Wind and solar can reliably supply 25 percent of Oahu's electricity need, new study shows

Mar 17, 2011
This is the Kahuku Wind Project, which was included in the Oahu Wind Integration Study. Credit: Hawaiian Electric Company

When combined with on-Oahu wind farms and solar energy, the Interisland Wind project planned to bring 400 megawatts (MW) of wind power from Molokai and Lanai to Oahu could reliably supply more than 25% of Oahu's projected electricity demand, according to the Oahu Wind Integration Study (OWIS).

For the purposes of the research project, the OWIS released today studied the impact on the Oahu grid of a total of 500 MW of and a nominal 100 MW of solar power, though a good deal more utility-scale and customer-sited solar power is expected on Oahu.

The study found that the 500 MW of wind and 100 MW of solar power could eliminate the need to burn approximately 2.8 million barrels of low sulfur fuel oil (LSFO) and 132,000 tons of coal each year while maintaining system reliability, if a number of recommendations are incorporated, including:

  • Provide state-of-the-art forecasting to help anticipate the amount of power that will be available from wind;
  • Increase power reserves (the amount of power that can be called upon from operating generators) to help manage wind variability and uncertainty in wind power forecasts;
  • Reduce minimum stable operating power of baseload generating units to provide more power reserves;
  • Increase ramp rates (the time it takes to increase or decrease output) of Hawaiian Electric's thermal generating units;
  • Implement severe weather monitoring to ensure adequate power generation is available during periods of higher wind power variability;
  • Evaluate other resources capable of contributing reserve, such as fast-starting thermal generating units and load control programs.
The study notes that assuring reliability will require further studies, upgrades to existing and new infrastructure, as well as specific requirements on the to be connected to the Oahu system. With these and other proposed changes, the technical analysis suggests, Oahu can accommodate increased wind and solar projects with minimal limits on output of renewable resources.

The Oahu Wind Integration Study was conducted by the Hawaii Natural Energy Institute (HNEI) at the University of Hawaii at Manoa, General Electric (GE) Company and the Hawaiian Electric Company (HECO). The National Renewable Energy Laboratory (NREL), part of the U.S. Department of Energy (US DOE), assembled a technical review committee with representatives of industry and academia which met throughout the project to review findings. NREL also contracted the private firm AWS Truepower to develop wind and solar power profiles that were used in the study.

"The findings of this study show it is feasible to integrate large-scale wind and solar projects on Oahu but also have value beyond Hawaii. Both large mainland utilities and relatively small and/or isolated grids that wish to integrate significant amounts of renewable energy while maintaining reliability for their customers can learn from this study," said Dr. Rick Rocheleau, HNEI director.

Projects such as this one that enable increased implementation of alternative energy sources are made possible by the efforts of U.S. Senator Daniel Inouye, Senate appropriations chair, to ensure that the Department of Energy is adequately resourced to make these critical investments in energy technology. Additional funding was provided by Hawaiian Electric Company.

"GE has been working closely with HNEI and HECO to assess innovative solutions to help Oahu meet its with very high levels of renewable resources," said Hamid Elahi, GE Energy Consulting general manager. "GE is proud to be working closely with HECO and other forward-thinking utilities which are leading the industry in solving some of the most important challenges that face our grids."

Robbie Alm, Hawaiian Electric executive vice president, said, "To reach our renewable energy goals we need to use all the resources available to us. For Oahu, this includes the utility-scale solar, roof-top solar, waste-to-energy and on-island wind that we are pursuing. But on-island resources are not enough to meet Oahu's power needs.

"We know that more is possible on Oahu than was studied by the OWIS. However, this baseline study is an essential first step for the Interisland Wind Project. It shows that the technology may present challenges but these can be overcome. The questions now are financing, environmental impact and whether the effected communities can live with the project with community benefits. "

Explore further: Planned cut to renewable energy target 'a free kick' for fossil fuels

Provided by University of Hawaii at Manoa

5 /5 (1 vote)

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NotParker
1 / 5 (3) Mar 17, 2011
"Increase power reserves (the amount of power that can be called upon from operating generators) to help manage wind variability and uncertainty in wind power forecasts;"

Translation: Build more real power plants and have them sit idle 60% of the time to back up the unreliable wind power.

