Hydro One developed its net metering (NM) programme in accordance with the requirements of the provincial government’s ‘Net Metering Regulation’. This programme allows Hydro One’s existing load customers to connect generators to the distribution system, generate power and receive credit for sending power to the Hydro One distribution grid.

Ontario Regulation 541/05 specifies the following conditions for participation in a net metering programme:

  • The generator generates the electricity primarily for the generator’s own use.
  • The generator generates the electricity solely from a renewable energy source.
  • The maximum cumulative output capacity of the equipment used to generate the electricity that the generator intends to return to the distributor for net metering purposes is no greater than 500 kW based on the rated maximum output capacity of the equipment.
  • The generator conveys the electricity that is generated directly from the point of generation to another point for the generator’s own consumption without reliance on the distributor’s distribution system before conveying any electricity that is in excess of the generator’s own needs at the time of generation into the distributor’s distribution system.

Since 2003 and prior to the enactment of this regulation in late-2005, Hydro One connected 36 load customers with generator size up to 50 kW to the distribution system in a pilot net metering programme. Since the enactment of this regulation, over 60 customers have applied to participate. A majority of these have been connected without complications.

Programme management

Customers interested in participating in the net metering programme typically contact Hydro One’s Customer Call Centre (CCC) for information. Customers can also obtain information on this programme from Hydro One’s net metering website. Net metering applications received by Hydro One are reviewed by the Distribution Planning – Customer Operations organisation for impact on the distribution system. Generations up to 50 kW receive minimal review.

A more structured review is done for generations over 50 kW. Items reviewed include impact of the generator on power system power quality, equipment rating and protection adequacy.

Applications that meet the requirements in this review step are forwarded to the appropriate Field Business Centre (FBC) for net metering connection.Applications that do not meet the requirement are reviewed futher by the Distribution Planning – Customer Operations in conjunction with the Generation Connection department and thereafter either forwarded to the FBC for connection, or if the implementation issues are not resolved, the application will be handled through the normal generation connection process.

Challenges on implementing the programme

Customers expect the net metering programme to provide a simple process to connect embedded generators, and to involve minimal connection cost and time delay. Some customers begin purchasing and installing generating equipment before Hydro One has reviewed and accepted the connection. The subsequent results of the connection feasibility assessment may indicate that extra cost and time are required to implement the project. In this case, there is likely to be customer disappointment as the extra cost and time delay may make the original generation connection proposal not economically feasible.

The normal generation connection process involves preliminary assessment, connection impact assessment, preparation of connection cost estimate, signing of various agreements and other work. Recent interests triggered by Ontario’s Standard Offer Programme in distribution generation have generated a high volume of applications for generation connection to Hydro One’s distribution system. At present due to the high volume, it can take several months to complete all the procedural steps. The customer is required to pay for all the study and estimate preparation costs. It is difficult to meet customer expectation if, due to technical complexity involved (i.e. it fails to meet the screening criteria), an application has to be handled through the normal connection process.

Better customer communication will help to resolve the above issues. In order for Hydro One to assess the acceptability of the generator for connection to the distribution system, details of the generator control and protection equipment are required. In most NM applications, generator control and protection is integrated as part of the generator package. Details are not always readily available.

There is time delay in seeking and reviewing this information. For detailed impact assessment of a proposed generation on the distribution system, information on generator characteristics is required in study models. Technical characteristics of new types of generators such as the inverter type are still not easily available. More studies need to be done to model inverter-type generators in the distribution system.