Ricardo High Efficiency Excavator (HFX) with flywheel energy recovery technology

Ricardo first began flywheel development in connection with Formula 1 motorsport 4 years ago, and has continued its research and development efforts in order to exploit the wider opportunities presented by major transportation markets.
Ricardo's research and development effort has yielded an innovative and stable flywheel hybrid solution, which solves the fuel efficiency and emission problems at much lower costs than comparable hybrid solutions.

Flywheel Technology and Ricardo Innovation

The standard Ricardo flywheel holds about 1MJ (mega Joule) of energy, which is approximately equivalent to a 2 tonne car travelling at 70mph, in a package about the same size as a waste paper bin, inside of which an advanced composite construction flywheel spins very fast - at up to 60,000rpm. Unlike the large battery of the electric hybrid, this small form factor enables it to be retro-fitted onto the transmission of an existing vehicle without mechanical disruption or loss of passenger space.

Ricardo's advanced modelling techniques enable the optimal dimensions of a flywheel to be immediately determined for additional applications, such as trains, agricultural machinery and passenger cars. This means that unlike competitors, the Ricardo flywheel technology is not a point-product solution applicable to a single market, but can be quickly morphed to address many different applications and markets as required to ensure maximum return.

The Ricardo flywheel is also totally mechanical (save for its control electronics). There are no losses in converting mechanical energy into electrical energy, or the necessity for electrical motor/generators and power cabling as in competitive flywheel based systems. Minimised energy loss, fewer components and lower installation complexity means reduced cost.

Ricardo's 4 year research and development cycle has resulted in some key innovations; some with patents granted, others with patents applied for, which overcome the difficulties of making a flywheel efficient and achievable in production.

For instance, the flywheel rotates in a vacuum, which eliminates the friction that would be caused to it by air resistance. Air friction would result in the flywheel - once spun up to speed - slowing to a standstill and losing all its energy in seconds. The time taken for a flywheel to decelerate from top speed to half speed (and hence half energy) is called its half-life. Early prototypes exhibited a half-life of only a few minutes, but current models demonstrate a half-life of over 6 minutes. This is much more than the time for which, as an example, a bus is stationary at a bus stop, and demonstrates the maturity of Ricardo's technology.

This consideration of time identifies one of the key differences between flywheel and battery energy storage systems. Batteries can store energy for a long time, but to deliver power (the rate at which energy can be delivered) they must be over-sized, which increases size and cost. Flywheels can store much more power for their size and can receive/deliver energy at much higher rates. Batteries also have a hidden cost to the environment, both in manufacture and disposal at the end of life. Mechanical flywheels can be refurbished many times to extend their life simply by replacing the bearing, and have no such disposal costs or environmental impact.


Finally, no matter how good a technology is it will not achieve widespread acceptance and deployment unless it can be proven safe, and this safety engineered into the product cost effectively. The advanced composite construction of the Ricardo flywheel ensures that it remains safe and intact at very high rotational speeds, with additional safety features designed in such that it is contained and brought to a halt in the event of a serious collision. Unlike an electrical hybrid that will still hold significant energy and exhibit high voltage safety risks when the emergency services arrive, a Ricardo flywheel by comparison will be stopped and totally safe.


For more information please contact Mike Baker: Michael.Baker@Ricardo.com

Phone:+44 (0) 1926 319319
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