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Energy Efficiency in the Kitchen

Commercial kitchens are high energy users, consuming roughly 2.5 times more energy per square foot than any other commercial space, according to the US Environmental Protection Agency (EPA)

Of that, as little as 40% is used in the preparation and storage of food, says the UK’s Carbon Trust; much of the wasted energy is dispersed into the kitchen.

The technology exists for dramatic reductions in energy consumption, resulting in carbon-footprint reductions and significant cost savings. The EPA claims that restaurants that invest strategically can cut energy costs by between 10%-30%; Foodservice Consultants Society International (FCSI), the professional organisation for design and management consulting services, estimates that energy savings can be as high as 40%, equating to 3%-6% of operating costs.

FCSI has found two areas of real concern in commercial kitchens: equipment used is often only 50% efficient; and low capital cost drives the choice of equipment with little consideration for the whole life-cycle cost.

Case Study
Food waste specialist Biogen Greenfinch recently ran a trial with UK hotel and restaurant group Whitbread, which estimated that food waste made up a quarter of the waste stream from its restaurants in 2008/2009. Twelve outlets – mainly Whitbread’s Table Table brand – were chosen for the trial. Staff were trained to segregate food waste from the general waste stream, and the collected food waste was taken to an anaerobic digester for recycling. By the end of 2010, food waste from approximately 300 Whitbread outlets will have been diverted from landfill, saving over 3 million kilograms of carbon emissions.

For further information please visit www.whitbread.co.uk [1] and www.biogengreenfinch.co.uk [2].

Audit and monitor

Regularly record the energy consumption of the kitchen and set targets for reduction. Meter the kitchen’s consumption of electricity, gas and water separately to measure usage and improvements over time. On large, power-consuming appliances, consider installing individual meters. Then compare the consumption and operating costs of the kitchen with the number of covers served, say, on a weekly basis. Compare this benchmark with other similar operations and assess how much energy can be saved. A sudden, unexplainable rise in energy usage could be a warning sign that a piece of equipment needs maintenance. CSFG has, for the first time, published benchmarks giving the energy cost per meal for the main catering establishments (see the end of this article).

Average energy costs per cooked meal

Snack bars:4 pence
Coffee shops: Over 7 pence
Steak houses:18 pence
Traditional English restaurants: 19 pence
High class restaurants: 27 pence
Hotel restaurants: Almost 36 pence
Non-commercial catering: 9-11 pence (average)

As governments commit to reducing CO2 emissions, so the opportunities for businesses to benefit from energy-efficient incentives increases. In the UK, for instance, businesses receive 100% tax relief on their qualifying capital expenditure on energy-saving equipment under the Enhanced Capital Allowance (ECA) scheme, while the Carbon Trust provides interest-free energy loans to SMEs in England, Wales and Northern Ireland to fund the cost of buying energy-efficient equipment. The Department of Alternative Energy Development and Efficiency (DEDE) in Thailand offers businesses tax breaks of 25% on energy-saving appliances, including refrigerators and water boilers while, in the US, purchasers of commercial food service (CFS) equipment may be entitled to rebates and incentives from utility companies when purchasing ENERGY-STAR-qualified equipment (see below).

energy caption

Purchasing new equipment
When investing in new equipment, think in terms of the life-cycle costs, a sum of all recurring and one-time costs over a lifespan of a product. This should include factors such as preheat energy consumption, idle energy rate usage, production capacity, operating hours per day, and maintenance and disposal costs. When looking for green appliances and energy-efficient equipment, ideally choose one certified as energy efficient by a scheme such as the European Union Energy Label, Japan’s Top Runner programme or US ENERGY STAR (a steam cooker with the ENERGY STAR label, for instance, is up to 90% more efficient than a model without it). Labels introduced in Brazil, China, Tunisia and Iran use the European Union Energy Label as a model, while schemes in Thailand and South Korea follow the Australian Energy Rating scheme.

Retrofitting old equipment
If it isn’t practical to replace all kitchen equipment or redesign your kitchen, retrofit old equipment with high efficiency parts and accessories. Consider installing control technology, which automatically switches off or turns down unused cooking equipment. Automatic pan sensors are available for gas and electric hobs, which turn the hob off or down after pan removal. Install a door closer on refrigerators, hang strip curtains on in-coolers to maintain moisture levels, or use programmable thermostats to automatically adjust ventilation and air conditioning.

