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IEA working paper highlights potential role of natural gas in reducing global road transport CO2

The global natural gas vehicle fleet has grown rapidly in the last 10 years, but still represents less than 1% of global transport fuel consumption. Click to enlarge.

A new working paper published by the International Energy Agency (IEA) concludes that natural gas can play a significant role in cutting on-road vehicle carbon dioxide emissions, but that over the long term there will need to be a commitment to transition to very low CO2 gas sources, such as biogas or bio-synthetic gas. Natural gas may be especially important for cutting CO2 emissions from heavy-duty vehicles (HDVs) since other options such as electrification appear to be limited, the paper, written by Michiel Nijboer, notes.

The paper, which evaluates the potential costs and benefits of using natural gas as a vehicle fuel for road transportation, as well as the policy related to its market development, is intended to elicit comments and debate. As such, it is not an official expression of the IEA or a policy statement.

The global natural gas vehicle [NGV] fleet has grown rapidly over the last ten years, starting from a very low base of little more than one million vehicles to a current estimate of just more than 11 million vehicles. The global fleet of NGVs consists largely of passenger cars/LDVs, although there are some regional differences. According to the paper:

  • 44% of all NGV passenger car/LDVs are in Latin America
  • Almost two-thirds of all MD/HD natural gas buses are in the Asia/Pacific region
  • 53% of all natural gas trucks are in the Russian Federation and CIS
  • 78% of all other vehicles on natural gas (3-wheelers and tuk-tuks) are in Asia-Pacific.

NGV [natural gas vehicle] programmes are usually driven by other goals than greenhouse-gas reduction, although NGVs can certainly contribute to decarbonising transportation and as such should be part of plans to move towards sustainable transport. On average, a 25% reduction in carbon dioxide equivalent (CO2-eq) emissions can be expected on a well-to-wheel (WTW) basis when replacing gasoline by light-duty vehicles (LDVs) running on compressed natural gas (CNG).

While the technology for bio-synthetic gas is not fully developed yet, biogas could provide significant quantities of a low-carbon fuel in the longer term at low or even negative greenhouse-gas abatement costs. Europe is currently seeing an increasing number of projects aimed specifically at the production of biomethane and its use in vehicles. In principle, NGVs can also provide a pathway to hydrogen but more research is required to assess how and to which degree this can be accomplished. For various reasons, the potential to reduce greenhouse-gas emissions by replacing large quantities of diesel fuel consumption in HDVs by natural gas has been underutilised.

—“The contribution of natural gas vehicles to sustainable transport”

Among the other key messages of the paper are:

  • Despite strong past and continued growth in the number of natural gas vehicles (NGVs) and fuel stations, natural gas is still a niche market in transportation, representing less than 1% of world road fuel consumption and less than 1% of world gas demand.

  • Vehicle and fuel technology for natural gas is available today and relatively affordable, particularly in comparison with other alternative fuel vehicles (AFVs).

  • Depending on the context, NGV can have strong benefits in different countries including: improving air quality and reducing noise in urban areas; diverting oil from domestic consumption to export; improving energy security; and reducing government spending on road fuel subsidies.

  • Governments should carefully consider the role of NGVs compared to other AFVs, such as electric, fuel cell and biofuel vehicles, and weigh the costs and benefits of each for different modes of transport. In this context, it appears that NGVs may compare favorably in many—but perhaps not all—national contexts.
  • Natural gas can be competitive with gasoline where transmission and distribution grids are present; in countries where this is not the case, there is often an opportunity for simultaneous gas market development and increasing NGV market share. While investments in vehicles and retail infrastructure can generate positive returns, temporary government support may be required to establish an NGV market. Without such support, many countries are unlikely to achieve self-sustaining NGV markets with substantial penetration levels. Investments in grids are likely to take place only where other sectors can also benefit from natural gas supply.

The paper uses Brazil, India, Iran, Pakistan, the US and Europe as case studies.




Wouldn't it create less GHG and les transportation problems if NG was used in up to date very high efficient power plants and vehicles electrified? The higher efficiency from the combined cycle power plants could compensate for the double transformation loss.


If I take a therm of natural gas that I would have put into the delivery truck and put in in a gas turbine power plant I could get 40% of the energy out as electricity.

