Centre of excellence targets cutting emissions

GE has officially launched its Powering Efficiency Centre of Excellence in a bid to help the global fleet of coal-fired power plants reduce their overall emissions.

Ramagundam thermal plant in Telangana will be the focus for the COE team.

Credit: GE

The Centre of Excellence is headquartered in Switzerland and brings together experts from across the GE business to offer a total plant hardware and software solution to boost the efficiency of new and existing coal-fired plants.

In an interview with Power Engineering International, GE Power Services vice-president Michael Rechsteiner said that despite the global transition towards renewable energy, “coal is not going to disappear for decades to come”.

He added that the centre of excellence was needed because 41 per cent of the world’s electricity is still produced from coal and different countries are in different stages of their energy transformation.

GE has unveiled its Powering Efficiency Centre of Excellence, an initiative that sets out to boost coal plant efficiency and cut emissions. And the country it is targetting first is India.

Ramagandum coal plant in India. Credit: GE

“Each country is facing individual challenges in balancing the role of coal power in their own political and ecosystems. Regardless of each country’s unique balance, coal will not only remain part of the long-term energy mix but also in accordance with assumptions from the International Energy Agency, it will even increase in some capacity over the next two decades. So, it remains an important player.”

The first target for the centre of excellence is India, which has 60 per cent of its electricity produced by coal plants. A regional centre has been opened in the country and a deal has been signed with India’s largest utility, NTPC. The utility has picked GE to help increase the efficiency of three, 200 MW Ansaldo steam turbines installed more than 30 years ago at the Ramagundam thermal plant in Telangana. The Ramagundam plant is the largest in South India, generating a whopping 2600 MW of electricity each day.

GE will help NTPC improve the efficiency of each turbine by up to 14 per cent, increase plant output by approximately 30 MW and reduce the power station’s carbon footprint by around 5 per cent.

“This plant doesn’t need any new technology miracles,” says Mike Donohue, chief marketing officer at GE Power’s Power Services unit. “This is taking our existing technology and applying it to coal plants around the globe. It turns out that if we upgrade coal plants globally with the latest technology available, it will reduce emissions by as much as taking almost all the US cars off the road.”

Donohue says that if applied to all of India’s older coal plants, the technology would help India cut its CO2 emissions by roughly 12 per cent.

Donohue says that India is a great place for clean coal upgrades like the technology that will be deployed in Ramagundam. That’s because the country uses low-quality, domestic coal to produce about 70 percent of its electricity. When burned, this coal releases twice the heat-trapping emissions as natural gas. It also holds about 40 percent more ash content than the average coal lump. In addition to producing grime, ash lowers the coal burning temperature, which means that power plants need to use more coal to make a megawatt. It’s a vicious circle, Donohue says.

The upgrade has four crucial steps. First, technicians will coat the grinding surfaces of the plant’s coal milling machines with an ultra-hard tungsten carbide and cobalt chrome coating applied with a high-velocity air nozzle that can deposit a thick layer of the stuff. The tougher surfaces will allow the mill’s crushers to grind the coal to a finer dust that increases the fuel’s surface area and allows it to burn 10 per cent hotter.

The second step involves injecting ammonia into the flue gas leaving the boiler, where the burning coal transforms water into steam for the turbine. The ammonia reacts with sulphur in the gas to create ammonium sulphate. Rather than contributing to acid rain, the sulphur compound can be used as a fertilizer. Next, the team will open up the steam turbine and replace its blades with more modern and lighter ones. The steam will be able to spin the blades more efficiently and deliver more momentum into the power generator.

The fourth and crucial step doesn’t involve hardware at all. The team will deploy GE’s Digital Power Plant for Steam software that can analyze data coming from 10,000 sensors on the power plant’s equipment and help the operators gauge precisely the right amount of coal to burn and just the right temperature to maximize efficiency. The software can also predict when the utility should take the plant offline for maintenance and reduce unplanned downtime by as much as 5 per cent.

Combined experience

India is the fifth biggest coal producer in the world and there is a huge need for additional capacity in the country. The same applies to China, other Asian economies and even some countries in Europe.

“By bringing together the combined experience of a cross-business group of experts from GE’s Power Services, Steam Power Systems, Global Research Center and Global Growth organisations, we are showing operators how they can achieve emissions compliance and increased efficiency with their coal-fired power plants,” explains Rechsteiner.

“A study done by GE shows potential with our current technology to increase the average efficiency of coal-fired power plants by 4 per cent. If we do that, we take out 11 per cent of all CO2 emissions produced by coal-fired power plants.”

The average global efficiency worldwide is around 34 per cent so GE believes its technology can bring that average to 38 per cent, reducing both customer operating costs and CO2 emissions.

The average efficiency in India is 27 per cent, which makes it a priority for GE. The company says a typical plant with that average could see a steam turbine upgrade increase its efficiency by 20 per cent and a boiler by 6-8 per cent before digital optimization takes place.

“The solutions already exist to tacking the emissions problem now,” says Rechsteiner. “Today our steam plants are equipped with up to 10,0000 sensors and these digital solutions further expand the efficiency by 1-5 percentage points – so it’s done through a combination of old-fashioned hardware upgrades plus additional software digital solutions.”

Despite advances in utility scale storage, demand side response, digitization, energy efficiency, and decentralized energy all coming together to make for a more renewable-oriented future, Rechsteiner stresses that GE vision still sees a place for coal. “We are not taking a position for one or the other technology. GE is also one of the biggest players in the renewable market – we try to respond to the market and individual customer needs and coal continues to play a dominant role. We focus on providing the solutions that can increase efficiencies and reduce emissions.”

There is an argument that, given the inevitability of a coal-fired future, GE are more environmentally-friendly than agencies who want to dispense with coal altogether. “I couldn’t agree more,” says Rechsteiner. “These countries are going to continue [to use coal] if you leave them to themselves, so why not help them to reduce emissions?

“GE helps to calculate the returns on the investment. That could mean lower operating costs and lower fuel costs and potential subsidies because of environment bonuses customers can get – it’s attractive for export credit agencies and lenders and we help customers package their financial solutions together with the project.”

At a higher level, GE is re working with governments who are keen to reduce emissions and increase efficiencies in their electric power sectors. “We are in discussion with them and even developing policies with the Indian government involving how to control emissions in the country, and we are working with other countries on that as well in order to help them achieve their targets.”

And Rechsteiner adds that by-products associated with clean coal technology may well make more of an impact in India in time to come. “In Europe, by-products from removing NOx and SOx in the process are used in the cement industry. That has great potential in India where they are not extensively used as much so far. There is an opportunity to use it in construction.”

Ashok Ganesan, leader of the Powering Efficiency COE and managing director of GE Power India, adds: “Our initial focus is in India due to the country’s explosive energy demand projections. The overall efficiency of the existing power plant fleets, particularly the country’s aging coal-fired plants, is still relatively low. Our regional team in India is ideally suited to demonstrate the full potential of the Powering Efficiency COE to help the country’s coal plants operate more efficiently and reduce emissions.”

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