Flexi-Opt

The aim of the Flexi-Opt study was to perform a systematic review of the potentials of alternative flexibility options, i.e. all options except gas or hydrogen power plants. Based on existing literature and qualitative assessment, the analysis covered the following flexibility options: energy end-use efficiency, demand-side response, batteries (large, BEVs and home storage), flexible use of electrolysers, flexible use of heat pumps, and flexible use of power-to-heat equipment in heat networks, plus the flexible use of biogas plants and geothermal CHP plants. In addition, the analysis estimated the need for additional capacities of backup power plants that may exist in Germany in 2030 and 2035. 
Backup power plants are permanently available in the market but only used for a few hours per year to cover periods of high residual load, i.e. low power generation from renewable energies, that cannot be met with the alternative flexibility options.

Key results of the study include: No new gas-fired power plants are needed for regular operation in the market; only backup capacities will be required, if other flexibility options are optimally exploited. Flexible backup power plants need only come into play after 2030. However, in the interests of climate protection (CO2 emission reduction, efficiency, etc.), they may only operate as a secondary option to other flexibility options. The energy system analyses evaluated by the researchers show that a combination of reducing the annual peak residual load and constructing backup power plants with a total capacity of around 12 GW will suffice until 2035. After that, residual load and, hence, demand for this combination will increase.

The required capacity of the backup power plants depends on the extent to which it is possible to systematically reduce the annual peak residual load (in particular through additional targeted energy efficiency and long-term heat storage in heating networks with PtH plants). These measures should be implemented in a targeted and prioritised manner. Incentives for targeted energy efficiency measures and other systematic load reduction measures are, therefore, important instruments for reducing capacity requirements for load coverage and ensuring security of supply.

The actual medium to long-term demand for backup capacities and alternative flexibility options should be determined in a process that leads to an adaptive, step-by-step and technology-neutral expansion decision, based, i.a., on the Energy Efficiency First principle. 
The backup power plants should with priority be provided in the form of flexible biogas power plants. If further backup power plants may be needed to cover prolonged periods of high residual load with a generation gap, they should be hydrogen-ready from the outset. In the long term, hydrogen-ready power plants should be operated exclusively with green hydrogen, which seems realistic from today's perspective from around 2035 onwards.

In addition, the alternative flexibility options examined can also cover other flexibility purposes, such as balancing power and other system services, and redispatch. Therefore, policy-makers and industry need to create the appropriate framework conditions for investment and the operation of alternative flexibility options. This applies to residual load coverage, system services and security of supply in the event of outages. Particularly, backup capacities should immediately be tendered in a fair technology-neutral manner and particularly including storage and flexible loads, and with a view to climate neutrality in the future.