Maximum power

Published : Nov 07, 2008 00:00 IST

The research and development plant of Bharat Heavy Electricals Limited in Tiruchi. The plant demonstrated IGCC-mode power generation in March 1998.-BY SPECIAL ARRANGEMENT

The research and development plant of Bharat Heavy Electricals Limited in Tiruchi. The plant demonstrated IGCC-mode power generation in March 1998.-BY SPECIAL ARRANGEMENT

Steps have finally been taken towards using coal-based Integrated Gasification Combined Cycle technology for commercial power in India.

The research and

FOR nearly two decades, the prospect of using coal-based Integrated Gasification Combined Cycle (IGCC) technology for commercial power generation has been under discussion in the country. But it was only on July 1 that definitive steps were taken towards this objective, when the foundation stone for a 125 megawatt (MW) Technology Demonstrator IGCC plant was laid at the Vijayawada Thermal Power Station by R. Chidambaram, Principal Scientific Adviser (PSA) to the government.

Besides leading to higher (about 10 per cent) overall efficiency compared with conventional coal plants, IGCC results in much lower greenhouse gas emissions (see table). One per cent improvement in efficiency results in 1-2 per cent reduction in carbon dioxide emission. IGCC technology can also incorporate carbon capture and sequestration (CCS) technologies in the near future. Therefore, this initiative marks a significant step towards a low-carbon path for the countrys long-term energy strategy. Significantly, this development finds special mention in Indias National Action Plan on Climate Change, which was released by Prime Minister Manmohan Singh on June 30.

The project will be implemented as a joint venture by Bharat Heavy Electricals Limited (BHEL) and the Andhra Pradesh Power Generation Corporation (APGENCO) using technology developed by the former. A memorandum of understanding was signed between the two on May 10. The plant is estimated to cost around Rs.950 crore, of which Rs.530 crore will be invested by APGENCO and the rest by BHEL. The Prime Minister has approved a special grant-in-aid of Rs.300 crore to BHEL to enable it to meet its share of investment. Worldwide, however, government share in promoting IGCC has been around 50 per cent.

This milestone development is the result of recommendations made in October 2005 by an IGCC Research and Development Committee constituted by the PSA and the subsequent initiative by Jairam Ramesh, Union Minister of State for Commerce and Power, to implement them. The committee was chaired by S.K. Sikka, Scientific Secretary to the PSA, and had members from BHEL, NTPC Limited, the Department of Science and Technology (DST), the Council of Scientific and Industrial Research (CSIR) and the Department of Atomic Energy (DAE). According to Jairam Ramesh, the project is expected to be completed in three years with July 1, 2011, set as the target date for the commissioning of the plant.

Finally, there is light at the end of the tunnel, remarked Jairam Ramesh. But, unfortunately, it has come 20 years late, he added. He was referring to the successful setting up of a 6.2 MW IGCC pilot plant at a cost of Rs.15 crore by BHEL in Tiruchi in Tamil Nadu, the first coal-based IGCC unit in Asia and the second in the world, way back in 1988. It was set up soon after the successful operation of the first commercial-scale IGCC demonstration plant in the world, the Cool Water Plant in California (1984-88). Since then, a number of national-level committees have deliberated upon the introduction of IGCC at a commercial level in India but it has taken a long time for some concrete initiative.

The first report on a 100-120 MW IGCC plant was prepared by an expert group of the Department of Coal in 1988, following which nothing important happened. In 1992, the CSIR undertook a feasibility study for a 500-600 MW IGCC plant, primarily with the objective of selecting a coal gasification technology suitable for Indian coal, which has a high ash content of 35-45 per cent (see box). The study arrived at a cost comparison between entrained bed, fluidised bed and moving bed gasifier technologies (at 1989 prices), which showed that the second option had the lowest capital cost. However, it was still about a third higher than an equivalent pulverised coal (P.C.) thermal plant, according to the study.

