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Accelerating emission reduction from the coal sector in India

Image by Markus Distelrath from Pixabay

Thought paper by Prof Lesley L Sloss, International Project Manager

1) Thoughts on the evolution of the Indian coal sector

The focus of this USDOS project was the reduction of mercury emissions from the Indian coal utility sector through identifying means, procedures, and where possible, political drivers for mercury reduction. It is acknowledged that mercury is low on the list of environmental priorities for India, but mercury control comes as a co-benefit with almost every strategy to improve plant performance and reduce all emissions from a coal plant. This project therefore concentrated on training and capacity building in knowledge and skillsets which would help to consolidate mercury reduction strategies into current and future energy policy.

The coal sector in India is growing and, in the absence of reliable dispatchable alternatives (such as gas or nuclear) the transition to variable renewable energy (VRE) will be more challenging than for many other countries. The existing coal fleet will persist, and new coal plants will be built to ensure power demand is met in India. Over and above this, the scale and nature of the Indian power grid is such that coal plants are required to “flex” more than any other coal fleet worldwide. This means that Indian coal plants are often asked to run at as low as 50% load and/or are required to “cycle”, turning off and on in a weekly or even daily basis. Older coal plants were designed to run at baseload – flexing operation causes wear and tear which can lead to significantly increased outages and can reduce the lifetime of a plant by decades. More importantly with respect to this study, flexing operation can decrease plant efficiency and increase emissions by over 10%. Further, emission control technologies for SO2 and NOx perform less efficiently or sometimes not at all during flexing operation. This is therefore counterproductive for the energy transition – the coal plants being used to provide the bridge to cleaner power are becoming significantly more polluting as they do so.

India is considering options such as carbon capture and storage (CCS) with at least one trial plant being built. But with the scale of coal power in India and the current high cost and risk of these technologies, CCS is not yet an active route to zero-emission power for India.  Currently, India is focussing on faster uptake of VRE and supporting energy storage solutions. But these are also not yet available or applicable at the scale required to maintain grid capacity in India.

In the interim, therefore, it is critical that India maximise the performance of their coal fleet. The EPRI flexibility toolkit and associated training that was delivered during this project has been adopted by the major utilities such as NTPC and Adani.

This will help ensure that emissions from flexing plants do not increase and that outages are avoided. However, Indian stakeholders will need to stay on top of this issue. They must monitor fleet performance and prioritise power production from those plants with the highest efficiency and lowest emissions.

India is considering biomass cofiring at coal plants which could offset emissions from coal. However, as most coal plants are currently being asked to flex and to install pollution control systems (see below), the addition of a requirement for co-firing biomass (with the mechanical, economic, and logistical challenges this brings) will simply add to the technical burden on the operator and could lead to poor decision making and subsequently to significant reductions in plant performance. Rather than expecting all plants to comply with all these demands for change simultaneously,  it is strongly recommended that the sector  appoint different plant “types” to allow each to focus on one challenge at a time. This would mean a fleet divided into:

  • flexing plants (cleaner, younger plants which are less likely to fail or perform poorly under flexing operation)
  • biomass co-firing plants (older and smaller plants which are less critical to the grid, and which can operate experimentally as required)
  • plants which should undergo pollution retrofits as a priority (the “dirtiest” plants and those which have significant remaining plant lifetimes to recover the cost of investment).

And, in order for this type of coordinated approach to succeed, there needs to be more cooperation and coordination by the national and regional governments working with the utility stakeholders.

2) Thoughts on emission reduction

In 2015, after having little or no emission standards for pollutants other than particulate matter (PM), India introduced limits for emissions of PM, SO2 and NOx which are almost equivalent to those set in Europe and the USA. In these latter regions, the tight emission limits were achieved gradually over decades, allowing the development of control technologies to meet the needs of the standards. India is attempting to leapfrog to the same stringent standards despite having significantly different coals (around 50% ash compared to 5% or lower elsewhere), different plant configurations, lower water availability and a significantly lower national skillset. It should therefore not be surprising that the compliance rate with these new standards in India is below 5% across the fleet for pollutants other than PM.

