Electrical distribution networks will require greater resilience
Cliff Walton – Managing Consultant, Ricardo and visiting professor, Imperial College London
The demands on local power distribution networks in industrialized nations such as the UK were until recently, broadly static and certainly very predictable. Our homes and businesses may be filled with an increasing proliferation of electrical consumer goods including the chargers for our many mobile devices, but the parallel focus on energy saving and connection of wind and solar generation has meant that the overall demand seen by the transmission network has not increased, and indeed, has fallen on sunny, windy days. Morning and evening peaks still occur due to the requirements for cooking, heating and hot water, but it has been a fairly stable picture over time. Until now.
Local distribution networks have already had to cope with the imbalances of renewable energy microgeneration, with a seemingly random patchwork take-up of solar photovoltaic installations across their low voltage network feeders. If nothing else, this has served to demonstrate that the adoption of such green technologies can be unpredictable and is intermittent, in many cases with clusters of early adopters. This is a big lesson for the next thirty years as significant new energy demands are
placed on distribution networks by the increasing popularity of technologies such as ground source heat pumps, and the growth in the market for electric vehicles (EVs).
As the low voltage distribution network becomes increasingly loaded in this way, we are already seeing thermal and voltage issues to arise at the most vulnerable points, potentially impacting on the quality and reliability of the supply to customers as well as the longevity of key assets such as substation transformers.
In the lead feature of this issue of RQ we describe the work of the My Electric Avenue project. The scheme seeks to mitigate the increasing load of EV recharging through a feeder-based demand management technology. A further innovation that can address the same issue is that of micro energy storage – as in the FTS E-STOR system that Ricardo helped to develop (described in the RQ Q4 2015).
While these innovations – together with other technologies such as smart metering and real-time tariff-based incentives – have their place in helping to manage low voltage network demand, there can be no substitute for smarter network controls involving power electronics alongside targeted network reinforcements to optimize capacity and extend asset life. Ricardo has recently announced an OFGEM funded ‘Celsius’ project with Electricity North West to unlock additional capacity from the UK’s north-western electricity network. In this project, we will identify innovative methods to accommodate the increasing demandson low voltage networks by optimizing the capacity of substation assets, such as transformers. We aim to do this by analysing performance and capacity to handle increased electricity demand across a range of environments and demand characteristics, including time of day and seasonal variability. These insights will allow the team to develop operational strategies and retrofit cooling techniques that enhance thermal performance and capacity of existing systems, avoiding the need for early replacement and also safeguarding costs for energy users.
There is clearly a place for innovations that seek to reduce and manage loads through both local demand management and energy buffering. In my opinion, however, one of the major focuses for the electrical ower distribution network operators needs to be upon the management of their most vulnerable assets, ensuring that the maximum possible capacity can delivered through the existing infrastructure before reinforcement is required.
This view point featured in RQ Q1 2016 - click here to download the full publication.