Alterra Power Corp. a subsidiary of Innergex Renewable Energy Inc., is a diversified renewable power generation company based in Vancouver, British Columbia, Canada. It was formed in 2011 through the merger of Magma Energy Corp. and Plutonic Power Corp. It develops, owns, acquires and operates hydroelectric, wind, solar energy and geothermal projects. On February 6, 2018, Innergex Renewable Energy Inc. completed the acquisition of Alterra including all its assets.^[2][3]

On 7 March 2011, it was announced that Magma Energy and Plutonic Power would merge to create Alterra Power Corp.^[4] Magma Energy was renamed Alterra Power and each shareholder of Plutonic Power received 2.38 shares of Magma for each Plutonic share held. At the time, the merged company owned two geothermal power plants in Iceland, and one in Nevada (since sold), one run of river hydro plant and one wind farm in British Columbia and an option on a solar project in Ontario.

In 2010, during the Icelandic financial crisis, Magma Energy acquired 98.5% of shares in the Icelandic geothermal power company HS Orka.^[9] The deal created an opposition in Iceland. On May 21, 2010 Icelandic singer Björk wrote an open letter in the newspaper Reykjavík Grapevine, calling on the Icelandic government to "do everything in its power to revoke the contracts with Magma Energy".^[10] The deal was approved by the Icelandic Government.^[11] In 2016, Alterra owned 67%, while the Icelandic pension funds held 33%.^[12] In 2019 Alterra sold off its shares in HS Orka to Macquarie Infrastructure and Real Assets (MIRA).^[13]