Overview

Background to the Study

The IEA Greenhouse Gas R&D Programme (IEA GHG) has recently commissioned the British Geological Society (BGS) to conduct a regional assessment of the Indian subcontinent in order to gauge the potential for CO2 storage in geological reservoirs in that region. This is the 3rd regional capacity study conducted by the IEA GHG following on from assessments of Europe1 and North America2. It should be noted that the study only assessed the 4 main options of geological storage; deep saline aquifers, depleted oil and gas fields, and storage in deep unminable coal fields. In addition, the study has undertaken an assessment of the current large point source emissions from the power sector on the Indian subcontinent and assessed their geographical relationship with possible geological stores. This process is also known as source-store matching, and a good source of CO2 close to suitable geological storage reservoirs can significantly impact on the costs and technical feasibility of a CCS operation. Without nearby sources for injection, the transport element of the CO2 chain becomes more expensive, and thus can result in the classification of a proposal as uneconomical.

The choice of the Indian subcontinent for this third study is primarily down to 2 main reasons. Firstly, as an emergent economy, India is considered likely to experience high growth in energy demand due to increasing economic development, and this will naturally include a corresponding increase in anthropogenic CO2 emissions. Much of the increased power demand will come from increased use of fossil fuels and in particular coal. The growth in energy demand is likely to be met by government backed plans to install increased capacity in power plants throughout many regions. History has taught us that when a country undergoes rapid economic growth, there is a corresponding increase in the demand for power and subsequent increase in anthropogenic CO2 emissions. The second driver behind the choice the Indian subcontinent is the current lack of any other definitive study into the capacity for CCS in the area.

Scope of Study

One of the first tasks completed for the study was the compilation of inventories of CO2 emissions from large point sources (>100,000kt CO2/y) throughout the subcontinent, and these were then entered into the IEA GHG CO2 Emissions Database. This provided a valuable update to the database, further enabling it as an insightful source of information to the IEA GHG team and its member countries. Once this information was compiled and entered onto the database, it was then combined with a GIS system, allowing the point sources to be mapped onto the geographical map of the Indian subcontinent. The locations and extent of the known oil and gas reservoirs, coal beds, and saline aquifer bearing rock formations were overlaid onto the GIS to highlight any areas with close matching of source to sinks. At this point, the areas that were found to have large basalt formations were also identified and plotted, although they were to take no further part in the study. The decision to exclude storage in basalt formations was taken due to the relatively un-developed science of storage in these formations. It was felt that the technologies used in these processes are not sufficiently technologically advanced to be considered as a sound and secure storage reservoir at present.

However, it should be noted that these basalt formations are relatively extensive in the Indian subcontinent, and pending the development and advancement of technological options, the potential for storage in basalt formations could be of a significantly large scale. There is also a good correlation between the basalt formations and many of the large point sources, which will prove beneficial and cost effective if large scale storage in basalts becomes technically feasible. Comment on the future potential for basalt storage in India has been made in the report.

Due to the large spatial area covered by the subcontinent, the decision was made early on to address the countries involved on an individual basis. This removes issues related to national boundaries and political issues from the methodology used to assess storage capacity and matching point sources to storage reservoirs. The study therefore addressed point sources and storage options in India, Pakistan, Bangladesh and Sri Lanka independently. This overview will summarise the main findings and outcomes of the study in these sections to maintain the symmetry with the main report.

Results and Discussion

The results obtained from the study are summarised for each individual country on the Indian subcontinent.

India

Currently, India has annual CO2 emissions of around 1343 Mt3 and approximately half of this is from large point sources suitable for CO2 capture4. The main fuel used for energy generation in India is coal. The Indian government is backing an initiative to developing up to 9 Ultra-Mega Power Projects (UMPP) to meet increased energy demand. This development will add approximately 36,000MW of installed capacity, with a corresponding increase in CO2 emissions of approximately 275Mt a year. This first phase of 9 UMPP’s is planned to be operational within 7 – 8 years.

The recoverable coal reserves in India are the fourth largest in the world, and it is expected that both open cast and underground mining will occur in all coal fields to a depth of 600m regardless of the quality of the coal reserves. It is also expected that where the reserves are of a superior quality, the reserves are likely to be mined to a depth of around 1200m. By its nature, mining of this magnitude results in fissures and fractures opening in the overburden above the mined seams, and the structural impact of this means that any storage in coal seams would take place at locations that have either not been subjected to selective underground mining, or at depths of 100m below the deepest selective underground mining operations. This is better viewed in a table, see Table 1 overleaf to demonstrate the reserves estimated to be available to CCS in India.

