Connection of generators to Eskom's low voltage network

November 2014

RAVI MOONSAMY, project leader for the low voltage, small-scale generator framework, Eskom

The South African customer’s perspective on electricity usage is evolving. This is a result of a number of factors, including the rising electricity prices, the threat of load curtailment at a time when South Africa is faced with capacity constraints, the need to be energy efficient and also the ever-rising need to demonstrate good citizenship by using green energy.

These factors have resulted in some customers (large and small) considering alternative sources of energy. Among these alternative energy sources considered, is the increasing public interest to install an own generator. There is particularly an increasing interest by residential customers to connect PV installations on their roof tops.

This article sets out the current challenges that must be resolved first to enable such a connection in a sustainable and manageable way. These generators may not be grid tied, i.e. the customer generator operates in parallel with the Eskom grid and supplements the energy that would have otherwise been imported from Eskom.

If the intended installation is planned to be grid tied, permission is required from Eskom as there are legal, safety and power quality implications, whether energy is exported onto the grid or not.

Eskom is in the process of setting up the legal, technical, metering and tariff framework for the connection of small-scale generators to the low voltage network. There is an existing approved process to allow generators connected to Eskom’s medium voltage and higher voltage networks.

Customers are required to convert to Eskom’s large power tariffs. The large power tariffs have unbundled energy rates and metering which supports time of use (TOU) measurement. No premium is paid for this energy – it is credited at the TOU energy rates which reflect Eskom’s average cost of energy.

The Eskom process for medium voltage and higher connections is available here.

Small and micro-generator connection framework

Eskom’s framework for connecting small-scale generators is in the process of being developed and until such time it has been completed, no small-scale generator may be grid tied for safety, tariff and technical reasons.

This framework will consider:

• Resources to manage the additional customer requests (human and financial).
• Metering decisions – meters must be capable of measuring the imports and exports of energy.
• Customer understanding of implications that such installations can pose a safety and fire risk for the customer, and that the necessary national standards and accreditation needs to be in place in order for such an installation to be safe and that it is installed by accredited and authorised personnel.
• Administration and billing implications.
• Revenue impacts, tariff structures, tariff rates and rates for credit which will need to be approved by the National Energy Regulator of South Africa (NERSA).
• Technical issues – Eskom’s present low voltage network operating and maintenance practices are not compatible with the connection of low voltage micro generators, and the connection of these generators (even if they are not exporting into the grid) presents a safety risk for Eskom’s field staff and hence cannot be connected until the low voltage operating procedures have been revised to ensure the safety of utility staff and the public.
• Processes are being put in place for customers to apply and make the connections legal.
• Rules regarding month to month banking (carry-over of energy).
• Contracting – comprehension of customer and Eskom obligations in compliance with the Consumer Protection Act and other technical legislation.
• Safety of Eskom field workers and customers.

Until the framework is in place, customers connected at low voltage are not allowed to connect any generator that is grid tied, as this places the safety of the public and Eskom employees at risk. Eskom will not allow meters to turn backwards and has the right to disconnect any supply that does not have permission to be grid tied.

Enquiries

An Eskom work team is working on the framework to be approved within Eskom and, where required, by NERSA. Eskom is also working closely with the South African Local Government Association (SALGA) to ensure consistent application and connection processes.

For any queries for these types of connections, please refer them directly to the Customer Services Group, Grid Access Unit which is sponsoring the project – contact Ravi Moonsamy (project leader for the low voltage small-scale generator framework) at moonsar@eskom.co.za.

Publication: November 2014

Section: Focus on