Clean energy-focused investor Atrato Onsite Energy plc (<a href="https://www.londonstockexchange.com/stock/ROOF/atrato-onsite-energy-plc/company-page" target="_blank">LON:ROOF</a>) said today it has paid GBP 9.3 million (USD 11.8m/EUR 10.9m) to buy a portfolio of three operational solar systems in the UK with a total capacity of 13 MW.