Table 1: Summary of the assumptions made on CO2 storage capacity of Indian Coal5

Depth of coal beds Coal grade/category CO2 storage Capacity
0-300m All grades of coal Nil
300-600 Coking Coal Nil
Superior grade non coking coal Nil
Mixed (Superior: Inferior 1:1) 10%
Inferior (E-G) grade 30%
Inferior under thick trap 50%
600-1200 Coking coal Nil
Superior non coking coal Nil
Mixed grade (1;1 ratio) 50%
Inferior grade under trap 100%

This assessment of coal mining operations results in a theoretical storage potential in deep coal seams of approximately 345Mt across the country. It should also be noted however, that none of the fields that contribute to this value have the potential to store more than 100Mt. CCS involving deep coal seams is still considered as in the demonstration phase, and therefore not suited for full scale deployment, but as more demonstration projects become active around the world, there may be scope for a demonstration project within the Indian subcontinent, to ascertain the relevance of this technology for CCS in India.

Analysis of the oil and gas fields around India resulted in the discovery that many fields are relatively small-scale when considered for the purposes of CCS, and only a few fields have the potential to store the lifetime emissions from even a medium sized coal-fired power plant6. Despite this apparent lack of suitably sized reservoirs, recent off shore discoveries of gas reserves could provide opportunities in the future, although this would require further assessment of these newly discovered fields.

There is potential for CO2EOR operations, both onshore and offshore, but again this should be explored further on a basin by basin basis in further studies. The extent of the potential for EOR cannot be justified, and a capacity estimate cannot be given without further exploration of the exact size of the oil fields. It has already been pointed out that the exact size of many oil fields isn’t included in this report, which is due to limitations of public sector information availability

There is considerable potential capacity for storage in deep saline aquifers around India; although it should be pointed out that the survey of these areas was brief, and by no means definitive. The assessment of storage potential in these formations therefore was subject to certain judgements by the study team, however the survey is clear that there is likely to be substantial potential around the coast and margins of the peninsular. Specifically, there is potential in the shallow offshore areas, in Gujarat and Rajasthan. This can be seen on the map overleaf. The map also clearly shows aquifer storage potential in the areas surrounding Assam, although these reservoirs are approximately 750 - 1000km from 5 large point sources each with emissions greater than 5Mt a year, and therefore storage from these sources may prove costly depending on the transport element and cost of the CCS chain. It should be noted that there are 8 small point sources of up to 2.5Mt annual emissions in the north of the Assam field which could potentially utilise the Assam field to store their CO2 emissions.

Figure 1: Map showing point sources of CO2, storage basins and oil and gas fields of the Indian subcontinent

Pakistan

Of Pakistan’s annual CO2 emissions of 125Mt, large point sources make up around 45Mt of this, and 50% of these emissions are from power generation.

Oil fields in Pakistan are relatively small, none having the potential to store more than 10Mt of CO2. The gas fields are a slightly more attractive prospect, with 13 fields having the potential for storage of more than 10Mt, and 4 having the potential for storage of more than 200Mt. Coal fields in Pakistan are not considered to have any storage potential as, with the exception of 1 field, they are all shallow or subject to mining operations. This lack of storage potential means that Pakistan’s best option for CCS is the numerous saline aquifers in the Kohat-Potwar and Indus Basins.

In Pakistan’s favour for CCS, is the reasonably good matching of large point sources and sedimentary basins with good potential for saline aquifer storage, see figure 2. The second favourable aspect of CCS in Pakistan is the storage capacity in gas fields; estimated at 1602Mt, resulting in the potential to store over 35 years worth of CO2 in the gas fields alone. Pakistan, therefore, appears to have great potential for deployment of CCS technology in the near future.

Figure 2: Pakistan sources of CO2 emissions and potential storage reservoirs

Bangladesh

Bangladesh has relatively small annual CO2 emissions compared with both India and Pakistan, at around 37Mt. Approximately 17Mt of this comes from large point sources, and over 15Mt of that from power generation.

Bangladesh has no oil fields, but has 14 gas fields with storage potential of greater than 10Mt, and 2 with greater than 200Mt. Coal reserves are small scale in Bangladesh, and are not thought to hold significance for CCS.

However, this lack of suitable oil and coal reserves is not expected to impede the deployment of CCS in Bangladesh due to the estimated storage capacity in gas fields. The potential in gas fields alone is in the order of 65 times the annual emissions from large point sources, therefore, Bangladesh is in a strong position to develop and deploy CCS operations around the gas fields indicated as having large storage potential, as these are predominantly within 200km of the emission sources, and in some cases less than 100km.

