The Ontario Power Authority plays a major role in maintaining the reliability of the power system, complementary to that of the Independent Electricity System Operator, in that it is charged with making sure that future supplies meet anticipated future demand. Both organizations are governed by the same NERC reliability requirements, and as a result they use the same criteria to evaluate generation and transmission assets. Of the two, however, the OPA focuses more on the longer term and the need for investment in new resources rather than operation and maintenance of existing resources. But there is no hard and fast point of delineation between those timeframes, explains Bob Gibbons, Director of Resource Integration, in the Power System Planning group at the OPA. They try to use the same data set in both their forecasts. The two share information regularly.
To get the OPA’s side of the matter, APPrO conducted an interview with Bob Gibbons and Bob Chow, Director of Transmission Integration at the OPA.
The first question is one everyone will want to hear the answer to:
Will there be enough gas to do what coal used to do, in all its respects, out to 2014 and past (disregarding the questions about what happens long-term with nuclear)?
Bob Gibbons: We expect to have sufficient gas-fired resources, along with renewables and conservation, to more than cover the capacity reduced by the coal shutdown, out to the shutdown date and past. We’ve done a fairly rigorous assessment. We’ve done our sums. And that includes meeting regional demand in all parts of the province.
The OPA is procuring capacity in several categories for supply mix reasons, adequacy reasons, reliability requirements. How do reliability contracts differ from supply contracts? Also, a contract specifically for supply can provide reliability as well. Is there a distinction in the contracting process?
BG: Most procurements under the Clean Energy Supply (CES) program, and the peaker contracts, have a reliability component to them. They contribute to overall system reliability, and in many cases, local area reliability as well.
The IESO itself procures the Reliability Must-Run (RMR) contracts, with the Lennox plant the only extant example (that in fact expired in the fall of last year), procured to ensure reliability in eastern Ontario. By definition, these RMR contracts last only a year. These have particular financial and market-related provisions.
Dispatch of RMR is based on system conditions, rather than market price?
RMR resources are normally dispatched on market price, but there are conditions when an RMR resource could be operated out of merit, specifically for reliability reasons, though most of the time it would not need to.
When the OPA procures gas-fired resources for local area reliability, is the contract any different from a standard CES contract?
BC: In most of the local-area gas projects, there is both a system need and a local area reliability need driving decisions on the location of the plant. If there is a need to operate under contingency conditions in the local area, when the grid isn’t capable of supplying all the power needs of the area, a specific contract requirement would be included to require the gas-fired generating plant to be online relatively quickly to address that concern.
The OPA works with the IESO on determining the various technical requirements; for example, ramping rates, or unit output minimums at a given temperature, like a hot July afternoon. Such terms are built into contracts on a case-by-case basis. It’s the same as building a transmission line to particular temperature and voltage requirements. It’s very hard to standardize all the functions in any of the major facilities to meet the many specific needs we face across the system.
What are the special conditions in a generation contract that are likely to be reliability-related?
• Ramp rate requirements
• Ability to maintain load while islanded or connected to the grid through a low-voltage connection
• Ability to maintain frequency without frequency support from the grid
• Voltage requirements
• Excitation requirements
• Black start requirements, if needed.
The IESO will be involved in each major contract, to specify the exact requirements. It’s very interested in ramp rates, for example.
In certain cases, generators may be expected to be capable of operating in off-nominal frequency circumstances. For example, although this situation is rare in Ontario, generators that need to operate in an islanding situation may have to be capable of operating within some deviations from 60 HZ, i.e., off the nominal frequency. Generators that are not required to be operated in an electrical island situation may not need to have a specification for a wider band of operating frequencies and thus may be able to avoid that cost in their design.
Do special, reliability-related provisions in the generation contract have different time periods than the usual 20-year term for the supply itself?
BG: The OPA’s contracts are pretty much supply contracts with, occasionally, special reliability-related conditions, though every major project is an individual case.
