AGR is a leading renewable energy company specialising in low carbon energy generation, with over £350m of projects delivered to date in the UK, including a portfolio of gas peaking and combined heat and power (CHP) projects. AGR developed and is the main EPC contractor for a new 217,000m² glasshouse and energy centre in Cambridgeshire and has sold the project to funds managed by Greencoat Capital. AGR has selected Clarke Energy to supply and install the innovative energy centre that will supply electricity and heat to the project. Overall, the glasshouse facility will be used to grow cucumbers and will be able to grow 10% of the cucumbers consumed in Britain using 30% less CO₂ than conventionally heated glasshouses.

The Energy Centre for the glasshouse combines a 33MWth heat pump system with a combined heat and power (CHP) plant comprising three high-efficiency INNIO Jenbacher gas engines with CO₂ recovery. The installation of heat pumps will provide renewable hot water heating to the glasshouse and will qualify for the Renewable Heat Incentive (RHI). IES Energy are leading heat pump manufacturers and will be supplying and installing the heat pumps for the project. Their trusted partner Pure Renewables will be designing and installing the open-loop collection system which will run over a total distance of 750m. Clarke Energy and AGR opted for an ammonia (R717) refrigerant system as opposed to a hydrocarbon refrigerant from IES Energy as ammonia has a higher efficiency value and global warming potential of zero.

The liquid-to-water heat pumps will recover renewable heat from local reservoirs on site via the reverse Carnot cycle and through the use of an ammonia refrigerant. The open-loop collection system involves eighteen pumps floating on platforms spread across the three reservoirs which will extract water from the reservoirs and transfer any available heat to the ammonia refrigerant (approx. 10°C). The heated ammonia is pumped to the seven compressors located near the glasshouse where the ammonia is compressed, and heat is transferred to the site thermal stores at circa 50°C. The compressors are split into three separate, skid mounted systems, one single compressor (4.7MW) and two twin compressors (9.5MW), powered in part by the Jenbacher engines.

The CHP plant will consist of Jenbacher J416, J620 & J624 engines providing an electrical output of 9MWe, which will be used to power the glasshouse, the LED grow lights and various site auxiliaries. The waste heat generated from the engines is to be utilised as hot water which will be stored in two 6000m3 thermal stores and used to heat the glasshouses. The CO₂ recovered from exhaust gases will be transferred to the glasshouse to help accelerate the growth of the produce.

Source: Clarke Energy