http://www.thedailystar.net/newDesign/news-details.php?nid=166771
Tapping coal for clean, low-cost electricity
Australian firm proposes to generate 400MW power from Bangladesh’s unmineable coal by 2015
Sharier Khan
An Australian company with expertise in underground coal gasification (UCG) technology has proposed to produce 400 megawatts of clean coal power from Bangladesh’s unmineable coal within five years at a very low cost.
Making a presentation to Petrobangla last week, Mitchell Group of Australia said it could undertake a pilot project at its own cost in the deeper part of Barapukuria coal mine or in Jamalganj.
The first phase delivery of 10 to 40 MW power from the pilot project is possible within two years — 2011-12. By 2015, the company will be able to deliver 400 MW power.
Sources present at the presentation said it is very lucrative as power generated from such a plant will be as cheap as that produced by using gas.
A part of Barapukuria is presently unmineable by using open pit or underground mining methods as coal rests at a depth of 500 metres.
On the other hand, the coal deposit in Jamalganj is by far the biggest one discovered in the country. Jamalganj has more than one billion tones of coal. Unfortunately, the deposit rests between 600 and 1,100 metres below the surface, making it inaccessible using conventional mining methods.
But the UCG option makes coal in Jamalganj or Barapukuria accessible on a long term basis, said Raj Puri, chief executive officer of Michell Group’s Energy Division. He was accompanied by the company’s senior geologist and hydrologist Garry Love and two other executives.
They told Petrobangla officials, who included Chairman Hussain Monsur and three directors, that there would not be any environmental or social impact as in the case of typical coal mining.
Using the UCG technology will require small land acquisition as opposed to massive land requirement for mining. So, there will be no notable community displacement.
While theUCG can lead to surface land subsidence, the company said it can be avoided through proper planning. Land subsidence is inevitable in underground mining.
There will be no contamination of groundwater supplied to communities as such contamination risks could also be avoided through proper understanding of underground water reserve and planning on how to use it, the Mitchell Group said.
It also proposed to install modular power units, incrementally for rapid delivery.
The company said while preparing its proposal, it considered the fact that Bangladesh has a high population density and therefore “our project must have minimal social impact”. Land has value for agriculture, so its proposal must have small surface footprint.
“Our project must win the hearts and minds of the people,” Raj Puri said in his presentation noting that there was strong public opposition to mining.
The Mitchell Group, which has operated more than 50 rigs throughout Australia, India, Africa and China, made its first presentation to the energy adviser two months back. Last week’s presentation was made as a follow-up.
PROPOSALS FOR BARAPUKURIA-JAMALGANJ
The Mitchell Group proposes to apply UCG technology in Barapukuria to develop a power plant alongside Barapukuria Power Station.
In the first year, four to six wells will be drilled at a cost of around $ 4 million and groundwater will be investigated by spending another $4 million.
In the second year, the company will take approval of UCG design and other proposals, environmental clearance and begin a $30 million UCG pilot project. It will also demonstrate in the same year some of the outcomes by generating some power.
In the third year, the company will move towards commercialisation by expanding the power plant with an investment of more than $100 million.
In Jamalganj, the company proposes to drill complex branch wells from a single pad. Directional drilling will be undertaken to minimise surface impacts and leave the communities undisturbed. In this part, it will apply both UCG as well as Coal Bed Methane (CBM) to generate syngas.
UNDERGROUND COAL GASIFICATION
Gasification occurs when coal is heated with insufficient oxygen, it combusts partly and creates a gas known as syngas. This gas is of low calorific value that burns cleanly with a characteristic blue flame.
Syngas can be used for power generation as well as for other types of consumption. Even it can be converted into liquid and synthetic natural gas.
Worldwide, over 50 UCG pilot projects have confirmed its technical viability. UCG is being applied in USA, Canada, China, Russia, Japan, Australia, Germany, India, Pakistan and many other countries.
Coal gasification has been around for 200 years. But it has not become the mainstream energy technology due to easier availability of oil and natural gas. With the rising oil prices and demand, and scarcity of energy resources, different countries are now turning to it.
Gasifying coal in situ involves creating a gasifier in the coal seam. Two kinds of well are drilled for access to the coal seam. One well injects a controlled stream of air to partly combust coal and the second well recovers syngas.
Understanding and managing groundwater is essential for successful UCG as the water is needed to contain the process– to feed some of the gasification reactions and to effectively shut the process down. Poorly managed groundwater can lead to environmental disaster.
In general, UCG is a clean coal technology. While being the safest extraction technology, it does not require surface water. There is no ash or slag disposal. It also emits lesser air pollutants than other coal-based technology.
Many consider UCG as one of the main future energy technologies since 90 percent of the world’s known fossil fuel energy resources is stranded coal, which is inaccessible and unused. Presently, only UCG can ensure access to these resources.
