Western Power Distribution
Western Power Distribution (WPD) is the electricity distribution network operator (DNO) for the Midlands, South West and South Wales that currently delivers electricity to over 7.8 million people. It is the trading entity for four electricity distribution companies – WPD South West, WPD South Wales and WPD Midlands (formerly East Midlands & West Midlands). Each company acts as the DNO for its region but combined, this makes WPD the largest electricity distribution network in the UK. The network covers a 55,500 km2 area and consists of 185,000 substations.
WPD has received significant funding from Ofgem’s Low Carbon Network Fund (LCNF) to trial innovative low-carbon technologies as well as new commercial arrangements on its network:
▪ The Lincolnshire Low Carbon Hub aims to increase the amount of renewable energy that can be connected to the distribution network in the local area through wind farms and biomass power plants.
▪ Low Voltage Templates project encourages the use of domestic solar PV, heat pumps and the improvement of insulation around the house.
▪ Buildings, Renewables and Integrated Storage with Tariffs to Overcome network Limitations (BRISTOL) is looking for viable solutions to lower the stress low carbon technologies are bringing to the low-voltage distribution network.
▪ FlexDGrid: Advanced Fault Level Management in Birmingham is trialling a number of ways to overcome faults caused by the connection of low-carbon technology to electricity networks.
Of its Low Carbon Network Fund projects, WPD’s Flexible Approaches for Low Carbon Optimised Networks (FALCON) is the only one to incorporate demand response trials to date.
The FALCON project
The FALCON project began in 2012 and will operate for another two years. Awarded £13m from the LCNF, the programme aims to control the distribution of electricity to increase capacity on the 11kV network around the Milton Keynes area. FALCON will test six different alternatives to coping with electricity demand across 200 substations, four of which are based around engineering approaches, with the remaining two approaches related to commercial techniques.
▪ Dynamic calculation and utilisation of 11kV asset ratings to free up unused capacity
▪ Automated load transfer between 11kV feeders within primary substations to increase available capacity
▪ Creation of an interconnected meshed 11kV network in suburban and rural areas in order to maximise capacity
▪ Implementation of new battery technologies
Commercial approaches or demand response:
▪ Control of distributed generation to increase capacity on the 11kV network using new commercial techniques
▪ Control of customer demand to increase capacity on the 11kV network using new commercial techniques
The commercial approaches test different types of consumer responses to incentives to reduce their electricity consumption. Demand Response refers to when a company cuts back on its consumption to avoid peak time charges, or utilises embedded generation, which then awards participants for cutting back their consumption in response to a signal from WPD’s control centre.
These six approaches will allow WPD to assess the best ways to manage change in network demand that is expected to arise from increased usage of low carbon technologies. During these trials, the results will be put into a Scenario Investment Model (SIM), allowing WPD to choose which solution is best for a low carbon future under various smart grid scenarios.
WPD can combine these six different approaches to understand which combinations will be most effective on their 11kV networks. The model is expected to help WPD and other DNOs predict more accurate load profiles using 48 half-hour periods to analyse the different load and generation on the network throughout the day. When a network planner is using SIM and a fault or network alteration arises on the network, SIM can provide recommendations of techniques that can help resolve the fault efficiently and effectively. It will allow the planners to select the best tool from the toolbox.
FALCON demand response trials
WPD is working with aggregators, like KiWi Power, to recruit trial participants, as well as approaching potential participants directly in the trials area of Milton Keynes. The network that was chosen for the trials doesn’t currently suffer from constraints; however, it will be benefitting from the monitoring to test the six different alternatives of intervention.
The programme also requires adequate incentives to encourage enough users to participate in the programme. WPD will reward those users who successfully participate in its demand response programme when signalled by its control centre. For those industrial and commercial customers on the FALCON scheme, response is triggered during the winter, between 16:00 and 20:00. WPD expects a maximum of 40 hours in a year of demand response events, with each event lasting a maximum of two hours.
In order to monitor and assess the success of each demand response event, WPD requires metering consumption data to be provided for participating sites. A baseline methodology was also introduced to be able to accurately reflect the participating sites’ contribution in response to a WPD dispatch. WPD also created an internal billing system to assess pay for participants on the performance-based service before trials initiated. A back-end call-off system also had to be built in order to send events through to aggregators.
FALCON DSR trials so far
WPD understands that adopting trials to cover a broader region would lead to increased user participation, as the Milton Keynes area alone is not necessarily indicative of business as usual operational potential of demand side response (DSR). New systems and operations also need to be built for control room operation to help with the analysis. WPD believes that there is a skills gap; not only systems but also personnel developments are necessary to be able to implement DR as a business as usual operation for DNOs.
WPD also expects to initiate post-event surveys to determine the programme’s desirability and operational impact on customers. WPD is on track for creating the SIM, with low-level design currently underway. WPD found that there has been difficulty communicating the purpose and importance of FALCON and even communicating with other DNOs on their SIM model has been more difficult than initially expected. In addition to SIM, detailed data needs to be captured before, and after, a DR event to determine the real impact on the network. According to a recent progress report, WPD aims to use estimates as an alternative to physical substation monitoring. This change in approach will no longer be creating standard profiles through the SIM for non-domestic users but instead, will be using a variety of variables to measure energy consumption. For domestic consumers, WPD aims to narrow down the current 90 demand profile types so additional profile pruning may be necessary.
FALCON demand response trials will start in November 2013 and are expected to deliver valuable lessons from this and other trials to help the network move towards a low carbon future. FALCON is on schedule to test six approaches to a smart network and analyse the outcomes in SIM by 2014. Findings are expected to be shared with other DNOs across the country in 2015.