With India Getting Its First LNG-Powered Bus, Is It the Fuel of the Future?
Tata Motors has launched a trial run of LNG-powered buses in Kerala. (Photo: Tata Motors)
The prices of petrol and diesel never seem to come down which, in turn, is pushing automakers to look ta alternative fuel options. Tata Motors, one of India’s biggest automakers, seem to have found the solution to be Liquefied Natural Gas (LNG) and launched the country’s first LNG-powered bus in Kerala, where a trial run of these buses is currently underway.
With India expected to see an increase in demand for LNG over the coming years, owing to increased demand for the power, fertiliser and automotive sectors, the government also seems that it has plans to move towards a gas-based economy.
But is it actually possible it to be the next choice of fuel and what kind of obstacles were faced in coming up with an engine that could deliver in everyday scenarios while being efficient and easy on the environment? We had a chat with Dr Ajit Jindal, Head Engineering, Commercial Vehicles at Tata Motors and this is what he had to say.
Q. How did the initiative for an LNG-Powered bus begin?
A. We have been doing some studies since past few years on what kind of an alternate fuel can be used in the future and we saw that there has been a shift in trend towards LNG as an automotive fuel. It has been used by the US in small numbers for quite some time and in the last few years, China has taken a big stride in terms of migrating from diesel trucks to alternate fuel-driven vehicles, like CNG and LNG. There have also been a lot of studies in Europe and US about the total cost of ownership of these vehicles and LNG has been coming out as a favourable proposition. Initially, our focus was on the industrial use of LNG, however, there was always a possibility that it can be extended to trucks and buses.
When we started looking at LNG then a few issues came in light.
First was the range. In CNG vehicles, it is limited by the amount of gas the vehicle can carry. For example, if you want to carry a lot of CNG, then you have to carry a lot of cylinders, which means the kerb weight would be high. To strike a balance, you carry a limited amount of gas that gives you a range of 250-300 kilometres. This range is okay if the vehicle travels short distances, but not when you want to travel long distances.
Then there was the price differential between Diesel and Gas. In Delhi, the price differential is good and people are forced to buy CNG buses because of the diktats laid out by the Supreme Court and the regulators. But for other places, the pull towards CNG is not that strong.
While we evaluated range, there was also the fact that when people use CNG, there is a lot of unproductive running of the vehicle, be it a truck or a car, because of the small range that you get with it.
Looking at all these things, we thought we should look at some other alternative fuel which came out to be LNG. Then we started working with oil companies as to when and where can we get LNG as an automotive fuel.
Q. When you say oil companies, are you referring to Petronet LNG Limited (PLL) and Indian Oil Corporation Limited (IOCL)?
A. Yeah, initially we were only working with IOCL. PLL's interest in the automotive sector has started recently. IOCL supported us as they provided an LNG-filling arrangement in vehicles that were inside Tata Motors, as we could not run these vehicles on road.
We made an LNG-powered 'Prima' truck around four years ago and showcased it at the (2014) Auto Expo. The whole idea was to show the country that there was another alternate fuel available and, in turn, get people excited about this technology and get their feedback.
That's how we generated momentum to initiate this project and worked with the government, ARAI and certification agencies to get all the approvals in place. Now, the regulations have been formulated and the draft has come in. The final form will very soon come.
The oil companies are also working in parallel with these organisations to set up LNG-filling stations. So it isn't like we will just make a vehicle and start selling it as there are a lot of other associated regulatory framework and approvals that are required, and that's what we have been doing since the last 3-4 years.
Q. So when you showcased the LNG-powered Prima truck at the 2014 Auto Expo, the plan to have a commercial run of LNG-powered buses was already in place?
A. We have been doing trials with the Prima truck for the past one year and we are now going for a larger, fleet-trial kind of a thing.
Q. What kind of an investment was required and invested for coming up with the required engine?
A. For the shift from a CNG engine to an LNG engine, we don’t have to make a lot of changes and Tata Motors already has a wide portfolio of CNG engines.
The engine remains largely the same when you migrate from CNG to LNG. The changes include – having a cryogenic engine, an evaporator, suitable valving etc. so that when the fuel is delivered to the engine it is in the gaseous state, which is similar to CNG engines. Hence, I would say that our investments have been more in terms of testing, migrating and investing in getting the right cylinders. And, of course, running of the vehicles etc. When we go for heavy duty vehicles, we will have to develop a different engine and that is what we are working on right now.