Seeking professional help
Whether it’s a new build or major refurbishment, consulting an energy consultant or a commercial kitchen designer and installation team is advisable. UK-based Space Catering Equipment, for instance, has introduced a “green footprint” scheme to help businesses identify and incorporate kitchen equipment or design features that use less energy and recover capital costs more quickly. The siting of equipment is important, explains Space Catering Equipment managing director Mike Mellor: “For instance, by locating refrigeration compressors remotely and taking the heat away from the kitchen, refrigerators and freezers will work far more efficiently and use less energy, and it will reduce unwanted heat gain in the kitchen.”

Spotlight on Hilton
Hilton recently installed the Cheetah Energy Control system from Food Industry Technology, into its Birmingham Metropole property. Previously, the extractor fan ran 24 hours a day at full speed, using about 220.67kWh/day; the new equipment, which continuously monitors cooking activity and adjusts the speed of the extract and supply fan to match these conditions, has seen consumption drop to 105.59kWh/day. Together with the reduction in the need for conditioned air, the hotel’s total annual savings are £11,400 or 40,3569kWh.

Hobs and ranges

If you’re opting for electric cooking, fit an induction hob, which is up to 50% more efficient than a traditional electric hob because it only switches on when the pan is in contact with the electro-magnetic field created by its electrical coil. Premier Inn’s Mount Pleasant Hotel in Doncaster has recently installed a full induction cooking range, which is providing huge energy savings and keeping the kitchen cooler, which in turn is reducing energy ventilation costs.

The latest conveyor oven technology, incorporated in the Middleby Marshall PS640 Wow!, uses a patented “magic-eye” to sense when there is a product placed on the belt ready to cook. The machine automatically enters sleep mode if the product is not placed on the incoming belt within 30 seconds.

Simple energy-saving tips include using the right size pan for the ring, putting lids on pans to speed up cooking and minimise heat loss, and using stacker pans. Remember: open-top gas ranges with individual burners are more efficient than a large single burner.

Combi ovens
These ovens, which offer convection, steam and combination cooking, can reduce energy costs by around 50% because they offer faster cooking times. If it is gas, ensure it is direct heated (more efficient than one using a heat exchanger to apply indirect heat). Look out for other features, such as triple-glazed viewing windows (saving up to 40% energy), automatic fan switch-offs when the door is opened, and multi-speed fans. Some combi-oven models use their exhaust heat to preheat incoming fresh water for steam generation, saving 30% on energy.

Microwave ovens
These use 70%-90% less energy than a conventional oven, and are ideal for preparing smaller quantities of food. They require no warm-up or preheat period and use up little energy when not in use. Some models incorporate convection features for combination/convection cooking, while others will brown food using ultraviolet and infrared light.

The older style steamers are boiler-based, using on average 40 gallons of water per hour. The new, high efficiency models are “connectionless” and operate without a boiler or a drain and so consume far less energy and water (one or two gallons per hour). They also include improved insulation, which reduces heat loss, a more efficient steam delivery system (which can include forced convection) and control monitors, such as reduced energy input during idling.

The latest products can detect something placed underneath it and heat up in seconds. Hatco’s Quick Therm grill, for example, switches itself on only when activated by the product being placed under the heat source and its infra-red elements heat up in just eight seconds, offering energy savings of 79%. The HSG Panini Grill, part of the Electrolux Professional range, claims to be up to six times faster than a standard sandwich grill, toasting a sandwich in less than a minute.

The most up-to-date fryers offer faster cooking and temperature recovery times, require less oil, and are more efficient thanks to an advanced burner and heat exchanger design and insulated pans that retain heat. Units such as the Falcon Infinity fryer use highly efficient mixed gas burners combined with smaller oil wells to save on energy and oil use. The Evolution Elite from Henny Penny, for instance, uses an intelligent filtration system, which extends oil life by tracking frying statistics and telling operators when to change the filter.

Pass-through dishwashers are the energy-hogging workhorses of many professional kitchens but the new generation has lots of energy-saving features. Choose a dishwasher model with a heat recovery condenser device to reuse waste hot water to heat the incoming supply of water. The latest dishwasher models also have reduced-size wash tanks, more efficient wash and rinse pumps and better water filtration technology, which consumes less energy while improving the wash. Improved pump technology and better design of rinse arms and a reduction in the volume of required rinse water cuts water and energy consumption while improved insulation also makes it more efficient.

