Having sold its 1MW Uterne PV plant last week, SunPower has announced it has invested in Diamond Energy, a privately-owned, alternative energy project developer and clean electricity retailer headquartered in Melbourne, Australia. SunPower has acquired a minority stake of approximately 42% in Diamond Energy and under terms of the agreement has an option to increase its ownership percentage over time. SunPower will also assume a seat on the company's board of directors.