Integrating Wind and Hydro Power in Quebec

March 10, 2009, 8:35 am
Integrating Wind and Hydro Power in Quebec
By John Lorinc

Reuters; Businesswire

Can wind and water be combined to reliably produce clean power?
When Hydro-Quebec begins construction next summer on the 1550 MW La Romaine hydroelectric dam, the $2.8 billion-a-year utility will be simultaneously developing smart grid control and load forecasting technologies aimed at integrating hydropower with Quebec’s fast growing inventory of wind farms.

“Hydro-Quebec wants to be a world model for the safe integration of wind and hydro in a major electricity system,” said Louis-Olivier Batty, a spokesman for the company.

The $6.5 billion four-dam project will be completed by 2020, but the first one will come on line in 2014.

To prevent power fluctuations in the grid, intermittent renewables like wind need to be matched with highly flexible base-load sources that can be adjusted rapidly as weather patterns shift. Such load-balancing techniques, said Sean Whittaker, the vice president of policy for the Canadian Wind Energy Association, are difficult to achieve with coal or nuclear plants because their energy output can’t be modulated.

“They like to run at 100 percent or nothing,” Mr. Whittaker said.

But renewable energy advocates have long argued that in regions like the Pacific Northwest, wind and hydro are natural allies because hydroelectric plants can be powered up when the winds taper, and dialed down when it’s gusty, creating a reliable, all-renewable energy platform.

“You’re using the water in the reservoir as a giant battery,” Mr. Whittaker said.


More than 95 percent of Hydro-Quebec’s power comes from massive — and controversial — dam projects. But the Quebec government has asked private energy companies to supply 4,500 megawatts of wind power by 2015, equivalent to 10 percent of the province’s energy supply. In the past few years, numerous wind farms have been established in the Gaspe region, south of the St. Lawrence River.

While hydro electricity doesn’t produce emissions, large hydro dams inflict a heavy ecological toll up-river and have often attracted stiff criticism from environmental groups.

Some hydro-based utilities, like the Bonneville Power Authority in Oregon, have been receptive to calls from renewable energy advocates to promote wind energy.

Others, like B.C. Hydro, have been much slower to recognize the synergies, Mr. Whittaker said. In the case of Quebec, in fact, the policy initiative came from the provincial government, not the utility itself.

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1. March 10, 2009
9:11 am

Another possible wind/hydro coupling is Manitoba Hydro and wind in the Dakotas. There are large projects proposed for the Nelson River (e.g., the 1,400 MW Conawapa Project) that, combined with the BiPole 3 power line, could provide a large amount of renewable energy with the ability to swing power to match wind outputs. The Manitoba dams are not without controversy and neither is the additional proposed power line (Manitoba Hydro already exports a lot of power to the Upper Midwest through BiPole 1 and 2). At a minimum, they need to finalize licensing for the existing dams with the First Nations, although the Wuskwatim Project (with First Nation participation) may be a good model for cooperation.

But there are a number of positive aspects of the Manitoba Hydro/Great Plains wind strategy. First, the proposed dam lies between two existing large dams on the lower Nelson River and would simply exploit the additional change in river elevation between the Limestone and Gillam dams. Second, the Great Plains have some of the highest wind power potentials of any on-shore resource on the planet. Lastly, both resources (wind and hydro) could be offsetting one of the dirtiest, most coal-dependent areas of the nation’s grid. States in the Upper Midwest are very coal intensive, ranging from about 50% (Illinois) to 70% (Wisconsin) to nearly 100% coal-powered (Indiana), and are a critical region for addressing carbon dioxide emissions..

Peter Taglia

— PT

2. March 10, 2009
11:02 am

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The economic and environmental benefits of marrying wind to reservoir hydro are very clear when you have an existing reservoir hydro facility - it is in fact the only reason that Denmark has been able to expand their wind fleet as far as they have done. On the other hand, it is well settled that there is almost never an economic case for the construction of new “greenfield” reservoir hydro facilities for the purpose of balancing wind power - the power density of dammed hydro is simply too low, the cost too high and relative timelines completely out of synch. The environmental degradation from the creation of the reservoir - both from habitat destruction and from the release of CO2 and methane associated with most reservoir hydro projects - would also offset considerably any benefit to be gained. It would be a shame to see “fixing the wind problem” used as an excuse for the unjustified damming of more river systems. And by the way, Mr. Whittaker of CWEA reinforces the low credibility of the wind industry in talking about these issues, with his comments about the inability of coal plants to modulate their output. Nothing could be further from the truth. In fact, coal plants scheduled to operate at part-load, in order to be ready to provide system balancing services, is one of the most common methods of doing so. Many, if not most coal plants operate quite close to full-load efficiency down to about 50% of rated load, and they are frequently expected to do so. There is a reason the wind industry is not taken seriously by many people in the energy industry, and statements like this only reinforce that perception.

