PROJECT DESCRIPTION
BACKGROUND
The retail sector is a vital part of the European economy. Recent figures cited by the European Commission show that retail services contribute 454 billion to the EU economy, which equates to 4.3% of total EU GDP. The sector also employs around 18.6 million people. Including the wider wholesale and distribution sectors, the total contribution to the EU economy rises to 11% of GDP.
Food is an important element of the retail sector. In Spain alone there are more than 50 000 food retail outlets, with nearly 20 000 supermarkets. However, this sector is a particularly high consumer of energy. Without even including transport and distribution, food retail outlets themselves consume, on average, around 330 kWh/m2 per year. The cooling of perishable goods to around -10C accounts for around 50% of this energy demand, whilst a further 20% is consumed in the freezing of products (-35C). The rest of the energy demand comes from lighting (20%), air conditioning, and other uses.
Given its size and the levels of energy consumption, the food retail sector deserves particular attention in the context of trying to reach the EU 2020 targets of reducing greenhouse gas emissions by 20% compared to 1990 levels, and increasing energy efficiency by 20%. However, this challenge is not helped by the fact that energy consumption has generally been increasing rather than decreasing in recent years, nor by the complexity of the energy use in supermarkets.
OBJECTIVES
The objective of the LIFEZEROSTORE project was to demonstrate the first ever energy-neutral supermarket, based on both the introduction of energy-efficient systems and the generation of energy from renewable sources. The project aimed to show that it is technically and economically feasible to achieve zero consumption, not just in a newly designed supermarket but also by retrofitting existing ones. The project specifically aimed to turn a pilot supermarket with a surface area of 2 060 m2 and an estimated power consumption of 400 kWh/m2 per year into an energy-neutral operation by retrofitting it with a combination of three technologies: biomass; absorption; and co-generation. The implementation of this trigeneration technology, together with existing energy-efficiency techniques was expected to result in electricity savings of around 65%. The feasibility and reliability of the retrofitting solution was to be based on the introduction of bioclimatic architecture and on the integration of energy saving measures that can meet the energy requirements of cooling food to -35°C independently of the electricity network. By demonstrating the potential for retrofitting, the long-term plan was to transform all Eroski stores in Spain, with a dramatic reduction in energy consumption and greenhouse gas emissions.
RESULTS
The LIFEZEROSTORE project aimed to show an innovative energy trigeneration unit combining different technologies. The trigeneration systems have been successfully proven in certain buildings, but this project adopted the technology for the first time to supermarkets being biomass the primary energy. The project’s innovative energy trigeneration unit combined different technologies - biomass boiler, absorption unit, refrigeration system and co-generation. It could potentially deliver significantly reduced energy consumption in newly-built and existing retrofitted food retail stores. The unit should generate electricity, heat and cooling power, to provide the supermarket with its required electrical and thermal needs. It was based on biomass as an energy source, rather than using gas from combined heat and power (CHP) systems that generate CO2. The technologies can potentially be deployed with a relatively low initial investment to provide energy savings that deliver financial and environmental benefits. More specifically, the implementation of this trigeneration technology, together with other well known energy saving techniques, should have resulted in electricity savings of 65% in the pilot supermarket. Results from energy simulations of the system show that those savings could be achieved. The beneficiaries did implement a number of energy-efficiency techniques in the pilot Eroski supermarket in Spain, along with a new refrigeration module, bringing average energy savings of about 31%. Furthermore, all the technical specifications of the new trigeneration prototype were fully defined and the different modules were mounted and implemented. Although it was possible to keep the system working at maximum intervals of two days and always under supervision, it was not possible to put the energy-neutral supermarket prototype system into stable operation to demonstrate and validate it, due to technical difficulties. As supermarkets are intensive users of energy, the trigenerational energy concept has great potential for helping achieve EU policy for climate change and energy, including the ambitious targets for 2020 (20% reduction in emissions of greenhouse gases; 20% reduction in energy consumption by improving energy efficiency; and meet 20% of our energy needs with renewable energy). In Europe, the Energy Performance of Buildings Directive (EPBD, 2010/31/EU) obliged new public buildings to be Nearly ZEB (Zero Energy Buildings) by 2018, with the aim that all new buildings meet the Nearly ZEB standard after 2020. However, supermarkets present a unique situation in that the cold required for food cabinets is by far the main energy consumption. Therefore, the project represents a step towards integrating energy consumption and achieving the first real ZERO Emission Supermarket.
