Definitions

Distributed generation

Customer generation also is referred to as distributed generation (DG) and represents an evolving and promising set of power technologies that typically has the following attributes:

  • Sited close to customer or located at a substation to support the electric distribution system.
  • Output tailored to customer needs.
  • Generating capacity between 1 kilowatt and 15 megawatts (MW).
  • May be customer-, utility- or third-party owned.

Types

Primary power – Supplies majority of customer’s electricity needs and uses local utility electrical grid to provide backup and supplemental power.

Peak shaving – Allows customer to reduce electric demand charges. Peak shaving may provide a win-win for utility and customer by relieving electrical system stress during peak-demand periods and by allowing customer to avoid on-peak demand charges and higher-priced on-peak energy.

Stand-alone power – Provides primary electrical service for customer without utility backup. In this case, customer is completely isolated from utility.

Combined heat and power – Involves electricity production and usable heat energy by an electric generating device. This can be advantageous for customers with consistent daily electricity needs that coincide with heat or steam process requirements. Larger systems are typically referred to as cogeneration.

Backup power – Provides electricity in case of loss of electric supply from utility system and may include supplemental power during momentary outages. Also called emergency or standby power.

Technology options

Wind – Wind turbine generators, harnessing energy contained in wind to turn wind turbine blades connected to generator for electricity production.

Solar/photovoltaic – Photovoltaic materials contained in solar cell array convert energy from sunlight directly into electricity, typically connecting to utility distribution system via inverter.

Fuel cells – Produce electric and thermal energy through electrochemical process using hydrogen, which can be produced from natural gas or by renewable energy resources.

Stirling engines – A sealed external combustion heat engine that, in theory, can provide quiet and efficient power.

Energy storage devices – Batteries, flywheels, compressed air, super magnetic energy or other devices that store energy for later use. They also can be components in an uninterruptible power supply.

Biomass/agricultural digesters – Anaerobic digester processes farm manure through a process that converts waste products over time into methane, which then can be combusted in a device listed below.

Internal combustion engines – Devices much like an automotive engine, fueled with either diesel or natural gas, connected to and driving an electrical generator.

Microturbines – Small combustion turbines that burn natural gas to produce less than 500 kW. Simpler than internal combustion engines, they have only one moving part on a central rotating shaft that generates electricity. They are characterized by simple design, modularity and fuel flexibility.

Industrial gas turbines – Combustion turbines in the 1 to 15 MW range.

Selling power to others

A customer who generates electricity within our service area may sell power to another utility. In that case, we may transmit or “wheel” the power from your facility for a fee. You will need to make separate arrangements with us and the American Transmission Company to transmit power to others. We would continue to supply supplementary, standby and maintenance power as required.

Power transmission over electric utility facilities from a customer generating system directly to a retail customer or to another facility owned by the generating customer is a form of retail wheeling. Retail wheeling (transmitting electricity generated by one customer to another retail customer) is not allowed in Wisconsin at this time. Retail wheeling is allowed in Michigan if you are an Alternate Energy Supplier.