Thanks to efficient combustion in Volvo's Euro 4 and Euro 5 engines, these units ensure the most fuel efficient solution among competing technologies, which in itself is a gain both financially and environmentally. Although the catalytic reduction process requires an additive in the form of a fluid named AdBlue, with current estimates for the price of AdBlue the overall operating cost will not increase compared to today's Euro 3 specification.
Several European countries are already encouraging advance compliance with Euro 5 through incentives such as lower road tolls or more favourable depreciation rates for correspondingly equipped vehicles. Please contact the appropriate authority in your country for details. You can also turn to your Volvo Trucks Euro 4/Euro 5 contact for more information on this matter.