Gas and Steam Turbines Adapt

The turbine marketplace is undergoing a rapid transformation. The boom days of peaking and combined cycle plants fueled by natural gas appear to be over. Lobbying against natural gas is pushing it to the back of the queue behind wind, solar, energy storage, and other sources. Total MW orders per year are down 50% from a decade ago.

In response, turbine OEMs are investing heavily in areas such as hydrogen-based turbines and carbon capture, utilization, and storage (CCUS) to prepare their businesses for a cleaner energy future. Several of the big ones, too, are hedging their bets by adding divisions devoted to renewables, energy storage, and alternative energy.

Yet despite prophesies of doom, many believe there is plenty of life left in the turbine business. Tony Brough, an analyst with Dora Partners, believes gas turbines have a strong role to play over the long term. He noted all the attention on hydrogen and said this market will experience slow but steady progress.

“It is unwise to dismiss hydrogen, but a lot of challenges have yet to be overcome in its utilization,” said Brough.

To gauge the state of the market and the latest in gas turbine trends, we interviewed experts at GE, Siemens Energy, Mitsubishi, MAN, Baker Hughes, Triveni, Solar Turbines, Ansaldo, and Elliott. They lay out turbine trends, what is driving them, and how they are responding. They discuss their strategies with regard to hydrogen, sCO2, and other alternative fuels, and what they are doing in the carbon capture field. And they provide an overview of the different models they offer and their capabilities.

Let’s hear what they have to say.

Triveni

Triveni Turbine Limited (TTL) is a manufacturer of steam turbines up to 100 MW with more than 5,000 machines in over 75 countries across more than 20 industries generating more than 13,000 MW power. Arun Mote, Executive Director & CEO at TTL, said some of the key factors driving demand for steam turbines are reduced operating cost, self-sufficiency (in terms of captive power generation and consumption), and gaining carbon credits across segments such as: waste-to-energy (waste from municipal/industrial landfills); biomass (waste from forest/wood residues); and in steel (utilizing waste heat from processes, as well as gas engines/turbines) through combined heat and power (CHP) in applications such as district heating and combined cycle. Nonetheless, efficiency of power generation has gained utmost importance, which has induced the demand for high-efficiency steam turbines based on reaction steam designs.

"Efficient steam turbines based on reaction steam designs have gained popularity over traditional impulse designs for smaller-and-medium-size ranges of up to 100 MW," Arun Mote, Triveni Turbine.

“Traditional impulse turbines will still continue to find a place for steam turbines smaller than 3 MW for power generation, small-scale CHP, and industrial mechanical drive applications,” said Mote.

TTL has developed efficient reaction type designs from 3 MW to 100 MW. They incorporate upgrades for higher pressure and temperature steam cycles, blade redesigns to improve internal efficiency of energy conversion. They undertake programs to reduce the turbine footprint, and retrofit solutions for aging turbines to improve performance. In countries like Central and South America as well as Southeast Asia, especially in the palm oil segment, TTL has replaced single-stage with multi-stage machines to enhance efficiency. They comply with American Petroleum Institute (API) 611 and 612 specifications in refineries, chemicals, petrochemicals and fertilizers.

The CHP market is showing promise in the Americas. TTL received an order for an 18.25 MW extraction backpressure steam turbine generator from a Colombian paper producer. It will provide steam and generate power.

In cold countries like Europe, the district heating system is a promising segment. TTL can provide competitive steam turbine solutions for district heating plants. It has already established its references in Europe for this application. Additionally, the company provides renewable-based power solutions for sugar, palm oil, biomass,and waste-to-energy using low-pressure steam. The company is developing sCO2 steam turbines leveraging in-house R&D expertise and through association with technical institutes and domain experts.

Elliott

Elliott Group has seen many changes in the turbine markets throughout the past decade. Two of the more significant trends are the premium on operating efficiency as well as transitioning from fossil technologies to alternative sources. Users were previously focused on reducing upfront capital costs while accepting some sacrifice in operating efficiency. As fossil energy costs continued to climb, there was closer evaluation of capital investment versus operating efficiency. Higher efficiency provided a faster return on investment.

