A new spin on energy storage

BURLINGTON, ONTARIO - Jeff Veltri gives new meaning to the phrase "Break a leg!"

A compressor mechanic in the late 1980s, Veltri, in his mid-20s at the time, was helping a friend cut down a tree when the ladder he was on lost balance. Instinctively, he threw the chainsaw he was holding in the air and decided to jump off, landing on his right leg and breaking it in four places.

"It turned out the best thing that ever happened to me, besides meeting my wife," he half-jokes, rolling up his pant leg to reveal a long surgical scar.

If the leg break hadn't happened, Veltri, who was on crutches for three months, would have never gone back to high school to finish grade 13 math and physics. Without grade 13, he wouldn't have been accepted into the mechanical engineering program at Ryerson University. And without the Ryerson engineering degree, he wouldn't have become an inventor with five patents to his name.

But it was in 2008 that the self-professed garage tinkerer heard his true calling, after learning that Ontario was planning to introduce time-of-use electricity rates. What if, he asked himself, a homeowner could have an economical way to store electricity when it's least expensive and then use it as needed?

He investigated a number of technologies. Batteries? Nope - too costly, and they don't last long enough. Ultracapacitors? Nope - also too costly, and too quick to discharge. What got Veltri inspired, however, was the idea of building a better flywheel system.

The concept of flywheels is simple: An electric motor is used to spin a rotor, which is typically a heavy cylindrical mass made out of a high-strength material, such as carbon composite or steel.

The cylinder can be made to spin faster than 10,000 revolutions per minute, usually in a vacuum housing, and this gives it tremendous momentum. This momentum, or kinetic energy, amounts to storage of the electricity that got the mass spinning in the first place.

When you want to convert that kinetic energy back into electricity the flywheel drives the motor, making it function instead as a power-producing generator.

"How long it spins in standby mode depends on the amount of friction in the system," explains Veltri. The more sustained the spin the more energy that can be stored over a given period of time. "So the name of the game is to reduce friction as much as possible."

To reduce flywheel friction, many developers levitate the rotor on electromagnetic bearings. The problem is that some external power is required to keep those bearings magnetized. So while this approach reduces friction dramatically, the need for small amounts of electricity creates a "parasitic loss" that still limits how long the system can store the energy.

Indeed, that's why most flywheel systems today are used for temporary backup power or to manage short-term instabilities in the grid. That's because if they keep the flywheel in standby storage mode for too long — anywhere from tens of minutes to a few hours — all of the energy will drain out.

Veltri came up with a better, lower-cost design based instead on permanent magnets that require no electricity, meaning zero parasitic losses. He also figured out a way to integrate the various component of his system, including his magnets, to keep friction levels extremely low.

He claims, for example, that his flywheel system will be capable of holding 95 per cent of its charge for eight hours or longer. The end result would be a system that offers twice the power at half the cost of systems from its closest competitor, Beacon Power of Massachusetts.

A breakthrough in energy storage? Could be, but first Veltri has to back up his remarkable claims through commercial demonstration. That's what he plans to do.

His first prototype worked well but was small, only storing enough electricity to power three light bulbs for an hour. In spring 2009 Veltri received $300,000 through the Ontario Power Authority's technology development fund to build a one kilowatt-hour prototype. A third prototype that's 20 times larger is near complete.

No longer does Veltri have his sights set on a home energy system. It's simply not economical on such a small scale. The plan now is to build modules, each 50 kilowatt-hours in size, which can be used individually or grouped together as part of a large utility-scale system.

These modules would measure a metre in diameter and nearly two metres high. They would be capable of performing short but also longer-term storage functions, such as storing wind energy at night so it can be dispatched during the day.

"It doesn't seem like rocket science, but there is a lot of engineering work that goes into configuring how this all goes together," says Cam Carver, a local entrepreneur who in fall 2009 joined up with Veltri to co-found Burlington-based Temporal Power, where he serves as chief executive.

For example, the permanent magnets must suspend thousands of pounds of spinning steel with incredible accuracy, meaning the magnets must be fabricated and positioned with extreme precision. The final product, however, is expected to be incredibly low maintenance compared to battery alternatives.

"It has no aversion to temperature and no toxic components, and the way we're designing them they'll only need maintenance once every 10 years," says Carver, adding that it will be a made-in-Ontario technology. "It's amazing how many machine shops there are within five kilometres of us that can make parts for this."

Hydro One will likely be the first to test the system as part of a demonstration project that recently received funding from Sustainable Development Technology Canada. Temporal plans to deploy 10 of its flywheels on Hydro One's distribution network, where they will help smooth out power production from wind turbines in the area.

Another demonstration is also in the works.

I ask Veltri how a guy tinkering away in his garage could possibly do what dozens of deep-pocketed companies haven't.

"People ask me that all the time," he replies. "I honestly can't tell you why. I've personally reviewed 120 patents on flywheels and nobody has done what we're doing. Maybe it's because I bring a new perspective. I don't have blinders on.

"If an engineer were to look at this design, I'm sure he'd say, 'Duh, why didn't I think of that?' Fortunately, nobody did."

Fortunately for Veltri, he broke that leg.