In Delaware, net metering is available to any customer that generates electricity using solar, wind or hydro resources, anaerobic digesters, or fuel cells capable of being powered by renewable fuels. Grid-interactive electric vehicles are also eligible for net metering treatment for electricity that they put on the grid, although these vehicles do not themselves generate electricity. The maximum capacity of a net-metered system is 25 kilowatts (kW) for residential customers; 100 kW for farm customers on residential rates; two megawatts (MW) per meter for non-residential customers of Delmarva Power and Light (DP&L); and 500 kW per meter for non-residential customers of Delaware Electric Co-Op, Inc.(DEC) and municipal utilities. The DEC and municipal utilities are "encouraged" by statute to offer net metering for non-residential customers with eligible systems up to 2 MW in capacity. Systems must be intended primarily to offset all or part of a customer's electricity requirements. It is important to note that while state law requires the DEC and municipal utilities to offer net metering under certain terms, the administrative rules adopted by order of the Delaware Public Service Commission (PSC) only apply to DP&L.
Delaware expanded the state's net-metering policy with S.B. 267 to allow customers to aggregate individual meters, to participate in net-metering via a subscribers "sharing a unique set of interests" to community-owned system or and aggregation of a customer's multiple accounts, to allow net-metering systems to provide up to 110% of a customers' expected aggregate electricity consumption, extending net-metering to leased and third party owned systems, and for single or aggregation of a customer's multiple accounts, and extending net-metering to fuel cells as well as renewable energy fuel cells for community-owned systems.
Customers are generally credited in kilowatt-hours (kWh), valued at an amount per kWh equal to the sum of delivery service charges and supply service charges for residential customers, and equal to the sum of the volumetric energy (kWh) components of the delivery service charges and supply service charges for non-residential customers, for any net excess generation (NEG) in a billing period. NEG is carried over to subsequent billing periods to offset a customer's consumption in those billing periods until all credits are used or at least until the end of a 12-month annual period. In essence, NEG is carried over to the customer's next bill at the utility's retail rate. The default annual period begins during the month in which the system is interconnected, but the customer is permitted to change the period once in order to better utilize excess generation. An exception to retail crediting exists for certain community-owned systems (i.e., those with multiple subscribers). Subscribers to the output of a community-owned system that is located behind a customer meter or as a stand-alone facility only receive retail credit if they are located on the same distribution feeder as the facility. Those that are not on the same distribution feeder only receive credit at the wholesale energy supply rate.
Customers may request a payment for unused NEG at the end of the annualized period at the supply service rate, but it does not appear that they are required to do so, meaning that NEG can be rolled over indefinitely at the choice of the customer. Should the customer request a payment for annual NEG, the supplier is permitted to submit the payment as a bill credit if it is less than $25.00. Customers retain ownership of renewable-energy credits (RECs) associated with electricity produced and consumed by the customer.
Competitive utilities -- including competitive municipal utilities and competitive electric cooperatives -- must provide net-metered customers electric service at nondiscriminatory rates that are identical, with respect to rate structure and monthly charges, to the rates that a customer that is not net metering would be charged. Competitive utilities may not charge a net-metered customer any stand-by fees or similar charges, with the exception that the Delaware Energy Office will promulgate rules that allow DEC and municipal electric companies to request to assess non-residential net-metered customers a fee or charge "if the electric utility's direct costs of interconnection and administration of net metering for these customer classes outweigh the distribution system, environmental and public-policy benefits of allocating the costs among the [utility's] entire customer base."
All net-metered systems must meet all applicable safety and performance standards established by the NEC, the IEEE and UL. Competitive utilities must develop interconnection rules by using as a guide the Interstate Renewable Energy Council's (IREC) model rules and the best practices identified by the U.S. Department of Energy. Competitive utilities may not require eligible net-metering customers who meet all applicable safety and performance standards to install excessive controls, perform or pay for unnecessary tests, or purchase excessive liability insurance.
Net-metering is accomplished using a single meter capable of registering the flow of electricity in two directions. An additional meter or meters to monitor the flow of electricity in each direction may be installed with the consent of the net-metered customer, at the expense of a competitive utility. If the existing meter of an eligible customer is incapable of measuring the flow of electricity in two directions, then the utility is responsible for all expenses involved in purchasing and installing a bi-directional meter. However, if a larger capacity meter is required to serve the customer, or if a larger capacity meter is requested by the customer, then the customer must pay the utility the difference between the larger capacity meter investment and the metering investment normally provided under the customer's service classification. If an additional meter or meters are installed, the net energy metering calculation must yield a result identical to that of a single meter.
Utilities are authorized to disallow additional net-metered energy systems if the aggregate capacity of all net-metered systems exceeds 5% of the capacity necessary to meet the electric utility's aggregated customer monthly peak demand for a particular calendar year.
Net metering was expanded significantly in July 2007 by S.B. 8, which extended net metering to all customer classes, added biogas and fuel cells as eligible technologies, addressed the ownership of RECs, and increased the prior individual system limit of 25 kW, among other changes. The law was significantly amended by [http://legis.delaware.gov/LIS/lis145.nsf/vwLegislation/SB+85/$file/legis.html?open S.B. 85] in 2009 to extend net metering to farm service customers on residential rates; remove provisions requiring annual forfeiture of net excess generation (NEG); revise language relating to ownership of renewable energy credits produced by net metered systems; and, to expand the aggregate program capacity limit from 1% of Electric Supplier's aggregated customer monthly peak demand to 5% of Electric Supplier's aggregated customer monthly peak demand. Separately, [http://legis.delaware.gov/LIS/lis145.nsf/vwLegislation/SB+153/$file/legis.html?open S.B. 153] enacted in September 2009 extends net metering to the owner of a grid-integrated electric vehicle. Rules incorporating these changes were adopted by PSC Order No. 7698 in December 2009.
Delaware enacted legislation ([http://legis.delaware.gov/LIS/LIS145.nsf/vwLegislation/SB+267?Opendocument S.B. 267]) in July 2010 that expanded the state's net-metering policy. Regulations implementing these changes were adopted by the Delaware Public Service Commission (PSC) in June 2011 (see DE PSC Order No. 7984) with an effective date of July 10, 2011.