"We have developed turbine solutions that include an optimized aerodynamic flow path based on the required operating conditins and various options of working fluids, beyond steam," said Adam Neil, Elliot.

In response, Elliott has developed flexibility into its turbine designs to provide efficiency and accommodate alternative energy sources and working fluids at a wide range of operating conditions. The company has also added more automation in design tools, application sizing programs, and manufacturing processes.

Elliott Group base turbine and expander equipment offerings include:

MVMS – Multi-Valve Multi-Stage Turbines

Standard frame sizes: J/K-line, R-line, Q-line, N-line

Approx. max flow: 1,300,000 CFH

Typ. max pressure:2,000 psig

Typ. max temperature:1,019°F

SVMS – Single-Valve Single-Stage Turbines

Standard frame sizes: B-line, E-line

Approx. max flow: 188,000 CFH

Typ. max pressure:950 psig

Typ. max temperature:>950°F

SVSS – Single-Valve Single-Stage Turbines (YR Family)

Common standard frame sizes: PYR, AYR, BYR, CYR, DYR, MYR

Approx. power range: 5 up to 10,000+ HP

Typ. max pressure:700 psig

Typ. max temperature: 950°F

TH – Hot Gas Expanders

Standard frame sizes: TH85, TH100,
TH120, TH140

Approx. max flow: 330,000 CFM

Typ. Pressure: 50 psig

Typ. Temperature: 1,400°F

Large frame MVMS turbines, for example, are customized with extractions which export steam part way through the turbine to provide high efficiency usage. The steam being extracted supports additional plant processes that would otherwise be let down through a valve. After extracting some of the energy from the high-pressure steam, the lower-pressure extraction steam is used for plant process needs or in smaller horsepower steam turbines driving pumps. This demand for extraction steam may change over such that the turbine needs to balance the primary driven equipment with the required steam being exported.

“Each user has different requirements based upon the steam balance of the plant,” said Adam Neil, Manager, Turbine and Expander Product Development, Elliott. “Customizing the turbine flow path to meet the specific customer requirements or plant processes can greatly improve operating efficiency of the steam turbine.”

MAN Energy Solutions

The pursuit of decarbonization targets presents several challenges. The shutdown of coal-based power supply creates a gap in baseload supply, especially in winter periods, and increases grid imbalance. This situation is accompanied by an escalation in energy prices, resulting in a compulsion to reduce energy costs and increasing desire for self-sufficiency in energy supply for companies in the manufacturing sector.

“Modern, decentralized, low-emission gas turbines offer a sensible solution to this problem,” said Dr. Sven-Hendrik Wiers, Vice President Gas Turbines, Large Compressors & Screws and Head of Oberhausen Site at MAN Energy Solutions SE.

He noted another trend – the transition towards less CO2 emissions, which impacts steam turbine manufacturers via requirements such as the utilization of waste thermal energy. For steam turbines deployed as mechanical drive, there is growing demand for turbomachinery trains with higher efficiency. Part of the process steam is admitted into the turbine, and the remainder is expanded in the turbine up to the required pressure and extracted – similar to waste-to-energy applications in power generation.

“The socio-economic commitment to accelerated decarbonization requires a rapid phase-out of coal-fired power generation,” said Dr. Sven-Hendrik Wiers, MAN Energy Solutions

MAN Energy Solutions is responding on many fronts. This includes electrolyzers and power-to-X solutions, industrial-scale heat pumps as well as CCUS, LAES (Liquid Air Energy Storage), CAES (Compressed Air Energy Storage), and the further development of gas turbines and reciprocating engines). All MAN gas turbines can burn 20% hydrogen standard (up to 40% as an option). Depending on market requirements, they will be capable of burning up to 100% hydrogen either new or as retrofits.

“We are improving our gas turbines to make them more robust in terms of cyclic operation modes, while also improving hot start capability,” said Wiers. “Stable, low-emission part-load behavior also characterizes our gas turbine family.”

