The value of bifacial photovoltaics used with highly reflective ground materials on single axis trackers and fixed tilt systems: A Danish case study

The electrical performance and economic value of six 13 kWp crystalline silicon (c-Si) photovoltaic (PV) arrays - each with unique configurations - are compared. The systems are located within a 420 kWp test site in Roskilde, Denmark (55.6°N, 12.1°E). The different system designs studied include horizontal single axis trackers (HSAT) and 25° fixed tilt south facing structures, monofacial (single side active surface) and bifacial (dual sided) PV panels, as well as low and high ground reflectance (albedo). The economic value of the six system designs is assessed using onsite minute-resolution electrical measurements and hourly spot market prices from the Nord Pool electricity market. We use the Value Factor parameter to make our findings comparable to previous studies. We find that HSAT systems increase the annual Value Factor by 4 % relative to fixed tilt systems during the 11-month period studied here. The use of bifacial panels can increase the Value Factor by as much as 1 %, but a negligible increase in Value Factor was found using bifacial panels over the high reflectance surfaces. Therefore modifying the ground in bifacial designs does not likely justify the added upfront and O&M costs. Finally, through simulations we show that modifying the row-to-row distance does not offer the possibility to increase the Value Factor beyond what is demonstrated by our measured field data.