US DOE finalizes $43 million loan guarantee for (20 MW) flywheel project (NY)

[jpak]

http://www.platts.com/RSSFeedDetailedNews.aspx?xmlpath=RSSFeed/HeadlineNews/ElectricPower/6284123.xml

The US Department of Energy finalized Monday its third clean-energy
loan guarantee, closing a $43 million deal with Beacon Power for a 20-MW
flywheel energy storage facility in Stephentown, New York.

"This project demonstrates our ongoing commitment to helping bring clean
technologies to market," Energy Secretary Steven Chu said in a statement. "We
will continue to support the development and deployment of innovative energy
systems like this energy storage project that support our goal of expanding
renewable energy generation and reducing greenhouse gas emissions."

Boston-based Beacon said its Gen 4 flywheel system can store and quickly
release wind energy into the grid, which can help balance power generation and
consumption.

Flywheels are devices that store energy that can later be released to
generate electricity.

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[tridim]

1. Finally my giant flywheel idea comes to fruition!

I've been pitching it to skeptical friends for about 20 years now. :)

[NoNothing]

2. I wonder how much energy it will store.

I read the article but it doesn't seem to say.

[tridim]

3. All of it, minus friction.

Flywheels are very efficient, something like 80%.

If we ever get a space elevator we can put them in orbit and get 99% efficiency.

[NoNothing]

4. Yeah, that's obvious

I meant quantitatively, how much energy. Some ballpark numbers.

[tridim]

5. 20mw or 20 million watts.

The Hoover Dam produces about 1500mw.

[NoNothing]

6. That's a unit of power, not energy

All that really tells us is how quickly it accept and release energy. It doesn't tell us for how long it can maintain that power level. 20 MW for 1 second? 1 hour? 1 week? I have no idea.

[tridim]

7. It can store 20 MW.

I'm not sure how else it can be measured?

There will always be a draw on the output, so I'm not sure it really matters. It's just an efficient way of storing energy before it's delivered to customers.

This may help: http://en.wikipedia.org/wiki/Flywheel_energy_storage#Advantages_and_disadvantages

Physical characteristics For the basic physics of a flywheel, see Flywheel Physics.

Compared with other ways of storing electricity, FES systems have long lifetimes (lasting decades with little or no maintenance<2>; full-cycle lifetimes quoted for flywheels range from in excess of 105, up to 107, cycles of use)<4>, high energy densities (100-130 W·h/kg, or 360-500 kJ/kg)<4><5>, and large maximum power outputs. The energy efficiency (ratio of energy out per energy in) of flywheels can be as high as 90%. Typical capacities range from 3 kWh to 133 kWh.<2> Rapid charging of a system occurs in less than 15 minutes.<6> The high energy densities often cited with flywheels can be a little misleading as commercial systems built have much lower energy density, for example 11 W·h/Kg, or 40 kJ/kg.<7>

[NoNothing]

8. Energy is power times time

So it is typically measured in Kilowatt-hours or Megawatt-hours. That's what your electricity meter measures. The power rating tells you what kind of "oomph" it can supply, but the energy rating tells you how long it can do that.

(Power plants are often rated by their power capacity only because the assumption is that they will generate as much energy as possible by operating as much of the time as possible. A flywheel does not *generate* energy, however, it *stores* it like a battery, so its rating should, like a battery, be given in terms of energy, not power.

[Kolesar]

9. One kWh is equivalent to exactly 3.6 million joules

http://en.wikipedia.org/wiki/Energy#Units

Units

Main article: Units of energy
Throughout the history of science, energy has been expressed in several different units such as ergs and calories. At present, the accepted unit of measurement for energy is the SI unit of energy, the joule. In addition to the joule, other units of energy include the kilowatt hour (kWh) and the British thermal unit (Btu). These are both larger units of energy. One kWh is equivalent to exactly 3.6 million joules, and one Btu is equivalent to about 1055 joules.<16>

[NoNothing]

10. Yes

My question is how many joules - how many kWh - this flywheel will store.