I will then have 36% after I transmit it, then 33% through the charger and then 30% into the batteries. 27% out of the batteries 25% through the controller and just over 20% through the motor to the wheels on the pavement.

A good diesel CNG delivery truck could probably to the same without the expense, load on the grid and range limitations.


GE's Natural Gas combined cycle plants have a cycle efficiency pushing 68%. This is where we need the push. Also Honda's NG cars already in production offer a low cost alt to gasoline for people w/ NG to their house.

The US needs to run a parallel effort w/ electric cars which includes NG for both transportation and electrical power generation.



Average combined cycle efficiency is 85% (gas or any other fuel). It means that you get 30%-50% electrical efficiency and 55%-35% heat. For gas CHP average electrical efficiency for full CHP cycle employing gas and steam turbine in series is 50% electricity and 35% heat and 15% loss. You are mentioning new development of GE for condensing cycle when you can extract even 68% electrical efficiency.



There is no existing gas condensing (without heat offtake) with such low efficiency. Since we are talking abot future transportation we should talk about future power generation. Condensing gas power plants (construction contracts) are based on 60% electrical efficiency and combined cycle gas are based on 90% overall efficiency. So your comparison at least two times wrong.


Can a very high efficiency combined cycle NG power generating units be scaled down to supply variable e-energy + heat for an average size residence? The unit output should be completely variable (from 1 to 10+ Kw) without efficiency loss to avoid use of batteries for e-energy storage. This way, existing piped in NG could be used for high efficiency heat pump equipped HVAC + PHEV-BEV chargers + all other electrical requirements etc. There would be no real need to be connected to the power grid.

Would the increase in local (city or town) GHG become unmanageable?


I would opose natural gas strategy being main fuel for transportation for several reasons:

1. Natural gas not abundant resource. In Europe surplus natural gas needed for transportation could come from one source - Russia. Price of natural gas for long time was tied to oil price and this link still valid in Europe. Natural gas price is double of US spot market price. The US gas consumption increasing rapidly and therefore US will be importing LNG from middle east. It is just repetition of oil consumption pattern.
2. I would support development DME strategy like it goes in Sweden. There are several advantages of DME over natural gas: DME can be synthesized practically from any source including biomass, cellulose, lignite, coal or natural gas; available LPG distribution network would be suitable for DME; low preasure (6 bar).

The was reference in the article of Russian natural gas application for heavy transport and public transport. Natural gas solution would be perfect for Russia with it's huge and biggest in the world natural gas reserves. But I am quit sure this will not work for any other country for long perspective.


Harvey D,

There is some developments of residential (distributed) power generation. This is really wast subject. There is some limitations for in-house power generation. Main are noise maintenance and investment cost. Actually to make really CHP (combined cycle) you have to have good match of heat and power off-take. In order to be complete island operation you apartment this ration is difficult to achieve. In case you would like stay connected to the grid, you have to have smart grid solution with advanced price setup. In other case you will be eligible for grid charge since you will be consuming grid service. And for retail (apartment) consumers grid service constitutes two thirds of final power price. In order to mitigate noise and reliability issues has been developed natural gas fuel cells. Anyway calculations demonstrates, that distributed solution is far more expensive (power price vise) than centralized power generation. Now days distributed power generation has meaning of small generations at big office and industrial locations with even heat/process steam off-take.

Henry Gibson

Combined heat(cooling)and power generation of electricity at home is now commercially available from a very few sources. Honda is the most sold one at the moment. The electrical efficiency is secondary to the total efficiency of the use of the heat which can approach 100 percent or more with sufficient capital expense. The electrical efficiency can approach 40 percent in small systems. It seems to me that a variation of the the NOAX hydraulic free piston could be the most efficient small scale engine.

All new commercial buildings including condominiums should be required by law to have cogeneration if natural gas is available and going to be used. If insulation is required by codes so should cogeneration. There will always be a payback to the operator of such buildings even though the original owner will have to pay more to get it built. How many bathrooms would be be built if they were not required by code.

The electricty produced by such buildings can be used also to charge plug-in-hybrid cars with very high efficiency.

Methane can be made from corn with far greater efficiency than than ethanol can be made, but coal and any form of organic materials, including biomass that usually goes to landfills, can also be used to make methane.