Fluidised bed gasifier is the best suited for Indian coal, but operating experience with fluidised bed technology is limited globally. In fact, the first Pressurised Fluidised Bed Gasifier (PFBG)-based IGCC plant (107 MW) was established only in 1998 in Reno in the United States (the Pinion Pine Plant). But it was plagued by equipment and start-up problems and never achieved a steady-state operation.

In this context, BHELs achievement of 4,000 hours of operation with PFBG as compared to just about 100 hours logged in by other PFBG-based units in the U.S. and elsewhere is significant. The Tiruchi IGCC plant, in fact, began its operations first with a pressurised moving bed gasifier and, after successful demonstration of combined cycle power generation about 0.4 million units of power was delivered to the Tamil Nadu Electricity Board grid with moving bed technology, the plant was retrofitted with PFBG in January 1996. After a series of trial runs, IGCC mode (as against only combined cycle mode, see box) power generation was demonstrated in March 1998.

In February 1998, the Ministry of Power (MOP) set up two committees to look into commercialisation of IGCC an Inter-Ministerial Steering Group (IMSG) and a Project Advisory Group (PAG). The former, which had the Power Secretary as its Chairperson, apparently never met.

The latter, which was led by the Chairperson, Central Electricity Authority (CEA), and included representatives from BHEL, the NTPC, the CSIR, the DST and the Ministry of Environment and Forests (MoEF), however, submitted a report to the MOP in January 1999. The report estimated the cost of a 100 MW plant to be around Rs.610 crore and recommended that the Global Environment Facility (GEF) be approached for funds and that an international consultant and an Indian consultant be appointed. However, the GEF did not agree to fund the project.

The issue was once again taken up in 2000 by the DSTs Technology Information, Forecasting and Assessment Council (TIFAC) and the Confederation of Indian Industry (CII) at the initiative of A.P.J. Abdul Kalam who was then the PSA as well as Chairperson, TIFAC.

A committee comprising representatives from TIFAC, BHEL, the NTPC, the CEA and the CSIR examined the setting up of a 100 MW plant, which was estimated to cost around Rs.700 crore. The committee recommended that TIFAC may fund the project up to Rs.300 crore if the NTPC would fund the rest. However, no decision on its implementation was taken essentially because of the general penchant of politicians and bureaucrats for foreign collaborations, funds and consultants.

The TIFAC initiative got sabotaged by the India-U.S. agreement for cooperation in advanced power generation technologies that was signed on September 13, 2000, during Prime Minister A.B. Vajpayees visit to the U.S. A Protocol of Intent was signed between the United States Agency for International Aid (USAID)/U.S. Department of Energy and the MOP/NTPC from the Indian side. The protocol said:

[A]s a first step towards this cooperation, USAID will collaborate with MOP and NTPC in conducting [a] detailed technical and economic feasibility study for commercial-scale IGCC demonstration plant at one of [the] NTPC power plant sites.

The study will seek to establish: (i) the most suitable IGCC technology for Indian coal and environment conditions; (ii) explore possible financing structures to make the technology most competitive for India; (iii) and develop a time-bound implementation plan for technology demonstration in India.

As we shall see, this agreement continues to be the proverbial spoke in the wheel of indigenous development of commercial-scale IGCC technology.

Soon after taking over as the PSA in 2001, Chidambaram took up the IGCC initiative of Abdul Kalam in November 2002 and sought to bring BHEL and the NTPC together to work towards the indigenous development of a 100 MW IGCC demonstration plant. From the PSAs perspective, this synergy was important if the objective of a home-grown technology was to be realised because technologies from abroad were only for low-ash coal and BHEL had already done pioneering work in fluidised bed technology, which was suited to Indian coal. Also, partnering a utility like the NTPC was important so that the plant could be operated as a regular power plant and power could be supplied to the grid.

