Hybrid thermoelectric-photovoltaic solar harvesters: technological and economic issues

The possibility of recovering heat released by photovoltaic (PV) solar cells into electric power by using thermoelectric generators has attracted a remarkable research effort over the last two decades. Views and results are not fully converging, however, ranging from overoptimistic estimates of power gains to fully negative opinions about the convenience of hybridization. The aim of this paper is to review both energetic and economic profitability of photovoltaic-thermoelectric hybridization, as both issues are to be considered in the design of hybrid solar harvesters. It will be shown how the PV material rules the total system efficiency and its economic competitiveness compared to standard PV modules. Marginal opportunities are reported for roof-top concentrated solar harvesters. Yet, hybridization may leverage novel PV materials, currently not considered due to their lower efficiency compared to polycrystalline silicon. Much more significant is instead the window of opportunity when thermoelectric generators are coupled to perovskite solar cells.