The UK’s largest solar developer Lightsource Renewables has refinanced yet more of its solar assets, this time raising £284 million (US$438 million).

Lightsource worked with financial advisor Royal Bank of Scotland to refinance a 101MW portfolio of 33 operational ground-mounted solar assets, each accredited under the feed-in tariff.

A statement issued by Lightsource on Wednesday said the move represented its first into the long-dated institutional market. M&G Investments provided the majority of the funding – £247 million of 22-year inflation linked financing – while AMP Capital provided a £37 million, eight-year mezzanine facility.

Mezzanine financing allows the lender to convert a loan into ownership or equity interest in the debtor if the loan is not paid back in time and in full.

Paul McCartie, structured finance director at Lightsource, said the deal was a “significant milestone” for Lightsource. “We have raised over £1.1 billion of project financing this year which is an amazing achievement and wouldn’t have been possible without the support of the lenders and advisors who work with us,” McCartie added.

Last month Lightsource shifted a new batch of its projects to investment partner Octopus Investments as part of a wider £400 million refinancing totalling 522MW, spread across 74 separate projects.

Lightsource has been prolific in its development of utility-scale solar farms and its recent refinancing initiatives come as it has amassed a significant pipeline of potential assets at a crucial period for the UK market.

With the renewable obligation (RO) support scheme set to close next year, developers are currently facing a further rush to have projects complete before the window shuts on 31 March 2016.

John Mayhew, head of infrastructure finance at M&G Investments, said that the injection of finance would be used by Lightsource to develop further sites across the UK.