What a waste of money!

Shootist
1 / 5 (3) Mar 17, 2011
Wind and solar can reliably supply 25 percent of Oahu's electricity need, new study shows


And Vulcan is a planet orbiting Epsilon Eridani.
Eikka
5 / 5 (1) Mar 18, 2011

Translation: Build more real power plants and have them sit idle 60% of the time to back up the unreliable wind power.

What a waste of money!


Actually, it's the opposite case. With wind power, the conventional plants would run 75% of the time and dip down to let the wind power into the grid.

That's because the power of wind is to the cube of wind speed, so it ramps up very quickly when the wind picks up. The windmills either turn very little, or a lot.

That's also why you can't really add much wind power to the grid. The nominal power of the windmills cannot exceed the amount of power you can sink into the grid at any given moment. Without a way to store the energy somehow, it is practicallyl impossible to integrate more than about 20% of wind energy into the system.
Eikka
not rated yet Mar 18, 2011
And before you think "Oh well, let's just take 20% of wind power, 20% of solar energy, 40% nuclear..." and so on, you have to understand every other form of energy that you use must conform to the ficklety of the wind.

If you build a large nuclear power plant in order to make use of the economy of scale to gain efficiency and cheap energy, you also get system inertia and the powerplant is then unable to meet the power variation of the wind. It is incompatible.

Same goes for solar energy. The only way you can adjust the output down is to let the energy go to waste. What's the point, if you're going to waste energy at one place so you could produce the same at another? Again, incompatible.

Using wind energy, even just a bit, requires that you make smaller, faster, less efficient and more expensive powerplants that run on fuels like diesel, oil, coal and methane to meet the demand on time.

Wind power doesn't break the addiction to fossil fuels. It makes it worse.
kaasinees
1 / 5 (1) Mar 18, 2011
Not entirely true Eikka. Have you heard anything about wind prediction models?
Eikka
not rated yet Mar 18, 2011
Not entirely true Eikka. Have you heard anything about wind prediction models?


How does that change anything I said?

You can know a year in advance that today at 3 PM the wind is going to blow at 6.89 m/s for exactly four hours and 20 minutes, give or take 15 seconds, and that doesn't solve any of the problems. It still takes something like 6 hours to dial down an average size nuclear reactor or a big coal plant. Of course you could just slam the brakes on the generator and dump the heat into the ocean, but that would be an idiotic solution.

It won't do it in time, so some other powerplant must do it, and if you intend to increase the amount of wind power in your grid up to the point where it will sometimes generate all of the power that you need, then you can't have those big cheap and efficient powerplants.

The only way it works is if you have massive hydro power reserves with pumps to sink power into, or a great big neighbor with a grid massively larger than yours.
Eikka
not rated yet Mar 18, 2011
Of course, based on that criticism, some people then argue that centralized power production is actually a bad thing that we don't want - that it is so precisely because it can't easily accomodate renewable energy into the grid - as if it was not the problem of wind power that it doesn't work.

So, you got the "bloombox" in every basement, or a generator on ever street block like in the Edison days. How are you going to distribute fuel? What fuel are you going to use? How safe it is? How much harder is it to clean the exhaust? How much is it going to cost? How much energy do you lose in doing all this? How do you control the system of a million nodes so you can move energy from one branch to another when one side of the grid is getting more than they need? Is it even possible? Who has the authority to control it? Who owns it?

Do you really want to open up that can of worms?
3432682
not rated yet Mar 18, 2011
If you had nuclear as part of the power generation system, why would you ever want to turn it down? Pointless.
Nichevo
not rated yet Mar 19, 2011
And before you think "Oh well, let's just take 20% of wind power, 20% of solar energy, 40% nuclear..." and so on, you have to understand every other form of energy that you use must conform to the ficklety of the wind.


For those with hydroelectric power wind is a good supplement. I don't know about the efficiency, but excess power could be pumped into the reservoir as well, no?
NotParker
not rated yet Mar 20, 2011
Did anyone notice that GE consulted on the report that recommends wind turbines?

GE sells wind turbines. Conflict of interest.