Horizon Wind Energy Signs Power Purchase Agreement with AmerenUE

Energy from Pioneer Prairie Wind Farm to Power Missouri Homes

HOUSTON, June 18 /PRNewswire/ -- Horizon Wind Energy, LLC, a leading wind
project developer, owner and operator, owned by EDP Renovaveis, has just
entered into a 15-year Power Purchase Agreement with AmerenUE to sell
renewable wind energy from the 102.3 MW second phase of its Pioneer Prairie
Wind Farm, which has a total installed capacity of 300 MW already in
operation.

"This is Horizon's first Power Purchase Agreement with AmerenUE and we applaud
AmerenUE for making a long-term commitment to supply their Missouri customers
with pollution-free wind energy," said Gabriel Alonso, Chief Executive Officer
of Horizon Wind Energy. "This is the third PPA closing for our 2009 project
portfolio; we find this to be encouraging and are proud to partner with
AmerenUE."

The second phase of the Pioneer Prairie Wind Farm is located in Mitchell
County, Iowa. The wind farm spans approximately 10,000 acres and is comprised
of 62 Vestas V82 wind turbines that produce 1.65 MW each. The second phase of
the Pioneer Prairie Wind Farm began full operations in January 2009.

About Horizon Wind Energy
Horizon Wind Energy LLC ("Horizon") develops, constructs, owns and operates
wind farms throughout North America. Based in Houston, Texas with over 20
offices across the United States, Horizon has developed more than 2,800
megawatts (MW) and operates over 2,000 MW of wind farms.

Horizon is owned by EDP Renovaveis S.A. (NYSE Euronext: EDPR), a global leader
in the renewable energy sector that designs, develops, manages and operates
power plants that generate electricity using renewable energy sources. With a
sound development pipeline, first class assets and market-leading operating
capacity, EDPR has undergone exceptional development in recent years. Energias
de Portugal, S.A. ("EDP"), the parent company of EDPR, is a
vertically-integrated utility company, headquartered in Lisbon, Portugal.
Through its various constituent businesses, EDP holds significant electricity
and gas operations in Europe, Brazil, and the United States. For more
information, visit www.horizonwind.com and www.edprenovaveis.com.

About AmerenUE
Founded in 1902, AmerenUE -- Missouri's largest electric utility -- provides
electric service to approximately 1.2 million customers across central and
eastern Missouri, including the greater St. Louis area. UE serves 57 Missouri
counties and 500 towns. More than half (55 percent) of UE's electric customers
are located in the St. Louis metropolitan area. AmerenUE is a subsidiary of
Ameren Corporation (NYSE: AEE) -- Ameren utility companies provide electricity
to a total of 2.4 million customers across Missouri and Illinois. For more
information, please visit: www.ameren.com.

SOURCE Horizon Wind Energy, LLC

Sarah Bray, Communications Manager, +1-713-265-0310, cell, +1-832-226-2116,
fax, +1-713-265-0365, or sarah.bray@horizonwind.com