Electrifying industrial gas and steam turbines

By Anand Jha

According to the International Energy Agency, the demand for fossil fuels will peak by 2030. But while the use of coal will experience a sharp decline after the end of the decade, it’s likely that oil and gas will still be used for decades to come, even as the world moves in favor of renewable energy. This dual approach, combining traditional energy sources with innovative technologies and renewables, underscores the industry’s dedication to decarbonising while continuing to meet global energy demands.

A key example of decarbonisation in action is the electrification of gas turbines. Traditionally, gas turbines have been the workhorses behind various processes, however, the industry is now experiencing a notable shift towards electric alternatives, powered by highly efficient motor-drive systems, also known as eTrains.

The challenges of traditional gas turbines

While widely used in the energy sector for both power generation and industrial applications such as pipeline compressor stations or LNG liquification trains, gas turbines pose several challenges. Not only do they incur substantial operational costs, require frequent maintenance, and generate excessive noise, but gas turbines are also inefficient (the efficiency of a simple cycle gas turbine is around 20 to 35%), exacerbated by their susceptibility to variations in load demand, resulting in suboptimal performance during periods of low demand or operation in high ambient temperature (hot weather) 1. 

If a plant’s power infrastructure is not initially designed to allow for the integration of electrical power from renewable energy resources, turbine driven operation also hinders the flexibility to do so.

In the context of the climate crisis, the most significant issue with gas turbines is their environmental impact. By their inherent design, gas turbines burn gas to produce energy, which directly results in the release of greenhouse gas (GHG) emissions. The industrial sector is now hard at work to address these challenges.

Globally, and throughout the entire value chain, oil and gas companies are actively striving to achieve ambitious decarbonisation objectives. Their emphasis is on adopting cleaner fuels, methane management, utilising renewable power, and implementing carbon capture technologies. Further efforts are being made downstream to improve energy efficiency, enhance leak detection capabilities, and upgrade equipment. Across the board, electrification emerges as pivotal force, offering a raft of operational benefits alongside the crucial environmental advantages of reduced emissions and optimised energy use.

The transition to electric

To facilitate the transition to eTrains, chemical, oil, and gas companies can replace turbines or engines with a complete motor-drive system. This system includes essential components like a variable speed drive (VSD), electric motor, cooling system, and safety features. The evaluation can also extend to include electrical houses (eHouses) and LV or MV switchgears, for example, on a case-by-case basis.

The integration of these elements ensures precise control over motor speed in varying conditions, resulting in heightened energy efficiency, reduced emissions, and increased operational flexibility. In fact, electric drives offer efficiency rates of around 95% compared to a simple cycle gas turbine with efficiencies ranging between 20 and 35 %. 

Additionally, the system facilitates remote condition monitoring and predictive maintenance, contributing to overall reliability and sustainability in operations. The elimination of mechanical components extends process lifespan, lowers maintenance needs, ensures emissions reduction, and improves process control.

Ensuring successful electrification, especially in brownfield projects, could involve other key steps. These steps include conducting feasibility studies that encompass foundation analysis, harmonics and control or power interconnection analysis. Additionally, the scope may involve new electrical infrastructure, process control integration, torsional analysis, and commissioning.

Foundation analysis is necessary to ensure that the current civil or mechanical infrastructure can support the addition of a new motor and gearbox if required. Harmonic studies are conducted to evaluate how integrating a VSD into an existing or new electrical network will impact it. Torsional analysis, on the other hand, assesses and manages vibrations and stresses in electrified drive trains. This is achieved using mathematical models to simulate the effects, identify potential issues, and make necessary adjustments to designs for improved reliability, safety, and overall performance, considering the intricate characteristics of electric motors.

Success stories, such as the Troll oilfield in Norway and LNG plants in the US, showcase the benefits of electrification.

Electrification in action

The Troll oilfield in Norway is one of the most important in Norway’s sector of the North Sea. After nine years’ operation it became necessary to boost production by installing compressors on the immense Troll A platform.

ABB provided these devices with a revolutionary solution. It consisted of an electrical drive system that brought together two groundbreaking technologies: the world’s first high-voltage DC power-from-shore connection to a platform and the first commercial installation of very high voltage synchronous motors, each with a power rating of 40MW.

This method of bringing power to the compressors was better than installing gas turbines on the platform – the conventional solution – because the capital, operating and maintenance costs were all significantly cheaper. It has also reduced the environmental cost of running the compressors by 230,000 tonnes of carbon dioxide a year.

Meanwhile, electrification has emerged as a pivotal solution in North America and worldwide, transforming the landscape of oil and gas operations, particularly in compressor trains where traditional gas-powered turbines are being replaced with electric drives, leading to heightened operational efficiency. 

According to the all-electric LNG study, a comparison was made between a 6.25 MTPA LNG plant using a conventional gas turbine system and an all-electric drive configuration (eLNG). The conventional system includes six 30 MW gas turbine-driven trains in a 5+1 configuration, along with two 30MW electrical power generation units. In contrast, the eLNG configuration consists of four 40MW trains powered by a 200 MW power plant that takes advantage of electric drives. Additionally, the eLNG configuration offers the flexibility to obtain power from alternative sources such as hydro or nuclear power plants. By implementing the eLNG configuration, over 100,000 tonnes of CO2 emissions could potentially be saved compared to the conventional gas turbine system.

An example of this concept in action is ABB's collaboration with an LNG plant in the USA. They successfully delivered 18 highly optimised and modular 0.6 MTPA electrical LNG trains (eLNG) with a total nameplate capacity of 10 MTPA. ABB’s role was confined to providing the aforementioned drives and motors, rather than the construction of the entire LNG trains themselves. These trains were manufactured in factories and were completed within 15 months after the project's final investment decision. This represents a significant milestone in LNG construction and showcases the advancements brought about by the adoption of electrical LNG technology.

As these examples show, electrification not only contributes to a greener energy future; it can also improve efficiency rates, reduce downtime and optimise costs.

Future projections and industry adoption

Looking ahead, projections indicate a significant peak in electrification activities between 2022 and 2035, driven by a collective imperative to achieve decarbonization goals. A recent electrification study commissioned by ABB forecasts a spike in electrification activities around 2030, with an estimated 140GW (best case), 65GW (realistic), and 45GW (worst case) of new cumulative electrification demand. 

And it’s not just gas turbines that signal potential. Fracking (hydraulic fracturing) and cracking (ethane cracking) also stand to benefit significantly from electrification, ushering in a new era of efficiency, precision and environmental responsibility in pump and furnace operations.

In eFracking, adopting electric power improves operational efficiency and reduces environmental impact. Electric fracturing pumps provide precise control during injection, optimising fluid distribution and enhancing overall productivity. Additionally, electrification facilitates the incorporation of renewable energy sources, such as solar and wind power, into the process. 

In eCracking, using electric power for ethane cracking in the petrochemical industry yields energy efficiency and emission reduction benefits. Electrifying the process improves temperature control, enhances reaction kinetics, increases conversion rates and lowers energy consumption compared to traditional methods. The use of electric arc furnaces further reduces greenhouse gas emissions by electrifying a large Cracked Gas Compressor (CGC) in place of a steam turbine.

Electrification is set to become the industry standard as its adoption moves from being an alternative option to the norm.

As operators increasingly prefer electric drives over turbines or engines, the chemical, oil and gas sector progress toward an all-electric future, contributing profoundly to a greener, more efficient global energy landscape.

Anand Jha is with the Chemical, Oil and Gas Segment at ABB


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