Prof D Chandrasekharam

Recently a news item hit the geothermal magazines stating that some school in Boston will be using  a new energy source from groundwater for space heating and cooling.

Heat pumps are being in use for several decades in refrigerators and air conditioning units.  It is a well insulated unit that move heat from one “space A” to ” space B. When heat is removed from space ‘A’ and space ‘ A’  becomes cool and ‘B’ becomes hot.   Based on the need and space ‘A’ can be made cool or hot. This concept is in use since 1850 when James Harrison made the first refrigerator.  The ground source heat pump works on the same principle.  The ground source heat pumps (GSHP) are also known under several names: Ground Heat Pumps-GHP, Ground Coupled Heat Pump-GCHP,  Groundwater Heat Pump-GWHP.

The basic principle on which the GHP works is “refrigeration cycle”. The refrigerant carries the heat from one “space” to another. The heat pump’s process can be reversed.  The earth is the main source and sink of heat.  In winters it provides heat and summers it takes the heat.  The heat pumps are very common in USA, Europe, E. Europe and China. The heat pumps can be adopted to any kind of building at any place.  In the United States of America, over 400 000 GHPs are working in schools, hospitals, commercial complexes and government buildings. GHPs have low carbon dioxide emissions, low energy consumption (~ 40-60 % lower than the conventional systems),  low operating cost and competitive life cycle cost compared to the conventional HVACs.

The common two types of GHPs in use are 1) earth-couple (closed loop) system that uses sealed pipes/tubes-placed vertically or horizontally, through water or a mixer of water and antifreeze circulates transferring heat to and from the earth and 2) water source (open loop) system where water from the underground aquifer pumps water to the heat exchanger. Between the two, earth coupled GHPs are very popular because they are very adoptable.

The technology is very matured and systems can be installed adopting the local temperature variations. According to the reports published in the World Geothermal Congress 2010, up to the year 2010 (ending December 2009) the installed capacity of GSHP in the world is 50583  MWt and the energy generated was 438071 TJ/year (121696 GWh/y: CF of 0.27). The country that has the highest installed capacity of GSHP is USA (12611 MWt) followed by China ( 8898 MWt).  In China the amount of utilizable geothermal energy (for space cooling and heating) at shallow depths, according to a news  published in “Renewable Energy World.com” in 2011, is equivalent to about 350 million tons of standard coal, which is equivalent to 2.8 million GWh of electricity. If this energy source is tapped, then this will reduce emission of 500 million tons of CO₂ by avoiding to mine 250 million tons of coal. The extractable geothermal energy in China’s 12 major geothermal provinces is equivalent to about 853 billion tons of standard coal that could generate seven billion GWh of electric power!!

China is using its GSHP technology to adjust/ modify its energy structure to reduce CO₂ and other GHG emissions. Today in China research on GSHP technology is given top priority with full government support. Thus academic institutions, industries and companies are enjoying a boom with regard to this technology and it is paying rich dividends to the country today. According a paper published in the Proceedings of the World Geothermal Congress 2010, China has proved its supremacy in GSHP technology by providing 26% of energy to the Olympic Games in 2008 from geothermal sources. Excellent examples where such GSHP technology in the Olympic games is seen from the Olympic tennis courts, the National Olympic Stadium ( Bird’s nest), National Swimming Centre and Olympic Gymnastics Hall and Badminton Hall. Besides this, the hostels for the athletes were also temperature controlled through GSHPs. For the tennis courts, 35 holes were drilled within a 7 x7m layout. This GHP unit has 138.2 kW heating capacity ( in put power 37.5 kW) and cooling capacity of 139.6 kW (in put power 32 kW). The Olympic National Stadium (Bird’s Nest) drilled 140 holes with depth of 80-100 m. With such a strong GSHP technology in hand, it is not surprising to read about China’s determination to reduce CO₂ emissions and phase out HCFC by 2015 by adopting clean technology for space heating and cooling.

The performance of a heat pump is a measure of its COP ( Coefficient of performance). Commercially available HVAC systems have COP of 3 to 4 while GHPs have greater than 6. The COP also depends on the temperature difference.  When the temperature difference is small then the COP will be large.  Similarly the cooling performance, measured as energy efficiency ratio (EER). The GHPs EER, depending on the seasonal temperature variation is about 80% and above.