Dakota Gassification has made a lot of methane from coal with Carbon capture and use. They could demonstrate %100 CO2 free generation of electricity from coal tomorrow or at least by next week with a little bit of creative operation and accounting. Not all of the CO2 produced by Dakota Gassification is in demand but most of it is, so they can demonstrate CO2 free generation from coal by reducing the production of methane for a few days.

In case you are wondering what equipment would be used. It would be an ordinary spark engine generator fed with a mix of pure oxygen and methane and carbon dioxide. The water would be condensed with a long pipe and the remaining CO2 fed into the CO2 system and recycled or sent in the pipe to Canadian oilfields.

Every spark ignition and diesel car sold in any country should be required to have a place where natural gas can be injected into the manifold with a simple valve controlled by the computer. The natural gas will not run the car alone but it might reduce the use of gasoline or diesel by half or more for some trips. The natural gas tanks can be designed to be removed if luggage space is needed for long trips. Homes can have their own compressors(PHILL). The natural gas is intended only for local trips, but some service stations can be equipped to sell it without much effort, but since the car can be run on and requires gasoline or diesel at all times there is no need for service stations to sell CNG. Methane can be made legally at home. ..HG..


Just watched a documentary program on shale gas exploration in Penn State USA. The unexpected long lasting extensive damages to the environment are almost unbelievable. Local ground water has been deteriorated for decades if not centuries to come. Gas and harmful chemicals are slowly migrating to the surface and most living species will have to leave the immediate and nearby areas. Some of the most beautiful areas are being destroyed. Local residents have been had by major producers.

Can better regulations stop this carnage?

One can wonder if that type of NG is an acceptable solution. It is certainly more damaging than Solar and Wind power.

Tim McAuliffe

Darius, Natural gas reserves have actually been growing substantially and are much more geographically disperse than oil. Australia has massive reserves, is a major exporter of LNG and the US is about to become self sufficient due to huge coal seam gas expansion.


In 2005, the Republican Congress and President Bush signed into law making natural gas drillers exempt from EPA regulations. Cheney was a natural gas guy and G.W. Bush sat on the board of an oil company.


Another point is the 600 coal fired power plants. They are not going to be torn down and replaced with combined cycle natural gas plants any time soon.

When you look at the whole power production plant mix that runs on natural gas you have a good snap shot of where we are now, not where some wish us to be and hope we will be in the near future.


By continuously leveling at the lowest cost and higher profit solutions, Americans, Canadians and Australians (any many others) are progressively mutilating their environment and endangering the life of many species including ourselves.

Shale Gas, Tar Sands explorations and Coal fired power stations are perfect examples of what should be avoided and/or cleaned up.

The (R) Drill baby Drill attitude is damaging Penn State areas beyond repairs. It is a good thing that New York State has applied a moratorium on Shale Gas exploration, at least until such times as safer methods are available. The St-Lawrence lower valley is being attacked and mutilated in hundreds/thousands places very near local farm buildings an houses. It is not a very wise thing to do in an area with a surplus of clean electricity. Large operators bought undr ground mining rights for 10 cents an acre and force their way on beautiful farms without asking. It is a real mess. People are 98% against such irrespective methods and the latest town hall meetings have been very noisy. Operator's personnel had to be escorted out.

Shale Gas is currently a multiple (ground, under-ground, air, water etc) polluting adventure. Objection is mounting. There are many cleaner ways to provide essential energy.


Someone pointed out that once ground water is polluted it can not be restored. I guess the trade off is suppose to be that you will be able to heat your house in the winter even if you have no clean water for washing, cooking, cleaning, drinking or any of those other needs.


Yes SJC, with gas, oil, chemicals, heavy metal, radiation, mud, slim etc flooding drinking water wells, streams and rivers and oozing out of the ground for decades, life around shale gas operations may never be the same again.

We are doing it one more time and on very large scale. We need the low cost energy from shales, regardless of the consequences. We have found a way to reduce crude imports. We are very smart, Drill baby Drill again.

We are our basic values and common sense?


There were no societal considerations, the laws were changed in 2005 to make it easier and cheaper to bring in wells. They can sit on them and write contracts as the prices rise, once again it is about big money.

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