H+K was invited to pitch for the business after working with SunEdison on an ad hoc basis on a number of profile and issue management projects.
SunEdison retained H+K's Energy + Industrials team, led by director Chris Pratt, to work on community engagement and stakeholder management across a portfolio of large-scale solar developments across the UK.
Simon Whitehead, managing director of Energy + Industrials at H+K, said: "We already have a strong relationship with the company... and will continue to foster this through local and national campaigns including proactive engagement with communities around solar projects and overall media support."
The H+K team will report to SunEdison director of marketing for EMEA and Latin America, Virginia Amador, who said: "As we continue to enhance our visibility and number of large-scale solar projects across the UK, SunEdison realises the importance of stakeholder engagement and communications.
"We currently work closely with H+K in Spain and are confident the Energy + Industrials team in the UK, with its vast experience in renewables, will be an asset to our communications. Working closely with local communities is imperative as we grow our UK portfolio, and we have engaged H+K to work closely with our internal UK stakeholder manager, for which we are currently recruiting."
Whitehead added: "We look forward to sharing SunEdison's progress as it forges its path as a worldwide leader in solar power development."