Erda Energy helping supermarkets towards their carbon goals
The UK’s major supermarket chains are setting ambitious goals to reduce their carbon emissions, with Morrisons, Sainsbury’s and Tesco all pledging to be net zero by 2035. For supermarkets to meet these goals, reducing demand and transitioning from carbon intensive heat sources, such as gas boilers, to sustainable methods of heating is a necessity.
The installation of Erda’s geo-exchange system can help accelerate such a transition. These systems use an Erda | deep ground array to store waste thermal energy from the refrigeration system, in the Earth throughout the warmer, summer months. When it comes to winter, this heat is extracted from the ground and delivered to the store, providing the optimal temperature for staff and customers. The exciting part of this technology is that the heating does not burn any fossil fuels, but instead requires electricity for the pumps, this produces a fraction of the emissions, as seen in figure 1.
There have already been a number of geo-exchange systems installed in UK supermarkets. Looking at 16 sites with these systems throughout the UK, we see the effect on their emissions from their earlier gas usage. The average annual emissions from these sites before the Erda system was installed was 393tonnesCO2e, although, this can range from 234 to 600 tonnes, depending on building size and system efficiency.
Figure 1: The graphic above represents the 16 sites and their emission change, transitioning from gas boilers, on the left side, to a geo-exchange (GX) system on the right. Because of the large variation in sizes, it works with percentages, so no matter how great the emissions, all the boxes are the same size. The best performing sites will show the greatest decrease in carbon released from gas to electrical, and therefore, the largest area of green, representing savings of carbon emissions from the original setup.
The sites are split based on the operator, which can be a third party or Erda itself. On average, these third party sites reduced their heating emissions by 74% following the removal of the gas system. These emissions’ savings tend to increase every year due to the national grid becoming greener over time. Erda operates the remaining sites in figure 1, where the average emission reduction following the installation of a geo-exchange system is 80%. Erda continues to improve the efficiency of the systems and raise the coefficient of performance (CoP) through monitoring and optimisation, thus leading to the further 6% emission reduction.
Addition of renewables
Moreover, these savings can be improved further by implementing renewable electricity sources, such as solar. Even a modest sized solar roof, in a cloudy area, can produce enough energy to save a further 7% compared to solely the Erda operation. If the five largest supermarket chains in the UK were to install an Erda system, with the addition of a renewable electricity source, they would reduce emissions by around 87% from the original gas boiler figures. These savings would be the equivalent to all carbon emitted in Cardiff in 2019.
Lastly, the highlight of this system, is that, with a completely renewable national grid, it will run fully carbon neutral, and therefore, will eliminate heating contributing towards the climate crisis.