Smart Energy the Ensto Way

Energy storage brings system flexibility to smart energy control systems created to optimize energy generation and consumption. The intelligence for energy storage is being developed by Ensto engineers.

In September 2020, HSK Sähkö Oy installed 450 solar panels on the roof of Ensto's main factory building in Porvoo. The panels will generate an estimated annual output of approximately 130,000 kilowatt hours – enough to fully charge 1,700 Teslas.

The panels themselves will only generate between three and four percent of the energy Ensto needs to operate the plant, but they are a major step forward toward helping to minimize total electricity usage, as well as reduce costs and emissions in an industrial plant. Energy storage, the solar power plant, and energy control system may be key elements in a new Ensto product.

A bigger ecosystem

Even if Ensto’s solar panels were capable of generating more electricity than the factory needed, the taxes levied do not make it attractive to sell surplus electricity back to the utility.

But the genius of this project is not about revenue: it’s about balance. "The panels are a small part of the big picture, a bigger ecosystem," says Anssi Savelius, Ensto's Senior Vice President for R&D and Technology.

That ecosystem also contains a battery and an energy management system with edge intelligence, this intelligence developed by Ensto engineers. An interesting use case is demand response. During consumption peaks, when the frequency drops, Ensto can push energy to the utility network. "When there is too much electricity generation in the network and the frequency increases, the utility can dump excess energy into Ensto's battery," says Savelius. "The frequency containment reserve market offers an improved ROI for this kind of virtual power plant."

An Ensto product

Since selling back to grid isn't always a good business decision, Savelius says, optimizing photovoltaic self-consumption makes sense. The battery can shave peak loads and optimize the use of stored energy by enabling consumption at times when grid prices are unfavorable. It can also be used to charge EVs in front of the factory or as a source of backup power.

Since this project is on the vanguard of R&D, Savelius says it's hard to estimate the return on investment. The investment itself – panels, battery, and control system – will run between 200,000 and 300,000 euros, the solar panels constituting the majority of the investment. "The point of the energy management system is that there's an embedded computer that knows when to feed electricity back to the grid or demand electricity from the grid, when to participate in the electricity market, and when to offer the battery to the factory or to EV chargers. This logic makes the ROI on this project a lot shorter than it might otherwise be, but it's still likely several years."

"Once all the elements are in place and connected," he says, "this could be a viable business. If we can combine the TSO [Transmission System Operator] and DSO applications to it, electricity market information, then one plus one is more than two. Connect enough applications and it starts to pay back. That's the case we're chasing." 


At this point, it's not yet a business. But if the energy control system works as Savelius believes it will, Ensto will have a product. Its partner in the project is HSK Sähkö, the electrical contracting company that installed the solar panels and battery systems. “You can’t just sell the control system,” says Savelius. “You need to sell the whole system solution, and that’s why we’re collaborating with HSK.”

"Think of supermarkets and industrial plants," he says. "Our system could help them reach payback time much faster when they invest in a solar power system. They can make their CO2 footprint smaller and gain energy independence."

“We’ll install the battery storage system in spring 2021. The control system will be prototyped next summer or autumn, with proof of concept in 2021, and the first iteration of commercial pilot on the market in 2022,” Savelius says.

“These dates are dangerous promises, of course, when you’re pioneers in a field,” he says. “It’s amazing to have a real environment, to see real numbers, and Ensto Porvoo plant is the laboratory.”