M1L7 : Conventional and unconventional gases-I

In the previous lecture, we studied about Biofuels. In this lecture, we shall go one step ahead and cover the fuels that can be used. But before that, let us revise, what we have covered till now.

From this diagram, we find that almost 50% of energy module is over. We covered clean coal technologies and AUSC under coal sector in India, Biofuels in the previous lecture and e-vehicles, fuel cells and BSIV to BSVI in prior to it.

In this lecture, we shall cover, forms of Natural gas viz. PNG, CNG, HCNG and LNG (not to be confused with NGL) and contrast them with Biogas/Bio methanation process and LPG.

Finally, we shall cover the other unconventional forms of gases that can be useful for the energy security of India. This part includes Shale gas, CBM and Methane Gas Hydrate.

Let us start with the basics. First of all, what is natural gas? The obvious answer is Methane.

Now the next question, why do we find methane releasing from landfill sites, where we pile up municipal solid waste and garbage? Because, whenever anything rots, it releases methane. So, may I ask now, if coal and crude oil are products of organic waste, were they releasing methane when the organic matter was decomposing/rotting? An obvious answer would be yes. In the case of coal seams, we call this methane as coal bed methane, whereas in case of crude oil or petroleum, it is called natural gas.

Think over it. You just used the word ‘gas’. Can we convert this gas to liquid? We studied this in our school life that, in the case of gases, the molecules are located at far distances from each other. If we can bring those molecules closer, we can convert this gas into liquid form. The same technique is used here

When we compress NG, it first becomes PNG (piped natural gas). Since the molecules have come closer, the energy density in PNG is more than normal/regular NG. Where do we use it? This PNG is now used as a replacement for LPG bottled gas cylinders.

This means, that by compressing the molecules of NG (Natural gas/methane), we can bring the energy density of it closer to propane and butane which are the major constituents in LPG.

Now, what if we compress this PNG further? Then it becomes CNG (Compressed Natural gas). CNG is used as an alternative to petrol.

Can we compress CNG further? Obviously yes since it is still gas. But further compression will bring the molecules closer to an extent that it becomes liquid. At this phase, it is called Liquified Natural Gas or LNG.

Compression level: Gas → Liquid → Solids

NG (methane)

→

PNG as an alternative to LPG

→

CNG as an alternative to Petrol

→

LNG as an alternative to Diesel

So, we find that CNG can be used as a replacement for petrol and LNG can be used as an alternative to diesel. Why is this important? Because gas burns cleaner than solid and liquid fuels. Let us understand this with an example.

The government has rolled out a scheme wherein certain families are given free connection to LPG cylinders. The reason being is, they are still using charcoal and biomass in open sigrees that contribute to indoor air pollution. Since LPG is basically a gas, it burns cleaner and therefore doesn’t leave any residual ash or particulate matter, unlike open sigrees that use firewood and small twigs and sticks or biomass or charcoal. Therefore, in order to relieve them of such problems, the government has come out with a policy to give them LPG connections at minimal cost. This will also help in enabling them access to better opportunities. For e.g. when a lady and her teenage son or daughter go to collect the twigs and sticks as a source of firewood, they waste their time in it, which can otherwise be used for other productive activities like studying. A well-educated person can prepare himself/herself for better opportunities, that may come in future.  Similarly, a lady collecting firewood risks getting exploited by the chief warden of wildlife is she is doing this in protected areas. So, the crux is, by shifting these families to LPG, it will help them invest their time in more productive activities which was otherwise lost. And let’s not forget that since LPG burns clean, it will help to reduce the problem of indoor air pollution that is one of the major reasons for infant deaths (IMR), miscarriages and deaths of women at early ages. Reduction in IMR and MMR, will help India improve its SDG ranking.

Therefore, with this example, one thing is clear. Gas burns clean. Be it LPG or be it CNG. So, when we shift from Petrol to CNG or from Diesel to LNG, wont this help to reduce the problem of air pollution? Answer is obviously yes. But, the billion-dollar question for India is that since it doesn’t have enough reserves of natural gas, from where will procure these huge amounts of it to make a successful transition to gas-based economy? (#Energy security)

For this reason, we are working on three pipeline projects. They are TAPI, IPI and BMI as follows.

Now in the earlier lecture, I had asked what will be the impact of sanctions on Iran on our clean energy targets? Iran and Qatar sit on one of the largest natural gas fields in West Asia known as South Pars. As per India’ commitment to Paris Agreement, India has pledged to reduce carbon emissions by 33% compared to 2005 levels by 2030. In order to do this, India cannot avoid the requirement to shift existing petrol and diesel vehicles to CNG and LNG. Since, the climatic conditions of India are not favorable to LNG since LNG needs cryogenic temperatures to operate, at this moment, the government is working only on CNG as the infrastructure for the same is readily available. However, it should also be noted that Iran sits north of one of the major maritime choke up points known as Strait of Hormuz. In case a war breaks out between Iran and her neighboring countries, it can create a major disruption in the supply of natural gas to India. India is, therefore, trying to diversify its supply of natural gas and Australia is ready to fill that gap.

In the next image that I show now, you will notice one more thing. The places where we have fertilizer plants lie on the gas pipeline network. Why?

Natural gas is used to make urea. And we import most of this natural gas from Iran. One option to reduce the high costs of it would be to use Underground coal gasification (already discussed) as an alternative to natural gas to make urea in India. This will help in two ways

Fertilizer subsidies hold a major share in government expenditures and contribute to the fiscal deficit. This is due to the fact that the raw material for the same is sourced from outside, for which we pay in foreign exchange. Using UCG to get methane will reduce our dependence on externally procured natural gas and help us to save a lot of valuable foreign exchange.

Additionally, this will help us start using unproductive coal and lignite mines as well as promote Make in India program.

So finally, we need methane for CNG and making urea. But what about H-CNG? Recently, the Delhi government held trials for H-CNG. Isn’t it?

Hydrogen-enriched natural gas or Hydrogen-CNG or H-CNG contains 4%-9% hydrogen since, beyond this limit, it may lead to overheating of an engine and abnormal combustion of fuel (which may then contribute to knocking (engine vibrations)).

H-CNG offers a faster rate of burning and combines the advantages of both hydrogen-based fuel cell technology and methane-based CNG technology. While it is safer to handle than hydrogen, it also offers an advantage of producing considerably less amount of NOx emissions, less than what we can achieve through BSV levels. (Pls note that now we have decided to skip BSV and jump directly to BSVI) It improves engine efficiency and lowers fuel consumption.

Any natural gas engine is compatible to run on HCNG and therefore allows governments and agencies to promote the use of hydrogen to a greater number of people at less cost.

So, in this lecture, we saw how can methane help to reduce pollution. In the next lecture, we shall drive one step ahead and study the scope of Methanol based economy, Shale gas, and CBM in India.

Do you know? The government of India has recently decided to extend the gas pipeline network from Jagdishpur in Uttar Pradesh to Bhubaneshwar in Odisha. This project is named as Urja Ganga