When you walk into a supermarket, it’s never silent. There are usually squeaking carts being pushed, children asking their parents for candy, and cashiers making small talk with the shoppers. However, even if you were to be the only person standing in the store, it still wouldn’t be quiet. You would be able to hear the buzz of the lights overhead and the humming given off by the vast amount of appliances used to keep food fresh. With aisle after aisle of electricity-hogging refrigerators and freezers, supermarkets seem like they would be demand-response program superstars. And yet, few grocers participate in utilities’ demand-response initiatives.
The good news is that this lack of demand-response participation may be changing. According to a Zondits article, many European and some U.S. supermarkets are engaging in pilot demand-response and smart grid programs with local utilities. These programs are unique even in the DR world because not only do they save money in energy usage, but they can also provide new energy-related revenue streams for the grocers. This is done through innovative thermal-storage initiatives controlled by new technology like intelligent central refrigeration system managers.
How does this work? Temperatures in supermarket refrigerator and freezer cases are lowered during off-peak hours to keep the cases cool during peak hours and allow energy-inefficient case compressors to run less frequently. This saves peak energy fees, and it also provides the aspect in which most grocers are most interested: a revenue stream.
The revenue is produced by a district heating and cooling (DHC) system, which can be set up in a strip mall anchored by a supermarket. Underground piping between the supermarket and adjoining stores can transfer excess steam and hot or cold water generated by the refrigerator compressors to the nearby buildings. This thermal heating and cooling system reduces the adjoining stores’ energy use, and they in turn pass a portion of their savings on to the supermarket. This linkage between the supermarket and other businesses multiplies the savings as each business is able to then reduce their energy consumption as well.
This can be a small but steady revenue stream for supermarkets, which typically operate on razor-thin profit margins. Zondits cites a study showing that a mid-sized European supermarket collected between $6,500 and $9,000 per year from neighboring stores for its surplus heat.
Most supermarkets use some sort of centralized system to control the temperatures in their cases. An intelligent central refrigeration system manager acts almost like a smart thermostat for refrigeration systems. It connects to the internet and can be programmed to automatically connect with a utility’s demand-response programs. These systems may be costly, but they could potentially be paid off in less than two years through the revenue they help generate.
Investing in a major intelligent control system isn’t the only way for a supermarket to experience energy savings. Supermarkets can implement lighting control strategies to reduce peak demand. They could also schedule energy inefficient tasks for off-peak hours, like relegating high-energy tasks such as in-store baking and forklift battery charging to the morning or late evening. They can also monitor defrosting; cases should only be defrosted when there’s frost on the coils rather than automatically defrosting on a schedule and potentially wasting energy. Supermarkets could also switch to carbon-dioxide coolants as CO2 is not only a more environmentally friendly option than the standard hydrofluorocarbon refrigerants, but it also makes compressors more energy efficient.
Supermarkets use massive amounts of energy, so why shouldn’t they be included in demand-response and smart-grid programs? They may have been an overlooked option in the past, but new energy efficiency technology offers viable savings options, which is some interesting food for thought.
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Greg Wassel understands that grid optimization is key to our industry’s future. He is responsible for identifying new and innovative approaches to integrated demand side management programs, forging partnerships with industry-leading companies to enhance operations and developing new products and services for clients. Greg also leads our grid optimization product line and monitors demand response and other distributed resources program performance, ensuring quality every time. Greg supports our existing clients and business development teams by conducting regular best practice and innovation meetings to ensure that each client is kept up to date regarding the rapidly changing demand side management industry. He has a master’s degree in geography from the University of Georgia and is a certified energy manager (CEM).