NOTE: Legislation enacted in 2011 and 2012 (S.B. 1652, H.B. 3036, and S.B. 3811) has changed several aspects of net metering in Illinois. For customers in competitive classes as of July 1, 2011, the law prescribes a dual metering and bill crediting system which does not meet the definition of net metering as the term is generally defined. Click here for information regarding competitive classes, and here to find utility switching statistics. The law also increases the system capacity limit to 2 MW and the aggregate capacity limit to 5%. Additionally, agricultural residues, untreated and unadulterated wood waste, landscape trimmings, and livestock manure are added to the list of eligible resources. More information will be posted here once the ICC develops new rules.

 
Illinois enacted legislation in August 2007 (S.B. 680) requiring investor-owned utilities in Illinois to begin offering net metering by April 1, 2008. In May 2008, the Illinois Commerce Commission (ICC) adopted final rules for net metering, effective May 15, 2008. While Illinois's investor-owned utilities and alternative retail electricity suppliers must offer net metering, the state's municipal utilities and electric cooperatives are not required to do so.

 
Eligibility and Availability 

 
In Illinois, net metering is available to electric customers that generate electricity using solar energy, wind energy, dedicated energy crops, anaerobic digestion of livestock or food processing waste, hydropower, and fuel cells and microturbines powered by renewable fuels. Systems up to 40 kilowatts (kW) in capacity that are intended primarily to offset the customer's own electrical requirements are eligible.*

 
Each investor-owned utility and retail supplier must provide net metering and dual metering until the load of its net-metering customers and dual-metering customers equals 1% of the total peak demand supplied by the utility during the previous year. For residential customers, net metering is "typically" accomplished through use of a single, bi-directional meter. For non-residential customers, net metering is "typically" accomplished through the use of a dual meter. Dual metering is required for non-residential customers with systems greater than 40 kW but not greater than two megawatts (MW). The utility must provide the necessary metering equipment for systems up to 40 kW in capacity, while customers with systems greater than 40 kW but less than 2 MW must pay for the costs of installing necessary metering equipment. (Net metering and dual metering are not available to systems greater than 2 MW.) An electricity provider may choose to allow meter aggregation for community-owned wind, biomass, solar, or methane digesters, or other situations where multiple individual customers are served by the same renewable generating facility (such as an apartment building).

 
S.B. 1652 added a provision that requires all net-metered systems to be installed by a certified contractor. In March 2012, the ICC opened a docket (Case No. 12-0213) to determine the specific certification requirements

 
Net Excess Generation 
 
For systems up to 40 kW in capacity, any net excess generation (NEG) during a billing period is carried over as a kilowatt-hour (kWh) credit to the following billing period. At the end of an annualized period, any remaining NEG credits in the customer's account expire. Customers may select an annualized period that ends with last day of either their April or October billing period for this purpose.

 
For customers taking service under a time-of-use (TOU) tariff, any monthly consumption of electricity is calculated according to the terms of the contract or tariff to which the same customer would be assigned to or be eligible for if the customer was not a net-metering customer. When net-metering customers under TOU tariffs are net generators during any discrete TOU period, the net kilowatt-hours (kWh) produced are valued at the same price per kWh as the utility would charge for retail kWh sales during that same time of use period.

 
Credits for NEG may be used to offset other charges assessed by the electricity provider. In addition, all net-metering customers (and dual-metering customers) hold ownership and title to all renewable-energy credits (RECs) and greenhouse-gas credits associated with customer generation.

 
*Illinois allows dual metering for systems greater than 40 kW but not greater than 2 MW, although the customer must pay for the metering equipment, and non-residential customers must pay for "all taxes, fees and utility delivery charges" for the gross amount of electricity delivered by the utility. As an economic incentive, dual metering is generally less favorable to customers than net metering.