Siemens Energy SGT 800 gas turbine at Finspång in Sweden. Image credit: Siemens.

How a research project is paving the way for hydrogen-based energy systems. By Aasa Lyckstroem.

The energy landscape has been changing since the Paris Agreement was signed in 2016 with the aim of strengthening the global response to the threat of climate change.

This article was originally published in Power Engineering International Issue 5-2020. Read the mobile-friendly digimag or subscribe to receive a print copy.

The ambition was to keep a global temperature rise this century well below two degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.

The primary focus of this effort to decarbonise the world’s economy has been centred on the power sector, that, according to the latest figures from the International Energy Agency (IEA), accounts for 47% of global emissions.

The strategy has witnessed a dramatic shift away from coal to gas generation, allied with aggressive renewable growth.

The initial thought was that natural gas, as a cleaner fossil fuel option than coal, could act as a bridging fuel to marshal the power sector into the zero-carbon age of renewable energy.

“The hydrogen that we produce would be used as fuel in the next gas turbine test”

While renewables do not produce carbon emissions, they introduce a high level of intermittency due to changing weather conditions and variations in solar irradiation. This is often coupled with mismatches between the demand and supply of energy, which potentially causes electrical grid instability.

While demand-side management can play a large role in handling these mismatches, supply management through curtailment of renewables during times of oversupply, energy storage, and providing backup power with conventional fossil fuel plants is also required.

One option that is gaining traction is that by burning hydrogen as a fuel, either through co-firing or complete displacement of natural gas, gas turbines can provide low-carbon or even carbon free power solutions.

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These capabilities make gas turbines ideally suited to helping to meet the World Energy Council’s trilemma of secure, affordable, and environmentally sustainable energy.

With that aim in mind, in January 2019 the EU Turbines Industry Association members committed to developing gas turbines capable of operating on 100 percent hydrogen by 2030.

Going green with hydrogen

These are some of the challenges that are being investigated at the Zero Emission Hydrogen Turbine Centre, based at Siemens Energy’s Finspång facility in Sweden.

The facility is home to the development, manufacturing and testing operations of the company’s mid-size industrial turbines and the centre is part of an EU-funded study to develop a gas turbine test facility as a zero-emission demonstrator plant.

The test facility performing a test on an SGT-700 gas turbine.

At the core of this zero-emission cycle is green hydrogen. What is green hydrogen and how can it be produced? One answer is the proton exchange membrane (PEM) electrolysis.

The PEM is a process that allows the use of green electricity to produce green hydrogen, that can then be used for numerous industrial processes, as well as for grid services.

Like all forms of electrolysis, hydrogen is produced by splitting water into hydrogen and oxygen, with the help of electricity.

A direct current is passed through water and oxygen is formed at the positive anode, while hydrogen is released at the negative cathode.

In conventional electrolysis, something that promotes the conductivity, often salt, is added. In the PEM electrolysis however, a proton exchange membrane is used.

It allows for the necessary particle transport between anode and cathode and therefore replaces any additives to the water. This makes the whole process more environmentally friendly.

No-waste energy

The journey began back in May 2018 when key staff in Finspång gathered together to share their ideas around what role the site could play in helping to meet the 2030 targets.

At Siemens Energy’s Finspång facility the mid-size industrial turbines such as the SGT-600, SGT-700, SGT-750 and SGT-800 are developed and manufactured.

Prior to delivery, the machines are tested to ensure that they meet all the performance criteria. Each test takes around four hours and produces a lot of energy.

Only some of it can be sent to the electrical power grid. We had various ideas on how to best utilise this excess energy and one idea that was considered was to use it to produce hydrogen.

Hydrogen will be an important part in the energy mix of the European power grid going forward because of its role as an energy carrier. The idea was to use some of the produced excess electricity, together with additional electricity from solar panels that we would install, to feed into the electrolyser and produce green hydrogen.

The hydrogen that we produce would be used as fuel in the next gas turbine test, together with natural gas. The goal was to create a sustainable energy loop with the electricity produced from one test used to create hydrogen, which is then used to power the next turbine test and so on.

