1. What is the Amber Kinetics Energy Storage System?
The Amber Kinetics storage system is an electro-mechanical battery which uses flywheel technology to store 32 kWh of energy in a 5,000 lb. steel rotor. When combined in groups of flywheels, the battery can be scaled up to tens or even hundreds of megawatts for charge/discharge durations of up to 4 hours.
The mechanical battery can charge from any available input source: from the electric grid; from solar & wind; or from diesel generation. The stored energy can then be provided back into the grid or supplied to a load as required and directed. The mechanical battery is uniquely capable of being charged as quickly as it was discharged, can respond to all forms of power quality variations and can be operated as a UPS as well. It has very high round trip efficiency of 88-90% due to its unique yet simple design, has unlimited cycling capabilities and very low maintenance requirements. It requires no external temperature conditioning and can operate from -40 to 50C.
Amber Kinetics uses a medium speed, steel flywheel with a rotational speed <10,000 RPM, making it extremely robust and simple.
2. How does a flywheel work?
A flywheel converts electrical energy and stores it in a rotating mass. There are two general classes of flywheels:
- Low & Medium speed flywheels which primarily use steel and operate below 10,000 RPM (Amber Kinetics’ flywheel)
- High speed flywheels made from fiber composites and typically operate between 10,000 – 100,000 RPM.
The amount of energy stored in a flywheel is roughly equal to mass x velocity squared. So, doubling mass doubles the stored energy for a given velocity, but doubling the rotational speed quadruples energy storage. The mass is a function of the size and material used in the rotor. The absolute speed of the rotor is limited by the properties and performance characteristics of the rotor material.
3. What are the target markets/ applications?
- Telecoms: Small units used for communications and/or substation battery replacement are in the 30kWh 48Vdc size range. These units are outdoor rated and adhere to cell phone tower, battery backup standards
- Microgrids: Microgrids and on-site hybrid power systems for commercial and industrial applications. Multiple flywheel units can be integrated in parallel with 800Vdc outputs coupled to a PCS similar to large-scale solar parks, to provide MW-scale solutions for utilities or island micro-grids.
- Utilities – flexible & fast-ramping capacity, ancillary services, resource adequacy (4 hours), and transmission and distribution deferral
4. Why have flywheels not been developed in this longer, 4-hour duration before?
Flywheels are one of the oldest forms of energy storage dating back thousands of years to the potter’s wheel. More recently, they are used in multiple military applications such as railguns, aircraft carrier catapult launches, by NASA, and in buses and even in amusement parks to manage the sudden power surge requirements for various park rides. For the most part, the flywheels are used to provide short duration energy storage. In buses, for example to recapture energy when decelerating, in trains for capturing regenerative breaking energy, and in grid connected systems for smoothing sudden large power demands and thus reducing maximum demand charges. More recently, frequency regulation and market trading has been a target.
The challenge of achieving long duration 4 hours of storage has centered on the following:
- The ability to control the rotor material consistency and accuracy of design;
- The ability to obtain long life low friction, sealed bearings to support the rotor mass; and
The ability to economically manufacture in volume, high quality systems.
Amber Kinetics has addressed these challenges in several ways. First, it re-engineered the flywheel rotor’s metallurgical properties, evolving & refining certain low-carbon steel alloy chemistries and processing steps to achieve a nearly ideal crystalline structure in the final part. Then, the company leveraged advances in CNC machining developed for the semiconductor industry to engineer high-precision, high-quality steel rotors in rapid fashion. After solving the rotor cost challenge, the team then developed several patented innovations to reduce the friction and apparent weight seen by the bearings, including operating the system in a continuous vacuum. Finally, using modern, sealed, self-lubricating bearings, which are now available, Amber has been able to leverage off-the-shelf technology to bring reliable and high-performance operations to flywheels.
In the manufacturing process, in working together with large outsourced vendors, Amber has developed a material quality processes and noninvasive manufacturing and inspection steps to examine every part for quality during production. By integrating these, the Amber flywheel has overcome previous limitations to produce simple steel rotor, low cost, high efficiency and low maintenance systems, providing 4-hour storage durations at medium speed.
5. What are the benefits of Amber’s battery versus chemical batteries?
Depending on applications, the Amber flywheel system provides considerable advantages over chemical batteries.
- >88% round trip efficiency (DC)
- No daily cycling limitations
- Zero degradation over time
- Passive air cooling, no HVAC required
- Operates in hot and cold environments (-40C to 50C)
- Fast response time
- All-steel design is fully recyclable
- Minimal O&M
- 30-year design life
- 10-year manufacturer warranty
6. What are the limitations of the Amber Kinetics battery?
The energy density or energy stored in the rotor limits the use of the Amber battery outside of constrained spaces. The system footprint is approximately: 4 MW | 16 MWh per acre.
7. What are the weights of the system components? What is the footprint?
Please refer to the technical spec sheet. Each flywheel is rated at for 8 kW | 32 kWh and weighs around 10,000 lbs. Each unit is approximately 2 cubic meters in size.
For single unit installations, a choice of 48Vdc or 800Vdc are available. A power converter system can be connected to connect to the grid or load. In telecom applications, the output is 48Vdc nominal over the whole charge-discharge range.
A signal indicating the SOC is always available from the system to start an onsite diesel generator or to transfer back to a grid.
In larger installations, we can provide engineering drawings which show the standardized layout or building blocks for systems up to 10MW 40MWh. Amber partners with project developers and construction companies to design and install total systems which consist of the flywheel energy storage system, the site construction, central control, PCS and switchgear and provides a 10 year or 20-year warranty.
Permitting is primarily driven by electrical and grid codes and civil construction /building codes. These are all well-known and standardized allowing for straightforward installations. Safety is a primary consideration of Amber Kinetics so all designs have been developed to provide maximum safety.
8. How many hours are required to charge for each hour of discharge?
The charge-discharge ratio is very close to 1 to 1 (charging takes slightly longer than 4 hrs due to one-way efficiency losses). This allows the system to be cycled more than once a day as well as to fast charge to 100% rating without impact on life. Where diesel engines are the source of energy as with telecoms and microgrids, this is a key driver to lowering the LCOE.
9. What is the life cycle of the Amber Kinetics flywheel?
The Amber Kinetics flywheel has a design life of 30 years. It can be cycled more than once a day and with rapid charge times can meet the double peak that is beginning to appear on many grids across the world – morning and evening peaks. Chemical batteries are challenged due to heating and life cycle limitations.
10. What is the time required to complete an installation of MW scale?
Delivery schedule for a 10MW system is approximately 18 months from order to energization.