LONDON (Reuters) – Macquarie Asset Management, part of Macquarie Group, said on Thursday it has agreed to buy a 50% stake in UK-based renewable energy developer Island Green Power for an undisclosed sum. Island Green Power develops utility-scale solar plants and has projects in Britain and Spain, among other countries. It has developed more than 1 gigawatt (GW) of renewable energy projects and has a further 11 GW of capacity under development. Macquarie Asset Management said it will invest in the firm alongside Island Green Power’s current shareholders and senior management team. The transacti…