The Council owned 60 acre site near Triangle Farm is now producing enough energy to power around 3,500 homes.
This week saw the site start to generate electricity. Income from the sale of the electricity will then be used to fund frontline services at the Council. Once the loan is paid off the Council will move from making Â£350,000 a year to more than Â£one million.
The move is part of the County Council's drive to find new ways of producing income and also helps provide renewable energy at a time when the County has the fastest population growth in the country.
The site is built, with co-operation from the tenant farmer, on Grade 3 agricultural land, putting it at the lower end of land quality in Cambridgeshire.
It is intended to keep the panels in place for a period of 25 years "“ but that period could be extended.
Cambridgeshire County Councillor Steve Count, Chairman of the General Purposes Committee, said: "When I talk to our communities they are rightly keen that we spend our money wisely and by finding a way to create income, these extra millions can be spent on much used frontline services. This County Council project is a great investment as it means we are producing renewable energy and income while reducing the need to either make cuts or ask our residents to make up through taxes. But this is just one example of what we are doing at to make the best use of our assets. For example through the Moblising Local Energy Investment project we have a commitment to invest Â£28 million in similar projects that help make schools and other public buildings more energy efficient. This is not restricted to solar energy, for example we've installed new boilers in schools, retrofitted insulation and we are developing a Smart Energy Grid Project for St Ives Park and Ride projects which proposes using battery storage technology and will be the first of its kind at this scale in the country. These measures not just save us money but our partners and schools so they can spend their limited budgets on helping the people of Cambridgeshire."