Government agency Indigenous Business Australia plans to use its first investment in large-scale solar as a model for future injections into other renewables projects across the country, chief executive Rajiv Viswanathan says.

Under a binding terms sheet announced on Monday, IBA and the Perth Noongar Foundation (PNF) will together take a 50 per cent equity stake in ASX-listed Carnegie Clean Energy's Northam solar project, a 10 megawatt solar farm to be built in Western Australia, about 100 kilometres east of Perth.