The Welsh government’s proposed £1bn M4 relief road south of Newport will be carbon neutral, the inquiry into the scheme has heard.
Giving evidence as behalf of the Welsh government at the inquiry into the scheme, Arup director Tim Chapman said yesterday that there are two main ways the road will save carbon: a shorter route and by reducing congestion.
The main option on the table will be 2.8km shorter than the alternatives. In addition, the whole life carbon emitted by the road, during construction and after it comes into use, will emit less carbon overall than sticking with the M4 as it is.
The Welsh Government’s preferred route option, the so-called “black route”, is a new six-lane motorway which would run below junction 23a to junction 29. It includes a new bridge over the River Usk to the south of Newport. This is the main route the inquiry will consider. The majority of opponents to the black route favour the alternative blue route, which runs further north.
Chapman told the inquiry the road modelling took into account traffic growth and the initial spurt of use from the pent up demand, as well as the stop-start nature of traffic on the existing M4 and at associated junctions in the area.
He said: “Whole life carbon neutrality on a highway project may be achieved after several years or decades of operation as a result of relieving congestion from the existing alignment and the associated wider network around it, thereby reducing the user carbon until it offsets the capital carbon in its creation.”
Modelling showed that overall carbon emitted in the construction of the scheme, at around 522,516t, would be repaid after the road was in operation for around 50 years.