Silicon heterojunction solar cell technology (HJT) takes advantage of ultra-thin amorphous silicon layers deposited on both sides of monocrystalline silicon wafers, enabling excellent silicon wafer surface passivation resulting in high device power output and in addition to efficient use of thin wafers. A full cell processing platform was developed in our laboratory, enabling to achieve > 22 % cell efficiency. Advanced concepts for metallization and interconnection are under study, from fine-line printing combined with SmartWire interconnection to Copper plating. Importantly, we show that the HJT technology intrinsically enables high bifaciality of the cells (> 95 %), and further demonstrates a low thermal coefficient (< 0.2 - 0.3 %/°C). The high performance of heterojunction cells and SmartWire interconnection based modules allow for very low cost of electricity for Heterojunction based solar systems, with a potential below 6 Euro cents per kWh in Europe, bringing photovoltaics as a very competitive electricity source. It further provides upgrade potential towards 24 % cell efficiency.