MAN supplies utilities, compressor stations, and industrial production sites with MGT series gas turbine packages. Single-shaft engines for power generation feature a range from 6.6 to 8.9 MW electrical. As twin-shafts, the MGTs drive compressors and pumps (6.8 - 8.3 MW mech).

The MGT single-shaft engine is suited to simple cycle and CHP applications. With efficiencies of up to 34.7% and exhaust temperatures of up to 520°C, service intervals are up to 40.000 EOH. A recent project in Germany involved replacing an aging gas turbine with a new one to fulfil current and projected emission standards. In addition, it needed the capability to burn 20% hydrogen blends and a commitment to extend to 100% by 2030. A similar Brownfield project in Germany is currently in the commissioning phase.

The company’s steam turbines are usually configured to meet customer and market requirements and thus are not “off-the-shelf” products. In the power range of 1 to 180 MW, it can scale the turbine within its modular system and equip it with the required admission extraction. This approach allows steam turbine configuration regardless of the application. MAN steam turbines can be flexibly adapted in regard to volume flow, admissions and extractions.

MAN’s MST series steam turbines can be used for power generation and mechanical drive applications and cover the 1 MW to 180 MW range. Models include MST 010, 020, 040, 050, 060, 080, 100, and 120. Each can be equipped with a condensing or a back pressure module, and can contain an extraction or an admission, or a few of them. The exhaust module can be axial or radial downwards, also the whole inlet module depends on the inlet temperature and pressure of the steam. Up to the power range of 10 MW, the blading can be either impulse or reaction.

They are in high demand. Last year, MAN received many steam turbine orders for applications such as PTA, FCC, air separation, nitric acid, blast furnace, paper IPP, distillery, and sugar. Mechanical testing of steam turbines as well as string tests of the entire train are part of MAN’s capabilities.

The company is developing a low-emission combustor for 100% hydrogen, which will be available in 2025. The Wobbe index of hydrogen fuel is similar to natural gas and, thus, the sizing of the fuel system and other components will not require significant changes in terms of volume.

Mitsubishi Power

To preparae for future demands, Mitsubishi Power is expanding and integrating its T-Point 2 facility with Hydrogen Park, a new facility for systematic validation of the entire hydrogen value chain from production to power generation. Mitsubishi Power has announced its 30% hydrogen co-firing for large frame gas turbines and will use Takasago Hydrogen Park to commercialize small and large frame gas turbines on a path to 100% hydrogen firing starting in 2025. Its Hydaptive green hydrogen packages augment renewables with on-demand power from gas turbines and lithium-ion battery storage, and green hydrogen production and storage.

“Aeroderivative gas turbines fulfill urgent requirements, including disaster relief and emergency power,” said Bill Newsome, Mitsubishi Power Americas

The company is developing partnerships to create hydrogen hubs and infrastructure throughout North America. The first hub, a joint venture with Magnum Development, is the Advanced Clean Energy Storage hub in Delta, Utah. The utility-scale hub will use renewable power to produce green hydrogen through electrolysis. Hydrogen will be stored in a salt dome at the site, using technology that has operated for 30 years in the U.S. Gulf Coast. Stored renewable hydrogen can be used for intra-day power when wind and solar availability are limited, as well as providing seasonal energy storage. Another hydrogen hub is being developed in North Dakota in partnership with Bakken Energy. This hub will include facilities that produce, store, transport, and consume clean hydrogen. It will be connected by pipeline to other clean hydrogen hubs being developed throughout North America.

Bill Newsom, President and CEO, Mitsubishi Power Americas, noted that many customers now require power generation equipment to deliver power in extremely short lead times, sometimes from contract to commercial operation less than four months. In these cases, compact, lightweight, aeroderivative packages can be an ideal solution. These units are capable of running on natural gas, liquid fuel, LPG, and in the future, hydrogen blends. The company addresses such needs with its MobilePac units, which are modular and can be delivered and installed quickly. For example, it supplied a five-unit turnkey project in early 2021 that entered commercial operation 110 days after the contract was signed.

