The UK has set into law a target reduction of greenhouse houses of 78% by 2035 and 100% by 2050. Heavy Goods Vehicles (HGVs) represent 16% of UK road transport emissions are one of the ‘difficult-to-decarbonise’ sectors owing to their large mass and range requirements. An Electric Road System (ERS) with overhead charging wires presents an attractive solution to rapidly decarbonise HGVs at minimal cost and without the need for megawatt-scale batteries. In this work, we investigate some of the technical requirements for a proposed UK ERS demonstrator comprising 25 km of ERS on the M180 motorway in North Lincolnshire, including battery sizes and static charging infrastructure. A range of theoretical journey scenarios were considered, using simulated journeys and a detailed dynamic model of a 44 t ERS electric lorry. The results indicate the need for three vehicle types: a 150 kWh ‘small-battery’ ERS vehicle, a 500 kWh ‘medium-battery’ ERS vehicle, and a 300 kWh battery variant with a range extender for journeys with significant off-ERS driving requirements during the demonstrator.