To compensate the volatile power generation from renewables, hydrogen-fired gas turbines will be an important part of the future energy system. Besides novel combustor architectures it is crucial to also provide retrofit solutions to achieve the CO2 reduction targets. The development process of today’s combustion systems relies on assessments at atmospheric pressure. This is possible because for lean natural gas flames, the turbulent flame speed is insensitive to the mean pressure level. For alternative fuels, especially for H2, however, the turbulent flame speed strongly depends on the mean pressure level. Therefore, the established development procedure for natural gas cannot be applied. AETHER aims at modifying and extending the existing approach such that the thermoacoustic behavior of pressure-sensitive fuels can be deduced from atmospheric low TRL tests. By doing so, a reliable, time and cost-effective development approach for alternative fuels will be established.