The Prime Ministers Office, too, backed up this initiative by providing the required political support. In January 2003, the PSA set up the R&D Committee mentioned in the beginning of this article. Around the same time, an IMSG was also constituted by the MOP. The IMSG, chaired by the Power Secretary, decided in January 2003 itself that the proposed 100 MW plant may be set up at the NTPC thermal plant site in Auraiya in Uttar Pradesh.

In October 2005, the R&D Committee came to the conclusion that a 100 MW IGCC plant using high-ash Indian coal was technically feasible. This was based on the results of extensive analytical and experimental studies and computer simulations carried out over two and a half years at BHELs gasification and IGCC facilities in Hyderabad and Tiruchi, as well as other institutions such as the Indian Institute of Technology in Chennai, the National Chemical Laboratory (NCL) in Pune, and the Bhabha Atomic Research Centre (BARC) in Mumbai. The studies were conducted under the supervision of a scientific working group that included members from the NTPC, BHEL and the DAE and was headed by R.R. Sonde, who was then at the DAEs Heavy Water Board.

BHEL has set up three R&D plants based on PFBG. These are the Advanced Pressurised Fluidised Bed Gasifier (APFBG) with a 200-metre diameter reactor and a coal feed of 1.2 tonnes a day (t/d), the Performance Evaluation and Demonstration Unit (PEDU) with a 450-millimetre diameter reactor and a 18 t/d coal feed in Hyderabad, and the 6.2 MW Combined Cycle Demonstration Plant (CCDP) with 1.4-m-diameter reactor and a 150-170 t/d feed in Tiruchi.

By using these plants, operating at different regimes of coal and air/steam flow, notes the report on IGCC issued by the PSAs office in December 2005, there was a unique opportunity to carry out experiments and their simulations. These simulations could then be reliably used for arriving at the design of the 100 MW plant. Based on such analyses, BHEL had already evolved a design for a 100 MW plant. This was an upgraded version of the 6.2 MW plant based on a similarity principle.

In fact, the principles of geometric scaling and capacity scaling have been used by BHEL in going from PEDU to CCDP. The NTPC, however, had some technical reservations on the design, according to the report. It was to validate the BHEL design that the working group under Sonde was constituted.

The Working Group established the technical feasibility of upgrading the 6.2 MW CCDP of BHEL to a 100 MW IGCC plant and endorsed the scale-up methodology of BHEL. On October 14, 2005, it recommended that BHEL and the NTPC jointly prepare a Detailed Project Report (DPR) for a 100 MW plus plant within three months. The Working Group also set the following parameters for the 100 MW plant: carbon conversion efficiency of around 85 per cent; cold gas efficiency of around 71 per cent; gross efficiency of around 39 per cent; gas calorific value of 1,000-1,100 kcal/cu m.

Accordingly, a DPR for a 125 MW plant was submitted. The power generated, according to BHEL, depends on a number of factors, some of which are site specific. The 100 MW rating was a nominal figure, which got revised in the DPR to 125 MW after detailed engineering for Auraiya. According to Sikka, since some power would be required for equipment, effectively it would be about 100 MW in Vijayawada. According to Jairam Ramesh, however, there will be no separate DPR for Vijayawada and the parties are going ahead with the project as such.

The recommendations of the PSAs report also formed part of the December 2006 report of the Working Group of the Planning Commission for R&D in the Energy Sector during the Eleventh Plan, which was chaired by the PSA. This report recommended the provision of Rs.350 crore as grant-in-aid to BHEL for the BHEL-NTPC IGCC project to compensate, in a sense, for the money invested by BHEL in technology development. It is this recommendation that Chidambaram reiterated in a letter that he wrote to the Prime Minister on July 9, following which a grant-in-aid of Rs.300 crore was sanctioned.

But the NTPC opted out some time early this year essentially for two reasons, according to reliable sources. One, the NTPC was not agreeable to the financial terms even though it had originally agreed to invest Rs.4 crore per MW. Apparently, the NTPC desired that its share of investment should also be supported through a grant-in-aid from the government. Second, there were apparently some differences between BHEL and the NTPC on intellectual property rights issues as well. As a result, the financial closure between the two could not be concluded.