— Michael Hogan

3. March 10, 2009
12:04 pm

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Sure, La Romaine’s hydro complex was controversial, but not as much as the abandoned Suroit combined cycle turbine project Hydro-Québec was pushing 5 years ago.

Of course, major hydro projects have consequences on host rivers ecosystems — the environmental assessment for the project is here ( http://www.hydroquebec.com/romaine/documents/etude.html ) –, but a project such as La Romaine also has its advantages.

This hydro project will deliver a massive 8.5 TWh a year of energy for 50-100 years for a low energy investment — the EROEI is 200 to 1. Quebec’s reliance on hydro in the last 50 years helped stabilize our GHG emissions at 1990 levels, it reduced the use of foreign oil and generated a steady flow of revenue (C$2.1 billion in 2007) for the provincial government, Hydro-Québec’s sole shareholder.

The positive impacts of these large-scale hydro projects already have positive repercussions south of the border. Vermont gets one-third of its power from Hydro-Québec — and has the lowest per capita carbon footprint in the US. La Romaine dams and various wind projects in the northeast will reduce the region’s reliance on coal-fired generation without compromising the reliability of the electric supply in New York, New England and Ontario. What’s not to like?

— ClaudeB

4. March 10, 2009
5:33 pm

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Another reason why we need a national High Voltage DC transmission network. The only HVDC in the US is the Pacific DC Intertie running from Oregon to Los Angeles.

— D Sakarya

5. March 11, 2009
12:29 am

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Michael Hogan,

While Mr. Whittaker of CWEA exaggerated when he says coal plants like to run at “100% or nothing ” there is absolutely no dispute that large steam cycle power plants have longer ramping times and are less efficient at partial loads.

A recent 300 MW CFB application in Wisconsin (Alliant Energy’s Nelson Dewey 3 Proposal) with a conventional subcritical steam cycle had a heat rate of approx. 9,764 btu/kWh at full load (HHV), increasing to approx. 11,435 btu/kWh at 50% load (CPCN application, page NED 112, Wisconsin PSC). Thus, a nominally 35% efficient plant requires over 17% more fuel to produce each unit of electrical energy at half load than at full load. It takes much longer for these plants to ramp up or down than hydro or natural gas combined cycle plants, with the more efficient supercritical pulverized coal plants requiring even more time to cycle. Finally, in the coal-dominated Midwest, plant dispatch under the security constrained economic process administered by the Independent System Operator tends to result in the largest units operating at 100% output most of the time while the smaller, even less efficient, coal plants vary output on a more diurnal cycle following the load. These inefficient coal plants, and their associated noxious emissions, are a huge problem.

One coal plant in the state, the 1,200 MW Pleasant Prairie unit owned by Wisconsin Electric and built in the early 80’s, was designed to load follow under a future scenario where baseload nuclear plants (steam plants that dislike cycling even more than coal plants) dominated the grid. Unfortunately, that plant operates at full bore most of the time and the same physical attributes that made it more amenable to cycling (thicker boiler tubes, etc.) make it even less efficient (heat rates of almost 11,000 btu/kWh). Low efficiency also equals even greater cooling water requirements- another major stress to our water resources.

