The RABA/IKARUS project seeks to transfer technology to enable Hungarian industries to produce buses with compressed natural gas engines. The technology will be provided by Deltec, a producer of gas-fuelled engines, and the TNO research organisation, both in the Netherlands. Participating firms are the Hungarian RABA, producer and installer of bus engines, and IKARUS, the Hungarian bus manufacturer. It is estimated that some 3-4 000 buses (mostly diesel powered) provide transportation in the major Hungarian cities. The installation of CNG engines on all Budapest buses that currently have an old diesel engines would prevent emissions of 6 400 tonne of CO2 per year. The AIJ partners estimate that in Budapest all full-size buses (90 passengers or more) together cause CO2 emissions of 120 000 tonne per year. Since, the AIJ projects ended. The JI projects in Hungary focused on renewable energy utilization.