[skids]

12. IIRC the array will be 5MWh, technically

Nameplate capacity is based on a 15 minute discharge, if I remember correctly from when I looked it up. I think it's an array of 24KWh flywheels.

As to whether those really like to be discharged to full depth, I do not know. Not really important as they obviously size it for its intended application. But the company is looking towards storage as well, longterm, if they can get their costs competitive with chemical batteries -- right now they are taking advantage of the premium their fast response time can demand on the frequency regulation market.

[txlibdem]

11. I had to go to the source for this information

The answer to the question, "how much energy will it store," is that the question has no answer. The flywheel won't store the energy like a battery. According to the Beacon Power website, the flywheel will be used for "frequency regulation."

The Stephentown plant is the first of its kind in the world. Its flywheel systems will provide frequency regulation services to help stabilize and enhance the performance of the New York power grid and enable greater use of renewable energy sources like wind and solar. The flywheel plant's emissions-free operation will also significantly reduce CO2 levels compared to fossil fuel-based regulation methods used today. At 20 MW, the facility will provide approximately 10% of New York's total frequency regulation capacity on a typical day. As more intermittent renewable energy resources are added to the grid, the regulation market is expected to grow.

The $43 million loan is funded by the U.S. Treasury's Federal Financing Bank, and covers 62.5% of the plant's estimated $69 million cost.

http://phx.corporate-ir.net/phoenix.zhtml?c=123367&p=irol-newsArticle&ID=1457909&highlight=

What in the world is frequency regulation good for?

Flywheel Energy Storage and Frequency Regulation

Frequency regulation is an essential grid service that is performed by maintaining a tight balance between electricity supply and demand. Beacon's 20 MW plant has been designed to provide frequency regulation services by absorbing electricity from the grid when there is too much, and storing it as kinetic energy in a matrix of flywheel systems. When there is not enough power to meet demand and frequency falls below desired limits, the flywheels inject energy back into the grid, thus helping to maintain proper electricity frequency (60 cycles/second).

http://phx.corporate-ir.net/phoenix.zhtml?c=123367&p=irol-newsArticle&ID=1457909&highlight=

Well that still didn't explain it well enough for me. So, back to Beacon Power's website:

Frequency Regulation

To ensure a functional and reliable grid, the Independent System Operators (ISOs) that operate the various regional grids must maintain their electric frequency very close to 60 hertz (Hz), or cycles per second (50 Hz in Europe and elsewhere). When the supply of electricity exactly matches the demand (or "load"), grid frequency is held at a stable level. Grid operators, therefore, seek to continuously balance electricity supply with load to maintain the proper frequency. They do this by directing about one percent of total generation capacity to increase or decrease its power output in response to frequency deviations.
What is frequency regulation?

Not all generators can operate reliably in such a variable way. Changing power output causes greater wear and tear on equipment, and fossil generators that perform frequency regulation incur higher operating costs due to increased fuel consumption and maintenance costs. They also suffer a significant loss in "heat rate" efficiency and produce greater quantities of CO2 and other unwanted emissions when throttling up and down to perform frequency regulation services.

http://www.beaconpower.com/solutions/frequency-regulation.asp

There's a video at that link that seems to explain it quite well.

[NoNothing]

13. Thank you for the effort!

That was very interesting, I appreciate it. It sounds sort of like they are using it as an enormous capacitor.

[txlibdem]

14. That's a good analogy

Sounds just like a capacitor.

[skids]

15. Though to pick nits...

These present an inductive profile, as opposed to capacitive like a battery bank would. Rather important difference in the complimetary capabilities they present. Capacitors can throw a lot of current when the voltage dips. Flywheels can throw a lot of voltage when the current dips. Not sure exactly how these are tied in so it may not make much of a difference other than the cost of the components to tie them in.

[Massacure]

16. Wouldn't voltage be more important than current?

Granted the two are linked by P=IV, but transmission lines transmit electricity with elevated voltage and reduced current to minimize loss. Is the energy lost to friction in the flywheel less than the losses by converting a raising the voltage/lowering the current of the power stored in the capacitor?