Coal power goes digital

Andreas Lusch, president and CEO of GE Steam Power Systems, discusses the company’s newest offering that uses digital technology in combination with hardware improvements to harness the power of big data for efficiency gains in coal-fired power plants

This month, GE Power launched its new SteamH solution for coal-fired power plants, which it says is the first advanced ultra-supercritical technology combined with digital solutions.

According to the company, SteamH can deliver a 1.6 per cent efficiency improvement over today’s most efficient operational plant and more than 15 percentage points of additional efficiency beyond the global average installed base, nearing 50 per cent for the first time.

GE also claims 99 per cent reliability, 96 per cent greater availability and a 3 per cent reduction in CO2 emissions compared to the most efficient plant operating today.

The technology is based on GE’s ultra-supercritical design with key components upgraded. The firm’s scope of supply covers individual components to full turnkey plants, between 600 MW and 1350 MW.

We spoke with Andreas Lusch, president and CEO of GE’s Steam Power Systems business, about the new technology.

PEi: What is new about the SteamH plant?

Andreas Lusch: Its advanced ultra-supercritical technology goes to even higher pressures and temperatures and, as such, increases efficiency and lowers emissions.

On the software side, we’ve put a lot of digital applications into the SteamH plant to improve efficiency, and to go to optimal operational points. We’re focused on improving flexibility because it’s a big issue today with all the renewable energy in the grid.

We already have the first customer, Shanghai Boiler Works, with whom we signed a contract for the Pingshan II project in China’s Anhui province. For this project we’ve already implemented to go to 630à‚°C steam temperature, together with digital technology to improve flexibility.

The project features a 1350 MW boiler. Our scope of work is technology, design, engineering and manufacture of the main pressure parts.

And there is a second SteamH project where we have been selected, but not yet awarded: Turkish company Yildirim Energy Holding’s 2×800 MW Karaburun plant, where we will also apply our technology going after 670à‚°C. This includes physical technology ” the boiler and steam turbine generator, manufactured at GE’s factories in China ” combined with digital solutions.

PEi: First, please tell us a bit about the technology.

AL: To get 1.6 percentage points against today’s best operational plant is a significant efficiency improvement, and we do this through increases in the pressure and temperature at which the plan operates.

We also improve the operational efficiency of the plant. Today we read approximately 2 per cent of the data we glean from thousands of sensors on control systems. By analyzing the other 98 per cent of the data and really optimizing the whole plant operation ” for example, for the boiler we can optimize its operation (excess air, temperatures in the boiler, etc) ” we can improve the efficiency quite significantly, but we can also improve flexibility and lower plant operational costs. With new boilers we can go from 20 per cent loads to 100 per cent loads without oil firing, even with quite good efficiency.

Our Plant Optimization tool is a digital replica of the physical steam plant that is continuously monitored in real time to identify pinch points or areas of the facility in need of attention.

The tool shows the difference between the plant’s current status and its ideal performance so the operator can take steps to ensure it is running optimally. Known as systematic gap analysis, this futuristic feature helps improve overall plant performance and minimize unplanned downtime. It is also central to reducing costs by increasing plant efficiency.

Although at first glance the efficiency gains appear relatively small, they represent a huge value of around $2 million per year for the operator. Over a ten-year period, that is $20 million in added value as a result of efficiency, output and availability improvements.

PEi: But there are also improvements in the hardware?

AL: Yes. The low-alloy steels T23 and T24 are in the boilers already. These materials can handle much higher temperatures and pressures than ultra-supercritical. In addition, we have areas where we need to apply other materials, and we had developed those materials together with some suppliers.

In certain areas we are using, for example, HR6W, a nickel-based material for key boiler parts and steam piping superheater and reheater, and Inconel [a nickel-chromium alloy] material for some parts of the turbine, in the inlet. Both materials have been extensively tested, with more than 30,000 hours of experience in operational plants.

PEi: And are you adding more computing power to crunch the numbers from the sensors?

AL: Our Predix Cloud-based platform is designed for collecting, analyzing and processing data. We are using Predix and developing two things: first, a digital twin of the boiler and the whole plant, more or less simulating any time of operation under any operating conditions. Second, we have developed and have also acquired certain applications for operational optimization, for example the BoilerOpt boiler optimization software from US-based NeuCo.