India has no national pollution control industry and no major manufacturers of emissions control technologies – it may not even have the raw materials available to build such systems in the timeline proposed. Pollution control systems are relatively new in India, and so the sector faces a steep learning curve. Plant operators are therefore hesitant to be the first to invest heavily in control systems that may not work, or which may run well over cost. Those plants which step up to forge ahead in this area should be recognised and, if possible, financially rewarded for doing so.

It is vital that they share their learnings to accelerate the advancement of sectoral skills across the fleet.

However, the problem then becomes one of who will pay – both the Indian government and the end-user, the Indian population, are already economically challenged.

Mercury control can be built into emission control strategies which focus on PM, SO2 and NOx.

However, it is clear from our workshop feedback in India that most stakeholders still do not consider mercury as a real problem.

There are still many who believe that Indian coals either contain low concentrations of mercury or none at all (not true) or that mercury emission in India are not a concern (again, not true). However, to date, all inventories for mercury emission in India are created from emission factors – there are little or no data on actual emission concentrations. Real data are vital for proving that the issue in India is real and for raising awareness of the importance of applying mercury control.

Finally, whilst economic and technical challenges may be responsible for some of the delays and derogations in emission reduction on Indian coal plants, the ever-expanding timeline of policy development is the real issue. Delays, derogations, and dilution of the emission legislation have been persistent and continuous since the first legal notification in 2015 and remain ongoing. Why would any plant operator spend money to comply with legislation when the legislation continues to weaken in real time? If the Indian government want coal plant operators to comply with emission reduction requirements, then they must hold firm on the standards and deny any further flexibility. Over and above this, they must ensure that the regulations are held firm by regional and provisional government throughout the entire country, which may require additional oversight and monitoring.

3) Thoughts on compliance monitoring

As mentioned above, India has little or no real data on mercury emissions and therefore many stakeholders we spoke to use this as an argument as to whether a problem really exists. The same issue is relevant for emissions of the other major pollutants, PM , SO2 and NOx. Without accurate data it is challenging to determine which plants are in compliance with emission limits and which are not. Emission data are critical for creating regional and national inventories which can inform policy development and regional deployment and make targeted change, when appropriate.

Continuous emission monitors (CEM) have become a legal requirement to ensure compliance with the emission limits introduced in 2015. In order to maximise the choice of available equipment, India has adopted both European and US CEM methodologies. This indeed opens up the international market but, at the same time, introduces confusion and complexity to the guidance documents. European CEM must be certified by an accreditation body in Germany before use. Certified CEM system are regarded as “plug-and-play” as they have been certified fit for purpose for defined uses. US CEM are not certified – any CEM can be used as long as it passes tests on site to confirm that it is fit for purpose. To date, Indian stakeholders are showing a distinct preference for certified CEM systems as the certification implies suitability and ease of use. US vendors are finding it challenging to find footing in the Indian marketplace as a result.

The Indian government has complicated things further by insisting that data from CEM systems are delivered live and in real-time to the regulators. This approach is intended to curb data tampering, which was reported as persistent and rife. However, in reality this results in the regulator being overwhelmed by the sheer volume of data, none of which has been flagged with any clarification. In Europe and the US, the source operator collates CEM data on site and sends in hourly, daily, or monthly summaries, as required. This allows the operator to flag issues such as limit excursions which occurred to common issues such as start-up and shut-down, which would otherwise be flagged as offences. From our discussions with plant operators and regulators in India, both parties agree that delivery of raw data is currently not working – regulators are overwhelmed with alerts which could otherwise have been avoided and they admit that they do not have the workforce to assess and react to the data coming in.

