Background

The ENA Open Networks Project (formerly known as TSO-DSO Project) has been established to build on the work of the TDI-Steering group, and ensure a structured project delivery approach. The previous TDI working group and subsequent workstreams will be built into this project.

The way in which we design, build and operate the UK’s electricity network is changing due to a range of factors, which are causing a move away from how we have traditionally produced and consumed electricity. These factors are also driving a change in the way that the high voltage grid and lower voltage local distribution networks work together in order to manage the overall system. These factors include:

  • Increasing uptake in renewable generation, both at a large scale (transmission/distribution) and at a local scale (residential/industrial embedded generation)
  • Increasing uptake in electric vehicles
  • Increasing uptake in new technology such as ground and air source heat pumps and electric heating, which have the effect of increasing the demand for electricity
  • Shifting demand and diversity patterns, especially considering the uptake in smart meters, smart appliances, Demand Side Response (DSR) and the role of aggregators
  • The connection and use of energy storage, both at a large and small scale
  • Aging assets and an increasing need to plan investment and reinforcement of the network in a smart and cost efficient way
  • Increased level of IDNOs (Independent Distribution Network Operators) and private wire networks

As of May 2016, there was approximately 28GW of distributed generation (DG) or embedded generation (EG) connected to the distribution networks, with the majority of this being connected in the last two years. This unprecedented increase in DG has meant that in a short space of time, Distribution Network Operators (DNOs), Transmission Owners (TOs) and the System Operator (SO) have had to respond and change the way that they work together to maintain an economical and secure network.

The scale of the change in the way we produce and consume electricity is posing the industry with new challenges and opportunities to manage the system efficiently and reliably. The SO, TOs and DNOs are working closely together to address short term issues, but also to develop medium and long term enduring approaches to managing whole system issues.

The Transmission-Distribution Interface (TDI) working group was set up by the ENA in late 2015. This group considered several pressing areas of T-D interaction through a number of focussed workgroups. These workgroups covered areas including the Statement of Works process, High Voltage Management, Shared Services, Active Network Management, the consistency of T-D charging and more integrated T-D approaches to providing network capacity.

In their Call for Evidence on “A Smart, Flexible Energy System”, BEIS and Ofgem reference the existing TDI work but also emphasise the need for electricity network operators to make greater progress around T-D interactions, with industry best placed to address these requirements. Furthermore, network companies will need to map out the transition from a DNO to a DSO model, as well as improve the customer experience across the boundary.