The commercial food sector is responsible for 20% of the UK’s total greenhouse gas emissions. Retail and di stribution of food contribute approximately one third of this, mainly through the burning of non-renewable fossil fuel to provide heat and power. This project aims to investigate ways of reducing greenhouse gas emissions and the climate change impacts of the UK`s food sector through the utilisation of solar energy to replace some of the carbon-based fuel currently used in the food sector.
Some 40% of supermarket energy demand is for refrigeration, and 20% each for lighting and space heating. 80% of total energy use is electricity and 20% gas. The challenge in this study is to examine the real potential for solar substitution in food retailing and distribution, and also to compare its benefits with alternative strategies of using other renewable energy, e.g. wind power, biomass, and also with improving energy efficiency.
Commercially available technology already exists to convert solar radiation to electricity from roof-mounted solar panels. The most efficient of these photovoltaic panels use mono crystalline silicon cells operating at 15% efficiency, followed by multi-crystalline and amorphous silicon cells at around 12% and 6% efficiency. The less efficient cells are cheaper but still expensive. Nevertheless examples exist in the UK and elsewhere of retail stores incorporating PV technology. In the USA, a large wholefood supermarket had 125 kW (peak) PV generating capacity installed (providing more than 20% of the store’s needs) at no cost to themselves; instead they agreed to buy the electricity for 20 years at a pre determined rate. This is similar to the Merchant Wind Power scheme in the UK for promoting the uptake of electricity generation from wind energy.
There are many barriers, both real and perceived, to adopting solar energy. These include: cost, maintenance needs, space requirements, suitable access to the sun. However, many supermarket chains are keen to embrace more environmentally benign technologies and practises and have considerable potential power in promoting the use of solar energy. This project will seek the views of all relevant sectors: manufacturers of equipment, energy suppliers, consultants specialising in supermarket design, the larger supermarkets and other retailers. The investigation will reveal both the currently perceived barriers and the forward thinking of the key stakeholders.
The objectives of the study are to:
a. establish the current state of the art in relevant available solar technology including good exemplars of existing applications
b. identify the barriers for the adoption of solar technology
c. appraise the potential of solar energy technologies for energy conservation in food distribution and retail
d. appraise alternative relevant technologies for providing renewable energy
e. assess the benefits from energy saving technologies
f. consider the alternative strategies for the next 5 to 10 years
g. consider the merits of specific research programmes to accelerate the development and adoption of solar energy in the food sector.
One of the barriers to adopting solar technology – suitable space – can be addressed by collecting solar energy indirectly through harvesting biomass, or wind energy in rural locations. The electricity from wind energy, or bio fuel derived from biomass, can then be transported to the site of use, at the supermarket. This alternative using bio-fuel will be included in a range of micro-generation possibilities that will be examined and compared with direct solar energy capture.Regional distribution centres for food can be sited in less urban areas and may provide greater opportunities for the use of other renewable technologies. A distribution centre at East Kilbride uses a 600 kW wind turbine to provide 30% of its total annual electricity need. In transportation of food, lorries have been trialled in the UK using roof-mounted PV panels and battery storage to provide refrigeration to chilled trailers.
One of the most important examples of attempts to reduce greenhouse gas emissions – by 50% – in the retail sector is at a large supermarket store in Greenwich. This store provides an opportunity to evaluate the many ways in which energy demand can be reduced and the remaining demand met from more environmentally benign sources, including: solar energy for daylighting, electricity from photovoltaic and wind energy to power outdoor signage, and natural rather mechanical ventilation. The study will include valuable feedback from the design and operation of this store.
The results from the project will enable DEFRA, other Government Bodies, and the food sector to make informed decisions on the formulation of policies and research and development priorities that will lead to the wider adoption of solar or other renewable energy technologies to reduce greenhouse gas emissions, the energy burden and the impact of the food sector on climate change.