Ion is teaming up with the GLIL Infrastructure Fund to create Flexion Energy Holdings, which will provide grid-scale storage.
GLIL, which has GBP2.5bn-worth of assets under management, has committed GBP150mln to the partnership.
Ion, meanwhile, is transferring its portfolio of UK energy storage projects to Flexion, as well as future UK storage business.
The plan is to have 300 megawatts (MW) of assets operational in two years extending to one gigawatt within five years.
GLIL, which is backed by certain pensions funds, will own 95% of the Flexion venture, with Ion holding the remaining 5%.
Coro chief executive Mark Hood said: “The highly accretive transaction sees a material commitment by GLIL to Ion’s UK energy storage portfolio, whilst securing a fully carried interest in the portfolio for Ion, and therefore Coro.
“We are excited in particular by Ion Ventures’ potential for further growth in south-east Asia, in relation to which we retain a right of first refusal to invest in Ion’s south-east Asian projects.
“We will continue to update shareholders in the coming months as we look to build on this success.”