For those that don’t follow such things, the Ontario Power Authority (OPA) has issued a Request for Qualifications for companies to build a natural gas fired power plant to service northern York Region. Companies can submit a proposal for a plant to be located somewhere in Newmarket, Aurora, King Township, Whitchurch-Stouffville, East Gwillimbury, Bradford West Gwillimbury or Georgina. More specifically, the OPA has identified where the proposed plant must connect into the Hydro One owned transmission system, so you have the expect the proposals they receive will not be too far from those lines.
The OPA are looking for a 350 to 400 Megawatt “peaking” plant, which means certain things to those of us in the industry:
- that it would only run for a certain small number of hours per year, typically during the summer “peak” hours when the air is hot and we all have our air conditioners going.
- that it be a simple-cycle design, which generally means that the plant will be very quick to start but will have an efficiency of 35-40%. (This means that only 35-40% of the energy in the fuel will create electricity. The rest will go up the exhaust stack as wasted heat.)
Jack Gibbons from the Ontario Clean Air Alliance wrote an article in the Era Banner on Tuesday January 29, and made the point that peaking plants are inherently inefficient and that we should be favouring both conservation and a combined heat and power (CHP) plant.
Is Jack correct? Well, yes and no.
First let me say that I fully support Jack in his goals. He wants a closure of the coal plants in Ontario to clean up the air, and he favours higher efficiency over lower efficiency since there are fewer emissions per unit of electricity produced. He also wants Ontario to put much more emphasis on conservation (as opposed to their complete lack of effort) since there is no better efficiency than not needing to generate the electricity in the first place. The emissions from not using power is zero, after all.
However, I think his article only tells part of the story which leads to misconceptions for people not in the industry.
Power plants come in all different sizes, shapes and flavours, from coal to nuclear to natural gas to wind and other renewable energy sources. To make my point here, I’m only considering three different forms of natural gas fired plants.
UPDATE: As a friend at work and one commenter noted, I had a typo here in the efficiencies which I have corrected.
First is Simple Cycle. This is typically one or more gas turbines engines attached to generators. Think of it as an airplane engine strapped to the ground and that’s pretty much it. The rest of the equipment you see is support systems to make it all work, including cooling towers to keep the equipment from overheating. This type of plant is normally 35-40% efficient. The OPA refers to this as a “peaking” plant since it will only be used to meet the peak demand which occurs for few hours per year. So while this type is inefficient, it really won’t run all that often. For the purposes of discussion, assume about 10% of the time, or 800-900 hours per year.
Second is Combined Cycle. In basic terms this is just like simple cycle with the addition of a piece of equipment that uses the hot engine exhaust to make steam which turns another generator. This type of plant can be ~60% efficient, but does not come on line or go off line as quickly since it has to have time for heating up and cooling down, and it’s hard on the equipment to have too many stops and starts. These plants could be built to run full time for weeks at a time, or perhaps they might be intended for 7 am to 11 pm, Monday to Friday.
Third is Combined Heat and Power (CHP) plant. This is just like combined cycle except that some of the heat/steam is used for heating something like an industrial process or a building or a district energy system (multiple buildings). Since the heat is used for something other than steam, they are usually higher efficiency still, in the ~80% range. Typically these are not started and stopped the same way based on electricity needs since someone needs the heat and this need may occur at a different time than the need for electricity. Because of this, the financial operation of these plants is very different.
So when Jack says we should not build a peaking plant in York Region, but instead should build a combined cycle or combined heat and power plant, I agree with him that this would be more efficient, but it’s not really comparing apples and apples. It’s more like apples and oranges. Both fruit, but you get different things out of them.
In Part 2 I’ll talk about peaking vs baseload power, and why the OPA thinks we need a peaking plant here.
[Disclosure: My employer is in the business of building and operating power plants, and would/could be bidding on any proposal that the OPA requests. I disclose this because I don't want to be accused of not really being Green just because we are responding to the requests of the OPA. Whether I personally agree with the OPA, the Supply Mix Directive or not is beside the point.]
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I’m betting that the peak season we are trying to accomodate is probably summer air conditioning season so why don’t we put a solar trough plant on top of various unused toxic sites like the keel dump. I’m not sure how it will work in the dead of winter but long days and sodium storage for night it should cover the summer peak, no carbon.
