What do supermarkets do with their products when the expiry date has been reached? Surprisingly, there are only a limited amount of options. Belgian retailer Colruyt has found a sustainable angle: they convert it to green power.


Steve Clemens | UBI

EarthToys Alternative Energy Article - Thinking out of the box: Shelf-2-Energy
What do supermarkets do with their products when the expiry date has been reached? Surprisingly, there are only a limited amount of options. Belgian retailer Colruyt has found a sustainable angle: they convert it to green power.

EarthToys Alternative Energy Article - Thinking out of the box: Shelf-2-Energy

By Steve Clemens, Lecturer Environmental Economics at UBI, Brussels

When supermarket managers face decisions, the environment or sustainability is rarely their priority. First there are the commercial requirements, delivering shareholders a healthy profit through healthy sales margin and turnover. Then there’s the need to comply with food & health regulations, which keeps them in business. So how do they manage the drain on resources posed by products that reach their sell-by date?

Supermarkets provide food, now also clean energy.

Some retailers will identify products near expiration date and mark them down significantly, to shift them quickly. Instead of having supermarket staff remove the out-of-date items from the shelves, customers actually do the ‘shelve-clearing’ for them. Unfortunately, the reduced-price products compete with the regular-priced products of the same kind, so there’s an amount of commercial cannibalism going on.

Moreover, retailers constantly negotiate with their suppliers on shelve space, brochure sponsoring, in-store sales promotions, discounts, etc.  For the supermarket managers there is an extra problem when their past-date-discounts (for health & safety requirements) seem to be interfering with their suppliers’ sales-promotions success.
E.g. when Unilever is investing millions in temporarily discounting it’s Calvé brand of mayonnaise by 20% to increase volumes sold, they will not take it kindly if the store is clearing its shelves of out-of-date Kraft mayonnaise at 50% during the same week…

Some retailers avoid this commercial quagmire altogether by removing possible conflicting close-to-sell-by date products altogether, sometimes sending them to food banks, where homeless and otherwise disadvantaged people can help themselves for free. Obviously, the humanitarian aspect of this operation is a nice secondary benefit to the retailer. At times, unfortunately, this practice leads to these disadvantaged people consuming past sell-by date products, e.g. as they keep it in their fridges too long, and reported cases of digestion problems, even blood-poisoning, can severely backfire when traced back to the donating retailer or brand.

So what do retailers do with their past due-date products they’re left with? Part of it ends up in the cattle feed industry, most of it is simply landfilled. In both cases the nutrients in the food are converted to methane (CH4), a greenhouse gas 21 times as potent as CO2.

The people at Colruyt decided to link the commercial to the sustainable and convert these old food products to clean power.

The Colruyt distribution centre in Halle (Belgium), 80% of power delivered by their on-roof PV and wind turbine.

Belgian Colruyt is a retailer company established in 1925 which now employs more than 16.000 in Belgium and France, with a turnover of €5B. Their corporate mission is to ‘create sustainable value through advanced retail operations’, and while they don’t have a CSR department, their activities in Corporate Social Responsibility dwarfs many a larger corporation. It is not a coincidence that they are among the first to offer ‘company-bikes’ to employees, i.e. their Bike2Work program. In a country like Belgium, where traditionally all mid-level managers and up are offered company cars out of fiscal optimisation (over 50% of all new cars sold are company cars in Belgium), offering bicycles to employees is quite a way off from the middle of the road.

The 1000th company-bike awarded.

In their ‘commitment’ to society, customers and shareholders, they have developed an exhaustive program on recycling (over 90% recycling rate on packaging), social initiatives and energy.

420m² PV on the Colruyt retail outlet in Alsemberg (Belgium).

They have established a CO2 monitoring tool (ECO2) to evaluate every single project they undertake, they have installed 2 on-site wind turbines (2MW and 1,6MW) and have several retail outlets with a roof full of PV panels, many more planned.

As part of their continuous effort to reduce energy use and emissions, they have identified and exploited a largely untapped savings opportunity: open freezers in the store. Most supermarkets have frozen food laid out in open deep-freezer containers. This makes for a shopping experience resembling the shelves for non-frozen items, but it is very energy inefficient as mega-joules simply flow out of the freezer into the (heated) supermarket. Colruyt chose for closed deep freezers, with a lid. This requires them to put up posters above the freezers, advertising their content, but the energy savings mount up to 3.500MWh per year!

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A different merchandizing approach, freezers with closed lids, saves 3.500MWh per year.

Another energy saver was established when they installed a local incinerator for packaging waste. The heat is captured and used for space heating, saving about 2.600MWh per year, but they also heat process water that is used for rinsing wine bottles in a recycling operation.

Their recent initiative of having their past-sell-by-date foodstuffs converted to clean energy is truly a revolutionary contribution to society.

Packed or unpacked, expired foodstuffs go to the digester.

In 2007, about 12.000 tons of such food products were sent to the digester. The organic fraction of this waste consists of fruit, vegetables, dry foods, dairy, bread and pre-prepared meals. On average these items are processed (shredded, etc) and fed to the anaerobic digester where micro-organisms break them down to their basic nutrients, ready to feed nature as a fertilizer. During this decomposing process methane gas is produced, captured, filtered and then fed as fuel into the internal combustion engine of an electrical generator.

Digesters take 34 days to break down the food into basic nutrients, while producing methane-rich biogas.

The above-mentioned 12.000 tons have thus been converted into 2.760MWh of carbon-neutral electrical power, most of which is sold to the grid. Thermal energy from the combustion process is also captured (cogeneration) and mainly used to support the digestion process. Nearby offices are also heated with this free heat, as well as a few residential houses, in a nearby district heating context.

Jef Colruyt, Chairman of the Board at Colruyt Group: “Developing a sustainable energy policy remains a daily quest, every day improving on yesterday. Despite the often technical nature of some of our projects, our aim is mainly a story of people: employees, customers, suppliers, competitors and authorities.”

Now, should consumers swarm to Colruyt to reward them for an exemplary sustainability effort, or should they NOT buy at Colruyt supermarkets to increase the volume of unsold products and thus get more clean power? 

This pie is definitely getting higher. 
The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag

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