The review conducted for USDOS found that fewer than 50% of plants had CEM installed and performing adequately for PM, SO2 and NOx. CEMEG-India, the stakeholder group created as a legacy initiative from this project, has produced a draft report (Jan 2024) which reviewed CEM installation and maintenance. Although only a few hundred questionnaires were returned, it was apparent that the vast majority of CEM users, and even CEM vendors in India, have a basic understanding of CEM operation and significant mistakes are being made. For example:

  • CEM are being accepted as EU certified whereas the only certification is that from the vendor, which is not sufficient
  • vendors are the only consistent source of training for CEM implementation and yet, on the training course delivered by this project, several vendors had the lowest scores on the final competency test
  • over half of the replies demonstrated a complete lack of skills with respect to calibration and correction of CEM operation.

What this means is that, although CEM are now installed on the majority of coal plants in India, fewer than 50% are reporting data and, of those reporting data, it is highly likely that the data are flawed. And since there is no oversight, audit, or inspection system in place, it is not possible to determine which plants are doing fine and which need help.

This USDOS project produced additional report materials on Best Practices in CEM and a Checklist for CEM implementation, freely available to all stakeholders in India. However, until there is a coordinated effort to standardise a skillset in CEM use in India (and other emerging economies), the data will remain unreliable which will ultimately affect the efficacy of any emission reduction strategy.

In Europe and the USA there are organisations which have established standardised training in CEM use. Our project delivered such training in India to over 400 delegates. However, unless this training spreads and is benchmarked across the industry, the quality of data will remain low. This is an opportunity for India to create a whole new career sector – CEM installation, operation, and auditing. But to achieve this, they will continue to rely on support from Europe and the USA.

4) Thoughts on ash management

Indian coal plants have been collecting fly ash from PM control systems for decades. In many countries, this fly ash is a valuable commodity in the construction industry. Although the Indian government required 100% fly ash utilisation from coal plants in India, some plants, especially those in the highly industrialised central belt, find it a challenge to locate an end-user within an economic distance of the plant. Whilst better stakeholder cooperation and improved transport links will improve fly ash use, the challenge remains for legacy ash piles. These piles contain ash which has often been discarded for years, if not decades, and which are now damp or overgrown with weeds. Plants have an obligation to use 100% of this fly ash too, but it is often unsuitable for any construction uses other than mine backfill. There could be potential to make money from these piles if they are found to contain elevated concentrations of cenospheres (bubbles of fly ash which are valuable as lightweight filler) or even rare earth elements (REE). However, although these may indeed be potentially economically valuable, significant research and investment would be required to confirm these potential uses, to ensure a market for the product, and to develop extraction techniques to deliver volumes of product at economic scale. This is not something that individual coal plants have the time or money to invest in, rather the initiative would need to come from the regional or national government. The return on investment could be significant but will not be realised without external incentivisation. Many nations are currently looking to identify and recover valuable reserves of REE – India should collaborate with international stakeholders to share information and to ensure that the country is not left behind in this global race to secure these valuable new resources.

5) Proposed actions:

  • India has made significant efforts to catch up with the international community in terms of emission monitoring and control. However, they are doing so at such a rate that errors are being made. India must hold fast on its goals but must continue to take as much international help and advice as it can to help with this technical and intellectual leap.
  • The rushed emission standards were questioned by industry when they were introduced in 2015 and delays and derogations continue to date. The time has come for the government to hold fast and to enforce the legislation consistently across the country.
  • There is currently a “perfect storm” of challenges to coal plants in India – they are being asked to flex, to retrofit emission controls, and to co-fire biomass. All this at once is likely to result in plant damage and outages. Rather, there could be a coordinated or regional plant to allow plants to focus on one of these challenges at a time.
  • Accurate emission data are vital to a successful emission reduction strategy and so India must continue with our initiative to establish training in CEM operation
  • India has the opportunity to create new national areas of expertise in emission control, flexible plant operation, biomass co-firing, CEM operation, and ash management. By continuing to collaborate with international experts, India can build strong new skillsets and business models that would expand nationally and could be shared with other emerging nations in Southeast Asia.