Sri Lanka

In comparison with the rest of the subcontinent, and indeed many countries, Sri Lanka has relatively small annual CO2 emissions, at around 12Mt, and only 2.6Mt of this is from large point sources. The main sources for CO2 emissions on the island are 6 oil-fired power plants, a refinery and a cement plant. This is expected to rise with the installation of a new coal-fired power plant, but relatively speaking in the context of the whole continent, the emissions will still be low.

The geological make-up of Sri Lanka means that the storage potential onshore is non-existent, with no oil, gas or coal fields discovered. The only opportunity for CCS remains offshore to the north-west of the island, involving injection into saline aquifers on the Sri Lankan side of the Cauvery basin. The potential in this basin has been surveyed as good (see Figure 1) and it is conceivable that all the CO2 emissions from Sri Lanka could be stored here.

Storage in Basalt Formations

Storage in Basalt formations and salt caverns was identified in the study as potentially having a great storage capacity, but due to the classification as an immature technology (IPCC 2005), it was disregarded from this study. Despite this, it can be taken that there are two extremely large areas of India covered by thick basalt formations, namely the Deccan Traps and the Rajmahal Traps. If the concept of storage in basalt formations can be advanced sufficiently to be considered a mature option for CCS, then an assessment of the potential for storage in basalts should be undertaken for the Indian subcontinent. Figure 3 shows the areas of India covered by basalt formations, and there position relative to CO2 emission sources.

Figure 3. Basalt Formations in India

Expert Review Comments

The draft report was also sent to a panel of expert reviewers, and the comments received back were extremely complimentary. Mostly the comments focussed on typographical inconsistencies, but in addition, comments were made on the need for further work. One suggestion was of a potential follow-on study to determine the potential for CCS on a sub-continent basis and to incorporate the geo-political issues associated with this. This would be analogous to the Regional Partnerships programme in the US, and in particular the PCOR partnership which is working with international factors and cross-national boundaries.

Conclusions

The study has identified the most likely options for CCS throughout the Indian subcontinent, and this should form the basis for further investigation on a more localised scale, and will likely benefit any organisation or body looking to set up a demonstration project.

It is clear that there is potential for CCS to play an important part of the ongoing development of the Indian subcontinent, and that varying options are best suited to different areas. The geographical range of the study area means that some basins with good potential for storage are located several hundred kilometres from large point sources, in particular the point sources in the north and centre of the subcontinent are between 500 and 1000km from basins and reservoirs with good storage potential. The coastal areas show the greatest potential for successful deployment of CCS technologies, with good offshore potential for storage in the Mumbai, Krishna-Godavari and Cauvery basins.

Pending development of technological options, there could be potential for large scale storage in Basalt formations in India.

Recommendations

A follow-on study considering the geo-political issues relating to storage on a sub continental basis could be considered.

A more detailed assessment of the storage capacity in oil fields in India could be considered as cuurently relatively little is known regarding their potential for CO2EOR, and whether or not it has the potential to play a part in the mix of CCS options for the area.

Although the total capacity for storage in deep unminable coal seams is not high, the proximity of several large point sources of CO2 to the major coal fields in the Pranhita-Godavari Graben region, which are otherwise 500km from the nearest potential sedimentary storage basin, could theoretically provide a niche opportunity for CO2ECBM. As CO2ECBM is still considered as an emerging CCS technology, the development of numerous demonstration projects around the world could contribute to the establishment of a demonstration project in this region of India. A feasibility study could be of use to determine the likely potential of such a project.

There could be some benefit in undertaking a study into the storage potential in basalt formations in India in the future, once the technology has been demonstrated.

 

1 IEA Greenhouse Gas R&D Programme report no. 2005/2 Building the cost curves for CO2 storage, Europe, February 2005

2 IEA Greenhouse Gas R&D Programme report no. 2005/3 Building the cost curves for CO2 storage, North America, March 2005

3 Figure from 2004, United Nations Statistics Division 2007

4 IEA GHG set a benchmark indicator over which sources are classed as large point sources. This benchmark has been set at 100,000Kt/y. BGS have taken benchmark figure for this report, therefore only sources above 100,000 Kt/y have been included in the IEA GHG emissions database as a large point source for CO2.

5 For a greater detail breakdown of this table on a basin by basin basis, see Table 2.1.5 on page 36 of the main report.

6 As the exact size of only a very few oil and gas fields is known, approximations and estimates have been made. For the purposes of this study, and putting this size into context, a medium sized coal-fired power plant is assumed to have lifetime CO2 emissions of around 100Mt.