by Stephen Kishewitsch
Some of the latest work at the Centre for Urban Energy (CUE) at Ryerson University in downtown Toronto looks at the development of power storage to support the electric grid.
CUE’s current storage research covers:
• Lithium polymer batteries, built by Mississauga-based Electrovaya. The first phase has a 1.2 MWh battery array mounted in a trailer on a site adjacent to a large wind farm at the end of a long distribution line owned and operated by Hydro One. As this magazine has discussed before, distributors, notably Hydro One as the owner of the largest distribution system in North America, are increasingly having to deal with a system designed to supply loads in one direction only, that is now being used to bring in generation located on its distribution lines.
The battery being tested at CUE will be used to regulate the power flow in feeders explains CUE's Academic Director Bala Venkatesh. Wind farms come complete with inverters to regulate the facility's voltage output, however, they do not regulate power flow onto the distribution feeder – that's what this battery is being tested for. Power output of wind farms is a function of wind speed. Venkatesh explains that the battery bank can charge up during high wind speeds and release power when winds slow down, to keep the power flow in the line steady and from causing problems at the transformer station.
Phase two of the test will be on batteries installed right on the Ryerson campus, next to the 13.8 kV supply point from Toronto Hydro. CUE’s contribution is the development of test protocols: what tests are needed to comply with system requirements, and indeed what are the relevant system requirements? Once a test protocol has been developed, the idea is that it will ultimately be adopted as a national technical standard.
Finally, phase three will be to identify a suitable economic model to put a monetary value on the various services the battery can provide, such as frequency regulation or arbitrage. This part of the project will look at whether it should be offered through a FIT contract or through a marginal market price. Simply put, how do you sell it?
• A flywheel test in conjunction with Hydro One. The device is built and operated by Temporal Power, also in Mississauga (see also " Getting supply close to load: How they’re doing it," in the April 2012 issue of IPPSO FACTO). Flywheels are capable of response on the scale of 100 milliseconds to changes on the grid, and so can be used for a number of functions, such as frequency regulation and voltage support. Temporal Power's unit is also capable of energy arbitrage, explains Venkatesh. Ryerson’s role is to design a controller for the drive, which will allow the flywheel to spin up as it absorbs power and spin down as it releases it, through a generator, to the line. Physical testing is being done at Temporal Power’s location. Deployment is targeted between 2012 – 2014.
• Thermal storage in the form of ice, which is a form of demand response. The technology is from ICE Energy in Glendale, California, and is providing cooling on campus. This system is currently operational.
Two years ago, Ryerson University announced the creation of the Centre for Urban Energy, with a total ongoing funding of $7 million over five years from the Ontario Power Authority, Hydro One and the Toronto Hydro-Electric System Limited. Funding is also being supplied by the relevant sponsors for the individual projects listed above, either through the CUE or directly to the technology partners.
As the announcement at the time explained, the $7 million funding from the founding sponsors will be used in several ways. CUE will distribute up to $900,000 annually for approved research projects. In addition, each year CUE will grant $100,000 in bursaries, scholarships and awards to students, and $400,000 to distinguished fellows from industry and academia, who are engaged in CUE's work.
CUE's areas of research focus include:
• Alternative local energy/fuel applications and options;
• Conservation and demand management;
• Renewable energy integration;
• Carbon footprint reduction;
• Distributed generation and energy storage applications;
• Integrated planning methodologies and models;
• Plug-in hybrid vehicle and electric vehicles infrastructure requirements;
• Transmission supply enhancements;
• Transmission and distribution power engineering and utility applications.