The positive impact of WLTP

New emission standard generates new momentum for CNG-cars


As you are undoubtedly aware, there has been a new emission standard for cars since September 2018: the Worldwide Harmonised Light Vehicles Test Procedure (WLTP).  In brief, the WLTP is a measuring method that makes it possible to determine the fuel consumption and emissions of CO2 and pollutants of a passenger car. WLTP prescribes how this test must be performed in accordance to European laws and it is a tightening of the old New European Drive Cycle (NEDC).

More accurate measurement

Much depends on this new WLTP. Governments are namely setting policy on the basis of the results of the WLTP tests. For example, the purchase tax is in part dependent on the outcome of the WLTP. A new standard was very much overdue. The old standard, NEDC, had been inadequate for quite a while already. This standard entailed such a wide bandwidth that it was vulnerable to fiddling and the test consumption increasingly deviated from the actual consumption.

That is much less the case for the WLTP. The new standard is more precise and truthful. For example, the route is longer, it comprises more urban traffic, and separate tests must be performed with additional accessories if your car is equipped with them. This completely different from what is was before.

The introduction of the WLTP caused quite a stir in the automotive industry. The WLTP did not just result in all models having to be tested again. It also meant that the car had to be examined for each individual accessory. This generated a lot of work for the car manufacturers and caused a number of models, primarily of vehicles fuelled by Compressed Natural Gas (CNG), to become (temporarily) unavailable.

Positive results for CNG

A few months have elapsed since then, and the WLTP now offers a lot of positive news for driving on CNG. A large number of CNG-fuelled cars are available again: such as the Seat Leon, the Skoda Octavia, the Volkswagen Up, and the Fiat Panda.

These CNG-cars have all now been tested in accordance with the new WLTP standard, and with good results. The test results differ only slightly from those under the former standard. And all models running on CNG still outperform those running on diesel or petrol. This means that driving a CNG-car continues to be beneficial not just to reducing CO2 emissions, but also to the drivers’ wallets: they have to pay less environmental taxes than those that drive diesel cars.

Looking ahead, WLTP also bodes well for the transition to clean transport. In 2020, the average emissions of a fleet must remain below 95 grammes per kilometre. Manufacturers receive a fine if they exceed that ceiling. CNG-fuelled cars are already at or below this average. Therefore, engines on CNG already meet this standard without requiring modifications to the fleet or averaging.

The WLTP requires that a car can only be tested as a CNG-fuelled vehicle when CNG is effectively the main fuel. This was not the case under the old NEDC standard. Consequently, manufacturers have enlarged the CNG tanks in new cars and made the petrol tanks smaller. A positive side effect of this, is that they opted to outfit the CNG-fuelled cars with a newer engine model, as the model had to be modified anyway.

CNG as a transitional fuel

The introduction of the WLTP was a challenging period, but there is light at the end of the tunnel. All CNG-models will become available again at the end of February. Additional models, such as SUVs, might even be in the making. This means the (future) CNG driver will benefit from a wider selection of models. This will no doubt lead to more people opting for a CNG-car and, in turn, to more people being able to transition to cleaner driving today.

A win-win situation for clean fuels, and for the road to clean transport!

Marnix van Berkum