Growth, Sustainability and Energy Security– Coal Gasification Shows the Way
Coal has been the primary source of energy for homes, industries as well as transportation for over two centuries. Coal powered steam engines powered the industrial revolution as well as sea and land transport in Europe, in the eighteenth century. Even prior to this, it was extensively used for production of Iron which was needed for manufacture of implements, tools as well as machinery.
Even till the latter part of the 20th century, coal was the major source of energy across the continents and accounted for over 65 per cent of electricity generation world-wide.
With the increasing concerns around global warming and climate change, coal has been identified as a major contributor to the environmental crisis. Of the 38 Gigatons (Gt) of CO2 released into the Earth’s atmosphere annually, the lions share comes from the use of fossil fuels, with energy-related greenhouse gas emissions accounting for the majority of all emissions caused by human activity. According to the International Energy Agency, the power sector accounted for nearly two-thirds of global emissions growth, with coal use for power generation alone producing over 10 Gt of CO2.
India, with its huge reserves of coal, has relied on coal as the primary source of energy, with over 70 per cent of its electricity generation coming from coal. In the last decade, coal has gradually become a pariah in the international community with many developed countries announcing shutting down of coal power plants. Even funding as well as technology support for thermal power has gradually been shut off and it is becoming difficult even to get insurance covers due to non-availability of reinsurers.
In this scenario, India is, today, grappling with the conflict of balancing the aspirations of 1.41 billion people—more than one sixth of humanity, with the imperatives of sustainable growth. While the developed nations have achieved their economic growth on the use of traditional energy sources and in the process consumed 80 per cent of the planet’s carbon budget, today that option is no longer open to any country in the world. For a country the size of India, ensuring a well-planned and just transition away from coal is a challenging task.
India has seen a sharp stop to thermal ordering in the past years from 12,500 MW in FY2015-16 to Nil in FY2021-22, and no ordering for almost three years. The fallout of the Ukraine war on the international energy supply scenario and rising oil/ gas prices, has sharply brought into focus the dangers of over dependence on external sources of energy. A number of European nations have in fact, either restarted their coal based thermal power plants or are increasing the outputs from existing coal based facilities.
It is today, an accepted fact that it is not just coal but all fossil fuels which will need to be phased out. However, resource availability will be a key factor deciding any country’s energy mix. India is the fifth largest producer of coal with an annual production of ~770 Million Tonnes (MT) in 2021-22 and estimated coal reserves of 350 Billion Tonnes (BT) (including 163 BT of proven reserves—mostly high ash coal). Given India’s huge coal reserves and scarce oil and gas reserves, coal has now been recognised as an imperative for the country – at least in the short to medium term— from an energy security and economic stability perspective.
As such, we are seeing a resurgence in the tendering for new thermal power plants and it is estimated that somewhere between 15,000 to 20,000 MW of coal power plants will be ordered in the next 4-5 years. While there is a revival of coal-fired power plants in the short run, it cannot however be a long term solution, given that thermal power contributes to more than 40 per cent of all the carbon emissions in the country (with transport, steel and cement being the other major polluters contributing around 35 per cent). As such, the use of coal, will need to focus on clean coal technologies like coal gasification, carbon capture, etc.
Coal Gasification
While coal gasificaton and use of coal gas has been around for almost two centuries with coal gas having been used for street & home lighting in UK as well as a number of other countries in the early nineteenth century and again used in a big way by Germany during the 2nd world war for producing synthetic fuel for aircrafts and tanks (on account of its huge coal resources and scarce oil/ gas resources).
In today’s context, this process has become very relevant for India because of three major factors:-
1) SynGas produced from coal can be used to produce a range of chemicals such as Methanol, Ammonium Nitrate, Urea, Hydrogen, etc., which are currently produced from imported LNG. With increasing prices of gas and supply instability, this becomes economically viable as well as strategically important and can also help reduce the Current Account Deficit (CAD). It is interesting to note that China, with its vast coal reserves, has been working with western technology for coal gasification since 1950s and today, produces 90 per cent of its ammonia, 70 per cent of its methanol, 2.5MTPA ethylene glycol, etc., from this technology.
2) Coal gasification process gives a stream of almost pure CO2 as a by product which makes the task of carbon capture much simpler and cheaper thus making this process conducive to integrated gasification & Carbon Capture plants.
| BHEL – Pioneer in coal gasification technology |
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BHEL is a pioneer in the area of coal gasification for high ash Indian coals and the oldest player in the country. The development started with establishment of 150 TPD pressurized moving bed gasifier integrated to the power block which was commissioned at BHEL’s Trichy unit in the year 1989. BHEL then shifted the developmental focus towards fluidized bed gasification technology due to its various advantages like feed size flexibility, high throughput and no tar formation over other gasification technologies, especially for high ash Indian coal. A pilot scale development of fluidized bed technology for high ash coal in an 18 TPD Process Equipment Development Unit (PEDU) was taken up as a precursor for establishing a demo plant. Various coals with ash content ranging from 28 - 52% were tested and the gasifier model was validated. Based on the success of PEDU pilot plant, a demo plant of 168 TPD Pressurized Fluidized Bed Gasifier (PFBG) was designed and integrated to the 6.2 MWe IGCC. (4 MW GT and 2.2 MW ST) in the year 1996. During 2021, with guidance and support from NITI Aayog and DST, BHEL has successfully established India’s first high ash Indian Coal to Methanol 0.25TPD pilot Plant, generating methanol with 99.6% purity. This gasifier facility has also been operated with various other fuels like Lignite, Biomass, Municipal Solid Waste, etc. |
3) Due to the reduced cost of carbon capture through this process, cost of clean electricity from coal through the IGCC process is likely to become viable as compared to coal based power plants with carbon capture from flue gases.
The coal gasification technologies currently available from international players require low ash coal while almost 75 per cent of the coal available in India is high ash variety with ash content as high as 40 – 45 per cent. The BHEL technology is the only proven technology for gasification of such high ash coals.
Govt. of India has recently announced a National Coal Gasification Mission for a target of 100 MMT of gasification of coal with projects planned under 3 phases. In the first phase of the mission, MoUs have been signed by Coal India Ltd. (CIL) with BHEL for setting up a commercial scale Coal to Ammonium Nitrate plant, as well as between CIL & GAIL and CIL & IOCL for other chemicals like SNG, etc. Another MOU has been signed between BHEL & NLC India Ltd. for power generation through lignite gasification.
For the Ammonium Nitrate project, BHEL is well on track for the commercialisation of this technology and has already completed the design of the 2600 TPD gasifier with its proprietary PFBG (Pressurised Fluidised Bed Gasification) technology. The technology has been validated by leading international experts in this area and optimization has been done for ensuring lowest costs and best efficiencies. Work on setting up of the first plant (under the CIL – BHEL MOU) is expected to commence immediately on commercial closure/ JV formation.
The lignite-to-power plant, based on coal gasification, will also use BHEL’s own PFBG technology coupled with an IGCC plant (for which BHEL is the only organisation in the country with hands-on experience, having commissioned and operated its own coal gasification based IGCC plant at its plant in Trichy in 1992).
Clearly, Coal Gasification will be a major technology in coming years for generation of clean power as well as production of high value chemicals using indigenous resources as already envisaged under the National Coal Gasification Mission. BHEL’s indigenous technology development efforts in this area, coupled with the ongoing work on development of commercial CCUS (Carbon Capture and Utilisation/Sequestration) technologies will help support the AatmaNirbhar Bharat mission and the country’s growth aspirations as well as the imperatives of achieving the national carbon emission targets.
Dr Nalin Shinghal, Chairman and Managing Director, BHEL
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