Cold stores: how to achieve net zero emissions?
The UK Cold Chain Federation recently released a report presenting technologies to help temperature-controlled warehouses achieve net zero emissions.
According to the Cold Chain Federation, the energy efficiency in UK cold stores increased by 19% in 2019-2020 compared to 2008, the baseline year, therefore exceeding the government’s original target of 12%. Nevertheless, major changes are still required to support the ambition of a net zero UK economy by 2050. There are two significant sources of GHG emissions from cold stores: indirect emissions related to electricity and other energy used by refrigeration and supporting infrastructure; and direct emissions from refrigerants used in commercial refrigeration. Indirect emissions from energy consumption in UK cold stores were estimated at 0.46 MtCO2eq, while direct emissions from refrigerant leakage were estimated at 0.18 MtCO2eq.
The Cold Chain Federation recently released a report presenting energy-saving technologies that can help temperature-controlled warehouses achieve net zero emissions.
In older cold stores, temperature monitoring is extremely basic, for instance with one or two simple thermometers read manually several times a day. With more sophisticated systems, multiple sensors are connected digitally to an alarm system which enables a more accurate and comprehensive overview of the temperature within a cold store. Combined with increasingly efficient and accurate refrigeration systems, such systems would allow to raise temperature setpoints in order to reduce energy consumption.
On-site energy production
The authors of the report have noted a rapid uptake of solar panels on the roofs of cold stores in recent years. This can provide a significant proportion of energy needs, although it is rarely sufficient to power the whole site. Other possibilities include wind turbines as well as biomass energy.
Combined heat and power (CHP)
Combined heat and power (CHP) or cogeneration can allow the heat produced in electricity generation to be reused. According to the authors, CHP converts around 88% of the fuel input into useful energy with a split of around 42% electricity and 46% heat. Heat can be used in conjunction with an absorption chiller system thereby delivering combined cooling, heat and power (CCHP) often referred to as trigeneration. In a typical cold storage operation, a CHP plant can be powered from on-site produced energy from biomass boilers or anaerobic digestate plants, but the system is more typically driven by natural gas. In the future, where CHP is used, fuel will have to come from a renewable source for a site to meet its 2050 net zero target.
Significant energy savings could be achieved from ‘centralised cooling’, where a single system provides refrigeration to multiple facilities and businesses within a local system or district. Central heat rejection systems could also be a solution, as the heat rejected from cold stores could be used to produce hot water for district heating systems.
A wide range of options are available for cold storage businesses looking to produce their own energy to protect themselves against volatility in electricity prices. However, the deployment of these technological advances faces a number of obstacles including high capital costs, national energy efficiency targets or planning constraints for new, larger cold stores with integrated infrastructure such as on-site power generation.
For more information, the complete report is available for download on the Cold Chain Federation website: Shaping the Cold Chain of the Future. The Cold Store of 2050.