Sweco has a key role in the development of alternative fuels and has been honoured by Stockholm Public Transport to convert the South Bus Depot to gas fuelled buses.
The first project phase involve 21 CBG buses and will service up to 130 buses of which 120 are in daily service.
Stockholm Public Transport’s long term goal is to have the whole inner-city bus fleet running on biogas fuel to optimise the environmental benefits.
The CBG is supplied by Stockholm Water from Henriksdal Sewage Treatment Plant situated on the other side of the Danviks channel.
Sweco's role covers all aspects from the initial feasibility studies through permits and approvals, technical design and project coaching to the final inspections.
• The bus depot will service 120 biogas buses
• The gas will have a supply pressure of 3-4 bar through a 165 mm PE pipeline.
• Compression capacity is 2 X 800 Nm3/h in normal operation plus 1 X 800 Nm3/h for redundancy and working pressure 350 bar (5100 psi). Compressor packager is YIT & CNG Technology using Ariel compressors.
• Gas storage in phase 1 is 35 no vessels of each 2000 litre resulting in a total storage capacity of more then 25 000 Nm3 CBG and working pressure 350 bar (5100 psi). Supplier is Chesterfield Cylinders in UK.
• The filling equipment is based on 2 dual hose 3-line dispensers for temperature compensated filling pressure up to 250 bar (3600 psi). The dispensers compensate the filling pressure due to internal heating in the vehicle cylinders. The dispensers’ working pressure is 350 bar (5100 psi) and 4 buses can fill in parallel. Supplier is Compac NZ.
• Both the buses and filling equipment are designed for high gas flows of 6000 Nm3/h and expected fill time for a bus is less then 5 minutes