In the case of HVAC systems, the heat is transferred between the inside and out side air to cool or heat the space. The COP of such systems vary drastically since air temperature variation is  diurnal and as well as seasonal.  This problem does not arise in the case of GHP system. The heat transfer takes place in the ground/soil that maintains more or less constant temperature. This is a very great advantage where GHPs score its COP. The GHPs can be installed vertically/horizontally, before the construction of the building or after the construction of the building. It is cost effective if the design of the system goes along with the building plan. The builder and the architect should work in collaboration in the installation of GHPs for cooling and heating.   Besides heating and cooling the space, GHPs can also provide hot water to the house hold at no cost.

The GHP technology is very well matured and can be bought off-the-shelf. Countries in Europe have installed GHPs at district level and residential spaces, office buildings and commercial establishments have been put under GHP technology. This is  why Europe is able to earn carbon credits and  trade with countries like India and other develoing countries. Buying carbon credits is not good to any country, especially those that are on the development path. China is ahead among all the non-OECD countries in controlling carbon dioxide emissions without compromising the industrial and commercial growth. India, with its large geographical spread and with a large temperature variation, GHP technology will bring a sea change to Indian economy, GDP growth and provide carbon free environment to the future generations.

The 8.9 magnitude Honshu earthquake of March 11, 2011, occurred due to thrust faulting within the Japan trench. The tectonic configuration of Japan and its surroundings is very complex with 4 plates meeting just below Japanese islands. The islands lie over four plates: the Pacific, North American, Eurasian and Philippine sea plates. The Pacific plate  subducts into the Eurasian plate, the junction of these two plates lie just beneath Hokkaido and Honshu. This is the main Japanese trench and the rate of subduction of the Pacific plate is about 83 mm/year. The length of the Pacific plate is about 2000 km. Thus the geological and tectonic settings of the Japanese islands is very complex and at any given point of time one of these four plate move/thrust giving rise to major earthquakes. The depth of focus of the earthquakes vary from 700 km to 25 km or below.  The eastern margin of the Japanese islands, along the subduction zones is the loci of several active volcanoes. Earthquakes of this magnitude is not uncommon in and around Honshu. This is not a rare event that occurred at this site.  Over nine earthquake of magnitude >7 occurred in this area since 1973. An earthquake of magnitude 7.8 struck in an area 260 km north of the 3/11 earthquake in the year 1994. This earthquake caused injuries to 700 people.  Similarly in 1978, an earthquake of magnitude 7.7 struck 35 km south west of the current 3/11 event. This caused injuries to 400 people. Besides this,  8.4 magnitude earthquake of Sanriku in 1933, 8.3 magnitude earthquake of Tokachi in 2003 are note worthy earthquakes in this region. All these earthquakes occurred due to thrust faulting below the Japanese Islands.  Between 9^th March and 11 March, 2011, Honshu experienced several foreshocks of magnitudes of   7.2 to 4.2. before the 3/11 earthquake. The main shock was followed by > 100 aftershocks and the after shocks are still rocking the region.

We have  witnessed two devastating earthquakes of magnitudes 9.1 ( Sumatra)  in 2004 and the recent 8.9 magnitude earthquake of Honshu accompanied by tsunamis. The Honshu tsunami occurred even before Sumatra tsunami faded out of our memory. The Sumatra earthquake occurred due to thrust faulting, similar to the one occurred in Honshu, where 1600 km long ocean plate fractured with a slip of 15 mts. The land near Banda Ache was lifted to a height of about 30 m. The tsunami generated due to this major event caused over 250000 deaths in Indonesia, Sri Lanka and India and causing dislocation of population in several coastal regions bordering the Indian Ocean. In the case of Honshu earthquake, the lateral shit currently estimated is about 8 m. More data on the slip amount is being calculated. Both the earthquakes are shallow with the focus depth placed between 25-30 km. But the dimension of Sumatra earthquake and tsunami is larger by several factors compared to the Honshu earthquake. The Sumatra tsunami could travel 3500  km from the source caused devastating damage. A similar features was expected from Hnashu tsunami but the energy of the waves attenuated even before they could reach the nearby islands. The wave height measured at Hawaii islands, located at a distance of 6300 km from the epicenter was about 0.7 m.