Q. The LNG-powered bus LPO1613, which was recently launched as part of a trial-run in Kerala, is claimed to be lighter than buses powered by conventional fuel. What was done to keep the weight in check?
A. When we say lighter, the comparison is to the equivalent CNG vehicle. There are two ways of having CNG in vehicles – one of which is to have cylinders, which are heavy. The advantage of switching to LNG is that you eliminate the need of having all those cylinders. The LPO1613 in particular carries around 6-7 cylinders and each cylinder weighs around 150 kilos. Once we switched to LNG, all that weight was eliminated and that is why it is lighter.
As far as the range is concerned – by design, in liquefied form, the energy density per litre is 2.5 times the gas. So, when there is a gas cylinder of 100-litre water capacity, then the CNG you can fill is only 16 kilos. Whereas you can store around 41 kilos of LNG in the same cylinder. Usually, the LPO1613 carries around 116-120 kilos of CNG gas. Whereas, the cryogenic tank (used in LNG vehicles) of 420 kilos carries 160-180 kilos of LNG gas. Since we carry extra fuel and the weight to be carried by the engine is lighter, the end result is a higher range.
Q. LNG-powered engines are prone to ‘methane slip’ wherein some methane gas escapes due to incomplete combustion which, in turn, adds to the greenhouse effect. It can also evaporate during the refuelling of the vehicle. The global warming potential of methane is about 25 times higher than CO2 but since the implementation of LNG-powered buses is an eco-friendly model, what steps have been undertaken to prevent methane slip from the engine?
A. From vehicles, there is no escape of methane as such. The filling mechanism is designed as per international standards and as per Euro norms. So, there isn’t a lot of evaporation.
I do agree that while refuelling, some evaporation may happen but that's a minuscule amount. There's no exact data to show the amount of methane slip while the vehicle is being filled. As far as the combustion of the engine is concerned, even at Euro-4 regulatory levels, there is a limit of 1.1 g/KWH and as per our testing and data, we are very well below that limit of methane slip.
Also, as compared to many other benefits of LNG, this is minuscule of a number. The focus is on reducing the CO2 emissions, which in LNG and CNG powered vehicles, is a lot less as compared to other fuels.
Overall, the greenhouse potential of CNG and LNG vehicles is much less than petrol and diesel vehicle counterparts.
Q. So are you saying that your LNG-powered bus will comply with euro-4 Emission norms?
A. Yes, if you compare with diesel, the particulate emissions are a lot lower than gas engines. You are right, from a PM perspective, gaseous fuels are proven to be best than any other fuel.
Q. What’s your take on GST and what kind of an impact from it do you see on the alternate-fuel driven vehicles in the coming future?
A. I am not an expert on GST, our goal is considering that the how the LNG emissions compare with Diesel and other vehicles. This is my personal opinion, we are not looking at any specific subsidy for LNG. Whatever is there for CNG, is there for LNG and we look at it from that perspective.
Q. Tell us about the future plans of Tata Motors. What can be expected in the coming future given that you also showcased a fully-electric bus at the 2016 Auto Expo named ‘Ultra’?
A. We have showcased electric vehicles, we have been working on hybrids for quite some time and we have an order from MMRDA for 25 hybrid buses and we are also working on fully-electric. You will see soon see hybrid vehicles running on roads and electrics are not very far off.
Q. Any timeline as to when can we expect for the LNG vehicles that could be commercially used?
A. The timeline which we are hoping for the vehicles to be on road, considering that a lot of regulatory things have to happen, is sometime by April 2017. For heavier vehicles, it could be some quarters down the line – around the end of 2017 or early 2018.
Q. Could we expect this LNG technology to make its way in something other in your portfolio other than buses?
A. It depends on the infrastructure availability, but the next target is trucks that would be powered by an LNG engine. It maybe that initially they are lighter duty trucks but in times to come, heavy duty vehicles might get LNG engines. As you know, it all depends on the road map the oil companies have for gas stations, because without gas stations in place, no one will buy them. People will buy these vehicles the moment they see gas stations.
So that’s how we are working and that's how the whole launch happened together with PLL and IOL. Hopefully, everything will get sorted out quickly, then we will have more vehicles on road.
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