When a photovoltaic system is producing more energy than is required, the surplus is exported via the grid and sold back to the utility company. This page explains the metering options, ROCS and provides details of energy companies operating 'BuyBack' schemes.
Metering Options
Total Generation Meter
An Ofgem approved kilowatt-hour (kWh) meter is installed with all Solarcentury systems which gives a running total of the energy in kWh that the system has generated. It is possible to enter into a buy back agreement based on the total energy generation of the system and this meter gives that reading.
Export Meter
An export meter can be installed which calculates the amount of electricity being exported rather than total generated. Exported energy is the extra energy produced by the renewable generator which is exported to the electricity network after the site (i.e. home, commercial property) has met its energy demand. The electricity company will pay for each kWh exported. The electricity company will stipulate if the meter is to be read by the owner or their own meter reader and whether the system owner will be paid annually or bi-annually. Export meters can be purchased from and installed by a local area meter operator.
Renewable Obligation Certificates (ROCs)
Since 1 April 2004, all renewable generators, independent of size, have been entitled to receive ROCs. Awarded by Ofgem, the electricity regulator, ROCs have a market value approximately 3 - 5 p/kWh. One ROC is awarded for every 1000 kWh (1 MWh) of renewable electricity produced. These can be claimed on an annual basis from Ofgem.
From 2009, two ROCs will be awarded for every 1 MWh of renewable electricity produced (Subject to Parliamentary approval - expected Autumn 2008). ROCs are rounded up to the nearest MWh from 0.5 MWh upwards. For example, a system generating 0.5 MWh annually will receive one ROC accreditation from Ofgem.
ROCs can be managed in different ways. Increasingly, companies are acting as ROC agents, claiming ROCs from Ofgem on behalf of customers. Where this is the case, payment tariffs to customers include for ROC awards and customers do not need to claim these themselves. Some electricity companies do not claim ROCs on customer’s behalf and it is the responsibility of the customer to claim and sell their own ROCs.
*The current ROC value is circa £45 and ROCs can be claimed for the life of the system. From 2009 onwards every 1MWhr will be eligible for 2 ROC's (ie £90).
*The value of ROCs is predicted to rise as the demand for renewable energy increases. ROC can provide a guaranteed income stream that can be claimed by the owner of the system.
Energy Companies Operating BuyBack Schemes
Scottish and Southern Energy (SSE), Solar Energy Plus Scheme
Good Energy, Home Generation Scheme
Good Energy, Smart Generation Scheme
E-on, Solarnet Scheme
EDF, Power Purchase Scheme
Npower, Micro Generation Scheme
Companies Trading ROCs
Trade Link Solutions, Micro Generation Scheme
Please note that response times from different companies can vary due to demand. This information was correct at the time of publishing please refer to each utility for the most up to date deals.