A frequency-domain analysis of electricity market prices for multi-timescale flexibility of Power-to-X facilities

Power-to-X facilities can operate flexibly at different timescales, from yearly to hourly resolutions. Load profiles of grid-connected facilities can therefore be adjusted based on electricity market price variations at these different timescales. This raises the question of which timescales to prioritise in load profile scheduling, and whether load profiles simultaneously planned across multiple timescales can increase savings. This paper evaluates the financial benefits of multi-timescale flexibility in the context of a PtX facility adjusting its load profile to price variations in the Nordic day-ahead electricity spot market. Electricity market price variations are analysed in the frequency domain using the Fourier transform of price signals. Results show that market prices are characterised by specific frequencies over which price variations are particularly strong. By adjusting loads to these different frequencies, savings compared to the baseload are achieved and are significantly improved when multiple frequencies are considered at the same time.