Smoothing the transition from DNO to DSO

Long gone are the days when electricity distribution was all about delivering power in a linear, one-way flow from producer to consumer based simply upon supply and demand. The rapidly changing landscape of power generation, which extends across multiple sources of energy – the outputs of which cannot be controlled at will – has added considerable complexity in terms of managing these resources and responding to demand based upon the unpredictable outputs of renewables and the restrictions that climate change protocols impose upon the burning of fossil fuels.

‘Distributed generation’ is now a fact of life. It has come about largely as a result of the huge investment in renewable sources of energy such as wind and solar (with wave and tidal now also peeking above the horizon) together with their associated micro-grids and storage systems. The impact of this evolution in power generation is changing the classic Distributed Network Operator (DNO) model, and those charged with the responsibility of meeting today’s growing demand for electricity face new paradigms in terms of the design, operation, maintenance, and development of their distribution networks.

The increasing decentralisation of the energy system, with much more small-scale renewable generation and demand-side management activity, challenges DNOs to think differently about their role – thinking beyond the traditional distributed network operator model to something more appropriate to this changing power generation landscape: the Distributed Service Operator (DSO) model.

While the National Grid currently has prime responsibility for balancing the supply of electricity with demand at a national level in the UK – ensuring that there is sufficient inertia in the power system to manage imbalances in the short term and by having sources of power in reserve that can adjust output quickly over the longer term – most of the potential for storage and demand flexibility will eventually be embedded in local networks. This places greater emphasis on the adoption of a DSO approach that actively manages and balances network activity, rather than simply ensuring that there is basic capacity for electricity distribution.

The DSO will consequently face challenges beyond those of the traditional DNO. The DSO must cope with the vagaries of demand while operating networks that can accommodate many different and geographically widespread sources of energy input, the production levels of which are largely uncontrollable. Complications associated with load imbalances that cause voltage variations or other power quality problems must be overcome, as will the inherent inefficiencies of remotely located power sources serving the peak demands of distant high load centres, such as cities and industrially dense conurbations.

Examples of other challenges that the DSO must meet include the growth in the take-up of electric vehicles (EVs) and increasing interconnector capacity between the UK and its European partners. The UK has witnessed a rapid growth in EV sales since 2010, when just 111 such vehicles were sold, whereas in 2014, 6,000 EVs were sold between January and August alone. EVs present a number of challenges for electricity networks, such as simultaneous recharging of cars at peak times and the level of unpredictable demand.

Interconnectors between the UK and European partners will make an important contribution to energy security in the low carbon economy. There are currently four electricity interconnectors linking Great Britain to France, the Netherlands, Northern Ireland and the Republic of Ireland, providing over 4GW of capacity. The Energy Networks Association is now looking to see a doubling of UK electricity interconnector capacity to 8-9GW, adding further complexity to the DSO’s control strategies.

As an established systems integrator with more than 40 years’ experience of delivering control, automation and real-time management solutions to the Energy and Utilities sectors, Capula is uniquely positioned to assist companies in their transition from the DNO to the DSO model. We have been involved in electricity generation, transmission and distribution since the early 1980s, and today we are the leading supplier of substation control systems for the transmission and distribution network in England and Wales.

Capula’s IMPERIUM substation automation system and network visualisation and optimisation offering, for example, has an established client base and utilises the latest IoT technologies to advance the digital transformation of networks. IMPERIUM balances the ever increasing demand for power with surety of supply and allows network providers to integrate low carbon energy sources into their networks with a focus on reducing energy loss and capital spend, whilst improving reliability and control for consumers.