The Maidaid Evolution pass-through dishwasher from Maidaid-Halcyon is one of the latest energy-efficient models, claiming reductions of up to 30% in wash water consumption (it has a 15-litre wash tank compared to the standard 33 litres) and rinse water usage (2.5 litres per cycle compared to the standard 3 litres).

Spotlight on The Scarlet
The new 37-bedroom luxury eco-hotel, The Scarlet, in Cornwall, commissioned Space Catering Equipment to build an efficient kitchen using its Green Footprint scheme, which helped to identify the following equipment and energy-saving features:

  • Induction cooking with a central cooking island comprising the Dawson Mareno 700 Series and a Hatco rise and fall electric contact grill, which operates when it senses plates placed on its base.
  • Rational 10 Grid Electric Combi Oven.
  • Upright freezers by Gram.
  • Gram Blast Chiller for rapid cooling of food products before they go into the cold room.
  • Winterhalter GS502 Energy Plus dishwasher, which has an energy-saving hose and reuses energy from steam and drainage water to help heat the input water.

Refrigeration running costs have improved significantly thanks to better insulation, new coolants, and remote condensing units, where cabinets and coldrooms are powered from one system, usually located outside.

The latest refrigeration products offer up to 50% energy savings. They feature advanced electronically commutated motor fans, circuit design that optimises performance and improves air movement delivering much lower energy consumption, high density foam for better insulation, heavy duty gaskets to reduce the chance of heat getting in through the door, self-closing doors, hydrocarbon refrigerant, automatic shut-down on ice-making equipment, and fan cut-out switches when the door is open.

Intelligent controllers, such as those found on selected Williams refrigeration equipment, offer up to 15% in energy savings by detecting changing situations and altering the way the refrigeration system operates to ensure that energy use is kept to a minimum. Demand defrost controls are more economical to run because defrosting is initiated only when required via an infra-red sensor that measures the temperature or pressure drop, frost accumulation and humidity.

At London’s Park Plaza Westminster Bridge hotel, owned and operated by Park Plaza Hotels, over 120 of the hotel’s kitchen and bar fridges have been fitted with a new product called ECube, which provides a more accurate temperature reading and determines when additional chilling is needed to retain the right temperature, reducing the compressor’s load and saving energy.


The kitchen ventilation system represents one of the largest consumers of energy in the kitchen, often because it operates at full capacity even during idle times. EDF Energy, a UK energy supplier, has estimated that while 50% of the cost of a meal bought in a restaurant can be contributed to the cost of energy, 30% of this energy cost is taken up by kitchen ventilation alone.

Intelligent demand control ventilation
Ventilation products with variable speed drives (VSDs) are efficient because the output speed of the fans can change to match the requirements at different service times. This technology can be fitted to both the exhaust air and combustion air intakes.

MARVEL (Model-based Automated Regulation of Ventilation Exhaust Levels) from Halton, for instance, has a control system that monitors cooking activity via multiple sensors matching automatically the proper exhaust rate to remove heat and impurities. It offers energy savings of up to 50%.

Food Industry Technology’s (FIT) Cheetah is a similar system, which uses a processor to control the extract and air supply fans to the lowest speed to suit the conditions. It slows down to between 30% and 50% of maximum operating speed during levels of low activity, saving up to 97% energy. During a trail period with Cheetah, Hotel Des Indes in The Hague, a member of the Starwood Hotels and Resorts Worldwide, recorded energy consumption and required conditioned air dropped dramatically with energy savings of 60% and a payback of just 1.25 years.

Heat recovery ventilation
Heat recovery ventilation systems recover the heat from the outgoing warm air using it to heat the incoming air or water supply via a heat exchanger. Energy that would otherwise be lost is used with substantial energy savings.

One restaurant group enjoying the benefits of heat recovery system is Orlando-based Darden Restaurants in Florida with eight of its restaurants achieving the US Leadership in Energy and Environmental Design (LEED) certification. The Olive Garden’s Jonesboro restaurant in Arkansas supplemented the heating of its water supply for the kitchen by using reclaimed heat expelled from the condensing units of the HVAC system and the freezer/cooler condensing units.

With hoteliers and caterers becoming more focused on reducing the cost of running equipment and prolonging a product’s lifespan, manufacturers need to be able to provide a true-life cost of the products they sell, says Steve Mitchell, managing director of UK-based Lincat, major suppliers to the hospitality industry. “Increasingly customers are asking us about whole-life costs of a product, where aspects such as product life and running costs are relevant.

