting interconnection standards; there are both technical and institutional models at the national, regional and state levels that have been successfully implemented by California, Ohio, Oregon, and other states. See the resources below for interconnection standard model language.
Emerging interconnection best practices include:
- Coverage of all distributed generation technologies (including CHP)
- Use of existing technical standards: IEEE 1547 and UL 1741
- System capacity limits for small systems up to at least 10 MW
- Screens for complexity and size, allowing fast-track processing for smaller, less expensive, less complex systems
- Standardized interconnection agreement forms
- Transparent, uniform and accessible application information and procedures
- Prohibition of unnecessary external disconnect switches
- Prohibition of requirements for additional insurance
The Interstate Renewable Energy Council has produced a list of each state's interconnection standards. Also see the Network for New Energy Choice's 2009 version of "Freeing the Grid" for a state-by-state scorecard on interconnection and net metering standards.