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India takes strides in sustainable energy with international Geothermal Conference

Experts on Geothermal Energy from around the world came together in India last Friday, 26th July 2013. They were hosted by the School of Petroleum Technology, belonging to Pandit Deendayal Petroleum University in Gandhinagar.

Named after Mahatma Gandhi, Gandhinagar is known as the “Green City” and India’s “tree capital” because of its 54% tree cover. It is the capital of Gujurat province, and it made the perfect natural setting for the Geothermal Energy Initiative and Development Conference.

The knowledge-packed day was split into six sessions: Inaugural, Overview, Indian Perspective, Regional Case Studies, Issues and Modelling and Geochemical Modelling.

“What a perfect venue for springboarding  geothermal energy development in the country of India, where there are four main geothermally active regions on land”, commented George Lockett—one of 27 speakers who addressed some 300 delegates, many of them University students poised to enter the world of sustainable energy.

Lockett travelled from the UK to describe his geothermal work in the North Sea Continental Shelf, involving the development of Supercritical CO2 EOR for when decommissioning of the oil and gas industry infrastructure begins. He opened up similar prospects for India’s offshore oil and gas industries, quoting a well which showed that a geothermal gradient of 44 degrees Celsius was present, due to the fact that the Earth’s crust gets thinner as we move offshore. He was then invited to chair Session 2: Geothermal Energy – Indian Perspective.

The initiative was jointly sponsored by Pandit Deendayal Petroleum University (PDPU); the Energy and Petrochemicals Department of the Government of Gujarat; Gujarat Power Corporation Limited (GPCL); and the Indian Ministry of New and Renewable Energy (MNRE), with the aim of collecting and collating knowledge on Geothermal Energy from around the planet and applying it to Geothermal Development in India.


Design Study may Lead to Two North Sea Interconnector Hubs to Service Geothermal Power
21st November 2012


One hub would be 100 miles east of Aberdeen, interconnecting Scotland and the Nordic countries (Norway, Sweden, Denmark...), and the other about 100 miles east of Hull, interconnecting England, Holland and Germany.

Deep Geothermal is coming of age, and North Sea Geothermal has huge potential when compared to nuclear power. Here is some data for the Magnox type of nuclear fission reactor which was at the now decommissioned (2003) Calder Hall Magnox plant in Cumbria. One of the last Magnox reactors closed down this year; originally Wylfa (Anglesey)'s Reactor 2 was due to be shut down on 30 April, but it finished generating electricity on 25 April when the reactor was shut down at 19:02 BST.

This data refers to the high temperature steam that used to drive the turbines at the Calder Hall Magnox power plant:

• Flow rate: 180 tonnes per hour

• Pressure: 14 bar (about 200 psi)

• Temperature: 310 degC

The current knowledge of the Geothermal Gradient in the North Sea at these two hotspots where the Interconnectors will be situated is 35 degC per kilometre of depth, and to have a temperature of 310 degC coming to the surface we would need a bottom-hole temperature of 350 degC or 10,000 metres' depth.

This is about the current maximum design depth for North Sea drilling rigs. Here is an example:
“Lamprell self-elevating Mobile Offshore Drilling Platform of a
Super 116E (Enhanced) Class design, valued at US$ 227 million. The rig is designed to operate in water depths of up to 350 feet and will have a rated drilling depth of 30,000 feet”

The main difference in the above data will be the operating pressure: the Magnox had an operating pressure of 14 bar (about 200 psi); geothermal well pressures may be much higher and may need to be controlled by a choke. For example:
“Elgin-Franklin is the world's largest high-temperature / high-pressure (HT/HP) development. A new, record-breaking well was drilled to a depth of 6,100 m. with a temperature of 197 degC (387 degF) and a pressure of 16,750 psi (1,155 bar).”

As it is the pressure which does the work to generate electricity, and as the pressures are so high, perhaps a lesser depth may be appropriate and still produce the same power as a Magnox reactor did, which was about 40 MWe per reactor of power 24/7.

So how big will the Geothermal Reservoir need to be to achieve the same flow rates as a Magnox reactor did (180 tonnes per hour)?

