Investment urged for clean coal technologies

Paul Boughton

As the World Coal Association (WCA) hails coal’s vital role in electricity supply, generators are investing in the clean generation technologies needed to boost its use. Sean Ottewell reports.

The World Coal Association (WCA) has called for greater investment in cleaner coal technologies, both in order to meet growing global energy demand and to reduce carbon dioxide emissions.

The London-based organisation points out that coal plays a vital role in society by providing over 40% of global electricity, and as an indispensable ingredient in modern infrastructure. Here it cites the International Energy Agency’s forecasts that coal use is set to grow by around 17% in the next 20 years.

The WCA highlights technologies such as high efficiency, low emissions (HELE) coal plants and carbon capture, use and storage (CCUS) schemes, as being able to make a significant contribution to reducing global carbon dioxide emissions as part of the energy mix.

Benjamin Sporton, WCA’s acting chief executive, stated: “The WCA recognises the vital role that all low emission technologies can play and has created a global Platform for Accelerating Coal Efficiency (PACE) to promote adoption of these technologies. PACE’s vision is for the most efficient power plant technology possible to be deployed when coal plants are built.”

PACE’s objective is to raise the global average efficiency of coal-fired power plants and so minimise carbon dioxide emissions, whilst maintaining legitimate economic development and poverty alleviation efforts.

“Calls for divestment ignore the global role played by coal and the potential offered by HELE and CCUS technologies. We cannot meet our energy needs, tackle energy poverty and reduce global emissions without utilising all options available to us, including low emissions coal,” he added.

One such option is being utilised by Alstom and Veolia. They have signed a turnkey contract for the construction of a Flue Gas Desulphurisation (FGD) plant to treat flue gases from five steam boilers at Veolia Energia Lodz’s combined heat and power plant in Poland.

Due for commissioning in 2017, the FGD plant will use Alstom’s NID technology. A typical NID set-up comprises a hydrator/mixer, J-duct reactor and typically a fabric filter – although it can be used with electrostatic precipitators as well. In the J-duct reactor, acid gases such as sulphur oxides, hydrogen chloride and hydrogen fluoride react with hydrated lime, produced on-line from quick lime. Once bound to the particulate matter, the gaseous pollutants are removed from the flue gas in a downstream particulate collection device. To further enhance mercury collection, powdered activated carbon (PAC) can be injected. The collected particles are recycled to the mixer where freshly produced hydrated lime and water are added to the process.

This order comes almost one year after Veolia and Alstom signed a contract for another desulphurisation plant at Poznan, also in Poland. The FGD plant at Lodz will use a six-module version of the four-module unit installed at Poznan.

When complete, the Lodz FGD plant will keep sulphur dioxide and dust concentrations in the flue gas  below the 200 mg/Nm3 and 20 mg/Nm3 limits respectively demanded by the  European Directive regulating industrial emissions. It will also bring the total flue gas flow being treated by NID in Poland to over 5 million m3/h – making it the leading technology in the Polish semi-dry desulphurisation market, according to Alstom.

Meanwhile Siemens is to supply two steam turbine generator units specially designed for the Balkhash coal-fired power plant in Kazakhstan. They will be used primarily for power generation in the plant, although the plant itself is also designed for co-generation of heat and power and district heating. Commissioning is scheduled for summer 2019.

The Balkhash coal-fired plant is located on the shore of Lake Balkhash, one of the largest lakes in central Asia, in eastern Kazakhstan. Siemens' scope of supply for the order includes two SST5-6000 steam turbines, each with an electrical generating capacity of 660 megawatts (MW), and two generators of type SGen5-3000W, including control systems and all auxiliary and ancillary systems.

Steam turbines of SST-6000 series are typically operated in conventional steam power plants with a power output up to 1200 MW. The SST-6000 features a barrel-type high-pressure cylinder, an intermediate-pressure cylinder and up to three double flow low-pressure cylinders for 50 and 60 Hz output.

Finally, Karachi-based K-Electric has hailed the decision by Pakistan’s National Electric Power Regulatory Authority (NEPRA) to approve a generation licence for the company to undertake a clean coal conversion project at the 420MW Bin Qasim power station. The company had previously signed a contract with Harbin Electric of China in 2013 to construct new coal-fired boilers at the plant. Older boilers are also being rehabilitated as part of the US$400 million (€369 million) project.

In a separate development the company has also announced a US$1 billion (€0.9 billion) investment in new coal-based generation capacity in Pakistan. To this end it has signed an accord with power plant construction specialist China Machinery and Engineering Corporation (CMEC) for the construction of a 700 MW power plant.

India’s coal-fired plants underperforming, says study

India’s coal-fired power plants are underperforming in a number of important areas according to a new a study.

‘Heat on Power’, from the New Delhi-based Centre for Science and Environment (CSE), rated 47 coal-fired power plants around the country in terms of efficiency and compliance with environmental regulations, concluding that together they are among the world’s ‘most inefficient’, with “immense scope for improvement”.

"The objective of the study was to give a clear picture of the environmental performance of the power generation sector. Our finding is that in India, where the demand for power is increasing, power plants are performing way below the global benchmarks," said CSE director general Sunita Narain.

Overall the power generation sector scored 23%; a plant that follows all best practices potentially could achieve 80%. In addition, 40% of the plants rated in the study scored below 20%.

Average efficiency of coal-generating plants was found to be 32.8% and average carbon dioxide emissions 1.08kg/kWh. The latter figure, notes the report, is 14% higher than China’s emission level.

The plants were also found to be collectively using an estimated 22 billion m3/y of water, roughly half that needed by the country’s domestic population.

The performance of the NTPC, the largest coal-power producing company in India, was found to be below par. NTPC did not disclose its data, and hence was rated based on a primary survey and publicly available information. The six plants of NTPC that were rated received scores of 16-28%, the poorest being Delhi’s Badarpur plant.

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