There’s no better way to test the realities of hybrid technology than with public transport, where significant reductions in fuel consumption and emissions are not just desirable, but a commercial necessity. London got a little greener this week with the delivery of six new Volvo B5L hybrid double-decker buses to Arriva London. The new buses are powered by Volvo’s parallel hybrid I-SAM technology which, used on bus routes in Gothenburg, Sweden, has delivered fuel savings of 30%.

This now makes London something of a competitive hybrid test market, with Transport for London having taken delivery of 17 buses equipped with BAE Systems’ diesel-electric HybriDrivepropulsion system late last year. The Volvo technology is not all that different: a combination of diesel and electric motors that can power the bus independently or in combination.

Service field trials have shown there will be significant reduction in carbon dioxide (C02) emissions as well as nitrous oxides and particulates. And the success of the Volvo 7700 Hybrid single deck in Volvo’s home city of Gothenburg, where fuel savings outstripped the anticipated 25%, suggest running costs will also reduce.

All in all, it’s happy news for London’s commuters: lower fuel consumption, less pollution and, because the diesel engine switches off when the bus stops, less noise.