The ARES (Advanced Rail Energy Storage) energy storage technology uses an electric traction drive shuttle-train, operating on a closed low-friction automated steel rail network to transport heavy masses between two storage yards at different elevations. When excess energy is available on the grid, ARES shuttle-trains uses the power, which drives their individual axle-drive motors, as they transport a continuous flow of mass uphill against gravity to an upper storage yard. When the grid requires energy to meet periods of high demand, this process is reversed. The shuttle-trains provide a continuous flow of masses returning to the lower storage yard with their motors operating as generators, converting the potential energy of the masses elevation back into electricity in a highly efficient process.
ARES facilities integrate significant recent advances in motor-generator traction drive and power control technologies with proven rail technology to produce a reliable and highly capable system that approaches an 80% charge and discharge efficiency. The facilities are highly scalable in power and energy ranging from a small installation of 100 MW with 200 MWh of storage capacity up to large 2 to 3 GW regional energy storage system with 16 to 24 GWh energy storage capacity. The components of an ARES Energy Storage System may also be deployed to create a robust Ancillary Services system which functions as a LESR (Limited Energy Storage Resource). These systems provide grid-scale including Regulation-Up, Regulation-Down, Spinning Reserves, VAR Support and Grid Inertia. The ARES Fast Response Ancillary Service technology bridges the power gap between large scale battery and flywheel installations and far larger pumped-storage hydro — at a lower life-cycle cost than batteries, a higher energy-to-power ratio than flywheels and a greater efficiency and far faster ramp-rate than pumped-storage. The system has a few advantages.
Reactive power production – The shuttle-trains onboard Dual 3-Level Active Rectifier/Invertors are capable of supplying 25% of generated system power as reactive power for grid VAR support in full discharge mode and in excess of 100% of system power as reactive power while synchronized to the grid in standby.
Heavy inertia – When in direct grid synchronization the ARES shuttle-trains provide beneficial heavy inertia — augmenting grid stability against the loss of heavy generating facilities and increasing reliance on solar energy. High efficiency regulation – While providing Regulation-Up and Regulation-Down support to the ISO a separate dedicated pool of loaded ARES shuttle-trains are available to dispatch from mid-system elevation complying with ISO regulation commands without having to overcome the efficiency loss of operating on pre-stored energy. As such an ARES facility is able perform a round-trip regulation Reg-Up/Reg-Down command at over an 86% operating efficiency.
Variable output at constant efficiency – Unlike CAES and pumped-storage hydro there is no loss of system pressure during discharge. ARES system efficiency is constant over the full range of discharge and power output.
Lowest levelized cost kWh Based on one full charge/discharge cycle per day, ARES has the lowest levelized cost per kWh of comparable technologies.
For a video of the working prototype: https://www.youtube.com/watch?v=zshJwVlbOeM
Filed Under: Energy storage, News