Demand response -- turning down big power loads to keep the grid running during peak demand times -- is a big business in the United States, but not as big in Europe. Mainly, that’s because Europe doesn’t face the same McMansion-air-conditioner-driven peak problems that the U.S. does.

But Europe has a different grid balancing challenge, and that’s keeping its massive share of intermittent wind and solar power in balance. That power can ebb and surge with the weather. Europe gets about 10 percent of its overall power from wind and solar, compared to about 2 percent in the U.S., and some European cities or regions are breaking the 50-percent mark.

REstore wants to help solve that problem through technology that can analyze, predict and adjust power-using devices to balance out those minute-by-minute or hour-by-hour fluctuations. The Antwerp, Belgium-based startup is managing a “couple of megawatts” of load right now in Belgium, Luxembourg, The Netherlands and the U.K., Jan-Willem Rombouts, a co-founder of the startup, said in an interview this week.

Most of that is in cold storage facilities in the Benelux area, which serves as Europe’s biggest logistics hub. But REstore also controls plug-in vehicles, with about 175 cars in a Belgian pilot that started last summer. This week, it launched a new project with French utility EDF that’s going to hook up about 150 plug-in electric vehicles in an automated vehicle-to-grid (V2G) load-balancing system.

Balancing the ups and downs of wind and solar generation requires technology that can turn down power loads at a moment’s notice, usually at the order of a technician manning some grid operations command center that needs to keep the power in perfect balance at all times to avoid blackouts.

That’s a prerequisite for playing in this market, but REstore isn’t the only one doing it -- companies like EnerNOC, Viridity Energy, Honeywell,  Siemens, BuildingIQ, Powerit Solutions, Enbala and others are doing fast, automated demand response of this kind in the U.S., Europe and Asia.

What differentiates REstore’s technology, called Flexpond, is its attention to the pricing side of the power equation, Rombouts said. As a former trading strategy and risk management software developer for Goldman Sachs, he looked at the energy market and saw a lot of room for improvement.

“Compared to mature markets in finance, like credit markets and interest rate product markets, in the energy market, we see an immaturity,” he said. “Demand is not really tuned well to supply in the market, and you see that in the pricing.”

For most of their history, electricity utilities have relied on huge central generation plants to provide plenty of stable “baseload” power, but intermittent wind and solar power challenge the system -- particularly when, like rooftop solar panels, the utility can’t even see how much power they’re producing, let alone control it.

REstore co-founder Pieter-Jan Mermans, who shares “co-CEO” tasks with Rombouts, saw firsthand the problems that Europe’s solar and wind power buildout has created for its grid operators in his decade or so as an energy and utilities consultant with Arthur D. Little. It’s not just that these weather-driven resources can stop producing all at once, he noted. Sometimes they can produce too much power.

Right now, grid operators use natural gas-fired peaker plants, which can spin up and down in 5 to 10 minutes. But power load can be adjusted in seconds, and perform some of the same grid-balancing functions, at much lower cost. Not only that, but they can reduce emissions while doing so. But they have to be as reliable as a peaker plant, or the grid won’t want them, he said.

Plug-in cars are a particularly “stochastically coupled” (i.e., really hard to predict) set of resources, Rombouts said. First of all, you never know how many are plugged in at any time, and secondly, you don’t know how many owners might disable their cars from being used as grid resources.

It’s important to note that REstore isn’t actually tapping the car batteries for power. That could weaken the batteries and mess with warranties. Instead, it adjusts the level of charging, using a technology called pulse width modulation (PWM), which allows power to go up and down gradually, versus all at once, which can harm the battery.

PWM is part of the IEC 61851 set of standards for car charging, and REstore is charging Nissan Leafs, Renault , and the Opal Ampera, Europe’s version of the Chevy Volt, in its charging projects, Rombouts said.

It isn’t the only one trying V2G. Nuvve, a company licensing technology from the University of Delaware, is testing the project in Denmark, and the same core technology is being used by NRG Energy in the United States. All the automakers with plug-in electrics are testing their V2G capabilities in multiple projects.

But REstore may have one of the first that’s actually putting power into the grid. While the new project with EDF is just getting underway, REstore is providing power from its Belgian EV project to grid operators, Rombouts said.

The startup’s megawatts of cold storage load add lots of predictable load balancing. At the end of the process, “These traders have a huge wall of computer screens, and one of these screens has the REstore interface to steer power demand, and they use us just like a gas-fired power plant,” he said.

REstore intends to become an aggregator of demand response, Rombouts said -- it’s not just providing the technology for someone else to use. The company has raised a little less than 1 million euros to date from ArkAngel Fund and angel investors, and is in the midst of raising 3 million to 4 million euros more, Rombouts said.

Of course, demand response providers like EnerNOC, Comverge, Constellation Energy, Hess and others interface with U.S. grid operations systems today in a similar fashion. But the bulk of their power is turned down in day-ahead or hour-ahead chunks, rather than in minutes or seconds -- suitable for North America’s predictable hot afternoon peak loads, but not as useful for managing fast response.