## 3 Discussion and Assessment of Future Application Areas  
In order to assess the practical applications potential of this emergent class of transparent solar window-based PV, it is necessary to refer to the industry-standard system-level performance indicators, the most common of which is Specific Yield. Specific yield (SY) quantifies the amounts of electric energy (in kWh) harvested annually (per typical calendar year, in each installation location), per each 1 kW\({}_{\text{p}}\) of installed PV generation capacity [43]. SY values are commonly used in industry to directly compare the performance of different PV system configurations installed at different locations. Typically, measured SY values in the United States reach up to about 1500 kWh/kW\({}_{\text{p}}\), according to the data reported in [43] for conventional solar PV module installations. For conventional (silicon modules-based) rooftop PV installations in Perth, Australia, average daily energy generation outputs of about 4.4 kWh/kW\({}_{\text{p}}\) have been reported [44], which translates into the estimated approx. SY values of near 1320 kWh/kW\({}_{\text{p}}\), based on 300 sunny days per year in this location. Accounting for the PV generation amounts during the other 65 days showing at least about a third of maximum generation (compared to the stable-sunshine days, from our observations of Warwick Grove Atrium energy outputs measured on rainy days in winter), a more detailed estimate for the SY figure for typical Perth-based PV systems is then also close to 1500 kWh/kW\({}_{\text{p}}\). These data sets are only valid, however, for the optimally-oriented, optimally-tilted roof-based, completely unshaded silicon PV module installations. In order to evaluate the expected annual energy generation and specific yield of Warwick Grove Atrium, local meteorological datasets for the monthly and yearly cumulative solar exposure values can be used, in conjunction with the data of Figure 5b for the energy yield per each M/m\({}^{2}\) of solar exposure. Quantified during sunny days in May, a conservative estimate (due to the weather being more suitable for PV generation over many other months over the year) for this energy yield per unit solar exposure, is near 1/11 kWh/(MJ/m\({}^{2}\)). According to the yearly solar exposure data summaries available from a local weather station [36], the annual cumulative solar exposure figures were consistently at near 7400 MJ/m\({}^{2}\)/year, in several recent years. Therefore, a conservative annual energy output estimate can be obtained, being at least 673 kWh. This figure will likely be exceeded by up to several hundred kWh, due to weather conditions being much more conducive to PV energy harvesting in spring and summer, when both the UV and near-IR irradiation levels are much higher, due to drier atmospheric conditions. Substantially stronger diffused and reflected solar irradiation backgrounds are also present during the warmer months, leading (in our group's experience) to improved energy capture rates in solar windows. It is possible to evaluate the (over-conservative) lower limit for the expected specific yield of Warwick Grove Atrium installation, by using a nominal, sum-total-based installed generation capacity of 18 solar windows (\(\sim\)0.54 kW\({}_{\text{p}}\)). Then, a standardized expected SY figure of \(\sim\)1246 kWh/kW\({}_{\text{p}}\) is obtained, which is still quite competitive to the typical conventional (even optimally tilted) PV installations in sunny locations like Perth, especially if shading considerations are taking into account, which strongly affected 2 out of 18 windows. Accounting for the real measured peak output powers, and the local site-specifics of windows deployment at Warwick Grove, particularly the geometric orientations of most modules being far from optimal, the actual electric output-related installed capacity rating cannot exceed about 300 W\({}_{\text{p}}\).