Holzle's investment is not linked to Google.
The Swiss-born software engineer has been at the cutting edge of renewables, having led the team that developed Google's global 24x7 carbon-free by 2030 commitment.
He is also a global leader on decarbonisation and the development of renewables.
McDonald said the company brings extensive global experience to the New Zealand market, with its leadership team having led the development of more than 2000MW of renewable energy projects across North America, the UK, Asia and New Zealand.
"While solar is an incredible opportunity to generate large volumes of clean, renewable energy, it needs to be done at genuine scale. Additionally, competitively financing large projects can be challenging, and responsible solar development requires long-term commitment to community partnerships," he said.
"The Helios team has built a track record of securing commercial funding for major solar developments around the world and is committed to building partnerships with landowners, communities and tangata whenua that deliver mutual benefit."
McDonald said Helios was proud to have one of the world's leading renewable energy strategists in Hölzle on board as an investor.
"We will be partnering with landowners and communities in service of developing cheaper, cleaner solar energy solutions, and will be providing regular updates on our progress," McDonald said.
"We're hugely excited about the opportunity to take a lead role in transforming New Zealand's energy sector in service of meeting New Zealand's climate change commitments and democratising participation in our energy system."