Diesel car scrappage policy ‘little benefit to air quality’

RAC Foundation analysis suggests oft-mooted policy ‘would cost hundreds of millions and barely dent the problem’

Bringing in a diesel car scrappage scheme aimed at removing the most polluting vehicles from roads would be “unlikely to do much for air quality” according to research by the RAC Foundation.

Many politicians, campaigners and thinktanks have advocated a diesel scrappage scheme to boost air quality

The Foundation said a scheme designed to incentivise diesel drivers to trade in their vehicle for a lower-emission replacement would cost hundreds of millions of pounds yet “barely dent” the air pollution problem from these vehicles.

It said policymakers should instead focus on encouraging electric vehicle uptake through government subsidy as well as tackling emissions form commercial vehicles and heavy duty lorries, buses and taxis.

Calls have increased in recent months from campaigners, politicians and thinktanks for a scheme aimed at providing drivers of older diesel vehicles that produce higher emissions with a financial incentive to trade in their car for a newer, less-polluting model.

Such a scheme was advocated as far back as 2014 by the London Mayor, Boris Johnson (see AirQualityNews.com story), and also by the MPs on the Environmental Audit Committee in November 2015 (see AirQualityNews.com story).

Both frontrunners in the upcoming Mayoral election Sadiq Khan and Zac Goldsmith have also backed a diesel scrappage scheme in the capital.

However, the RAC Foundation — a research and transport policy charity — has dismissed the idea as it would need to be rolled out “on a huge scale to have any significant effect”.

According to its analysis, around 1.9 million diesel cars in the UK fall into the oldest, most-polluting European exhaust standard categories of Euro 1, 2 and 3.

“The big problem is that not only have the oldest diesel cars failed to live up to official environmental standards, so too have many more recent ones. So a scrappage scheme could cost hundreds of millions of pounds and barely dent the problem” – Steve Gooding, RAC Foundation director

This accounts for 17% of the total 11.2 million diesel cars on the road, corresponding to 15% of the total NOx (nitrogen oxide) emissions from all diesel cars, based on estimates of real-world driving data and annual mileage from MOT records, RAC said.

Analysis

A scrappage scheme previously run by the then-Labour government in 2009/10 saw motorists receive a £2,000 grant to sell their old car and buy a new model, although this was designed to encourage the uptake of greener vehicles.

RAC’s analysis therefore calculated what might happen if a similar scrappage scheme was operated along these lines to encourage a move away from the most-polluting diesel vehicles.

This would take 400,000 of the oldest diesel cars off the road at a cost of some £800 million with the government and manufacturers both contributing £1,000 each to help people who trade in their existing vehicle replace it with a new model.

If all 400,000 of these cars were replaced with a new zero-emission electric vehicle, according to the analysis, this would only see an annual NOx reduction from the UK diesel fleet of around 4,900 tonnes, or 3.2% of the total emissions from diesel cars.

Furthermore, this falls to just 2,000 tonnes per annum (1.3% of the total) if the scrapped cars were replaced with the latest Euro 6 diesel models and driven the same distance as those scrapped.

RAC Foundation explained: “However there could be an annual increase of about 300 tonnes if the replacement Euro 6 diesels were driven as much as the other Euro 6 diesels being sold, with the mileages of all other vehicles remaining the same. Furthermore it would be hard to target a scrappage scheme at those cars being used in urban areas where poor air quality is of greatest concern.”

Scrappage scheme

Commenting on the findings, RAC Foundation director, Steve Gooding, said: “Instinctively a scrappage scheme to get the oldest, dirtiest diesels off the road seems like a good idea. But these numbers suggest otherwise. At best it looks like emissions would be reduced by only a few percent, unless government was prepared to launch a scheme on an unprecedented scale.

“The big considerations for any scheme include: where diesels are being driven, how far they are being driven and how do these factors change with the age of the vehicle.

“The big problem is that not only have the oldest diesel cars failed to live up to official environmental standards, so too have many more recent ones. So a scrappage scheme could cost hundreds of millions of pounds and barely dent the problem.”

Subsidies

Mr Gooding continued: “There needs to be a big drive to get more people, and fleet buyers, to commit to ultra-green motoring and that means government subsidies must remain in place to close the price gap that still exists between vehicles powered by alternative fuels and those driven by fossil fuels. Already some manufacturers have warned that the still fragile electric car market could be killed off if subsidies are withdrawn too hastily.

“As the government has itself recognised in its plan for clean air zones, the most pressing issue is what to do about commercial vehicles. A major proportion of the emissions of NOx from road transport come from heavy duty vehicles such as lorries buses and taxis.”