The FT8 MobilePac gas turbine is offered as a 31 MW mobile generation package and a 30 or 60 MW stationary package. The design enables fast-track installation and commissioning, as well as demobilization and relocation with minimal crew.

The FT4000 SwiftPac gas turbine combines the open cycle efficiency of an aeroderivative engine and design robustness. It offers greater than 41% simple-cycle efficiency with package output up to 144 MW. Utilizing the core technology derived from the Pratt & Whitney PW4000 turbo-fan engine, the SwiftPac can provide peaking and baseload power with a compact footprint.

Beyond aeroderivatives, Mitsubishi Power provides a wide range of gas turbines ranging from 31 to 574 MW in both the 60 and 50 Hz markets. Here is a summary:

H-25 Series gas turbines (41 MW) were developed for utility customers and industrial customers in both 50 Hz and 60 Hz regions. The first unit entered into commercial operation in 1988.

The H-100 Series two-shaft gas turbines first entered commercial operation in 2010 (105.8 MW, 60 Hz; 16.4 MW, 50 Hz).

The 1,500°C M501G gas turbine for 60 Hz power generation uses steam for cooling combustors. The GAC Series, which is the current model, adopts air-cooled combustors in place of conventional steam-cooled combustors. It uses compressor discharge air for cooling combustors to add operational flexibility by eliminating the need for steam for cooling from the bottoming cycle.

J Series gas turbines are an integration of the G Series and technologies for temperature increase as a result of the Japanese national project for the development of 1,700°C class gas turbines. They operate at a turbine inlet temperature of 1,600°C. M501JAC Series gas turbines adopt air cooling for combustors instead of steam cooling. With a performance equivalent to the M501J, they produce a high level of operability including a shorter start-up time. The M501JAC offers efficiency greater than 64% and reliability of 99.5%. It emits low levels of NOx, CO2, UHC and VOC. The JAC starts up and shuts down quickly. The installed fleet of J-Series gas turbines has accumulated more than 1.6 million hours of operating experience with 47 units in operation.

“With the increased emphasis on decarbonization, power producers are choosing hydrogen pathways to support their clean energy transition,” said Newsom. “At commercial operation, the gas turbine is capable of operating on a mixture of 30% hydrogen and 70% natural gas, which can be increased to 100% hydrogen in the future with minimal infrastructure modification.”

To achieve 100% hydrogen, a new multi-cluster combustor technology derived from Mitsubishi Heavy Industries’ (MHI) heavy launch rocket division is in development. With higher hydrogen concentrations, the risk of flashback rises, as does the concentration of NOx. Because the combustor must enable efficient mixing of hydrogen and air as well as provide stable combustion, the distributed lean-burning combustor incorporates multiple upgraded fuel delivery nozzles with smaller openings. It mixes injected air and hydrogen, without using a swirler nozzle, making the mixing possible on a small scale and allowing for low-NOx combustion. Several multi-cluster combustors, each consisting of multiple cluster burners in a can-type cylindrical liner and casing, are radially mounted at an angle to the compressor section casting to provide a dry low-NOx (DLN) combustion solution for hydrogen-rich fuels.

Siemens Energy

Siemens Energy thinks that the world is shifting towards a more diverse energy landscape consisting of many small, decentralized power providers, consumers and prosumers looking for reliable and affordable operations with less emissions closer to where the energy is used.

“Interest in fossil-free fuels from customers is high,” said Hans Holmström, Siemens Energy.

Many customers in the industry operate aged assets, some coal-fired. For them the first step is to increase their energy efficiency. This can be achieved by switching to the latest generation of turbines, as well as modifying and upgrading existing assets or better utilization of waste heat and optimization of plant performance.

Hans Holmström, Head of the Industrial Gas Turbine business at Siemens Energy, cites the International Energy Agency prediction that renewables will meet 80% of global electricity demand growth during the next decade. That will require energy storage complemented by gas turbines.

