| Advertorial feature


So, what to do? This is a question that TÜV SÜD and Siemens Energy asked themselves, too, and collectively they decided to do something about it. In early 2021 they started to develop a guideline with support from AZT to give an unambiguous definition for the hydrogen readiness of a natural gas fired CCPP. And while the guideline deals with CCPP, it can also be used as a basis and, where necessary, adapted to cover a majority of plant types firing H2.


A common transparent framework


The advantages of such an undertaking are obvious. First, a guideline focusing on a complete CCPP as an overall system didn’t exist. What there was – and still is –, mostly refers to detailed aspects related to the use of hydrogen in the field of energy production and transport, such as material compatibility. Other guidelines focus only on sub-parts of a CCPP, such as the fuel supply system. Finally, the documents with the largest coverage originate directly from original equipment manufacturers (OEM) and cannot be used as a basis for an independent assessment by third parties.


But with a guideline from an independent organization such as TÜV SÜD all participants in the market, such as OEM, plant operators or insurers, can finally use a common transparent framework. It helps building a bridge to a decarbonized energy future.


Certifying a roadmap In early October 2021, the guideline passed its final critical peer review test. So as of now, any manufacturer can apply – with TÜV SÜD’s assistance – the new guideline to ascertain the H2-readiness of their CCPP. That the certification came to see the light of day so quickly is obviously due to an excellent team making it possible: TÜV SÜD with its know-how in certifying technical solutions in the energy industry; Allianz Center for Technology with its deep knowledge in risk- analysis of complex energy projects; and Siemens Energy with a wealth of experience in innovation


kind of certification that is virtually unheard of, nonetheless, just as thorough, and reliable as any quality certification needs to be. And so, it’s not surprising that the certification process for ‘H2- Ready’ is a special one.


Three different certification stages


To get the certification, a manufacturer and/or plant operator needs to lay out the configuration of their CCPP, including the boundary conditions that will determine how this power plant will manage the transition to co-/firing hydrogen. For one, it has to be clear what the go-to state is, meaning the overall plant performance after transition to hydrogen, including changes in power output, emissions, or efficiency. It has to be stated when the transition should take place, how the operator intends to ensure the hydrogen to be of an adequate quality, and whether the plant is just going to fire a blend or pure hydrogen.


And that’s why the certification of a new CCPP-plant has not one, but three stages, each with its own certificate covering the major phases of a power plant’s life cycle. First, a concept certificate for the conceptual design of a CCPP plant (including boundary conditions) for the bidding phase; second, a project certificate for the realization phase, i.e., the final design and its specifications when initially built on natural gas use; and third, a transition certificate for the conversion of a built CCPP plant to firing hydrogen - including a review of retrofit measures, and its impact on safety and performance.


A close look at key CCPP components and systems While the overall plant is certified, it can only happen by looking closely at key CCPP components and systems that are critical for the use of hydrogen and/or significantly impacted by its use, namely the fuel gas supply, the gas turbine, and the heat recovery steam generator (HRSG). Additionally, the building,


Hydrogen is an important building-block for decarbonizing the energy supply. An independent certificate creates certainty for investments.


for power plants, producing and storing hydrogen even today, as well as developing gas turbines and control systems.


What does the guideline actually contain? Most importantly, it’s not a simple certification as in certifying an existing technical component attesting it meets certain quality standards. Instead, it is a certification of a complete power plant with all of its sub-systems. On top of it, this solution gets certified as ‘H2-Ready’ by approving not an existing power plant, but rather a roadmap detailing how a CCPP can be transformed into a hydrogen co-firing or even solely hydrogen firing plant over time. It’s a


heating, ventilation, and air-conditioning (HVAC) and instrumentation and control at the plant level (I&C) must be evaluated. Let’s take two critical systems as an example - the gas turbine and HRSG.


First the gas turbine: The changed flame characteristics of hydrogen/methane mixtures (compared to methane) lead to a movement of the flame towards the burners. Thus, the risk of a flashback increases remarkably. As research and development work is still on-going, especially regarding combustion, it is necessary to assess the technology readiness level for each component. One challenge of burning mixtures


with larger hydrogen rates is the higher reactivity of hydrogen, posing especially challenges for the


premix combustion. In detail, this implies: ● Increased flame speed of hydrogen compared to methane


● Lower auto-ignition delay compared to methane


● Increased flame temperature of hydrogen compared to methane


Second: HRSG. With increased hydrogen content, the flue gas volume may slightly increase, leading to a higher pressure drop that needs to be considered in the design. Depending on plant design, NOx emissions will also increase, making extra considerations concerning the design of the Selective Catalytic Reduction (SCR) system and ammonia tank necessary. While these changes have to be in place, the condensation of the higher water content of the flue gas that comes along with higher hydrogen blends is not expected to warrant a major change in the hardware design. Still, technical adaptions with, for instance, re- circulation of heat to increase the temperature, are amongst the possibilities to counter negative effects.


Also, it should be noted that the CCPP can only be optimized for a certain window of hydrogen/ natural gas mixing ratio, within which significant design changes are not required. Therefore, the plant operator should be in the position to communicate to the plant manufacturer a roadmap showing the amount of hydrogen planned to be fired in the CCPP over time. This way, the operator and the manufacturer can agree during the early design of the plant on the mixing ratio for which the plant should be optimized. This approach should help limit the magnitude of required changes and thereby maximize revenue during the entire lifetime of the plant.


Achieving decarbonization goals So, all participants must have clarity on the boundary conditions, including the roadmap from a plant’s initial design with natural gas to the actual transition to hydrogen, the technology readiness level of each component as well as the complete system, and the three different certification stages outlined above. The first certified project became official in November 2021, when Siemens Energy completed the certification for a “H2-Ready” CCPP concept. Also, conversations concerning the use of the certification as new standard in the market are ongoing.


For sure, to reach ambitious climate goals by 2050, hydrogen power plants will come in various forms and shapes, not just CCPP – and the certification offered by TÜV SÜD for CCPP over time should certainly be adaptable to a variety of solutions. For example, Siemens Energy already offers power plants with hydrogen production, storage, and re- electrification onsite. All these solutions reduce CO2 emissions, which in turn helps plant operators to achieve their decarbonization goals – and to build the new energy system we are all working towards together.


www.modernpowersystems.com | November/December 2021 | 17


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65