The answer to this and the size of the Geothermal Licence may come soon from this Scottish Renewables Routemap Team:
“Further research still needs to be done. I explained in my previous letter that we would be commissioning a research programme to identify the next steps to take forward the commercial exploitation of deep geothermal energy, including the scope for licensing. This research is now underway and the results are expected to be available by Spring 2013.”

So will the Geothermal Licence be by depth – remember the 35 degC / kilometre depth Geothermal Gradient – or by block, as in the oil and gas exploration industry?

Six power plant designs are being considered:
• Single screw turbine: The single screw turbine design from Turboden (www.turboden.eu) offers a 500 kWe to 12 MWe electrical output, in temperatures ranging from 90 to 200 degC (194 to 393 degF). For example, 4 x 12 MWe would be equal to a Magnox reactor – generating 48 MWe of electrical power.

• Natural gas let-down stations – twin screw turbine: The twin screw turbine design from Langson Energy (www.langsonenergy.com) produces 1 MWe electrical output, operating in temperatures of between 177 and 288 degC (350 to 550 degF) and up to pressures of 600 psi.

• Steam Screw Expander systems: The expander sets of Heliex Power Ltd. (www.heliexpower.com) are rated from 70 to 350 kWe, with energy recovery from steam and other fluids in the temperature range 150 to 300 degC (302 to 572 degF).

• Hydraulic thermal engine: The Natural Energy EngineTM from Deluge (www.delugeinc.com) currently offers 250 kWe of electrical output, although there are plans to increase this to 1 MWe. It can operate in temperatures up to 82 degC (180 degF) using CO2 as the working fluid.

• Kalina Cycle: Uses an ammonia-water mixture as the working fluid (http://www.wasabienergy.com). Compared to the conventional Rankine cycle, a Kalina cycle power plant may offer efficiency gains of up to 50% for low heat energy sources such as geothermal brine at 150 to 210 degC (302 to 410 degF). The Kalina Cycle is in use in Iceland.

For comparison – the High Pressure Steam of the Magnox Reactor Plant that was at Calder Hall:
Turbine system (2 units per reactor):
High-pressure steam pressure at turbine stop valve 14 kg/cm²
High-pressure steam temperature at turbine stop valve 310 degC
High-pressure steam per set (77% total) 90,000 kg/hr.
Low-pressure steam pressure at turbine stop valve 3.7 kg/cm²
Low-pressure steam per set (23% total) 26,900 kg/hr.

The final conditions for the Calder Hall reactors before closure were a dual steam cycle with an electrical output of about 40 MWe per reactor, with an inlet gas temperature of 336 degC and a steam pressure of 14 kg/cm². The corresponding outlet temperature and pressure are 140 degC and 3.5 kg/cm² respectively.

This outlet temperature in a geothermal situation in the North Sea could be sold on to the oil companies to do secondary/enhanced oil recovery on depleted oil fields, to extend the life of the oil output and to melt the heavy tars.

The Scottish Parliament has stated that no new nuclear power stations will be constructed in Scotland. In March 2012, E.ON UK and RWE npower announced they would be pulling out of developing new nuclear power plants, placing the future of nuclear power in the UK in doubt.

Geothermal Power in the North Sea could be a viable alternative.

Traditionally, once an oil or gas field reaches the end of its productive life its production platform is decommissioned. The structure may be removed and taken ashore for recycling/reuse, or part of the platform may remain on the seabed, perhaps creating an artificial reef. However, another alternative is becoming a more viable option – utilising the platform to extract geothermal energy.

This could create a whole new North Sea Industry employing thousands of workers in new productive jobs in the offshore and onshore support industries.

Geothermal power holds out enormous opportunities to provide affordable, clean energy that avoids greenhouse gases like carbon dioxide (CO2). Geothermal Energy is true base load, producing electricity 24/7.

The continental shelf in the UK where these platforms are situated has a relatively thin earth’s crust (about 10 km thick compared to 40–70 km thick on land), giving the wells high bottom-hole temperatures: typical Geothermal Gradients of 35 degC/km have been recorded in the continental shelf crust.