“GTs will be a cornerstone of the grid infrastructure but with a new role as backup power instead of peaking units, and as flexible mid-merit combined cycle plants instead of baseload plants,” said Holmström.

He added that gas turbine generator sets, whether in open cycle, combined cycle or cogeneration configuration, offer some of the highest efficiencies possible across a wide range of power outputs. With natural gas, the fossil fuel with the lowest carbon content, they produce among the lowest CO2 emissions per kWh generated. To decarbonize power generation further, green fuels such as hydrogen or biofuels can fully or partially displace natural gas.

Holmström also touts the efficiency and flexibility of CHP technology. When a CHP plant is combined with heat storage, the possibility to transition to green hydrogen with gas turbines such as the SGT-700 and SGT-800 enables further decarbonization of thermal energy use and at the same time provides renewable balancing power to the grid to allow a large share of wind and solar, he said.

Siemens Energy has released a hydrogen blending capability with natural gas with DLE (dry low emissions) technology between 30 and 75% by volume, depending on the gas turbine model. The company has set out a roadmap for achieving a 100% hydrogen with DLE by 2030 at the latest. It has sold an H2 upgrade to an existing customer, a chemical plant in Brazil, and is installing a new H2-ready SGT-800 gas turbine to the city of Leipzig, Germany. At the Braskem ABC petrochemical complex in São Paulo, the company has designed a CHP plant fueled with residual process gas (up to 60% hydrogen) that allows the petrochemical giant to reduce water use and carbon dioxide emissions. Two SGT-600 gas turbines will generate 38 MW and provide 160 tons of steam per hour.

The Siemens Energy SGT-800 is a single-shaft gas turbine for power and heat generation, where the performance/efficiency has been optimized for combined cycle applications. Over the 25 years that the unit has been on the market, more than 460 units have been sold to all continents. It is suitable for baseload, intermediate load, peak load, and grid support thanks to high inertia. It’s also designed for future upgrade possibilities in regard toefficiency, power, and fuels as they become available. The SGT-800 can be offered as a package, power island, power block, or a turnkey power plant. It’s designed for frequent starts and stops. It can already operate with up to 75 % hydrogen with a roadmap to reach 100%. It offers 15 ppm NOx on natural gas fuel and about 60% combined cycle efficiency. The latest 62 MW package offers 2-pole generator with sound screens, acoustic generator enclosure as optional, single-sided air intake system as standard, and a sliding door arrangement.

Baker Hughes

Baker Hughes stresses several trends impacting the industry. On the one hand, there is the ever-increasing use of data coupled with digital tools, machine learning, and artificial intelligence to improvediagnostics and inspection technologies. This allows higher reliability and availability, lower maintenance, and overall lower cost of ownership. Additionally, there is the drive for the reduction in harmful emissions and decarbonization. This has led to breakthroughs in combustion, fuel flexibility, carbon sequestration, and increased efficiency.

“As part of our decarbonization efforts, we are focused on the fuel flexibility of our turbomachinery portfolio, including our NovaLT and other aeroderivative turbines,” said Christ Barkey, Baker Hughes.

The NovaLT family of gas turbines for the 5-20 MW range is suitable for power generation and mechanical drive applications. They can reach over 37% efficiency in simple-cycle configuration, and up to 85% in cogeneration, thanks to the high exhaust temperature. Carbon emissions for NovaLT16 and NovaLT12 gas turbines have been reduced by 50% due to material and testing optimization and machining time minimized by design optimization.

The NovaLT family accommodates hydrogen as well as other lower-carbon fuels such as ammonia. These turbines can burn methane gas and hydrogen blends with as little as 5% to as much as 100% hydrogen. The company is working with a range of customers, from gas network providers in Italy and Greece to leverage their existing infrastructure to allow up to 10% hydrogen. Baker Hughes also has a relationship with to Air Products for whom it is providing 100% hydrogen fueled NovaLT16 turbines for a net-zero hydrogen energy complex in Alberta, Canada.

