As covered in a previous blog (LINK), Distribution Network Operators (DNO) are evolving into Distribution System Operators (DSO). The most prominent part of this transition is the publication of Flexibility Tenders by the DSO’s. In 2018, Distribution companies made a commitment to consider flexibility services as an alternative to installing new/improving existing network infrastructure[1]. Since 2018, the six distribution companies have procured c390MW of flexibility, while projecting to procure an additional 1980MW[2] in 2020 (these volumes are spread over the coming years, generally up to five years in advance).
Through collaboration in the Energy Networks Association (ENA) the distribution companies were able to define a range of standardised product types that would be procured across each licence area. The four different products types are: Dynamic; Restore; Secure; and Sustain. The table below provides a brief description of each (Source: ENA):
| Service | Description |
| Dynamic | The Network Operator procures, ahead of time, the ability of a Service Provider to deliver an agreed change in output following a network abnormality |
| Restore | Following a loss of supply, the Network Operator instructs a provider to either remain off supply, or to reconnect with lower demand, or to reconnect and supply generation to support increased and faster load restoration under depleted network conditions |
| Secure | The Network Operator procures, ahead of time, the ability to access a pre-agreed change in Service Provider input or output based on network conditions close to real-time |
| Sustain | The Network Operator procures, ahead of time, a pre-agreed change in input or output over a defined time period to prevent a network going beyond its firm capacity |
Additionally some of the DSO’s are attempting to procure Reactive Power. Scottish Power Energy Networks (SPEN) attempted to procure a small level of Reactive Power in their 2019 flexibility tender, and have followed this up with their recently published 2020 tender (LINK).
Generally, flexibility has been provided by small embedded generation sites or back-up generators. Homeowners will play an important role in the future. Already UK Power Networks (UKPN) have procured domestic household flexibility from a 2.1MW Virtual Power Plant[3] created by Kiwi Power and Social Energy, with the later providing use of the domestic household batteries that they operate. Social Energy are again at the forefront of this market, working with UKPN to create a ‘smart grid’, where batteries installed at households in London and South East England will be used by UKPN when they require additional power on the grid. The batteries work together with solar panels to provide homeowners with power, with spare electricity exported to the network if required.
[1] https://www.energynetworks.org/assets/files/ENA%20Flex%20Committment.pdf
[2] https://www.energynetworks.org/electricity/futures/flexibility-in-great-britain.html
[3] A group of a generators/and or demand units at different locations whose output is aggregated to form a single unit
Energy Strategy UK 