We welcome this development but find it frustrating that no industry-wide standards exist in this context. So we are developing test protocols to be able to give customers a realistic measurement of whole-life costs under typical usage conditions.”

In the past decade, “green” kitchen appliances and equipment have gone from niche to mass market in the commercial kitchen. With businesses increasingly likely to face levies or penalties for energy inefficiency from national or state governments committed to cutting CO2 emissions, the pressure is on manufacturers to develop even more sophisticated technologies. In the UK, for instance, the CRC Energy Efficiency Scheme has just come into effect, requiring businesses that are not covered by a Climate Change Agreement—and which spend £500,000 or more on their energy bill each year—to cut their carbon emissions or face a fine for non-compliance.

David Clarke, director of design consultants CDIS-KARM and joint chair of the Catering for a Sustainable Future Group, says we have already seen a complete redevelopment in products such as dishwashers and combi ovens in recent years. Even items, such as fridges, that have changed very little since they were first invented are undergoing radical design changes and approaches. Adande, for instance, has developed award-winning refrigerated insulated drawer units using patented technology that keep the cold air in and address the age-old problem of cold air escaping every time a fridge or freezer door is opened.

One of the next big challenges, says David Clarke, is to develop a central kitchen heat recovery system which, potentially, can recover over half of a kitchen’s “waste” heat. Central energy monitoring systems are also likely to be a growth area, allowing caterers to keep track of power consumption remotely and revise operations if necessary.

One new kitchen monitoring system currently under development, and previewed at Hotelympia 2010, is Serviceinvisible from Serviceline, which measures gas, electricity and water consumption, temperatures in fridges, freezers and coldrooms, and CO2 emissions using a series of wireless monitors fitted to incoming energy supplies, refrigeration and cooker hoods.

While significant energy savings can be achieved by purchasing energy-efficient appliances, equally important is establishing simple operational and maintenance procedures. These include:

David Clarke adds a note of advice: “There should never be a trade-off between energy efficiency and the quality of food that comes out of a kitchen. That’s why it’s essential to work closely with the chef, manager and other kitchen staff when planning efficiency in the kitchen to get them on board and to raise any potential problems that may compromise the food or service.”

Flex Your Power
www.fypower.org [3]

www.business.gov [4]

Carbon Trust
www.carbontrust.co.uk [5]

www.caterersearch.com [6]

Catering for a Sustainable Future Group
www.csfg.co.uk [7]

Catering Equipment Suppliers Association
www.cesa.org.uk [8]

Chartered Institution of Building Services Engineers (CIBSE)
www.cibse.org [9]

Energy Efficiency in Commercial Kitchens by CSFG and CIBSE, price £62
www.cibseknowledgeportal.co.uk/component/dynamicdatabase/?layout=publication&revision_id=143&st=Energy+Efficiency+in+Commercial+Kitchens+by+CSFG+and+CIBSE [10]

Consortium for Energy Efficiency
www.cee1.org [11]

Ener-G Group
www.energ.co.uk [12]

Energy Star
www.energystar.gov [13]

Foodservice Consultants Society International
www.fcsi.org [14]

Food Service Technology Center
www.fishnick.com [15]

www.greenbiz.com [15]

www.hilton.com [16]

Kyoto Commercial Kitchens
www.kyotokitchens.co.uk [17]

Space Catering Equipment
www.spacecatering.co.uk [18]

Specialist Electricity & Gas Resellers Association
www.segra.org [19]

US Green Building Council
www.usgbc.org [20]

Alliance Online
www.allianceonline.co.uk [21]

Department of Alternative Energy Development and Efficiency in Thailand ECube
www.ecubeenergysaving.com [22]

Enhanced Capital Allowance
www.eca.gov.uk [23]

Electrolux Professional
www.electrolux-professional.co.uk [24]

Energy Technology List
www.eca.gov.uk [23]

Eureka Heat Recovery Systems
eurekaheatrecovery.co.uk [25]

Flex Your Power
www.fypower.org [3]

Foster Refrigerator
www.foster-fridge.com [26]

Halton Group
www.halton.com [27]

Henny Penny
www.hennypennyevolution.com [28]

www.maidaid.co.uk [29]

Recharge Colorado
www.rechargecolorado.com [30]

Service Line
www.service-line.co.uk [31]

Sustainable Restaurant Association
www.thesra.org [32]

www.williams-refrigeration.com [33]