Nigel Thompson, sales manager for gas power solutions at Finning UK & Ireland, looks at why more bakery producers are opting for combined heat and power systems
Every year, industrial bakeries in the UK produce around 2.5 million tonnes of baked goods, consuming 200 GWh of energy and emitting 570,000 tonnes of CO2 as a result. This high and regular demand for heating and power generation makes the baking industry an ideal candidate for combined heat and power systems (CHP).
The baking process uses huge amounts of heat and, in the case of cookie and cracker production, consumes as much as 78% of the total energy input. Beyond this, the fermenting and proving process requires a significant amount of steam, while pan and equipment washing consumes a lot of steam and hot water.
While bakeries will use less electricity than heat, they will still require this energy to provide refrigeration and compressed air, as well as running lighting, ventilation and equipment such as mixers.
CHP offers benefits over traditional electricity generation systems by integrating the production of usable heat and power into one single, highly efficient process. CHP generates electricity while also capturing the usable heat produced during this process. Compared to conventional ways of generating electricity, where vast amounts of heat go to waste, CHP plants can reach efficiencies of 80%.
Many sites also benefit from a third aspect of CHP – trigeneration – when looking to keep ingredients stored at a cool temperature. Using an absorption chiller to convert heat into cooling energy, trigeneration is economical and environmentally friendly, as it eliminates harmful refrigerants and reduces overall air emissions.
In evaluating whether a CHP unit is the right solution for a business, a full energy audit will establish a firm’s annual heat and power requirements. The correct CHP size depends on the delivery of baseline heat needed, as any excess and unnecessary heat is wasted, thereby reducing the system’s overall efficiency. Finally, a trusted partner can help specify and implement a CHP system, with an operations and maintenance contract also advisable.
The payback period can be impressive. For example, if a typical bakery production site installs a 1.2MW gas CHP unit at a cost of £780,000, which then operates for 8,000 hours a year, it is estimated the annual savings the system could achieve would be £290,000, including O&M costs. This is a payback period of less than three years.