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Exploring the food and energy nexus

12 November 2017

Michael Kanellos argues that when it comes to energy savings the food industry needs to think small!

How cold is cold enough? This was a question that process engineers at Kellogg’s asked themselves as part of a company-wide effort to reduce energy. Chilled water was being served into a plant at 1.5°C. After a survey, however, it was discovered that two processes really required water chilled to that level. The rest could get by on water at 7°C. “For a small minor investment we were able to make big savings,” said John Gothberg, IT & control systems manager for Kellogg’s in the US.

In the food industry energy is a critical input. Some estimate that modern food production and distribution systems for food consumes 10 to 15 calories for every calorie of food produced and that the food chain itself accounts for 12% or more of total energy consumption in some regions. 

Energy efficiency can be elusive. Aggressive energy savings achieved in one year can evaporate in the next year. New compressors, solar arrays and other upgrades can cut calories, but justifying the benefits can be difficult. If energy efficiency plans even marginally increase the risk of lost productivity or a reduction in product quality then they will not even be considered. 

The best place to start making energy savings is to think small –  fine-tune your existing facilities, upgrade incrementally and keep accumulating the savings. Reducing energy by 2% to 3% may not sound impressive, but it does add up. Over a decade it could mean a cut in energy expenses of between 20% and 30%. 

Kellogg’s, for example, found that its warm and cold air demands counterbalanced each other. Air gets heated to reduce humidity, but then cooled before it can be used in the cooling system. By better coordinating its processes, the company saved $300,000 a year on six HVAC units. 

In total, Kellogg’s has reduced energy by $3.3 million a year and has qualified for $1.8 million in rebates. Another energy efficiency project started when an plant employee questioned why the company relied on a water chilling tower, rather than just getting already cold water from the city. That shift is expected to save $75,000 a year. 

Brewery savings
Deschutes Brewery, meanwhile, took on energy consumption indirectly. The Oregon-based craft brewer, was experiencing a temperature spike during a critical phase of the brewing process. It increased the number of temperature sensors on its 31,000 gallon fermenter to pinpoint the cause. The resulting fix meant that the cooling time before the next phase of the process could be reduced by several hours. Energy reduction wasn’t a goal but it became a benefit.

A number of companies are examining ways to sell energy conservation through demand response  (DR) programmes, turning an expense into a revenue stream.  Utilities, essentially pay their customers to curb power consumption during peak periods. Historically, DR providers mostly asked customers to turn down air conditioners or lights. Freezer cases, ice machines and cold storage units, however, will begin to play a more significant role in these programmess. One project in Oregon estimated that a utility could save 20 megawatts over its service territory by throttling back non-ice cream freezers for 1.5 hours. 

There are also examples of food manufacturers engaging in fine-tuning and capital upgrades. Irish Distillers, for example, set out to reduce energy consumption by 35% and water consumption by 30% per unit produced while increasing production and maintaining consistency and quality. A key element of the plan is the installation of new distilling columns that can cut energy in half while doubling production.  Heineken, likewise, has set a goal of reducing water consumption worldwide by 25% by 2020 and carbon emissions by 40%. The company’s Seville, Spain facility is the epicenter for ironing out the new processes and benchmarks for these goals. 

Ten years ago, sustainability was seen as a way to improve your corporate image. However, as companies begin to better understand how they can make energy expense go farther, it is now seen as a vehicle for sustainable profits.

Michael Kanellos is a technical and market analyst at OSIsoft.  

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