The Potential of using Power-to-Liquid Plants for Power Storage Purposes

The Power-to-Liquid (PtL) concept offers the potential to interlink the power and fuel market by producing high quality fuels from electricity and CO2. In addition, gaseous by-products from fuel synthesis can be used to generate electricity in peak load hours. In this work, a PtL concept comprising of a reversible solid oxide cell (SOC) is presented and evaluated in terms of 2014 fuel net production costs (NPC) and power storage potential. Results were compared with a reference system operating steady-state in electrolysis mode. A 100 % SOC run factor was realized, whereby the SOC unit runs primarily in co-electrolysis mode. Fuel net production costs (NPC) were slightly higher for the reversible SOC system, since increased capital costs exceed the revenue from lower average electricity costs. Though, fuel costs below 1 (sic)/l are possible if every kWh of effectively stored electricity is credited with 3-9 (sic)ct/kWh, which is the typical storage costs of state-of-the-art pump storage plants.