Silbat collaborates with IES-UPM achieving a World Record Efficiency in TPV Technology

Silbat is excited to announce the recent achievements resulting from our collaboration with the III-V Semiconductors Group at the Instituto de Energía Solar, Universidad Politécnica de Madrid (IES-UPM). This partnership has led to remarkable findings in the development of germanium thermophotovoltaic (TPV) converters for thermal batteries, boasting an unprecedented efficiency of 23.2%. This accomplishment represents a significant leap from the previous record of 16.5% for germanium-based TPV converters, which had remained unchallenged since 2007.

Ge-based TPV cell jointly developed by Silbat and IES-UPM with a 23.2% record efficiency and 1.34W/cm2 output power density when shone by 1 AlN/W emitter at 2073K.

At Silbat, we view germanium as a cost-effective and reliable material for developing our TPV modules. Our internal techno-economic analyses suggest that efficiencies exceeding 30% are achievable with this semiconductor. Such advancements have the potential to position Silbat as a leader in energy storage technology, particularly regarding the Levelized Cost of Storage (LCOS) in the Long-Duration Energy Storage (LDES) sector, which ranges from 10 to 100 hours. This could lead to highly competitive internal rates of return (IRRs) for applications such as Battery Energy Storage Systems (BESS) for arbitrage operations, whether in standalone mode or in conjunction with variable renewable energies (VREs). Moreover, this technology can support the firming of VREs, making them fully dispatchable while maintaining Levelized Costs of Energy (LCOE) comparable to those of fossil or nuclear power plants.

Ge-based TPV cell at varying substrate doping levels and shone by two different emitters. When shone by a W emitter at 1373K, as in the previous record of 16%, our cell reaches a maximum 20% TPV efficiency. When subject to a hotter AlN/W emitter at 2073K TPV efficiency of 23.2% is proven.

Furthermore, our analyses highlights significant potential for further efficiency improvements through the use of III-V semiconductors, which can achieve efficiencies exceeding 40%. This advancement would enhance our technology’s competitive edge in both duration and capacity factor ranges. Importantly, in LDES applications, LCOS remains resilient to power-related capital expenditures, allowing us to focus on achieving champion efficiencies without undue concern for manufacturing costs. We plan to integrate these high-efficiency cells into our patented cell and module technology, which has already been validated in our current demonstrators and is undergoing enhancements for manufacturability.

As we look to the future, we are excited about the possibilities that lie ahead in advancing energy storage solutions.