Whey to Go: Behold the Power of Cheese, Literally

Whey cool: Cheese can provide energy to a power plant Gines Valera Marin/Nito100/Thinkstock (c) 2015 HowStuffWorks

Tucked away near Albertville, France, is an abbey of cheese-making monks using the power of cheese for the electricity they need to make, you guessed it, more cheese. This cheese-driven power plant was the prototype for a much larger project that will benefit 1,500 residents of this town which hosted the 1992 Winter Olympics. In October 2015, Valbio, a renewable energy company, opened one of the largest cheese-to-power plants in the Beaufort cheese-making town of Albertville, in the Savoie region of France.

Using this dairy product for fuel puts a new spin on the phrase "cutting the cheese," doesn't it? So how does it work?

The cheese-making process turns out two things: curds and whey. The curds, Miss Muffet, are the solids that will become the cheese we'll eat. It's the whey, the leftover liquid that we're interested in, and it's abundant. Ninety percent of full-fat milk used in cheese-making never ends up as cheese. Only about 10 percent of the milk – the protein casein – transforms into curds during the coagulation process. 

A monk flips around cheese wheels stored in a cellar of the Tamie Abbey near Albertville, France. The monks use cheese-powered energy in their cheese production.

First, the cream is skimmed from the top, to be turned into butter and butter-flavored products. Then the whey protein is removed from the remaining liquid; this ends up in powdered form in energy drinks and dietary supplements.

What's left over is a sweet — and green — liquid, made of sugar and minerals salts, you wouldn't recognize as a dairy product. On its own, whey is a waste product, but add bacteria and heat to this leftover liquid and it becomes more powerful — literally.

To convert the waste into a usable energy source, microorganisms known as archaea, which are similar to bacteria, are mixed into the whey, and the mixture is allowed to ferment in an oxygen-deprived bacterial digester. Fermentation takes about four days for skimmed whey (whey that's had its fat and protein removed).

Through a process called anaerobic digestion (AD), methane is produced as the microorganisms feed on the whey, transforming the mixture into a biogas composed of methane (CH4) and carbon dioxide (CO2). AD is similar to methane production in cows' stomachs.

With the adoption of whey-to-biogas, roughly 99 percent of the materials from the Beaufort cheese-making process are used. The only factory-produced waste products left are (mostly) water and a small amount of compost (used as fertilizer). 

The resulting gas from the whey is, functionally, identical to gas from coal or oil, and is used to generate both hot water and electricity: The gas, powering a steam engine, heats water to 194 degrees Fahrenheit (90 degrees Celsius), which, in doing so, generates electricity. The Albertville plant, specifically, will generate nearly 3 million kilowatt-hours of electricity, annually.

While the Albertville plant gets its whey from the local Beaufort cheese makers, it doesn't, however, power the small town of roughly 18,000 residents. Instead, the generated energy, enough to support 1,500 people, is sold to Électricité de France.

Besides this power plant, and one the monks use, there are a few dozen other small cheese-powered energy providers scattered around the world. In the U.S, for instance, a Fage yogurt plant in New York powers its facility with its own dairy byproducts.