What is natural gas?
Natural gas consists mainly of methane and is attracted by gas wells. It also contains hydrocarbons such as ethane and propane, as well as other gases such as nitrogen, helium, carbon dioxide, sulfur compounds and water vapor.
Natural gas can be mixed with biomethane or synthetic gas from renewable sources and thus can significantly reduce CO2 emissions by up to 95%. Biomethane and synthetic gas are renewable energy sources with very low carbon footprints. When used as fuel, they allow gas vehicles to operate as carbon neutral.
Natural gas in transport
Natural gas is a fundamental player in a low-carbon future: clean combustion, low carbon dioxide (CO2) emissions (even carbon-neutral when renewable gas applies), technology maturity, availability and competitive fuel cost are key factors to boost the role of natural gas.
Through compressed natural gas (CNG) and liquefied natural gas (LNG), a complete range of applications can be supported, from small city cars up to long-haulage trucks, as well as in the maritime sector.
Benefits of natural gas in transport
Natural gas as a transport fuel offers important benefits to consumers, the environment and the economy. It provides a quick and cost-effective way to meet key EU objectives, including decarbonising road transport and improving air quality in cities.
Natural gas is an immediately available alternative to oil, with lower GHG emissions than any other hydrocarbon fuel and emitting virtually none of the pollutants (particulate matter and nitrogen oxides or NOx) that increasingly contaminate the air in areas with dense traffic. Vehicles fuelled by natural gas are quieter compared to Diesel and offer a lower total cost of ownership compared to conventional fuels. The technology used in natural gas vehicles is mature and safe.
Gas as a vehicle fuel is available as compressed natural gas (CNG) and liquefied natural gas (LNG). It can be used for cars, vans, buses and trucks, with many different models on the market today from established manufactures. LNG is also becoming the fuel of choice for the shipping industry due to its low sulphur emissions.
Natural gas also offers important synergies with biomethane from waste and biomass or synthetic gas produced using wind and solar energy. When using renewable gas, a quasi carbon-neutral mobility is achieved without any impact on the infrastructure and vehicle technology.
Biomethane & Synthetic Gas
Biomethane is refined from biogas produced by the natural breakdown of organic material in waste from agriculture, municipal waste, plants, sewage or food waste. It has the same composition as natural gas and can be injected into the natural gas distribution grid, or used directly by natural gas vehicles.
Power-to-gas means producing synthetic natural gas with surplus energy from wind farms or solar panels through a chemical process. It can be used directly by natural gas vehicles or injected into the natural gas grid.
NGVs can also use renewable hydrogen made from water electrolysis mixed with natural gas in the grid. Blending hydrogen with natural gas can bring additional benefits in terms of pollutant reduction.
Why natural gas?
Natural gas has many applications and uses. Natural gas for transport is one of the most important.
Here are 50 reasons to use CNG / NGV in vehicles.
- Almost 85 countries from all five continents use NGV/CNG.
- More than 20 million vehicles run on this noble fuel today.
- Cars refuel at over 25 thousand filling stations spread throughout 2,900 cities worldwide.
- There are 1,338 service stations under construction. By end 2020, 38,000 fuel dispensing points will supply methane for vehicles.
- 180 OEM NGVs are offered by vehicle manufacturers. OEMs’ interest is growing: Ford, Scania, Opel, GM, Mercedes Benz, Toyota, Hyundai, Tata, Fiat –among others- are clear examples.
- The relation oil reserves-demand has reached the critical point or “peak oil” while a similar situation is not foreseen in the case of natural gas.
- Natural gas exploration keeps expanding into both traditional wells and compact sand deposits. Coal bed methane constitutes a new alternative. Methane hydrate reserves on the sea bed are countless and several times larger than traditional reserves.
- Conventional gas pipelines networks continue to proliferate. Underwater pipelines are built across oceans and others over mountain ranges.
- The use of mobile natural gas pipelines –on trucks or trailers- makes NGV/CNG available where there are no physical pipelines either because of long distances or because of the scale of the demand.
- In typical NGV/CNG refueling stations, owners do not have to rely on the arrival of trucks for the fuel supply since it is constantly provided by the pipeline.
- It is possible for some users to refill their NGV/CNG cars at home because there are dispensers that take natural gas directly from the domestic distribution network.
- Liquefaction and regasification terminals allow –through LNG technology- that natural gas arrives at any place of the planet. LNG carriers guarantee its global distribution and the possibility of providing support for larger supply. LNG transport does not entail the huge risks of ecological disaster that oil poses.
- NGV/CNG industry involves an 800,000 people labour force worldwide, between technicians and workers.
- Natural gas for vehicles may replace all liquid fuels in all their applications and more, whereas the opposite is not possible
- Regarding land transport, there are cars, vans, scooters, motorbikes, tricycles, all types of buses and trucks that run on this fuel.
- In addition, cranes, farm machinery, snow cats, planes, light aircraft, motorboats, ferries and trains –among others- are already NGV/CNG-propelled successfully.
- Oil price is extremely unstable and its trend – especially after the last big international crisis – is definitely upwards again.
