The main progress beyond the state of the art can be summarized as follows:
- 1.5 percentage points higher reflectance achieved with ultra-thin glass mirrors compared to state of the art 4mm silvered-glass mirror technology.
- Durability of absorber coatings for molten salt towers (up to 750°C skin temperature) is estimated to be doubled compared to state of the art Pyromark 2500 coating, while maintaing the same optical efficiency.
- 2x2 m² receiver panels for solar towers can be coated automatically. A homogeneous coating application was achieved: the thickness variation is less than 10µm compared to 30µm for manual painting.
- Abrasion resistance of anti-reflective coatings for parabolic trough receivers was increased by factor 2.5 compared to the commercial coatings, without transmittance changes (0.972).
- Selective absorber properties for low temperature absorbers have been increased to α=0.955; ε=0.078 (250°C) compared to the state of the art α=0.92; ε=0.13 (250°C), without any degradation at 400°C after more than one year of testing.
- No significant mass loss was detected on aluminide diffusion coated samples in contact with solar salt at 580°C for 10,000h, whereas for non-coated T91 and VM12 the material loss is 193µm at 580°C and 68µm.
As a result of the testing activity in RAISELIFE, BSII will employ the developed receiver coating in the largest single-site CSP project in the world, the 700MW molten salt tower awarded by Dubai Electricity and Water Authority. The tower will be constructed in 2020, it will have the world’s tallest solar tower, measuring 260 metres, and the LCEO will be 7.3 $Ct/kWh. The work related to improvement of line focussing absorbers will help to trigger the solar process heat market with its huge potential (0.9 million GWht/year corresponding to more than 400'000 European jobs).
As one of RAISELIFE’s primary goals, we projected that commercial implementation of the subject technologies could account for as much as 2.5-3 Euro-cent LCOE reduction per kWh of electricity produced for solar tower technology between 2015 and 2020. Back in 2015 when this goal was set, the typical LCOE of CSP systems was around 20 Euro-cents/kWhe. Thus we aimed at reducing the LCOE by 12.5 - 15%. In the past years, the LCEO of CSP systems dropped significantly to 8.9 Euro-cents/kWhe. On top of this reduction, it was shown within RAISELIFE that an additional LCOE reduction of 0.9 Euro-cents/kWhe is possible using the novel material developments. This corresponds to relative LCOE reduction of 9.8%, thus almost achieving the initially set goal.