Driving a future without diesel

Government leaders from more than 60 countries have turned up the heat to combat climate change. The Paris agreement on climate change was concluded last year but will now come into force on Nov 4, making progress more quickly than sceptics thought and environmentalists feared.

Singapore has ratified the Paris Agreement and, while a minor emitter in total terms, it must play its part. As a modern city-state, we can indeed be a test bed and demonstrator for new policies and technologies in urbanisation and sustainability.

One key area will be in transport, which is projected in a 2020 business-as-usual scenario to make up 14.5 per cent of emissions — second to industry sources.

Achieving a car-lite city will require a range of initiatives, including more options for multi-modal transport such as bicycles, as well as disruptors such as Uber and Grab to make the taxi industry more efficient and competitive. Encouraging wider adoption of electric and hybrid cars is also important.

Despite these steps, other considerations must be factored in. Not everything that is climate-friendly is green. Take a look at diesel vehicles, once perceived as a fast way to reduce carbon emissions under the 1997 Kyoto Protocol climate change agreement.

Diesel vehicles have been touted as “green” and “climate friendly”. It is true that diesel engines produce more energy per litre of fuel, and therefore offer better mileage and lower levels of CO2 for the same distance travelled.

For this reason, some have actively promoted diesel vehicles by lowering taxes and other measures. Consequently, the market share of diesel cars in Western Europe has quickly soared, reaching 53 per cent in 2014. A similar trend is seen in Singapore.

Some 185,000 Singapore-registered diesel vehicles are on the roads, accounting for around 20 per cent of the vehicle population in 2015. Most are trucks, vans and commercial vehicles, rather than passenger cars.

Although diesel passenger cars comprise just 1 per cent, they have been the fastest-growing segment. In considerable part, this is because Singapore’s tax-incentive structure grants rebates (or penalties) purely based on a car’s carbon emissions.

CARBON LIGHT BUT DIRTY?

While it may be more carbon-friendly, diesel produces more pollution. The fuel is responsible for emitting four times more nitrogen oxide and dioxide (NOx) and 22 times more particulates — especially PM2.5, the tiny particles that penetrate deep into the respiratory system.

There have been PM2.5 controversies in cities in China and even in Europe, which prides itself for being environmentally conscious. In March 2014, Paris was enveloped in severe smog believed to be caused by diesel use. Half of the city’s car population was banned for a day and the pollution receded.

PM2.5 is also a special concern when cities are hit by the haze from land and forest fires.

While Singapore’s overall air quality is good, the amount of PM2.5 has hovered at, and at times exceeds, levels recommended by the World Health Organization.

A less highlighted issue is nitrogen dioxide where NOx pollution has been associated with various health conditions. Among these are inflammation of the lungs, which can trigger asthma and bronchitis, and a higher risk of heart attacks and strokes.

As Singapore aspires to be a liveable city with a high standard of environmental protection, measures have been put in place to reduce air pollution. Last year, the Singapore authorities extended their Early Turnover Scheme to expedite the replacement of older, dirtier vehicles with cleaner models. From January 2018, all new diesel motor vehicles must also be Euro VI compliant.

Still, there is room for improvement. In Parliament earlier this year, Minister for the Environment and Water Resources Masagos Zulkifli announced plans to conduct a study of pollution from diesel vehicles in the country. This will review diesel technology so as to minimise public exposure to pollution and related health risks.

DIESEL DOUBTS

Public health issues aside, diesel has already come into question because of international controversy. Consider the scandal with German carmaker Volkswagen (VW).

The company was exposed in 2015 for installing “defeat devices” in its diesel-fuelled cars — a software that enables cars to artificially cheat and pass tests for emission standards, while actual performance on the roads is more pollutive and less carbon-friendly.

The implications of the scandal are far-reaching not only for VW but for the industry. The integrity of similar claims by other automakers has come under question. To address this discrepancy, the European Union has mandated future vehicles to undergo a Real Driving Emissions test and meet the associated emissions limits in addition to the current laboratory tests.

For Singapore, there may be more reasons for caution against having more diesel passenger vehicles on the roads. As a city, there are many instances of stop-and-start driving. Studies show this causes incomplete diesel combustion and increased pollution.

This raises a particular concern about diesel engines in an urban setting. Paris has committed to ban diesel vehicles on its streets by 2020 and London is considering a similar move.

New Delhi’s Supreme Court has also halted registration of new diesel vehicles with engine capacity of 2,000cc and above, and mandated all diesel taxis to switch to compressed natural gas.

An outright ban is difficult because of existing commercial vehicles that run predominately on diesel. It is also necessary to look ahead to a future with more commercial vehicles that run on electric engines, and other urban delivery solutions with less carbon and pollution costs. More immediately, there are good reasons to reassess tax and other incentives in relation to diesel passenger cars.

ABOUT THE AUTHORS:

Nicholas Fang, Simon Tay and Lau Xin Yi are, respectively, Executive Director, Chairman and Policy Research Analyst (Sustainability) at the Singapore Institute of International Affairs (SIIA). The SIIA has a programme that seeks to address the haze and has advocated other measures to protect clean city air in Singapore.