Majority of the earthquakes over Honshu occurred due to slip at shallow levels. The buildings in Japan are built strictly according to the  codes. This is the reason one could see pictures in the television where tall structures in Tokyo were swinging at the time of the earthquake and returned to its normal poison. The death toll due to  earthquake in Sendai is far less compared to that due to the tsunami. We have to learn a lot from the Japanese civil engineers about making tall earthquake resistant structures. We do have codes on papers. Only an earthquake of magnitude half of that of Honshu will be able to prove how strong these structures are!!

The recent events all along the Pacific rim only demonstrates the dynamic changes that are taking place within the internal Earth system. We have a long way to go to  understand the dynamics of this system. Earth Sciences need to be given priority at school level itself, like other countries, to generate state-of-art young generation to tackle such natural disasters in future. As far as Indian coast is concerned, the east coast is more vulnerable to tsunami related disaster as the coast is in line of sight of the grate Andaman-Nicobar, Sumatra – Sunda arc system. The west coast is not facing such arc system and hence chances of tsunami related disasters are minimum. Only normal faulting, as evident from several earlier faults events, is a cause of concern, both on shore and off shore of the west coast, as reported in 1985 based on an integrated geophysical and geological analysis.

Heat pumps are being in use for several decades in refrigerators and air conditioning units.   It is a well insulated unit that move heat from one “space A” to ” space B. When heat is removed from space ‘A’ and space ‘ A’  becomes cool and ‘B’ becomes hot.  Based on the need and space ‘A’ can be made cool or hot. This concept is in use since 1850 when James Harrison made the first refrigerator.  The ground source heat pump works on the same principle.  The ground source heat pumps (GSHP) are also known under several names: Ground Heat Pumps-GHP, Ground Coupled Heat Pump-GCHP,  Groundwater Heat Pump-GWHP.

The basic principle on which the GHP works is “refrigeration cycle”. The refrigerant carries the heat from one “space” to another. The heat pump’s process can be reversed.  The earth is the main source and sink of heat.  In winters it provides heat and summers it takes the heat.

The heat pumps are very common in USA, Europe, E. Europe and China. The heat pumps can be adopted to any kind of building at any place.  In theUnited States of America, over 400 000 GHPs are working in schools, hospitals, commercial complexes and government buildings. GHPs have low carbon dioxide emissions, low energy consumption (~ 40-60 % lower than the conventional systems),  low operating cost and competitive life cycle cost compared to the conventional HVACs.

The common two types of GHPs in use are 1) earth-couple (closed loop) system that uses sealed pipes/tubes-placed vertically or horizontally, through water or a mixer of water and antifreeze circulates transferring heat to and from the earth and 2) water source (open loop) system where water from the underground aquifer pumps water to the heat exchanger. Between the two, earth coupled GHPs are very popular because they are very adoptable.

The technology is very matured and systems can be installed adopting the local temperature variations. According to the reports published in the World Geothermal Congress 2010, up to the year 2010 (ending December 2009) the installed capacity of GSHP in the world is 50583 MWt and the energy generated was 438071 TJ/year (121696 GWh/y: CF of 0.27). The country that has the highest installed capacity of GSHP is USA(12611 MWt) followed by China( 8898 MWt).  In China the amount of utilizable geothermal energy (for space cooling and heating) at shallow depths, according to a news  published in “Renewable Energy World.com” in 2011, is equivalent to about 350 million tons of standard coal, which is equivalent to 2.8 million GWh of electricity. If this energy source is tapped, then this will reduce emission of 500 million tons of CO₂ by avoiding to mine 250 million tons of coal. The extractable geothermal energy in China’s 12 major geothermal provinces is equivalent to about 853 billion tons of standard coal that could generate seven billion GWh of electric power!!

