MAN Diesel & Turbo’s vice-president, Gas Turbines discusses the Chinese market, gas turbines for combined heat and power applications and where the company’s R&D is headed

Dr Sven-Hendrik Wiers is vice-president, Gas Turbines at MAN Diesel & Turbo and co-author of the article on p14 of this issue. He is based in Oberhausen, Germany.

Tildy Bayar spoke with him about gas turbines for combined heat and power applications, the Chinese market and where MAN’s R&D is focused.

Q: Based on your sales of MGT6000 gas turbines in China, what are your projections for future growth in that market? And, do you have local manufacturing in the country?

A: Thanks to the change in regulations, China decided to shut down all coal-fired boilers up to 10 MW, and due to that fact a lot of coal-fired boilers in the class from 5–10 MW will be replaced by gas turbines.

Gas turbines are a clean technology if compared to coal and China definitely has an environmental issue with all the coal-fired power plants and boilers producing heat and steam for industrial processes.

One of the most efficient ways to produce power and heat/steam/cooling is, and will be in future, the combined heat and power (CHP) plant. For decentralized CHP plants, also in combination with renewables, I see a growing market.

As for local manufacturing: yes, the entire package including boiler and generator is local content manufactured by our partners in China.

We do the packaging at MAN’s workshop in Changzhou; however, the core gas turbine itself comes from our facility in Oberhausen in Germany.

Q: Besides the need to address air pollution, what other drivers exist for the growth of CHP in China, and in Asia more generally?

A: The main driver is the environmental impact and the shift from coal to gas. In certain areas they have also installed LNG terminals and China also signed a gas contract with Russia in order to secure the gas supply following its decision to convert from coal to gas.

A MGT 6000 power generation unit
Credit: MAN Diesel & Turbo

This accounts for China, but then look at Southeast Asia which is still a growing market. There is population growth on all Indonesian islands, and they all need power. Of course renewables are an option, but on a small island gas turbines or engines are definitely needed if you also want heat or cooling for industrial processes in the food industry, pulp and paper and households, for example.

Q: Have you taken special design, configuration or installation measures with the MGTs to deal with China’s pollution?
A: There is definitely a need for clean power in Asia. After the Paris Climate Agreement two years ago, there is a growing target to reduce the CO2 footprint worldwide and limit global warming by combining, in a smart way, renewables with clean power from gas turbines or similar technologies – and they can be also fired by renewable gases, for example.

Synthetic gases which are produced by renewables are a very clean option to produce power and steam. MAN can offer a hybrid system combining a gas turbine, gas engines, battery systems, renewables and power-to-gas technology.

One unique feature of MAN Diesel & Turbo is that we have both engines and turbines in our portfolio. If these machines are combined with renewables and battery systems and there is smart power management software as an umbrella which enhances the whole plant, the carbon footprint can be optimized substantially.

A growing number of countries will demand such systems in future, because global warming is not only limited to China. It’s an issue for all of us, and as an industry we are asked to develop innovative

We are also installing an online monitoring and diagnostic which is linked to our database. We can compare certain machine data and predict its behaviour. And of course we can also predict if failure could occur, and act in advance – the so-called predictive maintenance.

Q: What issues is your team focused on right now in terms of gas turbine development? And, where can you see future development needing to focus?

A: In the turbine, advanced cooling technologies have been applied in order to improve efficiency and reduce fuel consumption. We also introduced jet engine technology to our gas turbines to reduce gaps and clearances and to optimize sealing systems – all in line with the overall target of increasing the efficiency of our system solutions.

Of course, on the combustion side you have to develop and work on more advanced combustion chambers. This is key to reaching significant NOx values. Our current combustion chamber is able to do this, but of course we’re working on further improvements for the combustion process.

Additive manufacturing will gain importance in future, and we already use it today. By applying additive manufacturing we are able to introduce advanced cooling and repair technologies.

This represents an advantage for the customer, because they don’t have to exchange the whole part but can simply repair it – that’s an important operating cost advantage. We’re doing a lot of R&D to further improve this and to be able to introduce the best available technology.

For the industrial gas turbines in the power range from 5–20 MW, the matter of cost is also an important aspect. We can apply more sophisticated materials, coatings etc, but at the end of the day I think there is a limit to what the customer is willing to pay for efficiency improvements. This limits the technology the manufacturers are able to employ.

Look at the huge gas turbines in the field, which have an inlet temperature of 1600°C. Such technology could be introduced in an industrial gas turbine but the question is, would the customer be willing to pay for that improvement? There’s still a business case which has to be considered.

If the regulator and authorities would release stricter regulations, then maybe more companies will be willing to pay for advanced technology. Nevertheless, we work with a jet engine company in Germany and of course we use similar sealing and cooling technology, but we cannot apply the same materials and coatings because of their high costs.

Certain emissions standards must be met, because it’s state-of-the-art existing technology. Due to the fact that regulations did change worldwide, there was a need to develop this kind of combustion technology with a lean pre-mix combustion chamber.

For a couple of years we’ve talked about backup power and the need for gas turbines to be much more flexible, which requires a different kind of design philosophy. This is all driven by a change in regulations and the related growth in renewables.

Q: Are gas turbines or gas engines better for CHP?

A: You have a need for both solutions. The question is always about the process: is it power-driven or heat-driven? It really depends on the customer’s needs and what the driver is.

We as MAN Diesel and Turbo can offer both solutions to our customers and this is the real benefit.