The Most Beautiful Battery in the World

Oct 03, 2018, 07:00 PM


The man who keeps the electrons flowing inside one of Austria’s oldest power plants is actually often caught off guard when its turbines thrum to life with the thumping baritone of a giant washing machine.

The Kaprun hydroelectric station may be 70 years old, but Helmut Biberger’s job is to ensure it can handle the rapid swings in modern electricity markets. He’s helped rig the facility to generate power at a moment’s notice, using a network of winding tunnels and reservoirs built into the side of the country’s tallest mountains.

The station functions as a giant battery, by using energy when it’s abundant–and cheap–to pump water to a mountaintop reservoir. There it sits in the bluest of blue Alpine lakes until power demand spikes. At that moment traders 250 miles away in Vienna open the dam, spilling that same water downhill to spin those turbines, and selling the resulting electricity at higher prices.

For decades, plants like this one owned by utility Verbund AG were a little-seen corner of the electricity grid. Now, they’re getting fresh attention across Europe and the U.S. as governments struggle to accommodate the surging supplies from wind and solar, peaks that can overwhelm networks on clear and windy days. No less than the iconic Hoover Dam in the U.S. is being considered for a $3 billion retrofit that would allow the station to adopt the technology.

“It’s all remote controlled—a marvel of engineering,” said Biberger, 59, just as machines in the Limberg II generating hall started to whir, something it does five or six times a day.

The task will become more complicated on Monday as Austria splits its power market from Germany, curtailing a key source of cheap renewable energy. These plants, known as “pumped hydro” in industry jargon, are the “unsung hero” of electricity storage solutions, according to Bloomberg NEF, the researcher that convenes its Future of Energy Summit in London on the same day.

“Right now we’re at a tricky in-between stage,” said Jonas Rooze, a Bloomberg NEF analyst tracking Europe’s transition to renewables. “Although pumped-hydro plants will play an important role in the future system, their economics is currently under threat. They will probably have to reinvent how they operate several times to capture value from the ever-evolving system.”

About 94 percent of the world’s installed storage relies on this decades-old concept of pumping water uphill then generating power by releasing it downhill later, according to the U.S. Department of Energy. The biggest new investments, however, are going toward lithium-ion batteries being produced by companies from Tesla Inc. to Samsung Electronics Co.

These plants are filling a crucial niche for utilities looking for ways to store energy. While batteries are gaining use on the grid, the length of time they can feed power is limited to a matter of hours at any given moment. Pumped-hydro plants like Kaprun, with 830 megawatts of capacity, can store enough power to cover almost 100,000 households for more than a week.

This storage process first emerged in Italy and Switzerland in the late 19th century. Turbine technology breakthroughs in the 1920s accelerated growth. Outside the plant in Kaprun, its old turbines are displayed like trophies from yesteryear.

The Kaprun project itself was conceived in 1928 by a German utility that foresaw reservoirs stretching more than 1,000 kilometers through Alpine passes that could send power anytime across Europe. Construction began under the Nazis. It was finished by America after the war with Marshall Plan funding. A faded European Recovery Program shingle still dangles at the head of the dam.

Yet new generations of the technology are attracting attention from Israel to Morocco not just for their ability to store energy. Plants can also be optimized to work with power-hungry systems that convert the ocean into tap water for water-starved areas, according to a 2016 study from the Massachusetts Ins...