Carbon Trust takes the hot air out of baking bread

Analysis showed that dynamically matching exhaust fans to the volume of gases produced within an oven could provide energy savings of nearly 5 percent. This equates to savings of up to £14,000 per site per year, with payback times varying from one to five years depending on the condition of the existing oven.

Currently gas flow through ovens is not optimised for efficiency. To investigate the potential for improvement the Carbon Trust conducted two trials with Campden BRI and Spooner Industries. The trials measured gas volumes produced during baking, both from combustion and from the product itself, and the effect on oven efficiency of improved management of flue gas.

The Carbon Trust project showed that improved exhaust gas control has potential for cost savings. This can be implemented by installation of VSD’s to exhaust fans with links to burner fire rate. Further savings are possible by balancing gas flow rates in and out of the oven. One of the unquantified gas flows during baking is the volumetric flow rate of gases released from products. Campden BRI demonstrated that this was of similar magnitude to that from combustion products but increased towards the end of baking time as more steam was released. Further research is required before this can be taken into account using a gas flow optimisation algorithm.

- Gary Tucker, Head of Baking and Cereal Processing Department, Campden BRI Group

Spooner has long championed energy efficiency across all of the industrial markets that our technology supports. The drive to save energy, to be more environmentally friendly and ultimately to reduce operating costs makes energy efficient operation of process machinery such as ovens a real priority for our customers. Combining pilot machine tests conducted in our state-of-the-art R&D centre with our engineering expertise enables us to model relevant industrial processes and to develop bespoke, innovative solutions. Collaboration with Campden BRI and the Carbon Trust on this initiative enabled us to examine in greater detail the cost saving potential and environmental advantages of improved mass-balance in ovens. Ultimately it is the financial payback for customers together with corporate social responsibility programmes which are the driving forces for these improvements.

- Dan Kirk, Research and Development Manager at Spooner Industries

Improvements in industrial processes have the potential to make significant cross sector savings. The results of these trials are really positive and show that taking steps to improve ventilation in ovens thus optimising the gas flow rate can result in real financial savings.

- Al-Karim Govindji, Senior Manager at the Carbon Trust

According to Carbon Trust figures ovens are responsible for 35-45%[1]of total site carbon emissions of a bakery. In a typical direct-fired gas oven around 20% of gas use is wasted when hot air exits the flues. This energy makes no contribution to heating bread dough and is a direct loss.

The trials were part of a package of projects funded by the Government’s Regional Growth Fund (RGF), which aims to promote a step change in the energy efficiency of industrial processes.

For more information on this project please read the full case study here.


For further information please contact the Carbon Trust press office on 020 7170 7050 or email

About the Carbon Trust

The Carbon Trust is an independent company with a mission to accelerate the move to a sustainable, low-carbon economy. The Carbon Trust:

  • advises businesses, governments and the public sector on opportunities in a sustainable, low-carbon world;
  • measures and certifies the environmental footprint of organisations, products and services;
  • helps develop and deploy low-carbon technologies and solutions, from energy efficiency to renewable power

About the Government’s Regional Growth Fund

The Government’s Regional Growth Fund (RGF) supports eligible projects and programmes raising private sector investment to create economic growth and lasting employment. It has invested nearly £3 billion to help businesses in England to grow; so far generating over 100,000 jobs.

[1] Industrial Energy Efficiency Accelerator: Guide to the industrial bakery sector