• Energy Research

Sustainable energy, grids and networks 39, 101455 - (2024). doi:10.1016/j.segan.2024.101455 Published by Elsevier, Amsterdam [u.a.]

Sustainable energy, grids and networks 39, 101455 - (2024). doi:10.1016/j.segan.2024.101455 Published by Elsevier, Amsterdam [u.a.]

Abstract Based on previous long-term SOFC stack tests, two short stacks (one F20 and one F10 design) were tested in order to investigate stack performance under high fuel utilization (>40%) and possibly also high current densities (>0.5 Acm−2). The F20-design stack was still operated with relatively mild current densities (≤0.5 Acm−2), but with high fuel utilization of up to 90% with 10% pre-reformed liquefied natural gas (LNG). The F10-design stack was operated with 20% humidified H2, but with high fuel utilization of up to 90% and high current densities of up to 1.5 Acm−2. Preliminary analysis shows that both F10- and F20-design stacks can be operated smoothly at a fuel utilization of ∼85% in the temperature range of 750∼800 °C, although an increase in concentration polarization can already be observed at the fuel utilization of ∼80%. Operation with fuel utilization of 90% led to local oxidation of cells at a similar position in both stacks. Based on the calculations with a 1D model, such an effect was assumed to be due to the variation in fuel utilization caused by the temperature gradient in the cell.

Abstract Based on previous long-term SOFC stack tests, two short stacks (one F20 and one F10 design) were tested in order to investigate stack performance under high fuel utilization (>40%) and possibly also high current densities (>0.5 Acm−2). The F20-design stack was still operated with relatively mild current densities (≤0.5 Acm−2), but with high fuel utilization of up to 90% with 10% pre-reformed liquefied natural gas (LNG). The F10-design stack was operated with 20% humidified H2, but with high fuel utilization of up to 90% and high current densities of up to 1.5 Acm−2. Preliminary analysis shows that both F10- and F20-design stacks can be operated smoothly at a fuel utilization of ∼85% in the temperature range of 750∼800 °C, although an increase in concentration polarization can already be observed at the fuel utilization of ∼80%. Operation with fuel utilization of 90% led to local oxidation of cells at a similar position in both stacks. Based on the calculations with a 1D model, such an effect was assumed to be due to the variation in fuel utilization caused by the temperature gradient in the cell.

Renewable energy 145, 1578-1596 (2020). doi:10.1016/j.renene.2019.07.045 Published by Elsevier Science, Amsterdam [u.a.]

Renewable energy 145, 1578-1596 (2020). doi:10.1016/j.renene.2019.07.045 Published by Elsevier Science, Amsterdam [u.a.]

AbstractReliable and highly resolved information about onshore wind energy potential (WEP) is essential for expanding renewable energy to eventually achieve carbon neutrality. In this pilot study, simulated 60 m wind speeds (ws60m) from a km‐scale, convection‐permitting 3.3 km‐resolution ICON‐LAM simulation and often‐used 31 km‐resolution ERA5 reanalysis are evaluated at 18 weather masts. The estimated ICON‐LAM and ERA5 WEPs are then compared using an innovative approach with 1.8 million eligible wind turbine placements over southern Africa. Results show ERA5 underestimates ws60m with a Mean Error (ME) of −1.8 m s−1 (−27%). In contrast, ICON‐LAM shows a ME of −0.1 m s−1 (−1.8%), resulting in a much higher average WEP by 48% compared to ERA5. A combined Global Wind Atlas‐ERA5 product reduces the ws60m underestimation of ERA5 to −0.3 m s−1 (−4.7%), but shows a similar average WEP compared to ERA5 resulting from the WEP spatial heterogeneity.