Not unless you're referring to the air and water it produces as by-products of powering your vehicle. And, contrary to popular belief as well as Mr Elon Musk's recent remarks, hydrogen fuel cell electric vehicles (FCEVs) are not a thing of the distant future. Given automotive design cycles and progress by various participants in the ecosystem, you should expect to see yourself driving alongside an FCEV (or possibly sat in one) from 2015.
More importantly, the debate isn't about FCEVs versus battery electric vehicles (BEVs) - or at least it shouldn't be. There is room for both - as cleaner, more efficient electric vehicles. BEVs may likely be more suitable for smaller vehicles making shorter journeys, while FCEVs with fast refuelling and longer range give similar performances to current internal combustion engines vehicles. They are both a win-win for the automotive industry in delivering zero-emissions. In fact, when combined together in electric vehicles, fuel cell and battery technologies are actually complimentary.
As it stands, the number of passenger cars is set to rise to 273 million in Europe - and to 2.5 billion worldwide by 2050. As such, full decarbonisation will not be achievable through improvements in the traditional internal combustion engine or the use of alternative fuels alone.
Hydrogen is gaining popularity in the global energy mix. It is already manufactured and consumed on a large scale by industry across the globe; for instance, according to the Department of Energy, enough is produced in the US alone to fuel approximately 40 million fuel cell electric vehicles. But, hydrogen has the potential to be much more than just a transport fuel. For example, it can be produced renewably and can be stored at grid-scale, and used to generate CO2 free power for homes and businesses - in addition to fuelling zero emission FCEVS.
The growing popularity of hydrogen is matched by widespread interest in fuel cells across the board - not only from large, blue-chip companies, but also in the form of greater support and commitment from government and industry consortia around the world, especially in France, Germany, India, Japan, Korea, Scandinavia, the U.K. and the U.S.A. H2 Mobility consortia around the world are also swiftly mobilising the ecosystem to deliver action plans for the construction of nationwide networks of hydrogen refuelling stations. In reality, all types of vehicles require fuelling infrastructure, but for the motoring consumer, the FCEV refuelling experience will be very familiar, as they can be filled in minutes at the pump - much like conventional internal combustion engine vehicles.
Amongst the first movers, Toyota, Daimler, Hyundai and Honda have all bolstered their commitment to develop commercially available FCEVs, and some of them are on track to deliver FCEVs to the motoring consumer starting 2015.
Nissan has announced the TeRRA concept, a hydrogen fuel cell powered SUV; Mercedes is planning its fuel cell debut with the B-Class F-CELL compact; and Toyota has plans to reveal its FCV-R at the Consumer Electronics Show in Las Vegas in January 2014.
Back to Mr Musk's comments. It's not about one or the other - there is potential and need for both technologies. Both BEVs and FCEVs offer a viable low-carbon, zero-emissions alternative to internal combustion engines.