Exhibit 99.20

JOINT FILING AGREEMENT

This will confirm the agreement among the undersigned that the Schedule 13D filed on or about this date and any amendments thereto with respect to beneficial ownership by the undersigned of shares of Class A common stock, $0.01 par value per share, of TerraForm Power, Inc. is being filed on behalf of each of the undersigned in accordance with Rule 13d-1(k)(1) under the Act.

This agreement may be executed in counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

June 29, 2018

ORION US HOLDINGS 1 L.P. by its general partner ORION US GP LLC
By:	/s/ Fred Day
	Name:   Fred Day
	Title:     Vice President
ORION US GP LLC
By:	/s/ Fred Day
	Name:   Fred Day
	Title:     Vice President
BROOKFIELD INFRASTRUCTURE FUND III GP LLC
By:	/s/ Fred Day
	Name:   Fred Day
	Title:     Vice President
BROOKFIELD ASSET MANAGEMENT PRIVATE INSTITUTIONAL CAPITAL ADVISER (CANADA), L.P.
By:	/s/ James Rickert
	Name:   James Rickert
	Title:     Vice President,
	Brookfield Private Funds Holdings Inc.,               as general partner
BBHC ORION HOLDCO L.P. by its general partner ORION CANADIAN AIV GP INC.
By:	/s/ Adrienne Moore
	Name:  Adrienne Moore
	Title:    Vice President

BROOKFIELD BRP HOLDINGS (CANADA) INC.
By:	/s/ Jennifer Mazin
	Name:  Jennifer Mazin
	Title:    Senior Vice President and Secretary

BROOKFIELD ASSET MANAGEMENT, INC.
By:	/s/ A.J. Silber
	Name:  A.J. Silber
	Title:    Vice-President, Legal Affairs
PARTNERS LIMITED
By:	/s/ Brian Lawson
	Name:  Brian Lawson
	Title:    President