- More and more governments promote natural gas as the core of their energy matrix to break the dependence generated by the permanent liquid fuels importation.
- However, nations which are big oil producers, like Iran or Venezuela, encourage the use of natural gas in their domestic markets to increase their oil exports.
- Natural gas is the only abundant, eco-friendly, economically viable fuel with the infrastructure required to supply the world’s automotive fleet for the next 40 years.
- The world average indicates that driving an NGV is 66% cheaper than using a gasoline vehicle and 33% more economical than diesel.
- Countries that import fuels have to pay 50% less for natural gas (LNG) than for liquid fuels like diesel (per equivalent unit of energy).
- NGV/CNG engines produce 25% less carbon dioxide than gasoline and 35% less than diesel. The CO2 contributes to global climate change due to greenhouse effect.
- They reduce carbon monoxide emissions by 95% compared to gasoline, hydrocarbons emissions by 80% and nitrogen oxides’ by 30%.
- NGV/CNG does not contain sulphur (there are diesel engines that release 18.4 g/h), particulate matter, lead or heavy metals traces.
- NGV/CNG cylinders are hermetically sealed receptacles, while by using gasoline, part of it -contained in the tank- evaporates. This causes almost half of the contamination by hydrocarbons associated with the vehicular application.
- Unlike gasoline, natural gas for vehicles does not have toxic additives of organic lead or benzene, the latter being highly carcinogenic.
- Natural gas is not toxic or corrosive and does not contaminate groundwater at all. That is why there is no environmental risk in case of leakage, contrasting with the harmful environmental effects brought about by oil spills.
- NGV/CNG engines decrease noise pollution by having a smoother and more silent performance than gasoline engines and especially diesel ones.
- Biogas (methane from the breakdown of organic matter) turns natural gas into a renewable fuel that can be produced in the whole world. Biogas production from agricultural goods yields four more times per hectare than liquid biofuels.
- Natural gas complies with the strictest environmental standards required by governments and regulating agencies. It is the large-scale use fuel with the lowest contamination levels.
- It is the necessary bridge to hydrogen (immediate promise in terms of clean fuels, not yet available on a large scale), given its molecular structure and the logistics required for its implementation.
- NGV/CNG is not a new technology. It has 70 years of history. It is widely proven and its technological advances are constant.
- Being lighter than air, in case of eventual leakage, compressed natural gas rises and rapidly dissipates. Instead, gasoline spills and moves downwards, what increases fire and explosion risk considerably during an accident or leakage.
- NGV/CNG requires a 600º C temperature for ignition while gasoline and liquefied petroleum gas ignite at 450º C. This is the reason why it is much more improbable that an NGV catches fire, under any circumstance.
- The fuel circuit for natural gas is hermetic and has no air inside. Therefore there is no spontaneous ignition. On the contrary, in liquid fuels tanks, there is always flammable mixture, since they are open to the atmosphere.
- Cylinders are manufactured under very strict safety norms and are subject to tests with pressures much higher than the ones existing during a regular refilling. Design and testing pressure is 300 Bar, they do not explode at less than 460 Bar, and the working pressure is 200 Bar.
- Due to their robustness, structure, shape and its location inside the vehicle, cylinders are much less dangerous than a gasoline tank in case of collision. For example, they undergo tests with fire and firearms.
- Natural gas for vehicles has higher octane number than gasoline (125 vs. 90), what provides combustion without self-ignition, even in engines of higher compression and efficiency.
- Furthermore, combustion is total, because the mixture between NGV/CNG and air is perfect at any ambient temperature.
- The oil that lubricates the engine is less contaminated if natural gas is employed, and intervals between oil changes are twice as long.
- There are no sediments and the spark plugs are kept clean. The walls of the engine cylinders are not washed, what results in better and more effective lubrication.
- Combustion gases are not corrosive. By not damaging metals, the life of the exhaust pipe and silencers is longer.
- The gaseous nature of the fuel eliminates the scanning actions in the cylinders during fast acceleration periods, with the advantage of reducing the corrosion of metal surfaces.
- The engine presents great performance flexibility during accelerations without irregularities or backfires, even at low direct speed.
- Converted vehicles may switch from using NGV/CNG to gasoline by simply pushing a button or turning a knob while driving.
- NGV-gasoline bifuel system doubles the car’s driving range.
- Natural gas vehicles operate in all terrains, even across mountains. In this sense, a truck –with a 37-tonnes load- drove above 4,800 meters high in the Peruvian Andes in May 2008.
- NGV/CNG works fine under any climate condition. Since the fuel does not freeze –not even at low temperatures- the vehicle will always be ready to be used. NGV/CNG components are tested at -40°C during its approval process. Natural gas only liquefies at 165 °C.
- What is more, the speeds it may reach are similar to racing cars’ speeds. A biogas Audi A4 entered the Guinness Book of Records by achieving 364.6 km/h in April 2009, thus becoming the fastest NGV/CNG-driven car of the world. The milestone was reached on the Formula One Nürburgring race track in Germany.
DATA: NGVA Europe & NGVJournal