Elgin-Franklin is the world's largest high-temperature / high-pressure (HT/HP) development; a new, record-breaking well was drilled to a depth of 6,100 m. with a temperature of 197 degC (387 degF) and a pressure of 16,750 psi (1,155 bar).

Heat from these wells can be utilised to generate electricity on board the platform that can be sent to the national grid via subsea cables. North Sea platforms have the advantage of being surrounded by cold sea water, which is at a much lower temperature than the onshore air cooling towers that are the conventional means of condensing a generating plant’s working fluids after they have passed through the turbines.

It is also possible to reinject the waste heat remaining in the fluids back into the oil-bearing level in order to increase field pressure and flows, thereby enhancing secondary oil recovery and extending field life. Furthermore, it is also possible to discover lower oil fields when drilling to greater depths to tap the geothermal energy under the platforms.

Great potential
Geothermal energy has huge potential when put in context against other energy reserves. When one looks at the planet on which we live one sees that all the fossil fuels, i.e. coal, oil and gas, come from the earth’s crust. The crust makes up only 0.4% of the total mass of the planet, the remaining 99.6% being hotter than 500 degC within the crust, increasing to 5,000 degC at the core. The pressures within the earth are constantly generating this heat naturally. This means that geothermal energy is infinite in its nature, as it is naturally renewable.

There are many areas of the world where hot water/steam reservoirs (Hydrothermal Fields) exist naturally. These are usually associated with fault lines between continents, and volcanic areas where hot springs, geysers and fumaroles are common. Recent research carried out in Russia, in the Kola Peninsula, has revealed moving fluids and open fractures at depths in excess of 12 km. This discovery has led to a review of current deep geological thinking and has opened up the development of geothermal energy extraction for electrical power generation.

Research project
Geothermal energy could have the potential to extend the life of North Sea rigs and platforms by a further 30 years (platforms can be extended by 30-year increments, as a plant will need refurbishing every 30 years; concrete structures have a 300-year life) both by being used for electrical power generation and by bringing geothermal heat from a lower level to heat up oil fields to help recover heavier tar oils.

If it makes economic sense to connect the UK to France by cables to utilise French nuclear power, then it must also make economic sense to connect these platforms to the mainland to utilise geothermal power.

“Interconnectors in North West Europe will lead to electricity flows following the rules of supply and demand. So it will flow where it is needed, which is good for our security of supply”, the UK's Department of Energy and Climate Change (DECC) said.

UK energy minister Charles Hendry and the Icelandic ambassador have discussed the idea of an interconnector to transport renewable energy from Iceland's geothermal and hydro sources to UK homes.

With voltage drops over long distances it makes more sense to use North Sea Geothermal Energy than to bring Geothermal Power 500 miles from Iceland. Shorter Interconnectors must make sense; and to be producing the power in UK waters and selling it to other European countries would make commercial sense too for Scotland and other parts of the UK as well.

For more details regarding the research project, email the author: george.lockett39@gmail.com

*****

North Sea Geothermal Energy Potential Discussed At All-Energy 2012

George E. Lockett looks at the prospect of utilising North Sea platforms to extract geothermal energy once the oil and gas fields, on which the platforms are placed, are no longer economic to produce from.

George E. Lockett is the first speaker in the Geothermal Energy session on Thursday 24 May 2012 — 09.15-10.45 in Room 18-20 at Aberdeen Exhibition and Conference Centre AECC.

Traditionally, once an oil or gas field reaches the end of its productive life, its production platform is decommissioned. The structure may be removed and taken ashore for recycling/reuse, or part of the platform may remain on the seabed, perhaps creating an artificial reef. However, another alternative is becoming a more viable option – utilising the platform to extract geothermal energy.

This could create a whole new North Sea Industry, employing 1,000’s of workers in new productive jobs, in the offshore and onshore support industries.

Geothermal power holds enormous opportunities to provide affordable, clean energy that avoids greenhouse gases like carbon dioxide CO2.  Geothermal Energy is true base load, producing electricity 24/7.