Interestingly, when this project did not seem to be taking off, one of the eight scientists who opposed the India-U.S. nuclear deal apparently raised the issue of IGCC with the Prime Minister during their meeting and suggested that equal importance be given to indigenous development in non-nuclear energy technologies.

But actually, it would seem that the NTPC was not too keen on investing in a technology that was yet to prove itself in the Indian context, especially when it had an ongoing project under the India-U.S. agreement of 2000 and was pursuing its own non-BHEL route to establish commercial IGCC in India. In this USAID- (and Asian Development Bank)-funded clean-coal programme of the NTPC, the Nexant-Bechtel combine is the consultant for evaluating suitable technology. However, according to BHEL and the MOS, discussions with the NTPC are still on for setting up an IGCC plant in Auraiya.

We need a technology partner, says D.K. Jain, Director (Technical) of the NTPC. There are still a lot of issues to be sorted out with BHEL technology, with regard to both the gasifier and the gas clean-up system, he adds. How to extrapolate from a 6.2 MW plant to a 100 MW is not clear.

According to Jain, outstanding issues include the low gas calorific value, which is apparently varying; availability of the plant; maintenance problems; ash extraction; and control systems for stable operation. An IGCC plant takes 15 years to stabilise. But most importantly, the high capital cost is a major factor, which is why IGCC has not caught on, he says.

The gas calorific value of over 1,000 kcal/cu m achieved at BHEL meets the requirements of the gas turbine being used and there is no problem in this regard says G. Viswanathan, Additional General Manager, CCDP, BHEL, who answered queries from Frontline by e-mail.

He pointed out that the availability of the IGCC plants based on entrained flow gasifiers is initially low where the high operating temperature of over 1,600{+0}C caused problems. Owing to the lower temperature of operation in fluidised bed of about 1,000{+0}C, which is less than the Indian coal ash fusion temperature (an important consideration to prevent slag formation and efficient coal conversion, see box), this is not a problem with BHEL technology.

In fact, BHELs PFBG has also been evaluated by the NTPC through the foreign consultants. Results from BHELs PEDU and CCDP were compared with runs elsewhere, which include the Gas Technology Institute in Chicago, the South African company Sasol Petroleum International, and University of North Dakotas Energy and Environment Research Centre. Data from these tests agreed well with those of BHEL, according to Sikka, the PSAs Scientific Secretary.

Given this, it is not clear why the NTPC is still scouting the world for a technology partner. According to reliable sources, the NTPC appears to have identified Mitsubishi Heavy Industries (MHI) as its technology partner. But, interestingly, MHIs IGCC technology uses an entrained bed gasifier, which is not known to be ideal for Indian coal.

Enter Jairam Ramesh, who hails from Andhra Pradesh. He could get APGENCO to partner BHEL in double quick time. Also, BHEL has the experience of working with APGENCO, having set up a number of thermal plants for it. It will now essentially be a four-pronged approach to IGCC, the Minister said.

Besides the plant at Vijayawada, the 6.2 MW will be run as [a] continuous power plant. A joint NTPC-BHEL team is working out the investment details [about Rs.100 crore] as a 50:50 venture and the NTPC would run it. The report will be out soon, Jairam Ramesh added. We hope that, based on the BHEL data, a 200 MW plus IGCC plant can be set up in Auraiya. The boards of the NTPC and BHEL are discussing investment details. The fourth is to let the NTPC pursue its non-BHEL route based on technology sourced from elsewhere.

Sonde emphasises the importance of such a multi-pronged approach. We are at present only looking for a generic IGCC technology for Indian coal, he points out. Each component in it needs to be evaluated. We need multiple technologies for that, he adds.

So five years down the line we will know which technology really works for high-ash Indian coal. But the much-delayed beginning has finally been made.

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