What happens to the scenarios in the Integrated Power System Plan, released in 2007, now that the GEA and the FIT program have changed the way at least that renewable sources enter the picture?
BG: Now that the amount of renewables being brought in is greater than that envisioned under the IPSP, and is determined by the FIT program, we can’t use specific estimates. Instead, we look at scenarios, to ensure the flexibility in the resource mix to accommodate the outcomes from the FIT.
BC: In the IPSP, the OPA was proposing new transmission to accommodate renewables based on estimates of potential and where they might be. In a way the FIT Program gives us better information about likely development of renewables, because people are now coming forward, expressing their interest and starting to make actual commitments. Now the OPA has a better idea, at least over the near- to mid-term, of what facilities are being planned for, where, when and how big.,Analyzing the “pipeline” of FIT applications, in the case of wind generation, may give a firmer picture of developments than that based on potential studies.
What then is the OPA doing to reinforce reliability given the FIT Program? What is the range of initiatives?
BG: We are looking at the role that gas-fired resources will play in the future, and the role for storage, what kinds of flexibility, dispatchable resources and ancillary services will be on the system.
BC: This includes the build-out on the transmission system to integrate the FIT resources. Together with the IESO we are also looking at special control devices, such as static VAR compensators (SVCs) to control voltage fluctuations as result of these intermittent resources. (See backgrounder on SVCs below.)
Does the OPA anticipate getting reliability services from renewables?
BG: We are looking at 8-10% of total installed capacity being “dependably” available from wind generators when called upon, largely based on their wide geographical dispersion across the province. This is part of the assessment the OPA does when it’s looking at resource adequacy over the longer term, working very closely with the IESO in terms of the data and methodology used. As for solar, the data are very limited still, and as more data come in we will be better able to assess its contribution.
Once OPG completes the conversion of units from coal to biomass, will it then have to apply for an OPA contract for those units?
BG: That’s my understanding.
Has the OPA assessed the reliability characteristics of biomass units compared to the same units being fired by coal?
BG: There are a couple of impacts. For some of the units the output will be reduced. Also the energy they can put out will be limited by the availability of biomass fuel. So the OPA takes that into consideration. As for other technical characteristics, the OPA is relying on information OPG is providing: they’re saying there should be no degradation in performance, other than what’s just been mentioned. The ramping rate, for example, should be the same, albeit reflecting the reduction in total output.
Is there an interest in storage, either bulk or for ancillary services like frequency support?
BG: We’re considering it. At the moment there’s no procurement program for it.
What about flexible AC transmission systems, new transmission technology, smart grid developments: Do these have any relevance to reliability?
BC: the OPA tries to keep in touch with technological developments like that. For example, there are new conductors (wires materials) that don’t sag as much under high current and temperature. Given that current limits are often set by sagging, new conductor materials could allow more power to flow through the same circuits. The issue is always cost and the most appropriate technology for specific applications. The OPA looks at what it can do to use the existing system more efficiently whenever it takes on a new project. This isn’t specifically under the heading of reliability, but when building a new line, it asks how to push more power through the system without degrading its reliability, through the use of new technologies.
For example, Hydro One is using series capacitors on the north-south line between Sudbury and the GTA, something new for Ontario. These will go into service in the next few years. Series capacitors are inserted in series with the line that you wish to compensate, Chow explains. “The net effect is to make the compensated line look electrically shorter. That would improve stability and voltage performance. However, series capacitors introduce some technical challenges such as subsynchronous resonance that impacts negatively on generators and will need careful engineering to avoid.”
The OPA is also in the process of installing Static VAR compensators (see backgrounder, opposite) to manage the voltage issue that will arise in southern Ontario when Nanticoke is shut down. This is also a new application of the technology. OPA’s part in this is to identify the need, look at the options to find an economic solution, and if required, support Hydro One’s seeking of approval to the OEB.