The concept was to make use of excess power and at the same time build a demonstrator plant for a zero emission energy system.

Having received positive feedback on the concept and strategy from Siemens Energy management and backed by financial support from the EU ERA-Net, Smart Energy Systems and the Swedish Energy Agency, the project was up and running.

Proving the technology

Following closely the European funding organisation’s innovation model the project contributes to three layers of research: the technology, the marketplace and the adoption, running from November 2019 to 2022.

The first part is focused on the technology, sizing and dimensioning of the components and how they best work together. By incorporating renewable energy, an electrolyser along with hydrogen and battery storage into the existing gas turbine test facility it creates a closed loop system.

“To allow hydrogen to really start making inroads requires a change in regulations”

The long-term target is to burn 100% hydrogen, but that is not the immediate goal with this demonstration plant. The demonstration plant works with hydrogen contents that are currently feasible, which is up to 60% hydrogen volumetric content.

The aim of this project is to prove how these technologies, such as turbines, electrolyser, renewable energy, and storage, can be grouped together

in an energy system meeting global decarbonisation targets. Even though some of the hydrogen is produced using natural gas, it is still classified as green hydrogen because it used electricity that would have been wasted.

By working with our gas turbines for this project, we hope to set a positive and practical example for the energy industry globally. To not only encourage hydrogen as a future fuel for gas turbines but also as a medium to store renewable energy sources; a gas that enables a time shift of energy that can be stored and used later.

When it comes to energy storage, batteries will play a significant role but may not be the only solution for storage in the future, as they are often only suitable for short-term power shortages. A robust energy system will need storage for both short-term as well as for middle and longterm storage.

Gas turbines can support the grid with frequency control and support to stabilise a grid with lots of intermittent renewable energy. Energy storage in the future will most probably be a mix of many different solutions and in this scenario stored hydrogen will play an important role.

The second element is a study to learn more about the market requirements and how this technology fits into society and contributes to a sustainable energy system in the best possible way.

We have conducted several market analyses with external companies that we are working with, but also internally within Siemens Energy. We have had lots of interactions with our gas turbine customers to better understand their plans for future operational profiles. From this we have seen a clear trend with significant interest in flexible alternatives.

The third layer is about the stakeholders and adaption for commercialisation, where the project will deliver the results to a broad range of stakeholders to increase awareness in the benefits of burning hydrogen in gas turbines and make it useful for next generation energy systems.

This is where our two academic partners are involved. The performance of most of the individual components in the system is already well understood. This project is about how we integrate them into one system. To achieve this, researchers at Chalmers University of Technology and the University of Bologna are conducting studies into future energy systems that incorporate the technologies that we are testing and validating in this project.

Their work focuses on different optimisations of how to utilise energy carriers and combine them effectively.

We are using a gas turbine which is only one scenario. They are also looking at other scenarios and comparing cost and efficiency which will all provide interesting data for the stakeholders. For the local perspective of utilizing hydrogen and reducing CO2 in Finspång, Sweden our local partners from the region are involved.

Opening the market

The project is extremely focused on the energy system and how this can be optimised in different areas. Our system is just one example that can be used as a validation point. It will deliver real operational data that can be used by energy system modellers.

These types of energy planning scenarios have already helped in dimensioning some of the system components in this project as well as setting up operational profiles.

One of the reasons that there is a need for this type of demonstration study is to foster understanding and improve the utilisation of technologies that are already proven and could have a big impact.

The main reasons they have not had greater adoption to date comes down to cost, and with a better understanding of how a system works, this will improve. For now, burning hydrogen is more expensive than using natural gas and requires large storage facilities.

To allow hydrogen to really start making inroads requires a change in regulations that makes it costly to release CO2 and well-planned subsidies would also help.

Changing the regulatory landscape is of course outside the scope of this project but we hope that it can deliver one more piece of evidence that this is the future of energy systems and that it works.

The technology is ready today and we can close the gap between the technology and market awareness of how this can be best utilised.

ABOUT THE AUTHOR

Aasa Lyckstroem is Sustainability Officer & Manager of Product Positioning at Siemens.