China is using its GSHP technology to adjust/ modify its energy structure to reduce CO₂ and other GHG emissions. Today in China research on GSHP technology is given top priority with full government support. Thus academic institutions, industries and companies are enjoying a boom with regard to this technology and it is paying rich dividends to the country today. According a paper published in the Proceedings of the World Geothermal Congress 2010, Chinahas proved its supremacy in GSHP technology by providing 26% of energy to the Olympic Games in 2008 from geothermal sources. Excellent examples where such GSHP technology in the Olympic games is seen from the Olympic tennis courts, the National Olympic Stadium ( Bird’s nest), National Swimming Centre and Olympic Gymnastics Hall and Badminton Hall. Besides this, the hostels for the athletes were also temperature controlled through GSHPs. For the tennis courts, 35 holes were drilled within a 7 x7 m layout. This GHP unit has 138.2 kW heating capacity ( in put power 37.5 kW) and cooling capacity of 139.6 kW (in put power 32 kW). The Olympic National Stadium (Bird’s Nest) drilled 140 holes with depth of 80-100 m. With such a strong GSHP technology in hand, it is not surprising to read about China’s determination to reduce CO₂ emissions and phase out HCFC by 2015 by adopting clean technology for space heating and cooling.

The performance of a heat pump is a measure of its COP ( Coefficient of performance). Commercially available HVAC systems have COP of 3 to 4 while GHPs have greater than 6. The COP also depends on the temperature difference.  When the temperature difference is small then the COP will be large.  Similarly the cooling performance, measured as energy efficiency ratio (EER). The GHPs EER, depending on the seasonal temperature variation is about 80% and above.

In the case of HVAC systems, the heat is transferred between the inside and out side air to cool or heat the space. The COP of such systems vary drastically since air temperature variation is  diurnal and as well as seasonal.  This problem does not arise in the case of GHP system. The heat transfer takes place in the ground/soil that maintains more or less constant temperature. This is a very great advantage where GHPs score its COP. The GHPs can be installed vertically/horizontally, before the construction of the building or after the construction of the building. It is cost effective if the design of the system goes along with the building plan. The builder and the architect should work in collaboration in the installation of GHPs for cooling and heating.   Besides heating and cooling the space, GHPs can also provide hot water to the house hold at no cost.

The GHP technology is very well matured and can be bought off-the-shelf. Countries inEuropehave installed GHPs at district level and residential spaces, office buildings and commercial establishments have been put under GHP technology. This is why Europe is able to save carbon emissions and are able trade it to countries likeIndia. Buying carbon credits is not good to any country, especially those that are on the development path.Chinais ahead among all the non-OECD countries in controlling carbon dioxide emissions without compromising the industrial and commercial growth.India, with its large geographical spread and with a large temperature variation, GHP technology will bring a sea change to Indian economy, GDP growth and provide carbon free environment to the future generations.

For more details see ” selected Papers” on th main pge.

Arsenic poisoning in groundwater is a global calamity and millions of people are affected arsenic related diseases due to drinking groundwater contaminated with very high concentration of arsenic. Arsenic concentration > 10 ppb is recorded in groundwaters of theBengalBasinand nearly 60% of the population consuming such groundwater is affected by arsenic related diseases. This is more severe inBangladesh. This problem is existing for the last few decades. Children below the age of 12 are seriously affected.  Arsenic content in groundwater varies from less than 1 ppb to 3200 ppb. From water this problem has entered the food chain due to the prevalence of tube well irrigation in a large part ofWest Bengal. Over 5,50,000 bore wells operate now constantly pumping groundwater to the rice fields and the farmers have a happy, contended life since they can grow rice round the year without knowing the dark clouds that are lingering above them and their children!!.

Groundwater being used for irrigation has arsenic concentration about 10 to 32 ppm and it has been established now that the rice roots concentration all the arsenic from the irrigated water. The concentration of arsenic in the roots from rice cultivated in Nadia and Murshidabad districts of West Bengal varies from 56 to 136 ppm and the concentration of arsenic in rice grain is also high, over 3 ppm.

Since this practice of irrigation with arsenic rich groundwater is in place over centuries in India and other countries, and due to the age old practice of ploughing the roots back into the soil is being practiced by the farmers, the soil, over the period of time is accumulating arsenic to levels beyond ones imagination. Some of it enters the shallow aquifers due to subsequent crop cultivation seasons. 

