President of Chile Announces Grand Opening of Pattern Energy's El Arrayan Wind, Chile's Largest Wind Facility

Strong Coastal Winds Powering Up to 200,000 Chilean Homes Annually

SAN FRANCISCO, Aug. 28, 2014 -- The President of Chile,

Michelle Bachelet, together with Jean-Paul Luksic, Chairman of Antofagasta
Minerals SA ("AMSA") and Mike Garland, CEO of Pattern Energy Group Inc.
(Nasdaq:PEGI) (TSX:PEG) ("Pattern Energy"), officially opened operations at
the 115 MW El Arrayan Wind facility in a Grand Opening ceremony held on
Tuesday at the project site, which is located 400 km north of Santiago on
the coast of Chile.

The President of Chile, Michelle Bachelet, said "I'm very happy to be here
today because this project is important for our present and future energy
needs. El Arrayan is the biggest wind farm in Chile and we are pleased at
what we can achieve when we use the natural resources the earth has to
offer. This project is another step toward meeting our energy agenda
objectives. We want to have 45% of our energy come from clean energy
resources by 2025."

"Through this partnership, we have combined our financial and management
skills to be part of the solution to one of the major challenges facing our
country and the mining industry, which is the generation of clean energy
sources," said Jean-Paul Luksic, Chairman of Antofagasta Minerals SA.

"We are honored to be joined at the project site by Madam President as we
celebrate the opening of the country's largest wind facility," said Mike
Garland, CEO of Pattern Energy. "Chile is a great market because of the
President's strong support for renewable energy policies, the country's
strong, stable economy and excellent natural wind resources, which can
supply domestic energy to the country. We are also especially pleased to be
here with our strong partner AMSA, which is demonstrating to the world that
a global mining company can be a leader in clean, domestic energy."

The El Arrayan Wind facility, which completed construction in June, will
generate clean, renewable power equal to the needs of approximately 200,000
Chilean homes each year, according to the World Bank. The facility is
utilizing 50 Siemens 2.3 MW wind turbines, which Pattern Energy is also
using at other wind projects in Canada and the United States.

Pattern Energy owns 70% of the El Arrayan Wind facility, which it also
operates. AMSA owns the remaining 30% minority stake. The project sells
approximately 70% of its output to Minera Los Pelambres through a long-term
fixed-for-floating hedge. The facility sells its remaining output into the
Chilean spot market at the prevailing market price at the time of sale. In
addition to its minority interest in the facility, AMSA is the controlling
party of Minera Los Pelambres.

El Arrayan Wind connects to the Sistema Interconectado Central's 220kV
transmission system. The facility is located on approximately 15,320 acres
of coastal land on a long-term lease with a single landowner.

Approximately 200 jobs were created during construction, as well as up to 15
ongoing permanent positions. The project was constructed by Skanska Chile
SA, a subsidiary of Skanska AB and one of the leading wind-focused
construction firms in Chile.

Compared to generation from a coal-fired power plant, the electricity
produced annually by El Arrayan Wind will offset more than 300,000 metric
tons of carbon dioxide, the equivalent to the annual carbon footprint of an
estimated 70,000 Chileans, and will conserve enough water to meet the needs
of more than 11,000 Chileans, according to statistics from the International
Energy Agency, the World Bank and the U.S. Energy Information
Administration.

About Pattern Energy

Pattern Energy Group Inc. (Pattern Energy) is an independent power company
listed on the NASDAQ ("PEGI") and Toronto Stock Exchange ("PEG"). Pattern
Energy has a portfolio of eleven wind power projects, including one project
it has agreed to acquire, with a total owned interest of 1,472 MW, in the
United States, Canada and Chile that use proven, best-in-class technology.
Pattern Energy's wind power projects generate stable long-term cash flows in
attractive markets and provide a solid foundation for the continued growth
of the business. For more information, visit www.patternenergy.com.

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