Meter Aggregation Glossary

Meter Aggregation can be confusing: here’s a glossary to help you navigate the new policy.  You can also find answers to common Meter Aggregation questions in my previous post, “Meter Aggregation Goes Live

Aggregated Account

Accounts with energy loads offset using Meter Aggregation are collectively referred to as “Aggregated Accounts”. 

Behind the meter

A distributed power generation unit that delivers energy to load without using the utility’s transmission lines… it exists “behind the (utility) meter”.

Contiguous parcels

All five of these parcels are considered contiguous.

Under Meter Aggregation policy, all five of these parcels are considered contiguous.

Parcels are considered contiguous, provided they are within an unbroken chain and are all solely owned leased or rented by the customer-generator.  The existence of a dividing street, highway, or public thoroughfare does not affect eligibility.

Cumulative Allocation

Renewable energy allocated proportionally based on Aggregated Account consumption after adjusting for the prior billing periods’ Cumulative Allocations.  This provides for better avoidance of peak loads and rates, and reduces the chance of having a net surplus of energy, which is either forfeited to the utilities.

 Customer Generator

A non-utility producer of that is net metered and connected to the utility’s electric distribution system.

Demand Response

Changes in electric usage by end-use customers from their normal consumption patterns in response to changes in the price of electricity over time, or to incentive payments designed to induce lower electricity use.  Meter Aggregation customers remain eligible for Demand Response programs.

Distributed Generation 

Also called on-site power generation, allows collection of energy from many dispersed sources and often provides economies of proximity, lower environmental impacts and improved security of energy supply.  Any form of grid-connected power production installed behind the customer meter – including solar – is considered Distributed Generation (DG). 

Energy Service Providers

A company that contracts directly with its customers to provide electric supplies.  Meter Aggregation availability will vary with ESP involvement.

Generating Account

The metered utility account to which a solar or other distributed energy generating facility is interconnected.  Under Meter Aggregation the energy generated at this account is allocated to other Aggregated Accounts.

Generation Credits

Kilowatt hours (kWh) generated on a meter in excess of that meter’s load over a specific time period.

Kilowatt (kW)

A unit of power, it measures the rate of energy conversion, and is defined as one thousand watts.  A Watt is one joule per second.

Kilowatt-hour (kWh)

A unit of energy equal to one kilowatt exerted over one hour. 

Load Aggregation

The accumulation of energy loads under Meter Aggregation, Virtual Net Energy Metering or RES-BCT policies.

Net Energy

The difference between the energy (kWh) supplied by the utility through the electric grid to the eligible customer-generator and energy (kWh) generated by an eligible customer-generator and fed back into the electric grid over a Relevant Period.

Net Energy Metering

A service under which electricity generated by a customer-generator and delivered to the utility’s grid may be used to offset energy provided by the utility to the electric consumer during the Relevant Period.  Net metering is designed to foster private investment in renewable energy.

Net Surplus Compensation

The return customers get for the energy they produce but do not use under Net Metering in the course of a Relevant Period.  NSC rates are typically about $.04/kWh – a fraction of retail rates… which is why it usually makes sense to size your distributed generation system to offset no more than your annual domestic load. Meter Aggregation customers are not eligible for NSC compensation.

Otherwise Applicable Rate Schedule (OAS)

Utility tariffs are complex, many simply modify other tariffs under special circumstances.  The OAS is the underlying tariff that provides a baseline for rules and pricing. The OAS is important because it determines not only how you will be charged for net usage, but also how you will be credited for the net-generation that you export to the grid.

Relevant Period

A twelve month period starting on the anniversary of interconnection to the utility grid.


AB 2466 established the Renewable Energy Self-Generation Bill Credit Transfer Program (RES-BCT) which allows local government entities to generate electricity at one account and transfer any available or excess bill credits to another account of the same local government.  It’s like Meter Aggregation without contiguous parcel constraints, but under RES-BCT bill credits can only offset generation costs, which are a fraction of total energy costs.

True-Up Date

The start/end date of a Relevant Period.  True-Up dates can have a significant impact on annual utility billing.
– a collection of rules that defines the relationship between a utility and its customers.  Tariffs change frequently; current tariffs are typically accessible online.

Virtual Net Metering (VNM)

a tariff arrangement that enables a multi-meter property owner to allocate a solar system’s energy credits to other tenants.


HelioPower: The Meter Aggregation Leader

HelioPower installed among the first meter aggregation projects in PG&E, SCE and SDG&E territories; we have been allocating energy using meter aggregation to hundreds of meters for years.  We have deep experience in all aspects of meter aggregation policy, development, utility compliance, implementation and operation.  HelioPower understands meter aggregation’s economic levers, and will help you leverage the economies of scale and location afforded by meter aggregation and its sister policies Virtual Net Energy Metering and the Renewable Energy Self-Generation Bill Credit Transfer Program (RES-BCT).