There is no easy solution to this problem since its implementation needs political will. There are hundreds of short term solutions being proposed by a variety of scientists spending millions of rupees,  both from national and international organizations.  But the problem is not showing any downgrade trend but entering the subsequent generation of the population.

Several scientific papers appeared over the last two decades on the behaviour of earthworms in soils contaminated and uncontaminated with arsenic. Perhaps these papers may provide some clues to contain this problem. The solution to arsenic problem could be  earthworms! Earthworms are known to inhabit arsenic rich metalliferous soils and accumulate arsenic in their body and develop resistance to arsenic toxicity. The amount accumulated depends on the soil properties such as soil pH, organic content, microbial content etc. All of know that earthworms are the principal organisms responsible for mixing soil constituents. Countries where traditional agricultural practices are in place, farmers depend on earthworms to “plough” the soil before seeds are sowed. These animals help in soil fertility by removing partially decomposed litter (especially the stems and roots that were left after the harvest) from the soil surface, ingesting it and transporting it to the root zones. Since the earthworms are prey to many birds and animals, the toxic substances ingested by them from the soil is transferred to higher trophic levels. Arsenic concentration in soils is controlled by phosphorus, iron and organic carbon and redox state of the soils. Inorganic arsenic in soils are converted to organo-arsenic compounds by soil mirco-organisms. The toxic state of arsenic follows the order from most toxic to less toxic:

        arsenic gas> inorganic arsenic (III)> organic arsenic (III)> inorganic arsenic (V)> As (element).

 Earthworms are known to inhabit arsenic-rich metalliferous soils  and tend to accumulate arsenic in their bodies and are immune to arsenic toxicity. Chemoreceptor and sensory tubercles in the earthworms makes them very sensitive to chemical environment thus avoiding toxic environment.  But this sensitivity is selective! Experiments have shown that they are sensitive to sodium arsenate only when the concentration is > than 5000 ppm!! Although all species accumulate arsenic in the body, a few species like Eisenia fetida have a very high bio concentration factor ( ~ 10 – 18). This bio concentration factor is independent of the concentration of arsenic in the soil. It is not clear what control this factor. Again these features are earthworm species specific! The entire investigation suggests that, over a long period of time, earthworms are able to sequester arsenic in the tissues in less toxic form

 Again it all depends on the species. For example Lumbricus rubellus  can adopt both under toxic and non toxic conditions. Those adopted to non-toxic conditions can not survive in soils that have high arsenic concentration. Laboratory experimental results reported in the literature show that the above species adopted to toxic conditions are able to sustain arsenic concentration of 2000 ppm in soils and the tissues were able to accumulate 230 ppm of arsenic while the same species adopted to non-toxic conditions dies when exposed to such toxic conditions. Some earthworms of the same species develop yellow pigmentation when their tissues get enriched with arsenic. The above reported results on earthworms indicate that there are several species that are able to sustain high arsenic levels in the soils and some species are able to methylate arsenic in an organic form and pass the toxicity to higher trophic levels.

 Since earthworms are friends of the farmers, arsenic contaminated soils like those inWest Bengalcan find a solution to the perennial problem of arsenic contamination in irrigated soils.

Many non OECD countries’ economy relies heavily on coal, oil and natural gas. Their economy is ‘carbon intensive’. Carbon emissions reduction has been and will be very challenging for these countries. China and Indi arank first in high carbon emission among non OECD countries and rank high on emerging economic powers in Asia. In order to partially control carbon emissions, carbon tax (CT), an incentive based policy instrument for controlling emissions is being imposed by several countries. This policy is being studied in detail, and debated by several economists and researchers.  Inter-_­­ governmental pressure on countries ( non OECD) to control reduction in emissions, control global warming, contain sea level changes and melting of glaciers, compelling these countries to develop effective policy instruments to promote energy saving, reduce carbon dioxide emissions and effectively utilize non-conventional energy sources like geothermal and solar to supplement the reduction of development caused by reduction in coal based power generation. The very thought of carbon tax is sparking controversial debates in such countries ( i.e. imposing CT will have adverse impact on energy sector and economic growth of the country) and political parties are the most affected group by such debates ( by such tax!!).

