Arnergy, a provider of distributed solar energy solutions, has raised $15 million as an extension of its Series B round, adding to the $3 million it secured in an earlier round, bringing the total Series B funding to $18 million. The funding round was led by CardinalStone Capital Advisers, a West Africa-focused private equity firm with participation from British International Investment. Existing investors, Breakthrough Energy Ventures, Norfund, EDFI Management Company (EDFI MC), and All On also participated in the round.