Brian Wuebbels, who was appointed CEO of the yieldcos by parent SunEdison, resigned last month.
Blackmore was heading the office of chairman on an interim basis at both yieldcos. The office of chairman had been dissolved, the companies said in regulatory filings on Monday.
The two yieldcos are not part of SunEdison’s bankruptcy and have said they have sufficient liquidity to operate.
Blackmore also ceased to be a member of the Corporate Governance and Conflicts Committee.
Billionaire David Tepper-led Appaloosa, which owns 10.88% of TerraForm, had filed an amended lawsuit in April, seeking to overhaul TerraForm Power’s conflicts committee, claiming that SunEdison had breached its fiduciary duties.