Demand response, and companies that aggregate it to help balance supply and load on the grid aren't new. Traditionally, demand response works on a scale of an hour or more, interrupting some process on a major consumer’s production line to keep demand broadly in line with what generators are putting onto the grid. What Toronto-based ENBALA (the name is an amalgam of ENergy in BALAnce) Power Networks does is similar, but on a timescale of seconds, rather than hours. Using smart grid technologies that weren’t available even five years ago, the company’s system calculates the difference between the available supply and the momentary demand on the grid every four seconds, and invites its client companies – large power consumers – to tune down (or up) the rate at which some of their machinery – say, a compressor – operates, to keep a close match between what the grid is supplying – at that moment – and how much its consumers are drawing.
Conventionally, again, the only tools the system operator (in Ontario, the IESO) has to match supply and demand is its ability to order generators to ramp production up or down. At present, as ENBALA CEO Ron Dizy explains, the facilities in Ontario that provide such balancing service are basically the Sir Adam Beck hydro station at Niagara Falls, and some Brookfield hydro facilities. Up until the last few years, OPG’s coal-fired stations used to provide such a balancing function, but the control interval there was on a five-minute scale, and in any case coal is scheduled to be gone in another year and a half. But on the four-second timescale on which ENBALA’s service operates, adjusting load in this way is "by far" the most scalable and cost-effective way to achieve grid balance, says Dizy.
This the company does by attaching an off-the-shelf communications panel, plus some very fast and sophisticated software, to the various pieces of equipment that the host load allows – compressors and motors, for example, designed to operate at variable speeds within a range that has no practical effect on the host company’s production processes. The host load company tells ENBALA what machinery can be adjusted in this way, and what the acceptable operating range is. A signal in real time is then sent from the IESO as to how the grid balance needs to be adjusted, and ENBALA’s network processes the signal to all the host devices to adjust load accordingly. ENBALA’s customer, the IESO, pays ENBALA for the service, and ENBALA in turn pays the host load companies for their participation.
The IESO has indicated strong interest in technologies like these for the power system, and is issuing an RFP in August to select companies and technologies for delivery later this year or early next year. ENBALA is already operational in the PJM Interconnection in the United States. CEO Ron Dizy says that generators there welcome the service, because it allows them to operate their equipment more steadily, rather than ramping it up and down every few minutes, which tends to affect maintenance costs. Conventionally, Dizy says, generators tend to be less welcome to demand balancing services that work on timescales of several hours – that’s a realm where generators could be providing peaking services instead, they say, whereas this short timescale balancing suits them fine.
ENBALA announced June 25 that it has been awarded $1.8 million under the Ontario Government's Smart Grid Fund to help it expand its network. Currently the company has about twenty host companies signed up, and is shooting for ninety in Ontario. The IESO's RFP is likely to be for a total of 10 MW, which is about 10% of Ontario's grid balancing needs, but Dizy believes that loads will provide 50% of all ancillary services within ten years. "We think there is something like 500MW of real time flexibility that is capturable from loads in Ontario," he said.
The company is also using its same platform to do wind integration in the Maritimes; where instead of ramping generation up or down on this kind of timescale to deal with varying windfarm output, its network adjusts loads.
ENBALA’s service as an aggregator of this type is so far unique, Dizy says. The only other comparable service Dizy is aware of is being provided by an ALCOA plant near Chicago, which uses huge amounts of electricity in smelting aluminum, with some 80 or 90 MW of variability, in the MISO power system. There are of course other aggregators on the conventional scale, like Rodan Energy, and in fact Enbala will work with them in approaching customers to offer its particular service.