Baker Hughes’ portfolio approach to CCUS aims to design optimized solutions by application, recognizing there is no single approach. It recently joined a strategic partnership with and invested in NET Power to advance the technical and commercial deployment of NET Power’s low-cost, electric power system that generates no atmospheric emissions and inherently captures all carbon dioxide. The development of supercritical CO2 turboexpanders is part of the arrangement.

“We are investing in a portfolio of carbon capture technologies including chilled ammonia, compact carbon capture, and the mixed salt process,” said Chris Barkey, Chief Technology Officer, Turbomachinery & Process Solutions, Baker Hughes.

GE Gas Power

GE Gas Power is bullish about the gas generation market through the rest of the decade. Beyond that, Brian Gutknecht, Chief Marketing Officer for GE Gas Power, believes scenarios will diverge depending on which combination of technologies drive longer-term reduction of CO2 emissions.

“In any event, we see gas generation playing a valuable, but changing role as it is relied upon more and more to balance supply from renewables,” said Gutknecht. “Developments in hydrogen-based power generation and carbon capture and sequestration (CCS) solutions mean that gas turbines can be a destination technology and not just a bridging technology.”

“Gas generation will grow through at least 2030,” said Brian Gutknecht, GE Gas Power.

The company provides a broad range of turbines as follows:

GE’s 7HA.03 at 430 MW, for example, is capable of more than 1,280 MW and 64% efficiency (5,331 Btu/kWh LHV net plant heat rate) in a 2-on-1 combined cycle configuration with a ramp rate of 150 MW/minute and turndown to 15% load. The combined cycle plant can start up in less than 30 minutes (rapid response hot start). The gas turbine is capable of up to a 50% blend of hydrogen today, with a technology pathway to enable 100% capability within the decade.

GE already has over 100 units worldwide that have run fully or partially on hydrogen or hydrogen-like fuels and accumulated over 8 million operating hours. At Long Ridge Energy Terminal in Ohio, for example, there is a demonstration project burning hydrogen in a commercially operating GE H-Class gas turbine. This marks a first step in Long Ridge’s plans to generate carbon-free electricity by transitioning its natural gas plant to run on 100% hydrogen over the next decade. In Europe, with Uniper, GE Gas Power has started a hydrogen plant readiness assessment to enable operations using blends of natural gas up to 40% by volume hydrogen, targeting the decarbonization of a 1.365 GW plant over the next decade.

“We see gas power with carbon capture as a logical near-term pathway to cutting CO2 emissions,” said Gutknecht. “Post-combustion carbon capture can be installed on both new and existing assets, and amine- based carbon capture is the most mature technology, though many options exist.”

Ansaldo Energia

Ansaldo Energia gas and steam turbines are displayed on the next page. The Ansaldo GT36 evolved from the GT26. It offers high efficiency at full and part load, low emissions, a high turn-down capability courtesy of sequential combustion, and fuel flexibility. Its window for emission-compliant operation is larger than many other combustors.

The G36 has a capacity of 538 MW. It has an axial compressor with variable inlet guide vanes, and a compressor-side driven generator. The turbine is axial and air-cooled. The sequential combustor is Dry Low NOx.

Solar Turbines

Solar Turbines offers gas turbines packages from 1–23 MW. They are used around the world in the development of oil, natural gas and power generation projects, both onshore and offshore. They include gas turbine engines, gas compressors, and gas turbine-powered compressor, mechanical- drive, and generator set packages. The company offers a number of different product lines. Some are mainly used in oil & gas while others are used in power generation and in other fields.

Its Titan turbines range from the 16.5 MW Titan 130 up to the 23 MW of the Titan 250.

The Mars 100 provides 11.3 MW.

The Solar Taurus line ranges from the Taurus 60 at 5.6 MW to the Taurus 70 at 8.2 MW.

The Mercury 50 provides 4.6 MW.

Centaur turbines offer between 3.5 and 4.6 MW.

The Saturn 20 provides 1.2 MW.