GyroDrive - Flywheel Hybrid System for City Bus and Commercial Vehicle use

A spinning flywheel, lighter than a suitcase, could replace the heavy batteries in a diesel bus and cut its fuel use by a quarter. City buses and heavy goods vehicles face intense pressure to cut emissions, but hybrid systems remain too expensive and heavy for widespread adoption. Many diesel buses will stay in service for up to 20 years. The GyroDrive consortium—Williams Hybrid Power, GKN, GKN-Evo, and Go Ahead Group—will build and test a hybrid system that uses an electrically driven flywheel instead of a battery pack. The system weighs less than half of a current hybrid system and is small enough to retrofit into an existing bus without losing passenger space. If the fleet trial on multiple bus types succeeds, the consortium expects fuel savings of up to 25 percent and a payback period under five years at production price. That could make hybrid retrofitting economically viable for bus operators and fleet managers, cutting urban emissions without requiring new vehicles. The same flywheel technology could also be adapted for HGVs, extending its impact beyond city transport.