In fact The Chinese Study Group of Climate Change computed the impacts of CT on the economy by taking two cases of tax rates 1)  RMB¥ 100, and 2) RMB¥ 200/tc. Their study concluded that CT can significantly reduce the growth of energy consumption, improve the energy consumption structure, and effectively reduce the greenhouse gases emissions.  Further, this study also realized that low intensity CT will not have significant negative impact on the future economic growth. Countries  like Denmark, Finland, Sweden, Netherl and sand Norwayhave CT in place.

Recently the Australian Prime Minister introduced CT ( known as carbon pricing) as her government’s policy response to climate change.  This policy is beneficial to the geothermal sector. But this policy is against her election promise (not to introduce CT!!).  Once passed by the Parliament later this year, the largest emitters of CO₂ ( ~~ 500 in number) will pay CT of A$ of 23/t with 5% annual increase till 2015 ( to reduce 5% emissions by 2020). The outcome  of this policy is beneficial to  the geothermal sector since it will get new funding of A$10 billion through Clean Energy Finance Corporation.  This initiative is a boon to Australian geothermal stocks. Besides this the Australian Government separately announced A$ 60 million as additional funding for “Emerging Renewable programme”.  Geothermal companies can apply for this fund as well.  Good forAustralia but bad for Indian steel and power sectors!!

Australia’s CSIRO took a new initiative in making greenhouse gases (GHG)  data available over the southern hemisphere (SH) to the public. This site shows the data on GHG measured over the SH over the past 35 years. Data is updated monthly.

In contrast to other countries, India has a different view on CT! IndiaSaturday strongly opposed imposition of carbon tax as an additional source of funding to fight climate change. While addressing the G20 Finance Ministers and Central Bank Governors meeting on Development, climate and innovative finance, Indian Finance Minister stated that “India believes that some of the measures like carbon export optimisation tax and levy on CDM/offsets violate the principles of the Convention (UNFCCC) as their incidence falls entirely on developing countries and these cannot be recognised as a source of new and additional finance for climate change,” (web news).

Compared to all the countries, OECD Europe is expected to increase renewable energy share in its power source mix >  23%.  Europeis already at the top of low emission countries list and currently trading carbon at the rate of €~ 8-10 ( may be reduced in future) under CER.  India is a major customer (China tops the list) for carbon trade with Europe and continues to be so for the next decade, considering the future power demand and generation of power from coal based thermal power plants. China’s CT policy may bail out the country from carbon emission web by 2030. By the 2030Indiawill be fully under the control ofEuropewith huge piled up credit. Both wind and geothermal are playing a major role in primary source mix inEurope’s power scenario. This situation can be over come ifIndiautilizes its geothermal energy sources.

Geothermal energy resource can provide a stable supply of energy,  in contrast to many alternative domestic renewable energy resources like hydro, wind and solar photo voltaic in all the non OECD countries likeIndia. If such sources are not utilized to the fullest extent, then the carbon emissions in these countries will only see an upward trend unlike the OECD countries.

On an average, geothermal power plants emit 0.893 kgCO₂/MWhr while coal power plants emit 953 kg CO₂/MWhr. The combined (wet low enthalpy and EGS) geothermal potential of India, taking into account the150000 sq. km high heat producing granites, spread over the continent, on a conservative side, amounts to 18348 x 10¹⁴ kWhr.  Even utilizing this source  to the tune of 5 to 10 % will have tremendous effect on emission scenario by the country.

Further, 33% (245 x 10⁶ MWhr, only coal power) of electricity in India is consumed by the building sector (commercial and domestic). A major amount is spent for space cooling,  refrigeration and hot water supply. This amounts to emission of 234 x 10⁹ kg CO₂. If India utilizes low enthalpy geothermal sources (through GHPs) an additional revenue of €234 x 10⁷  under CER can be earned.

In addition to the building sector, implementing CDM in food processing sector also will provide additional benefit to the country in reducing CO₂ and in earning carbon credits. Indian food sector consumes about 13 % of the electricity (IEA, 2007) amounting to 63 x 10⁶ MWhr (from coal fired thermal power plants). Thus part of the capital, amounting to € 600 x 10⁶ can be raised through CDM and ploughed into this industry by using geothermal sources instead of conventional fuels.