This quote is misleading, as the most efficient combined gas turbine (Brayton) and steam turbine (Rankin) cycle is 60%. In my opinion, building a simple cycle plant in Ontario is irresponsible. I would support any effort to have this requirement changed. “In basic terms this is just like simple cycle with the addition of a piece of equipment that uses the engine exhaust to make steam which turns another generator. This type of plant can be ~80% efficient”. Anthony Watson
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Thanks. A friend at the office noted this too and I have tried to correct. I wish I could attribute it to a typo, but it’s more like a brain cramp that I did not proof read. Note that this is not meant to be completely accurate, but to give a general range for typical installations. –Glenn
The more I learn about what a 350 mega watt peaker generator really is, the less is I like the idea. If it is not intended to be used and is simply an insurance policy costing hundreds of millions of dollars and the OPA cannot find cheaper insurance then so be it. But if the OPA plans on running it, then it is a bad idea. It uses massive amounts of natural gas per hour of operation and what is worse, 65 percent of the energy created is wasted and simply heats our already over-heated planet.
I am particularly interested in what is happening since I live next door to a potential site. I am not sure that this thing belongs anywhere, but it certainly does not belong next door to my farm on the Oak Ridges Moraine.
I believe we are only getting part of the story from the OPA. Once this plant has been built, it could easily be converted to a combined-cycle which would increase runtime and overall emissions and water consumption. The whole RFQ for North York Region is short sighted by the OPA and we need to take a more responsible approach to cleaning up the air for all of us. We are all vulnerable to smog and this plant will only exacerbate a problem that is already out of control.
While the runtime for this plant may only be about 10% initially, it is safe to say that it would increase over time.
We only have about 50 years of natural gas left in Canada with current demands. Why would we even entertain the thought of wasting it on an application such as this?
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Interesting. While I disagree with a couple of your points, some of them are spot on.
On the issue of run time, we should be clear about how the RFP works and then how the system works after the plant is built, which are two different things. The OPA will determine the evaluation model that they use to compare the proposals. It’s based upon an assumption of the running time, in this case 10%. Part of what needs to be understood is that the OPA is still working toward the long term vision of an open market for electricity generation, similar to the Alberta model. For now we have a market, but compensation is a bit wonky. There are a lot more details, but basically the OPA’s 20 year contract is for the difference between the amount that the generator will make on the market and the amount that is bid in the proposal, which is a number based on the cost of building and operating the plant. This is the Ontario government’s effort to shield consumers from the true cost of power, which the Green Party sees as irresponsible policy.
Once this is all contracted, the generator can run more than 10% of the time if market conditions are such that profits can be made. This could be rare, or it could be more frequent, depending on how things are going elsewhere on the system.
Could the plant be “easily converted to combined cycle”? Yes and no. If the engineers design it right for this eventuality they could leave room in the plant layout sufficient for the new equipment. But since there is no compensation in the contract for changing the design like this, it likely would not happen during the 20 year contract, unless the OPA decided that it needed a different type of plant here say, 10 years down the road. I do believe though that building a simple cycle plant only vs building a simple cycle plant with plans to upgrade to combined cycle would usually, not always, result in a different equipment selection.
On the issue of smog, well, there is a valid argument to be made that this gas plant will produce less smog than the goal fired peaking generation it is replacing. In addition, the emissions from power generation in this region even with this plant will be so overwhelmed by the emissions from transportation, that perhaps we should be looking at the bigger picture. That said, there is no substitute for not generating the power in the first place, but this can only happen if we don’t demand the power through our everyday actions. The problem with this argument is that the OPA has no precedent, ever, from anywhere, to which they can point and believe that power consumption will go down while population increases. Not to mention the fact that the entire energy pricing structure is not promoting a conservation culture.
Your point about natural gas supply is spot on. It is in diminishing supply, increasing demand, and the establishments only answer seems to be that we will build shoreline LNG terminals so that we can use natural gas from other parts of the world. The LAST thing we should be doing is building electricity generation as a user for a diminishing commodity which has other, more beneficial uses.
–Glenn
[...] (see Part 1 here.) [...]