SOLAR 21, a Dublin-based investment firm, has paid €13m to buy its latest Italian solar energy farm.

The deal to buy the 3.5MW farm in Lazio, in the west of the country, brings to seven the number of solar projects the Irish company now owns in Italy. In November, it completed the purchase of six Italian solar farms valued at €25m that were owned by AEG Power Solutions.

The latest solar farm is known as Borgo Montello and was bought from Berlin-based Kokusai Europe, a unit of Japan's Kokusai Kogyo Group.

Solar 21 was established in 2010 by Achill Island native Michael Bradley as an alternative investment vehicle for well-heeled businesspeople. He's also a director of financial advisory firm Clear Financial.

Nearly one-third of the people who have invested in the company are self-employed pension investors such as dentists, barristers, solicitors, doctors and pharmacists.

Another 26pc are company owner-director pension investors such as hauliers and architects. Nearly 10pc of Solar 21's investors were retired before they put money into the firm.

Its investors typically cough up a minimum of €50,000 and the company aims to provide an investment return of 8.5pc simple interest. The investment term is usually 20 years but investors can exit after five.

Solar 21 plans to invest in €1bn worth of assets and has aimed to raise a maximum of €100m in equity. It's hoping to benefit from efforts by European nations to encourage renewable energy development with premium prices under long-term contracts.

Pension funds are looking for alternative assets as yields on bonds have fallen on the back of economic contraction. Solar 21 reckons its investment fund is stable because it's underpinned by European directives for emission reductions and sovereign guarantees on green electricity sales, which are accompanied by long-term power purchase agreements.

The cost of those are incurred by electricity users throughout Europe via their bills.