In the current industrial era, black carbon (BC) content in the atmosphere adds further misery to our lives!!  Changing weather pattern, fast retreating glaciers, droughts, flash and summer floods are the consequences of such uncontrolled BC emissions. Carbon dioxide also plays a major role but CO₂ has a long term effect while BC has a short term effect.

Coal, fuel wood, dung cake and agricultural waste are consumed maximum in that order inIndia. According to 1996-2001 data, 286 Mt (million) of coal, 302 Mt of fuel wood, 121 Mt of dung cake and 116 Mt of agricultural waste was consumed inIndia.  The consumption of these fuels has increased by several folds due to increase in population and hence demand. BC emission factor of these fuels in that order is ~ 0.8, 1.1, 4.4 and 1.3 g/kg.

BC  absorbs sunlight turning it into heat. Thus, a layer of BC in the atmosphere, while emitting a third of this absorbed heat back in to space, keeps the earth’s surface warm. More BC in the atmosphere means more heat over the surface of earth. As the BC increases the earth’s surface gets hotter and hotter!! Simple logic.  Thus BC causes change in the heat input at the top of the atmosphere. This is known as “Radiative Forcing (RF)”.  According to the Intergovernmental Panel on Climate Change (IPCC) 2007 report,  RF of BC is of the order of + 0.34 W/m² while forcing of CO₂ is of the order of + 1.66 W/m².

Thus the sources of BC are fossil fuels (coal, oil, gas), biomass, agricultural waste, dung etc. The life of BC in the atmosphere is about a week, while CO₂ lingers for several decades. Both BC and CO₂ have tremendous effect on global warming and glacier retreat. BC has strong light absorbing property. Thus short term control of global warming can be accomplished by controlling the BC emission. If BC emission is controlled then half our problems related to global warming is solved ( no more CT)!! In developing countries likeIndia andAfrica, BC emission emerge mainly from rural sector while transport sector is the main source of BC emission in the developed countries.  High percent of biomass and dung is used in rural regions for cooking, space heating and consumption of such fuels is high during winters.

The emission values reported in the literature for BC and other related aerosols in the atmosphere varies like the climate!  There is no consistency in the emission values reported. The values keep changing between the authors and sometimes with the same author!. Each authors claims that their value is the best!!

According a paper published in “Atmospheric Environment” in 2002 the BC (India) emission of dung cake  is 0.25 g/kg and that of crop waste is 0.47 g/kg. Another paper that appeared in the same journal in 2005 reported BC emission of dung cake from 2.2 to 6.6 g/kg and that of agricultural waste from 0.2 to 2.4 g/kg!! Value reported by the same author also varies with time!! Perhaps such discrepancies may be related to the betterment of analytical techniques and demographic data. Such uncertainties are ( E.g. seeJr.Geophy. Res., 2004) due to extrapolation of data such as population, per capita consumption ( varies by a factor of 3!), economic data etc. and also due to over prediction of fuel consumption measurements!!.

Irrespective of these numbers, the truth is, India, next to China, is the leader in BC emission!.

The total BC emission byIndia ( 2000 base value) as reported earlier, was 600 Gg (Jr.Geophy. Res., 2003, v,108) while in 2008 this value has changed to 1343 Gg (Geophy.Res.Lett., 2008, v. 35)!!.  Thus one gets two values for per capita emission of BC inIndia. One at 600 g and the second, just double this value!! It is safe to take the minimum value for all discussions.

In India, maximum BC emission is from rural areas like Leh. Leh is  located at an altitude of 4500 m in the Himalayas(in Ladakh province of J & K), where the temperatures falls 15 °C below zero in winters. Combustion rate of all fuels are low at this elevation. Dung cake, biomass and coal are extensively used to heat the homes and of course for cooking also. Guest houses, army and affluent society use cooking gas or “bukharis”,  a device that uses kerosene ( or some times saw dust) to heat rooms and homes. CO, CO₂ and BC are ejected out in to the space through an exhaust pipe.

