Ad description

A website for a hydrogen generator designed to reduce vehicle emissions, visited on 11 April 2011, stated "reduce CO2 emissions by up to 40% and overall carbon footprint ... Vehicles include: Buses, Trucks, HGVs, Fork Lifts, Transit Vans, Boats, Trains".


CNG Services Ltd challenged whether the claim "reduce CO2 emissions by up to 40%" was misleading and could be substantiated.


h2gogo provided data from testing carried out on their hydrogen generator when fitted to a Transport for London bus at the Millbrook Vehicle Emissions Laboratory (Millbrook Laboratory) in May 2009. They explained that a dynamometer had been used to create driving conditions that were normal for the bus being tested and that their agreement with the Millbrook Laboratory was for three initial tests without the generator fitted (pre-generator baseline tests) followed by three tests with the generator fitted (with-generator tests). They explained that any follow-up tests after the generator was removed (post-generator baseline tests) would have been meaningless as the vehicle would need to have been operated normally for a period before it would return to its pre-generator baseline output. They said there had been an issue with the placement of their generator during the first two ‘with-generator’ tests which invalidated the results and that it had not been possible to repeat those tests in the time they had available at the laboratory. They nevertheless believed the final test proved the technology worked as expected and they therefore evolved the product further and began live vehicle trials with potential customers.

h2gogo provided data from the live vehicle trials which they believed were consistent with the Millbrook test results. They explained that their generator was fitted to the trial vehicles which were then used in normal day-to-day operations and that the results were more significant for their customers than laboratory data. They stated that they had used the approved technology for vehicle MOT emissions testing in the UK to ensure the data from the trials was as accurate and reliable as possible and that their customers had witnessed and verified the emissions figures in each case.

h2gogo believed that they had conducted stringent and comprehensive testing throughout product development and post-manufacture and that the results had consistently shown that their generator could achieve a 30–40% reduction in CO2 emissions.



The ASA noted that the bus used in the laboratory tests was tested three times without the generator fitted in order to provide average pre-generator baseline emissions figures but that only one test was then done with the generator properly fitted. We noted that test had not achieved the claimed 40% CO2 reduction and we considered that, irrespective of the result of that test, repeated ‘with-generator’ tests would have been necessary to produce statistically significant results. Furthermore, although we understood the generator would have a residual effect once removed, we considered that the test cycle should have incorporated post-generator tests in order to help establish the extent to which the results were caused by the generator, as opposed to other changes in the vehicle during the test period.

We noted that the home page of the website stated “Vehicles include: Buses, Trucks, HGVs, Fork Lifts, Transit Vans, Boats, Trains” and we considered that readers would infer from this that the generator had been shown to achieve the claimed emissions reductions when installed on any of the types of vehicle listed. We noted, however, that the only vehicle on that list that had been tested in laboratory conditions was the bus and we considered that the results of that test could not support the claim as it related to other vehicles.

We noted that the customer trials demonstrated greater CO2 reductions than had been shown in the laboratory tests and that the majority showed the generator had achieved a CO2 reduction in excess of 40%. However, we considered that the nature of those trials meant that the results were not sufficiently reproducible to support the claim in the absence of acceptable laboratory test results.

Because the laboratory testing did not produce statistically significant results, because only one type of vehicle had been tested and because the results of the customer trials were not sufficiently reproducible, we concluded that the claim had not been substantiated and was misleading.

The ad breached CAP Code (Edition 12) rules 3.1 and 3.3 (Misleading advertising), 3.7 (Substantiation) and 11.1, 11.2, 11.3 and 11.4 (Environmental claims).


The ad must not appear again in its current form. We told h2gogo not to repeat the claims until they had robust laboratory test results to support them.

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