Peter Taglia

— PT

6. March 11, 2009
10:37 am

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Peter,

Nothing you’ve said negates my original point. The vast majority of coal plants are PC (pulverized coal) units, not CFB (circulating fluidized bed), and PC steam power plants are much more efficient at part load than CFB plants - that’s one of the reasons CFB technology did not become more widespread. Secondly, the ramp rate for a PC steam plant to go from say 60% load to 70% load is plenty fast enough for most system balancing services, perhaps not as fast as a reservoir hydro facility but more than fast enough to deal with the rate at which wind production can be expected to fluctuate. Thirdly, you can always find the odd plant that has been configured incorrectly for it’s actual service, or which sees service modes that have evolved over time away from the originally intended service, but the same cannot be said of thermal steam plants in general. Finally, I did not try to claim that we should continue to rely on coal plants for system balancing, or that there was any good reason to build new coal plants at all - I think new coal construction should be banned altogether, and I think existing coal plants should be completely remediated or phased out entirely by 2030 if not before. I was simply pointing out that most wind advocates base their various claims, and indeed their very business models, on a fundamentally flawed understanding of the prevailing power system model and the technical requirements of operating it carbon-free, reliably and affordably. One of those common misunderstandings is that coal plants are inflexible (”they like to run at 100% or nothing”), which is simply not true. Mr. Whittaker’s comments reinforce that point, and you have offered nothing that would alter the basic conclusion.

— Michael Hogan

7. March 11, 2009
10:31 pm

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I dug around and found perhaps the best demonstration of how poorly coal plants deal with wind fluctuations: the prevalence of minimum generation events that occur in the Western part of the MISO grid during periods of high wind output. See the days around Feb. 10th at http://www.midwestmarket.org/page/Real-Time+Notifications+Archive). The resource mix in this area (MN, IA, ND, SD) is dominated by coal and wind. It would be useful to put together a presentation showing the transmission topology and wind data for these events…. There are a lot of issues associated with bidding any unit into the MISO market, but coal steam plants have some issues with output set-point scheduling that add inefficiency to the market. This generally reinforces the point that the wind advocate made about coal and wind, albeit his characterization was a bit too strong.

Another reference would be from Xcel Energy, the utility with the greatest wind penetration in the U.S., gives a good description of coal and wind in Chapter 7 of their 2007 MN/WI Resource Plan:

“Beyond consideration of capital, O&M, fuel and emissions costs, we are also concerned that coal technology may not offer sufficient dispatch flexibility to handle the growing magnitude of fluctuations in wind generation on our system as the RES is fully implemented over the course of the planning period. Coal units typically have ramp rates that are in the range of 1% to 1.5% of their nameplate rating per minute between minimum load and maximum load set points. Coal unit minimum load set-points range from 20% to 50% of nameplate, depending on the design of the air quality control system being used. For example, a 500 MW coal plant may have a minimum load of 100 MW and would be able to ramp up at the rate of 5 MW per minute. In addition, it can take a day or more to bring a coal plant up to full load from a cold start condition. Natural gas-fired combustion turbines, on the other hand, can normally be at full load from a cold start in 10 to 30 minutes (which results in an effective ramp rate of 3.3% to 10% of their nameplate rating per minute).”

Peter Taglia

— PT

8. March 12, 2009
11:53 am

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Peter,

I will reiterate the points I made:

1) building wind farms in places where they can take advantage of the balancing services available from existing reservoir hydro facilities makes perfect sense.

2) no one should assume that new river systems should or will be dammed for that purpose - it makes neither environmental nor economic sense to do so; there is some re-powering that can be done at existing facilities to expand their production capacity, but that is about all that is likely to happen.

3) Mr. Whittaker was wrong about the ability of coal plants to operate in system balancing mode and about the frequency with which they do so; it is a claim often made by wind power advocates and only reinforces the largely valid perception that they are not particularly knowledgeable about or concerned with the specifics of what will be required to accommodate them on the system.

The gas turbines referenced in the Xcel citation are simple cycle gas turbines with a 32% efficiency. They are and should only be expected to run for less than 200 hours per year, and only on a limited basis. Xcel knows full well that for a much larger penetration of wind requiring many more hours of balancing service they will need to rely on combined cycle gas turbines with much higher efficiency in order to avoid significant rate increases to their customers, and combined cycle plants have ramping rates that are much more comparable to those of coal plants.

As I said before, the fact that coal can and does customarily provide load-following service does not mean that we should continue to rely upon it to do so. But I stand by my original points.

— Michael Hogan

Some technical jargon at the end that lost me in the process but generally a pretty cool setup of wind and hydro-electric power. As the wind fluctuates the hydro-eletric source has to be able to adjust accordingly to the demands made. Both clean, and cheap.