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Thursday, July 24, 2014

Flywheel

The most powerful flywheel energy storage systems currently for sale on the market can hold up to 133 kWh of energy


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Back to Energy Storage Index
1. Background

2. Acronyms/Definitions
3. Business Case
4. Benefits
5. Risks/Issues
6. Case Studies
7. Companies
8. Links

1.Background
  • Flywheels are based on mechanical inertia. A heavy rotating disc is accelerated by an electric motor, which acts as a generator on reversal, slowing down the disc and producing electricity. Electricity is stored as the kinetic energy of the disc. Friction must be kept to a minimum to prolong the storage time. This is often achieved by placing the flywheel in a vacuum and using magnetic bearings, tending to make the method expensive. Larger flywheel speeds allow greater storage capacity but require strong materials such as composite materials to resist the centrifugal forces.

  • The flywheel provides power during period between the loss of utility supplied power and either the return of utility power or the start of a sufficient back-up power system (i.e., diesel generator). Flywheels provide 30 seconds of ride-through time, and back-up generators are typically online within 5-20 seconds.

  • Traditional flywheel rotors are usually constructed of steel and are limited to a spin rate of a few thousand RPM. Advanced flywheels constructed from carbon fiber materials and magnetic bearings can spin in vacuum at speeds up to 40,000 to 60,000 RPM.


2. Acronyms/Definitions
  1. Angular Instability - A low-frequency (usually less than 1 Hz) undamped power fluctuation traveling from one end of a power grid to the other end. This traveling wave cannot be easily damped and can take up significant capacity on transmission lines.
  2. Energy Recycling - The ability to use braking power from one train to move another or capture energy generated in a shipyard crane’s lowering cycle to lift the next container.
  3. Frequency Regulation - Electric frequency must be maintained 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.
  4. RPM – Revolutions per Minute
  5. UPS – Uninterruptible Power Supply


Beacon's Smart Energy 25flywheel's rotor assembly is sealed in a vacuum chamber and spins between 8,000 and 16,000 rpm. At 16,000 rpm, the surface speed of the rim would be approximately Mach 2 - or about 1500 mph - if it were operated in normal atmosphere so the rim must be enclosed in a high vacuum to reduce friction and energy losses. To reduce losses even further, the rotor is levitated with a combination of permanent magnets and an electromagnetic bearing. (Beacon filed for bankruptcy on October 30, 2011)



3. Business Case
  • Flywheel-based energy storage systems, unlike fossil-fuel power plants that are used on the grid for frequency regulation, are sustainable "green" technology solutions that consume no fossil fuel, nor produce CO2 or other emissions during operation.
  • Additional Regulation is required for 33% Renewable Portfolio Goals
  • Economics of 10MW Flywheel
    1. Capital $3360 – 3920 per kW
    2. Variable $1340 - 1570 per KWh
    3. Hours 0.25
    4. Total Cost $3695 - 4313 per kW
      $kW + (Hours x $/kWh)


4. Benefits
  • Frequency Regulation – Flywheels are designed to smooth out transient fluctuations in load and supply, 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.

  • UPS Protection - Flywheel storage is also currently used to provide UPS systems (such as those in large datacenters) for ride-through power necessary during transfer - that is, the relatively brief amount of time between a loss of power to the mains and the warm-up of an alternate source, such as a diesel generator. As a replacement for battery-based UPS systems, flywheel technology has the advantage of being virtually maintenance-free compared to maintenance-intensive and less-reliable battery-based UPS.

  • Angular Instability Control - If the low-frequency oscillation could be damped, the transmission line capacity could be restored making it easier to relieve congested lines or reduce possible grid instability. In the past, this type of instability has been linked to wide-scale regional blackouts costing billions of dollars in lost productivity, goods and services. A flywheel energy storage system, combined with phasor measurements and an integrated communications and control network, has the potential to overcome this vulnerability and prevent such blackouts.

  • Railway Voltage Control – As the spacing between trains decreases, rail systems become more prone to voltage drops that impair performance and reliability. While substations can be upgraded to add power conditioning equipment, space constraints and the related difficulty of increasing local power distribution can make it very costly to upgrade some substations. Flywheels can boost voltage when necessary.

  • Very High Burst of Power - Applications that require very high bursts of power for very short durations use flywheel power. Examples include Tokamak and laser experiments where a motor generator is spun up to operating speed and may actually come to a stop in one revolution.

  • VAR Support - Reactive power support can be provided on either a unitary or small-system basis, or as a secondary overlay application for a full-scale 20 MW frequency regulation power plant. For industrial and commercial end users, potential benefits include lower fees from utilities resulting from improvement of power factor levels that would otherwise fall below specified minimums, as well as higher power quality for sensitive industrial and commercial applications. For grid operators or utilities, potential benefits include the ability to defer investments in transmission and/or distribution infrastructure.

  • Adaptabilty - Compared to sustainable energy storage solutions such as molten salt, flywheels may also be more portable and site-adaptable. They are also highly durable and they are already starting to pop up in some high stress environments.



5. Risks/Issues
  • Scale – A flywheel generally only provides 15-30 minutes of duration. The ranges of power and energy storage technically and economically achievable tend to make flywheels unsuitable for general power system application.
  • Cost - Price is a legitimate concern –but performance characteristics and emission benefits provide compelling motivations for particular applications.


6. Case Studies

  • Flywheel technology has been implemented by EDA in the Azores on the islands of Graciosa and Flores. This system uses a 18MWs flywheel to improve power quality and thus allow increased renewable energy usage.

  • Powercorp in Australia have been developing applications using wind turbines, flywheels and low load diesel (LLD) technology to maximize the wind input to small grids. A system installed in Coral Bay, Western Australia, uses wind turbines coupled with a flywheel based control system and LLDs to achieve better than 60% wind contribution to the town grid.

