TURBOmachinery REtrofits enabling FLEXible back-up capacity for the transition of the European energy system

Periodic Reporting for period 2 - TURBO-REFLEX (TURBOmachinery REtrofits enabling FLEXible back-up capacity for the transition of the European energy system)

Reporting period: 2019-04-01 to 2021-03-31

TURBO-REFLEX aimed at developing and optimising technologies used to retrofit existing power plants as well as new machines to enable more flexible operation, providing the back-up capacity needed for introducing a larger share of renewables in the EU energy system. The project mission of advancing current generation of fossil fuel power plants was translated into three ambitious key objectives.
OB1. Reduction of costs per cycle
Reducing the costs per cycle of a typical warm start in combined cycle plants from currently 50€/MW to ca. 35€/MW by increasing part load efficiency, by improving the resistance to wear and damage prevention through advanced cooling schemes and transient component monitoring, and by data driven optimization of existing fleets with machine learning.
OB2. Increasing low load capability of existing plants
Reducing the number of hot starts required by 33% from currently approx. 150 per year to 100 by increasing the low load capability of existing plants, thereby enabling operation at lower load levels for extended periods of time instead of going through wear intensive shut down/start-up cycles. For this, new, retrofittable technologies were developed, which increase the operability of compressor and combustor components within strict emission limits, and active life assessment of highly loaded steam turbine components during low load operation.
OB3. Increasing load following capability
Doubling the load following capability of existing combined cycle plants from a ramp rate of currently approx. 6% per minute to 12% per minute, thereby improving the resilience of the electrical power system to maintain balance between consumption and generation also with an increasing share of fluctuating and non-dispatchable renewable sources. This was accomplished by increasing the flexibility of combustors, reducing the thermal gradients associated with fast load ramps through advanced cooling schemes, and by online monitoring and analytics to enable plant operation closer to actual physical limits.
The individual component technology improvements under TURBO-REFLEX for more flexible operation of thermal power plants can be summarised in three categories:
• Compressor off-design and operability
• Hot gas path technologies
• Mechanical integrity in flexible operation
These are complemented by online plant analytics & monitoring. Aimed at better understanding the plant behaviour as operated rather than as designed or manufactured, plant operators will be in a better position to optimise plant control and to trade flexibility with operating cost while limiting the impact on lifetime.
To verify the impact of the new technologies, whole plant performance assessments were carried out in parallel. Taking the view of the operator, a simulation package was used to allow plants with the new flexibility characteristics developed by TURBO-REFLEX to virtually participate back-to-back against current state-of-the-art plants in a dispatch optimisation tool, which simulates different European electricity markets.

A wide range of new, retrofittable technologies has been successfully developed and validated under TURBO-REFLEX. The technologies were targeted at providing retrofittable solutions, that enable the existing thermal power plant fleet to shift their role towards providing highly flexible back-up power needed for the transition of the European energy system.
The translation of the validated improvements at component level to whole plant performance demonstrated a significant improvement in the flexibility of Combined Cycle Gas Turbines (CCGT) and conventional Steam Power (ST) plants (hard coal). The ramp rates of CCGT plants could be increased by 63% and ST plants by 25%. Start-up times of CCGT plants during hot starts could be reduced by 41% (warm start: minus 60 %; cold start: minus 40%). The cold start-up time of conventional Steam Power plants (hard coal) could be reduced by 17%. In addition, the minimal load of the GT could be reduced by 15%-points, while the ST minimal load could be reduced by 20%-points, which yields an overall reduction of 17%-points for a CCGT plant.
The improvement measures were evaluated individually as well as in combinations of several measures in seven defined retrofit cases. The investigations showed that a combination of measures does not always lead to an optimum result. While a combination of several measures may increase the overall plant’s flexibility, the impact on some KPI’s might be lower as compared to individual implementation. In addition, some of the improvement measures showed negative impact on GT NOx and CO emissions during minimal load, which would require additional emission abatement measures, such as SCR or CO catalyst to fulfil emission regulations. However, it is standard engineering practice to design the emission abatement measures according to the emission regulations, operational requirements and plant characteristics, which change between a standard CCGT plant and a modified, optimised one.
To conclude, the TURBO-REFLEX results significantly improve component and overall plant performance, with great positive impact on the power plant flexibility in terms of ramp rates, start-up times and minimal load.

TURBO-REFLEX brought together 26 partners from nine countries. Built around a core of nine European turbine industry OEMs and one power plant operator, the consortium also included leading European universities, research institutes and highly specialised SMEs.
This unique collaboration enabled the successful development of new, retrofittable technologies, which are critical for improving the flexibility of the existing power plant infrastructure. Most importantly, several TURBO-REFLEX achievements already became available to the market before the end of the project. For instance, novel methods for estimating disc burst integrity and prediction of Low Cycle Fatigue (LCF) life were developed, enabling faster and robust calculations, and thereby resulting in more flexible and safer turbine operation. A new online life consumption tool, which is based on measurements of High Cycle Fatigue (HCF), was implemented, and included in a newly developed Remote Monitoring System, which is available for use in an operational environment. Additional plant monitoring probes and concepts were developed, validated in a lab environment, and are ready for real plant application.
Aside from these solutions which are already available, most of the remaining TURBO-REFLEX achievements are expected to be ready for implementation in the near to medium future (1-5 years).
Overall, TURBO-REFLEX solutions have the potential to reduce fuel consumption and emissions due to shorter start-up times and higher part load efficiency. The technologies could allow a significant amount of the installed fossil capacity in Europe to be retrofitted by 2030. A retrofit potential of 10% of the installed fossil capacity (summing up to approx. 42 GW) until 2030 is technically possible.
However, the market environment for investments in flexibility products for conventional, fossil fuel-based plants, such as targeted by TURBO-REFLEX, is generally challenging at the time of the project’s end. Flexibility upgrades obtained through TURBO-REFLEX may thus be ahead of time for some of the European electricity markets.

An exemplified thermal power plant indicating the components and technologies investigated

Periodic Reporting for period 2 - TURBO-REFLEX (TURBOmachinery REtrofits enabling FLEXible back-up capacity for the transition of the European energy system)

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