Professor researches power-saving batteries for office buildings


David Xu, Ryerson engineering professor, and the small lithium polymer battery he is testing on. (Peter Lozinski / Ryersonian Staff)

David Xu, Ryerson engineering professor, and the small lithium polymer battery he is testing on. (Peter Lozinski/Ryersonian staff)

These aren’t your typical batteries.

While a regular AA battery can power a remote control for a few months, the lithium polymer batteries David Xu, a Ryerson engineering professor, is researching could power about 1,000 homes for an hour. Xu is hoping he can use these shipping container-sized batteries to help supply power to office buildings and to solve one of the major problems with wind power.

For now, Xu and his team of researchers work in the lab, testing smaller power systems. These one-KWh batteries are around the size of a desktop printer, and hold roughly enough power to run a toaster non-stop for an hour.

The batteries aren’t exactly new. Lithium polymer batteries are often used in electric vehicles. Xu’s batteries come from South Korea, but he isn’t researching how to build better ones — he’s interested in where they could be used.

The idea to use the batteries with wind turbines isn’t new either. One of the problems with wind power is it isn’t constant. Without wind, there is no power.

But according to Xu, an increase in the wind speed results in a cubic increase in power generation. This means that if the wind speed increased by two units, the amount of power created would increase by eight units. There is no way to store this excess energy.

Some suggest hooking up these large scale batteries to harness this excess power in order to use it when the wind stops blowing. But critics say these batteries are too big and hold too little power to be practical.

One of Xu’s batteries holds the energy of one megawatt for an hour. However, wind power critic and engineer William Palmer says a few megawatts of power aren’t enough — for two months’ of power, 8,000 MW would be needed.

“Say 12 million tractor-trailer-sized storage units. Where would you suggest parking them? That’s one for each man, woman and child in the province,” he wrote in an email.

Xu says this criticism doesn’t apply to his work. He doesn’t hope to store all of the power — He hopes to use the batteries to help the grid transition between different sources of power. For example, if the wind stops blowing, the batteries would provide enough power to switch to gas power plants without any interruption in service.

There is also an urban application for Xu’s research.

Office buildings in Toronto’s downtown core are connected to the electricity grid with aging power lines. In the summer, those old, thin power lines don’t always hold enough capacity for the electricity needed to run the increased load brought on by heavy-duty air conditioning.

To save money, unused power is stored during off-peak hours, and is used during peak hours when electricity is high in demand.

Xu also says installing these batteries is cheaper and easier than installing new, thicker power lines that are better able to handle the large load of electricity.

There are plans in the works to install a shipping container-sized battery at Ryerson to test Xu’s ideas.

This story was first published in The Ryersonian, a weekly newspaper produced by the Ryerson School of Journalism, on February 26, 2014.

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