Population of Leh is ~ 68,000 and with the reported per capita BC emission of 600 g (2000)  Leh alone is contributing minimum of about 0.04 Gg of BC annually. Similarly, Kargil with a population of 119,307 is contributing about 0.07Gg of BC to the atmosphere around the glaciers.  A similar emission figures can be assumed from other towns located at that altitude all along the higherHimalayas, extending from NW to E of India.  The BC emission from the foot hillHimalayasalso reach higher altitude. During winter ( where BC emission is maximum) snow brings down all the BC floating in the atmosphere. This is the reason why many Himalayan glaciers appear black. It is easy to estimate the BC content in ice. Since it is possible to date ice,  BC content in the atmosphere in the past can be estimated. The Gangotri glacier is retreating at a rate of 18 m/yr. This is really alarming and this observation is not disputed. The real “component” that is responsible for this retreat is BC

Simulation studies conducted by Lawrence Berkeley National Laboratory in Feb 2010 showed that major contributor (~90%) for fast melting of glaciers is BC. BC content in ice cores recovered from ERG glacier is about 20 mg/kg. while global average BC content in snow is about 5 mg/kg. This is alarmingly high!! 15 mg/kg of BC in snow reduces about 1% of its albedo. This is a clear indication that the 18m/year retrieval of Gangotri glacier is due to this huge BC emissions from rural Higher Himalayan villages/towns.

In addition, BC from Asian region also travel to the Himalayan region contributing additional amount to BC. Since BC heats the atmosphere, it creates local thermal anomaly thereby disturbing the normal atmospheric convection pattern that exerts tremendous influence on the precipitation. Perhaps this could be the reason for the flash flood that devastated Leh in 2010!

The residence time of BC in the atmosphere is far less than CO₂. So BC does not accumulate while CO₂ accumulates in the atmosphere. By controlling BC emissions, global warming can be controlled within in a short period of time.  It is very easy to control BC emissions without compromising life comforts!!  The pristine Himalayan ecosystem can be protected and fast deteriorating glaciers life can be restored by tapping the huge geothermal resources available in Leh.

Straight away 150 million grams BC emision from Leh and Kargil  can be stopped immediately by tapping 2 billion kWhr of electric power from Puga and Chumathang geothermal provinces ( Himalayan geothermal belt)!!. In fact, Leh and Kargil may need maximum 10 % to 20 % (assuming future demand of Leh) of this power. The remaining can be supplied to theKashmirvalley there by further reducing BC emissions from the valley during winters. Once clean power at affordable price is available, there is no need to burn bio-fuels to keep the homes warm during winters!

In fact, Lhasa, in Tibetgets it power from the Yangbajing geothermal province situated within the Himalayan geothermal belt that generates 0.2 billion kWhr of electric power.  In fact the geothermal energy in Leh can also be used for green house cultivation and the Leh population can be self-sufficient not only with respect to electric power but also with respect to food.  Chinahas a major plan to tap the huge geothermal reserves from the entire Himalayan geothermal province, extending from Puga belt to Arunachal Pradesh and provide CO₂,  BC free power to all its cities, towns and villages in the southern part of China including Lahsa. This will make China to reduce CO₂ and BC emissions drastically and earn millions of dollars under CER and become a major “carbon trader in the entire south and south-eastAsia.

There are other geothermal provinces in the mid Indian continent that can very well be used to have source mix for generating electricity thereby reducing dependency on fossil fuel based power and reduce carbon dioxide and BC emissions and also earn carbon credits through CER. The world as on today generates > 10,700 MWe of geothermal power. The technology is very well established. Now tremendous development in binary fluid / heat exchanger technology is rendering utilization of thermal waters with low temperatures ( as low as 80 °C) for generating electric power.  India has the expertise and technical know how. Only the policy makers need to have the will to develop it.

India can very well reduce carbon emissions to the levels specified by IPCC by 2050 and be the leader in green energy consumption by utilizing its untapped geothermal energy sources for power as well as for direct application. Technology and expertise are available with the country.  We don’t need CT, don’t have to fear emissions targets and provide socio economic benefits to a larger section of the society. The solution is in our hands!!