The hydro power facility consists of two water turbines and the deployment of a 11,000-volt cable to connect the system to the castle, reported the BBC.
Commenting on the developments Romney Weir project director David Dechambeau said that high water levels in river are an impediment to power generation.
"It needs to have a drop over the weir to make energy.
"After a month or so we will be running the turbines at night time and powering the castle and shutting them down in the day to continue testing," added Dechambeau.
The final phase of the project is expected to be completely operational in the next three months and is expected to generate 2,000,000KWh energy per annum that will provide about half the electricity required for the Windsor Castle.
Any surplus power leftover at the facility will be fed into the National Grid.