We are analyzing the heat transfer in the boiler, and temperatures, and optimizing the soot blowing in the boiler. There is a certain sequence. With BoilerOpt, which is already implemented in 140 boilers worldwide, if you analyze the heat transfer in the individual locations of the boiler you can minimize the soot blowing and cleaning, which means a huge efficiency increase. You get the cleaning when needed and do not stress the material that does not have to be stressed.

For another example, you have to clean the surface of the boiler during operation in order to maintain its heat transfer and efficiency. This cleaning has an impact on operations.

The cleaning is currently done in a certain sequence. In the future, or today with our new application, we no longer do it in a specific sequence. We do it based on a program that will analyze the heat transfer and only clean those areas which have not enough heat transfer and do not clean everything continuously. It’s a self-learning program, like machine learning. The program runs by itself, and it’s amazing how fast it arrives at the most optimum cleaning sequence.

Another example is the fuel analyzer. We have an online analyzer that enables real-time tuning of the combustion and exhaust management process based on the properties of incoming coal and ash ” for example, the moisture, ash content, sulphur content etc. The tool incorporates an early warning system to alert operators to a change in the quality of the coal and can recommend adjustments that help to limit emissions.

We do the analysis online on the conveyor belt before the coal enters the boiler, and based on those data we optimize the functioning of the plant online. It’s not anymore like in the past where you had to go to the laboratory to do an analysis of the coal and then get the result hours later in order to adjust the set points. Now you can do it online during operations.

PEi: Is this new technology more expensive for plant operators?

AL: The new technology is slightly more costly but the increase in investment costs is minor. In terms of the overall lifecycle cost, we have savings that are quite significant. It makes sense to invest a bit more to get more efficiency and flexibility.

PEi: How does the plant achieve greater flexibility?

AL: We have an application called the steam turbine startup optimizer. By analyzing the data properly, for example the stress in the turbine, and having the right models behind it, we can reduce the startup time, warm and cold, by 50 per cent ” just by analyzing all the data and really optimizing the ramp-up of the turbine.

If we compare SteamH to the state-of-the-art ultra-supercritical technology, we can offer performance that includes a better heat rate and 1.6 percentage points higher efficiency, which is quite significant, with more or less a 3.2 per cent reduction in CO2. And together with flexibility as well as availability, which we can do mainly due to software that we are developing and have developed already, on a typical 1 GW plant the improvements would be in the range of $80 million net present value. It depends on the price of coal and on circumstances, it can be higher or lower, but this is more or less what we can offer compared to today’s ultra-supercritical plants.

PEi: What are your target markets for SteamH?

AL: The markets for coal, for newbuild, are in Asia. That is why China was one of our first lines. They are still building coal plants as you know, not as much as in the past, but in the meantime they are considering the environment and are going now to high-efficiency plants for new builds.

The same applies to almost all countries, because if you want to build a coal plant nowadays in this environment, with the political and social and environmental considerations, you have to use the best technology available in order to get permitted or obtain financing.

The issues with coal are the efficiency increase to reduce emissions, and the cost, of course ” but on cost we are already quite good because our factories and engineers are in Asia so we’re competitive already.

On emissions, I remember very well that even 15 years ago we had efficiencies which were in the 40s or even 38″39 per cent. Now we are almost at 50 per cent with new technology, which is not bad if compared to the average efficiency of the existing coal fleet. In future I think it will go further to higher steam conditions, to bring efficiency higher and bring CO2 emissions down.

Also, digital is really a game changer because, specifically on coal plants, because they are big plants with a huge number of megawatts, they are operated in a very conservative way. They are very complex even in baseload operation. This is changing now, and the only way is by using digital to go to the optimal point at any time and to increase flexibility.

PEi: What are GE’s plans for the future evolution of the SteamH technology?

AL: It’s obvious that for coal plants you have to increase the efficiency, which we are doing. Our plant in Germany has the best efficiency at 47.6 per cent. We think we can go up to 50 per cent efficiency considering the same environmental conditions, cooling etc.

Definitely the focus in future will be on efficiency, on reducing emissions, and on flexibility.

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