Existing solutions to minimize the negative impact of wind power plants on the grid

[insanoff]

Hi folks,

I would like to know about field-proven solutions for integrating wind energy plants with high wind energy penetration.
What advanced technologies today available, which allow to minimize the negative impact of wind power plants on the grid? It can be any kind of existing electrical or electro-mechanical solutions applied to the grid or wind turbines.
I am very curious what challenges must be overcome to increase its share in electricity production.

Thanks!
Adam

 

[cranky108]

Challenge: Energy storage at the sites of wind farm point of common coupling, with ramp speeds to match total plant overspeed shut down rate.

Challenge: Under voltage and frequency ride through on wind farms.

Challenge: Dynamic var generation.

Challenge: storage of off peak wind generation, or match generation cost with that of generation demand.

Challenge: End-of-life disposal of wind assets, that include tower, and base.

Challenge: Step-up transformer fire plan, to prevent large scale property burns.

Do you need more?

 

[bacon4life]

On the few days a year with too much wind, some countries curtails excess generation. Other places subsidize wind based on kWh produced, even when the spot market price goes negative. These negative prices are then combined with additional government grants to built smart grid battery storage projects.

 

[insanoff]

Yes, of course I would need more. In terms of power engineering points of view first four aspects are important. And I would to know more about the power/electrical engineering side of the problem. There must be also many other solutions, i.e. electrical/mechanical control systems, power dispatching techniques, what tools (rights) grid operator have to regulate wind power plants, how energy system works in countries with high wind energy penetration, or any purpose oriented hardware solutions like e.g. AC-DC-AC inverters etc.

P.S. My purpose is to learn about renewable energy system. I have a knowledge in energy system and its components, but it's quite different when you combine all together, RE and conventional energy. Could you also provide any source where I can get additional information?

Thank you for your time.

 

[IrishPower]

The Transmission System Operator in Ireland, EirGrid, has carried out a number of studies looking at the challenges faced by power systems with high levels of wind/non-synchronous generation. The reports include a number of possible solutions which may be of interest. The reports are available at

http://www.eirgridgroup.com/library/index.xml

- refine by category using "DS3 Programme" and "Technical Studies".

Ireland is a relatively unusual case in that it has very high levels of instantaneous wind power penetration (often > 50 % of system demand) on an AC power system with only relatively small HVDC connections to the rest of Europe. However, some of the challenges and possible solutions may be applicable to islanded power systems with very high levels of wind power, as well as to better-interconnected power systems (at transmission level) where there may still be a lot of smaller wind farms (and other distributed/embedded generation) connected to the distribution system.

Hope this helps!

IP

 

[cranky108]

The biggest issue is that wind is non-dispatchable, like the other energy sources that it is co-operating with. The non-dispatchable nature actually increases the cost and maintenance of other generating sources, which has many in the power industry thinking that wind should paid for at a lowest cost of any energy production. However, the government seems to be in bed with the wind industry in that they demand the wind industry be paid more for that energy.

The dynamic var issue is a common issue with all generation sources.

The end of life issue is important because there seems to be little incentive to repower old wind farms, unless the space is of a premium. In fact other industries are required to set up a fund for disposal cost.

The fire issue in the west is a big issue, and may lead to increased maintenance for exclusion of weed growth around step-up transformers.

 

[jghrist]

End of life disposal issues are interesting and I haven't seen them addressed elsewhere. I would expect that abandoned large windfarms could be a real problem. Sometime in the future, we may come to our senses and quit subsidizing expensive alternative power sources. Without subsidies, it may not be economical to maintain large wind turbines.

 

[HamburgerHelper]

Cranky108,

The cost associated with needing spinning reserves on hand really isn't that much. It is less than a cent per kwh. I will try to find something that shows this but I have seen the numbers.

Ironically, the greater the penetration ,the more wind generation that you have over a larger area, the easier it is to forecast and plan for. Predicting the average wind speed at Amarillo is a lot harder than the average wind speed across the state.

 

[cranky108]

Maybe a bad example, but I have seen a 110MW wind farm go from 110MW to 0MW in five min. Can you get me the cost of spinning reserves with a 22MW/Min. with a 110MW total ramp rate?

