Supermarket giant Sainsbury’s is aiming to unlock the demand side potential in a network of 400 stand-by generators located around the UK.
Keeping the energy bill for Sainsbury’s in check is a major undertaking. It’s a challenge that we’re taking seriously and in recent years we’ve invested in more than 100 biomass boilers, 40MW of solar PV, introduced LED lighting, 27 Ground Source Heat Pumps and Green Gas CHP. As a result our absolute energy consumption today is lower than it was in 2005-06, despite opening 52% more space in that period.
So, we’ve made a good start, but we have only really scratched the surface in terms of what we could do through demand side response. The opportunity is huge because our business accounts for something like 0.6% of all electricity consumption in the UK.
Investigating the role of on-site generation
In the event of a power cut each of our sites has a back-up generator set in place, which starts up if the site comes off the grid for any reason. These generators produce enough power to enable each facility to function for a period of time and to get people out of the building safely. What we do know is that we have approximately 130MW of generation capability that could be put to use providing demand response. However, the hurdle we need to overcome is the complexity of getting those generators connected to the grid.
Sainsbury’s has approximately 130MW of generation capability that could be put to use providing demand response.
The process of connecting new on-site generation is complex and time-consuming. It’s also not set up to deal effectively with a situation like ours with 400 individual sites, each needing to be assessed as a separate entity.
At present we need to apply for each potential connection to one of the 14 Distribution Network Operators (DNOs) and the time between submitting an application and receiving a ‘yes or no’ decision is between 45 and 90 days.
In addition, because our generator sets are used as back-up currently, they are not connected directly to the grid. This necessitates a significant amount of investigative work to provide the necessary technical specifications and data to the DNO. We estimate that the cost of completing the application process for 350 sites would run to millions of pounds.
There is no easy answer because the DNO needs to be sure that any connection does not cause a problem on the local grid. It would certainly encourage businesses like ours if there was a process to validate potential connections en masse. We would also welcome a centralised fee with each DNO to provide clarity on costs.
It’s unlikely that all 400 of our sites will be suitable for connection, but certainly we think 250-300 is a realistic figure.
We have only really scratched the surface in terms of what we could do through demand side response.
We’ve reached an exciting point in the development of our demand response capability with the first 150kW generator set in Dewsbury, West Yorkshire going live this month. This will be followed by a 1.2MW generator at our Tamworth depot in Staffordshire, so we will be able to assess the success of both small and large scale options.
At the same time we’re looking at other technologies. For example, later this year we will launch a trial of battery storage at our Melton Mowbray store, which aims to store up off peak electricity to be released on demand. We want to prove the principle before assessing a wider roll-out.
In addition, we’re working with Open Energi, using their expertise in frequency response to examine what else we can do across Sainsbury’s to reduce our energy consumption.
I think the message is that, as part of Sainsbury’s 20×20 Sustainability Plan, demand response technology has a part to play. We have 130MW of generation just waiting to be used. It’s now about working with the energy industry to make it happen!