The continental shelf in the UK where these platforms are situated has a relatively thin earth’s crust (about 10 km thick compared to 40–70 km thick on land), giving the wells high bottom-hole temperatures. Typical Geothermal Gradients of 35C/km have been recorded in the continental shelf crust.Elgin-Franklin is the world's largest high-temperature / high-pressure (HT/HP) development.  A new, record-breaking well was drilled to a depth of 6,100m with a temperature of 197°C (387°F)  and a pressure of 16750 psi (1,155 bar).

Heat from these wells can be utilised to generate electricity on board the platform that can be sent to the national grid via subsea cables. North Sea platforms have the advantage of being surrounded by cold sea water, which is at a much lower temperature than the onshore air cooling towers that are the conventional means of condensing a generating plant’s working fluids after they have passed through the turbines.

It is also possible to reinject the waste heat remaining in the fluids back to the oil bearing level in order to increase field pressure and flows, thereby enhancing secondary oil recovery and extending field life. Furthermore, it is also possible to discover lower oil fields when drilling to greater depths to tap the geothermal energy under the platforms.

Great potential

Geothermal energy has huge potential when put in context against other energy reserves. When one looks at the planet on which we live, we see that all the fossil fuels, ie coal, oil and gas, come from the earth’s crust. The crust makes up only 0.4% of the total mass of the planet, the remaining 99.6% being hotter than 500°C within the crust, increasing to 5,000°C at the core. The pressures within the earth are constantly generating this heat naturally. This means that geothermal energy is infinite in its nature, as it is naturally renewable.

There are many areas of the world where water, water/steam (Hydrothermal Fields) reservoirs exist naturally. These are usually associated with fault lines between continents, and volcanic areas where hot springs, geysers and fumaroles are common. Recent research carried out in Russia, in the Kola Peninsula, has revealed moving fluids and open fractures at depths in excess of 12 km. This discovery has led to a review of current deep geological thinking and has opened up the development of geothermal energy extraction for electrical power generation.

Research project

Geothermal energy could have the potential to extend the life of North Sea rigs and platforms by a further 30 years — Concrete Structures have a 300 Year Life — both by being used for electrical power generation and by bringing geothermal heat from a lower level to heat up oil fields to help recover heavier tar oils.

If it makes economic sense to connect the UK to France by cables to utilise cheap French nuclear power, then it must also make economic sense to connect these platforms to the mainland to utilise geothermal power.

"Interconnectors in North West Europe will lead to electricity flows following the rules of supply and demand. So it will flow where it is needed, which is good for our security of supply," the UK's Department of Energy and Climate Change (DECC) said.

UK energy minister Charles Hendry and the Icelandic ambassador have discussed the idea of an interconnector to transport renewable energy from Iceland's geothermal and hydro sources to UK homes.

Hendry plans to visit Iceland again next month to discuss the matter further, DECC said.

The five power plant designs are being considered:

  • PureCycle power system – standard turbine: This project will demonstrate and validate Pratt & Whitney Power System’s (www.pw.utc.com) geothermal organic rankine cycle (ORC) power plant application on Quantum’s oil and gas fields. The turbine provides 250 kW electrical output per unit and operates at temperatures between 91°C to 149°C (195°F to 300°F).
     
  • Single screw turbine: The single screw turbine design from Turboden (www.turboden.eu) offers a 500 kW to 12 MW electrical output, in temperatures ranging from 90°C to 200°C (194°F to 393°F).
     
  • Natural gas let-down stations – twin screw turbine: The twin screw turbine design from Langson Energy (www.langsonenergy.com) produces 1 MW electrical output, operating in temperatures between 177°C to 288°C (350°F to 550°F) and up to pressures of 600 psi.
     
  • Hydraulic thermal engine: The Natural Energy EngineTM from Deluge (www.delugeinc.com) currently offers 250 kW of electrical output, although there are plans to increase this to 1 MW. It can operate in temperatures up to 82°C (180°F) using CO2 as the working fluid.
     
  • Kalina Cycle: Uses an ammonia-water mixture as the working fluid. (http://globalgeothermal.com)Compared to the conventional Rankine cycle, a Kalina cycle power plant may offer efficiency gains of up to 50% for low heat energy sources such as geothermal brine at 150°C to 210°C (302F to 410F).

For more details regarding the research project, contact the author at eMail: george.lockett39@gmail.com

 

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