As I said a bad example because that 110MW was about 20% of the companies summer peak, and it happened on a Winter night. Yes it was extreme for that company, but that was a real condition.

That cent per kwh would be on top of what is paid for the wind energy.

My point is that many wind farms don't address those issues, or even admit they exist.

Another issue is the voltage profile from changing power and var production levels. This makes the host utility maintenance of voltage regulating equipment increase, along with the associated costs.

Wind companies are like the bad neighbor (with a big dog) that don't maintain their fences. The damage done is not seen as their problem. (and is why some of us in the utility business don't like wind power).
Also the wind industry won't share their equipment models with utility people.

 

[catserveng]

I was involved on a RICE plant that was designed and constructed just for what was described above, it was neither cheap or easy but the end user was pleased with the results, here is a link to a video, note, it was developed by the generator manufacturer after the project completed so it is a "fluff" piece, but it does show the plant and some of what it does.

https://www.youtube.com/watch?v=FYsPrYLcan0&feature=em-subs_digest

If you prefer not to watch the video, the site is the Rubart Station for Mid-Kansas Electric, a google search provides more info.

MikeL.

 

[cranky108]

I wonder how many times they can ramp up, then back down as the steam and gas turbine units take over?

That's the big issue with SPP's vision of 1 GW of wind in that area of Kansas, Oklahoma, and Texas. The utilities don't have the resources to counter-balance the wind power that is intended to be exported, let alone the transmission resources. Most of what was built was to serve the customers, and not much more.

Strange we go back to IC engines for speed.

 

[HamburgerHelper]

Cranky,

"Wind companies are like the bad neighbor (with a big dog) that don't maintain their fences. The damage done is not seen as their problem. (and is why some of us in the utility business don't like wind power).
Also the wind industry won't share their equipment models with utility people."

I don't know where you are from but I believe this is all shared, in ERCOT at least. The people who do the dynamical studies at the utility I am with use VSAT and they get the modeling of the turbines from the customer who get it from the manufacture. I have seen interconnection studies carried out by third parties for SPP that include the turbine information for determining need and sizing an SVCs. For short circuit stuff I have done, I have been given the entire wind farm design drawings or an ASPEN model of their entire collector station.

 

[cranky108]

Not all of the grid operators have had the problems that ERCOT has had. So not all of them share the burden of the problems evenly.
Also not all of the transmission planners, who are the ones that talk with the wind developers, communicate with the protection people very much about the type of units.
It leaves the protection people to guess what type of equipment is attached to their systems.

The planners also did not know about the capacitor switching off on low voltage, which made fault recovery somewhat slow (what a shock the planners had).
Always ask about how the var support switching orders.

I now work with younger planning engineers (at a different company) who communicate much better, but lack some years. So things are getting better.

 

[cuky2000]

Integration of large scale wind power may have severe impacts on the power system operation such as frequency and power control, reactive power compensation and stability support.
The good news is that there is available power electronic based technology to solve or mitigate some of the new challengers with the win penetration.
There is indication that the wind penetration in the US energy market is a fact that we need to be prepared to address
We can choose to be opposed to the new challenger with renewable power or add new knowledge to address the new challengers in the power industry.

 

[cranky108]

I'm not opposed to wind power, but I am opposed to the government choosing wind power as a best renewable technology.
Yes ignore the problems, and it is almost perfect enough to throw money at it.

If you look at the present grid with no wind, then the present grid with 100% wind, and knowing the optimal amount is somewhere in between. What is the difference?
What is the point where the grid must change to work with more wind, and why should not the wind developers be paying for those changes? And is it really good to pass those costs to the utility customers?

Besides as you add more wind power, does that not slow down the wind? And if it slows down the wind, is that not causing climate change?

 

[LionelHutz]

Around here, the government throws big money at wind projects no matter where they are sited. By most standards, the wind in this area is considered poor to barely fair (around 4-5 m/s average wind speed) yet the wind companies are being very aggressive trying to get permits and leases to install wind farms. Most people just simply don't realize that wind power is proportional to the cube of the wind speed and likely equate it to being more like a direct ratio. Drop the wind speed to 1/2 of the turbine rated speed and you get about 1/8th of the rated output. But, this is a different problem then what was asked.