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 -10°C accounts for around 50% of this energy demand, whilst a further 20% is consumed in the freezing of products (-35°C). 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 LIFEZEROSTORE project aims to demonstrate the first ever energy-neutral supermarket. This will be based on both the introduction of energy-efficient systems and the generation of energy from renewable sources. The project aims 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 aims to turn a supermarket with a surface area of 2 060 m2 and an estimated power consumption of 400 kWh/m2 per year into the first energy-neutral supermarket. This will be achieved by retrofitting with a combination of three technologies: biomass; absorption; and co-generation. Together these represent a tri-generation solution. The project hopes to overcome the challenges of introducing bioclimatic architecture and meeting the energy requirements of cooling food to -35°C independently of the electricity network. It expects to show that such a system is not only feasible to implement as a retrofitting solution, but also reliable, with low ongoing maintenance requirements. By demonstrating the potential for retrofitting, it hopes to eventually enable the transformation of all EROSKI stores in Spain. This would result in a dramatic reduction in energy consumption and greenhouse gas emissions. Its use in all stores and supermarkets in Europe, for example, would reduce total EU electricity consumption by up to 3%. The project will also explore whether extra energy beyond the needs of the supermarket(s) can be generated and sold on the energy markets. Expected results: A power consumption reduction of 824 MWh per year in the demonstration supermarket through energy saving measures, equating to a reduction in CO2 emissions of 296.64 t/year; Successful application of a tri-generation energy solution, based on biomass, cogeneration and absorption technologies adapted to a 2 060 m2 supermarket. This will fully meet all energy needs, including the -10°C and -35°C temperature requirements for food storage; The demonstrated reliability and low maintenance requirements of the retrofitted system, and its overall economic and technical feasibility; An evaluation of possible energy reuses for surplus energy generated.