  • Vycon has created a flywheel application it calls "energy recycling" that captures the energy contained in cargo containers being lowered by cranes and feeds it back to the crane for the next hoist.

    Cranes need large amounts of power in rapid bursts in quick succession for several hours a day. A single hoist might require 160 kilowatts to 300 kilowatts, take about 30 seconds, and get repeated every five minutes.

    Although cranes now mostly run on AC motors, they aren't grid connected. . The constant movement (and gigantic power requirements) wouldn't allow that. As a result, cranes derive their power from polluting diesel generators. And because cargo loads vary in size, port operators have to install generators for the worse case scenarios, leading to more fuel consumption and emissions that are warranted in most circumstances. Some of the generators are capable of generating 500 kilowatts to 800 kilowatts.

    Besides needing power for the lift, cranes burn diesel when lowering cargo to control the descent. On the drop, the AC motor is run in reverse, generating 200 kilowatts of power.  In a Toyota Prius, that generates power for the battery. On a cargo crane, the power is burned off as waste heat.
    The white box between the center wheels of this container crane is Vycon's flywheel

     In Vycon's system, the energy is absorbed into the rotating mass of the flywheel, which stores the energy and feeds it back into the system. The fuel saving largely come in through the fact that port operators can employ smaller generators once they have a flywheel.

    Vycon sells both a retrofit kit (take it away for $120,000) and a kit for new cranes. One of the key selling points is the rapid installation. Diesel generators regularly undergo scheduled maintenance; an overhaul can take a few weeks. Vycon goes in and offers a complete new system-generator and flywheel-that can be popped on to the crane in three days.

    The flywheel also lasts 20 years, which Romo says is probably longer than battery-only systems.



7. Companies
  1. Active Power (NASDAQ: ACPW) Austin TX - Provides the most energy-efficient critical power solutions and UPS systems in the world. Their flywheel-based solutions ensure business continuity in the event of power disturbances.

  2. Amber Kinetics, Fremont, CA - Won a $4 million Smart Grid Demonstration Project funding from DOE to develop and demonstrate an innovative flywheel technology for use in grid-connected, low-cost bulk energy storage applications. This demonstration effort, which partners with Lawrence Livermore National Laboratory, will improve on traditional flywheel systems, resulting in higher efficiency and cost reductions that will be competitive with pumped hydro technologies. Total project value is $10 million.

  3. Beacon Power (NASDAQ: BCON) Tyngsboro, MA - Spun off of SatCon Technology Corp in 1997 and went public in 2000.  Makes 2 and 6 kilowatt-hour flywheel (kinetic-electric) energy storage units. Beacon started out applying their technology to the telecom market but soon moved into the frequency regulation sector of the utility energy market. Beacon estimates the frequency regulation market as well in excess of $500 million and about one percent of load. Although Beacon designs and manufactures the flywheel storage systems, the firm now utilizes its flywheels in its new role as an Independent regulation services provider (IRSP).

    In 2009, Beacon Power received a $43 million DOE loan guarantee that was used to complete a 20 MW flywheel energy storage project in New York now in operation.

    In August 2011, Beacon was awarded a $5-million state grant toward construction of a 20-megawatt flywheel energy storage plant in Hazle Township, Pennsylvania. In addition to the $5 million state grant, the $53-million Hazle Township plant was also awarded a $24-million Smart Grid stimulus grant from the U.S. Department of Energy.

    On October 30, 2011, Beacon filed for bankruptcy just a year after the energy storage company received a $43 million loan guarantee from a controversial Department of Energy program.Beacon Power drew down $39 million of its government-guaranteed loan to fund a portion of a $69 million, 20-megawatt flywheel energy storage plant in Stephentown, New York.
    There are several key differences between Beacon's loan and Solyndra's (See my blog article Solyndra Failure), an Energy Department spokesman said on Sunday, noting the Beacon plant continues to operate, unlike Solyndra, which shut down shortly before filing for bankruptcy.

    The Energy Department also had agreed to restructure Solyndra's debt in a last-ditch effort to keep the company alive, a deal which put taxpayers behind $75 million in private investment. But for the Beacon project, the government loan is the first debt the company must pay, the spokesman said.  The loan guarantee for the project included "many protections for the taxpayer," said DOE spokesman Damien LaVera, noting the department is not directly exposed to Beacon's liabilities, has the operating plant as collateral, as well as cash reserves held by the business.

    It said in documents filed with Delaware's bankruptcy court that it had $72 million in assets and $47 million in debts.  Beacon currently operates at a loss and its revenues are not enough to support its operations, it said in court documents.  It blamed the bankruptcy on its inability to secure additional investments due to the financing terms mandated by the Department of Energy, its recent delisting by the Nasdaq stock market and the current "political climate."


  4. Power-Thru - Livonia, MI - Designs, manufactures and markets advanced flywheel energy storage systems that provide ride-through power and voltage stabilization for power quality and power recycling applications. Pentadyne is the world's leading manufacturer of flywheel energy storage systems.

  5. Vycon Yorba Linda CA - Serves the UPS industry. Vycon’s proprietary system consists of a steel hub with magnetic bearings, a dual motor/generator (the motor charges the system, the generator dispenses the energy), high tech system controls, and a converter that transforms the flywheel’s AC power into DC.

    In January 2010, Vycon closed a $13.7 million round of funding, which includes conversion of $6.5 million in existing convertible notes and $1.1 million of existing trade debt.



8. Links

2 comments:

  1. That look likes a very heavy duty equipment. Thank you for sharing this.

    ReplyDelete
  2. This information is quite useful, I truly enjoyed.

    ReplyDelete