Refrigeration systems are responsible for a considerable share of energy consumption in the retail sector. INESC TEC led the European project InterConnect and developed a tool that addressed the consumption of said systems according to several scenarios, providing a potential source of flexibility for the DSO.
INESC TEC developed a service that can predict the energy consumption of supermarket refrigeration systems and recommend changes to this standard according to the power grid’s needs. The solution, developed within the scope of the InterConnect project – the largest ever led by a Portuguese institution – was tested in MC supermarkets, through Elergone Energia.
RefriFlex favoured flexibility forecasts for refrigeration systems where energy consumption increases or decreases with the activation of different operating modes, following an innovative approach in this sector.
How does this solution work? Ricardo Silva, INESC TEC researcher, explained: “MC, together with Schneider Electric, integrated a new system in several Continente stores, which allowed us to adopt an operation mode for refrigeration chambers and refrigerators. This translates into higher consumption – higher production of cold (BOOST) – or lower consumption – lower production of cold (ECO).”
That’s where RefriFlex came in. By resorting to consumption and operation data collected in the supermarkets, the RefriFlex service predicted the consumption of the cooling plant for the following hours (the next day, for example). With this information available – and depending, for example, on the greater or lesser availability of solar energy produced in the store – the service estimated the existing margin to increase or decrease consumption by activating the different operating modes (BOOST or ECO, respectively).
According to Amândio Ferreira, head of Innovation at Elergone Energia, this solution paved the way for active and efficient consumption management, ultimately leading to a “reduction in the energy and carbon footprint.”
The solution may even play an “increasingly crucial” role in how companies adapt their consumption to the context. Moreover, this endeavour can explore “new opportunities”, either by providing services to operators or simply by reducing energy bills, since consumption is avoided in the most expensive periods.
Refrigeration systems – which ensure temperature preservation within a pre-established range of each refrigeration unit in supermarkets, from showcases to freezers – represent a considerable share of all energy consumed in the sector. Adjusting the system’s electricity consumption represents a potential source of flexibility, which can be used to support the distribution system operator (DSO) – in this case, E-REDES, which also participated in the project – that manages the largest distribution network in Portugal.
“The difference between the baseline forecast (consumption in normal operation conditions) and this new mode of operation (BOOST or ECO) showed the flexibility of consumption, which can then be translated into a (paid) offer to the DSO,” added Ricardo Silva.
Focus on more refrigeration systems?
Now, the ECO system is allowing consumption reductions of around 2% on average; BOOST mode can increase consumption up to 4%. “For instance, certain stores operate systems that consume an average of about 20kW, while others exceed 80kW”, he said. Ricardo Silva stressed that, “at first glance”, they may seem “small figures”, but it is necessary to consider the “food quality requirements of the products stored”. This variation is even limited to 1.ºC in systems that preserve dairy products, for example.
“It is important to highlight that the immediate variation of power, when applying the new mode, is large, but we are talking about consumption averages for a period of 15 minutes, i.e., this effect is not felt for most of the period. This is the same as saying that we have a good response in instantaneous power but reduced in the energy consumed”, he added.
Which begs the question: can this model “shift” from the retail sector to the other domains? And the answer is: possibly. “When talking about the algorithm, it’s possible to adopt it in other sectors”, mentioned Ricardo Silva. However, “the system is adapted for cold systems and the flexibility estimation is very restricted to the predefined operating modes (ECO, NORMAL and BOOST)”. For now, the system has been tested in 10 Continente stores.
But there is room for technology to evolve within the retail sector. One of the possibilities is to complement the flexibility of these systems with other flexible loads in supermarkets, like AC units or even other buildings in the vicinity. By adding this flexibility in a single offer, it becomes possible to provide the DSO load flexibility services that can increase the resilience of the power grid at the local level.
Strengthening grid resilience was one of the goals of the InterConnect project, which brought together equipment manufacturers, research institutions, DSO, suppliers and consumers to jointly facilitate optimal management of energy systems, paving the way towards energy system interoperability.
INESC TEC played a “fundamental” role in creating methodologies for semantic interoperability, “developing algorithms and providing support for the use of the project’s various tools, namely in terms of their modular and transparent integration”, said INESC TEC researcher and project coordinator, David Rua, during the project’s final event.
The project demonstrated interoperable technologies and services on seven large-scale pilots: Belgium, Germany, the Netherlands, Italy, Greece, France and Portugal. In Portugal, the solutions were tested in domestic consumers (with E-REDES responsible) and in service/commercial buildings (as is the case of Elergone Energia (MC), which tested solutions in Continente stores).
The researcher mentioned in this news piece is associated with INESC TEC
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