Cheese Can Now Power a Town — in France, of Course

The small Alpine town of Albertville, which is best known for having hosted the 1992 Winter Olympics, has recently become home to a new type of power plant — one that turns cheese into electricity.

In a large snow-white globe on the edge of town, bacteria bred in whey, the liquid that remains after milk has been curdled and strained to make cheese, are hard at work generating biogas: a clean, renewable energy source that can also be used to produce electricity.

"We can power a city of 1,500," said local dairy farmer Yvon Brochet, who is also the president of the Beaufort Producers Union. Beaufort, a hard, raw cow's milk cheese, is a regional specialty known as one of the more noble Alpine cheeses.

Brochet has dedicated the last five years of his life to finding ways of turning local cheese into electricity. Opened at the start of October, the Savoie Lactée (Milky Whey) plant has been in operation for a month. Today, the business generates as much electricity as it consumes.

The process used to turn cheese into biogas is known as anaerobic digestion and works much like fermentation. Microorganisms known as "archaea" break down the organic matter in an oxygen-free environment. The waste is turned into biogas, which is primarily made up of methane (CH4) and carbon dioxide (CO2).

The gas is then purified and connected to engines. These engines drive the generator that produces the electricity, which is then sold to the French electric utility company EDF.

Most organic material apart from wood can be used to generate biogas, with varying degrees of success. Fat-free and protein-free whey can be "digested" in just four days. Other, less homogenous biodegradable substances can take up to 40 days to be processed.

"The process of anaerobic digestion has been around since the dawn of time," explained Marc Schlienger of Club Biogaz, a group of biogas producers within France's Advanced Technologies for Energy and the Environment network.

"In New Delhi, in India, people stick tubes in garbage dumps to collect the gas," said Schlienger. "In China or in Africa, where bacteria grow faster because of the heat, farmers dig holes for their trash and then collect the gas to cook with."

Biogas doesn't have to be used for electricity. Brochet and his partners also considered purifying the gas and channeling it into the gas grid — an idea that was eventually dropped because it would have generated lower returns than electricity.

100,000 liters of whey a day
Every kilo of beaufort cheese generates nine kilos of whey.

"Up until now, we used to sell the whey to a major group that processes it near Verdun [in northeastern France], but transporting it cost more than the actual value of the product," explained Brochet. Eager to limit their losses, the producers got in touch with French renewable energy company Valbio, which built the plant.

Nearly 100,000 liters of whey from nine different dairy cooperatives are processed each day in the plant. First, the factory rids the whey of its fat, which is made into butter. It also removes the protein, which becomes a powder used in energy drinks and supplement shakes. The remaining liquid — which is sweet and green — is then continuously introduced into a vat containing the microorganisms.

The only waste to come out of the factory is a skip-load of compost each month, which is used to fertilize fields, and water that is released into a nearby river. None of the waste is hazardous, and none of the milk gets wasted.

The factory, which today employs 10 people, cost 13 million euros ($14.2 million) to build, and investors hope to break even by 2022.

Anaerobic digestion on the farm
"There are between 400 and 500 anaerobic digestion units in France today," explained Marc Cheverry, head of prevention and waste management at the French Environment and Energy Management Agency. "Some 200 to 300 new projects that we have been funding since 2012 are expected to launch in the coming months."

Nearly 100 of these sites are operated by companies in the agrifood sector, including an instant-soup factory, several jam manufacturers, and many other food processing firms that have decided to turn waste into money.

But over the past five years, clean energy champions have been developing initiatives to introduce anaerobic manure digesters on farms. Farmers collect manure throughout the year to use for compost in their fields. When the manure is broken down, it releases greenhouse gases, including methane. Anaerobic digesters can consume the noxious compounds in the manure and turn animal waste into energy. On top of all that, it can also reduce odors.

Digesters have also been installed at a hundred or so waste water treatment plants and a dozen public waste management sites throughout France.

A learning curve
A study commissioned by biogas sector companies and published in late November showed that, out of 54 mainly agricultural sites, more than half of plants were suffering lower returns than originally anticipated.

Digesters experienced technical failures and malfunction at 24 of the sites. In most cases, the faults were traced back to equipment that was poorly adapted to the organic matter being processed at the site.

"In France, our processes are not as standardized as they are in Germany, where they sow corn for the sole purpose of producing biogas," said Schlienger. "Here we won't divert food crops — we are merely giving new value to waste. For this reason, it's different with every farmer and therefore the research costs are higher."

In March, French Environment Minister Ségolène Royal established the first national biogas committee, and the government has since simplified its regulation of biogas production. The state has also promised to increase the feed-in tariffs for biogas-derived electricity, and has pledged to green-light 1,500 new biogas installations by 2017.

But even though things seem to be going smoothly in Albertville, Brochet doesn't believe plants like his will become commonplace anytime soon. Investors are hard to find, he said, and launching operations is fairly complex.

"Lots of people are looking to us, including the major dairy groups," he remarked. "Some people see us as troublemakers, and are hoping that we'll fail."

Follow Lucie Aubourg on Twitter: @LucieAbrg Image via Wikimedia Commons