ROME—In the industrialised eastern Sicilian town of Priolo Gargallo, Italian energy company Enel SpA is about to begin testing a new form of solar power that, it says, has the potential to displace older technology.

In the coming weeks, Enel will switch on a power plant with a generation capacity of up to five megawatts, linked to an adjacent 752MW gas-fired facility. One megawatt of electricity can provide power for roughly 800 homes. By the end of the year, the utility expects to have enough data to determine whether the technology - tested mainly in the laboratory so far - works on a large scale.