Exhibit 99.1

    Gastar Executes Memorandum of Understanding with Macquarie Generation to
              Investigate Supply of Coal Bed Methane from PEL 238

    HOUSTON--(BUSINESS WIRE)--March 13, 2007--Gastar Exploration Ltd.
(AMEX:GST; TSX:YGA) announced today that it has executed, along with
its PEL 238 joint venture partner Eastern Star Gas (ASX:ESG), a
Memorandum of Understanding (MOU) with Macquarie Generation, a
government-owned electricity generator in the state of New South
Wales, Australia (NSW). The MOU sets the framework for negotiation of
a potential long-term agreement to supply natural gas for the
expansion of Macquarie Generation's Bayswater power station. A
potential long-term natural gas supply and purchase agreement could
reach as much as 500 billion cubic feet in total and increase NSW's
natural gas consumption by as much as 25%.

    J. Russell Porter, Gastar's President and CEO, and Dennis Morton,
Eastern Star Gas Managing Director, issued a joint comment on the
transaction. "This is a very exciting commercial development and
represents a watershed for both our Gunnedah Basin Gas Project and the
state of NSW. It could provide the PEL 238 joint venture with a large
natural gas market that will underpin development of a natural gas
pipeline infrastructure and act as the foundation for the large scale
development and sale of natural gas within NSW. The pipeline linking
the natural gas project to the Bayswater power station could bring
natural gas within 100 kilometers of Newcastle and provide for the
potential additional natural gas sales into the greater
Newcastle-Sydney-Wollongong area. NSW will at last have a truly major,
indigenous source of natural gas."

    Macquarie Generation, Australia's largest electricity producer,
owns and operates two coal fired power stations in the Hunter Valley -
Bayswater (2,640 MW capacity) and Liddell (2,000 MW capacity). These
two power stations can produce the equivalent of 40% of NSW's
electricity requirements. Macquarie Generation is investigating an
innovative gas fuelling initiative that could both increase the output
of the Bayswater power station and reduce the intensity of greenhouse
gas emissions.

    The key terms of the Memorandum of Understanding are as follows:

    --  Gastar and ESG will continue their PEL 238 Gunnedah Basin Gas
        Project work program to prove natural gas reserves.

    --  Macquarie Generation will investigate the use of natural gas
        fired power generation within the Bayswater power station.

    --  The parties will jointly investigate the installation of a 300
        km high pressure natural gas transmission pipeline linking
        Narrabri to Bayswater.

    Gastar and ESG are in the process of commercializing the Gunnedah
Basin Gas Project through the successful implementation of the
Bibblewindi Production Pilot with a target to achieve initial
certified natural gas reserves by the third quarter, 2007. PEL 238 has
an independently estimated gas resource of 17 TCF of gas-in-place.

    Gastar holds a 35% interest in the PEL 238 Gunnedah Basin Gas
Project (Coal Seam Gas), with ESG holding the remaining 65% interest
and acting as operator of the project.

    The Gunnedah Basin Gas Project (Coal Seam Gas Joint Venture) is
located in Petroleum Exploration License ("PEL") 238 that covers 9,100
square kilometers of the Gunnedah Basin in New South Wales. PEL 238
contains one of the largest estimated onshore natural gas resource
accumulations in Australia. The 256 square kilometer Bohena Project
Area within PEL 238 is currently under development with independent
gas reserves certification targeted for 2007.

    Gastar Exploration Ltd. is an exploration and production company
focused on finding and developing natural gas assets in North America
and Australia. The Company pursues a balanced strategy combining
select higher risk, deep natural gas exploration prospects with
low-risk coal bed methane (CBM) development. The Company owns and
controls exploration and development acreage in the Deep Bossier gas
play of East Texas and in the deep Trenton-Black River play in the
Appalachian Basin. Gastar's CBM activities are conducted within the
Powder River Basin of Wyoming and upon the approximate 3.5 million
acres controlled by Gastar and its Joint Development partners in
Australia's Gunnedah Basin, PEL 238 and Gastar's Gippsland Basins
located in New South Wales and Victoria respectively.

    Safe Harbor Statement and Disclaimers:

    The United States Securities and Exchange Commission (SEC) has
generally permitted oil and gas companies, in their filings with the
SEC, to disclose only proved reserves that a company has demonstrated
by actual production or conclusive formation tests to be economically
and legally producible under existing economic and operating
conditions. We use the terms "resources," "gas-in-place" or other
descriptions of volumes of hydrocarbons that the SEC guidelines may
prohibit us from including in filings with the SEC. Estimates of gas
resources or gas-in-place do not reflect volumes that are demonstrated
as being commercially or technically recoverable. Even if commercially
or technically recoverable, a significant recovery factor would be
applied to these volumes to determine estimates of volumes of proved
reserves. Accordingly, these estimates are by their nature more
speculative than estimates of proved reserves and accordingly are
subject to substantially greater risk of being actually realized by
the Company. The methodology for estimating gas-in-place or resources
may also be different than the methodology and guidelines used by the
Society of Petroleum Engineers.

    This Press Release includes forward-looking statements within the
meaning of Section 27A of the Securities Act of 1933 and Section 21E
of the Securities Act of 1934. A statement identified by the words
"expects," "projects," "plans," and certain of the other foregoing
statements may be deemed "forward-looking statements". Although Gastar
believes that the expectations reflected in such forward-looking
statements are reasonable, these statements involve risks and
uncertainties that may cause actual future activities and results to
be materially different from those suggested or described in this
press release. These include risks inherent in the drilling of oil and
natural gas wells, including risks of fire, explosion, blowout, pipe
failure, casing collapse, unusual or unexpected formation pressures,
environmental hazards, and other operating and production risks
inherent in oil and natural gas drilling and production activities,
which may temporarily or permanently reduce production or cause
initial production or test results to not be indicative of future well
performance or delay the timing of sales or completion of drilling
operations; risks with respect to oil and natural gas prices, a
material decline in which could cause the Company to delay or suspend
planned drilling operations or reduce production levels; and risks
relating to the availability of capital to fund drilling operations
that can be adversely affected by adverse drilling results, production
declines and declines in oil and gas prices and other risk factors as
described in the Company's Annual Report on Form 10-K, as filed on
March 31, 2006 with the United States Securities and Exchange
Commission at www.sec.gov and on the System for Electronic Document
Analysis and Retrieval (SEDAR) at www.sedar.com

    The American Stock Exchange and Toronto Stock Exchange have not
reviewed and do not accept responsibility for the adequacy or accuracy
of this release.

    CONTACT: Gastar Exploration Ltd., Houston
             J. Russell Porter, 713-739-1800
             Fax: 713-739-0458
             E-Mail: rporter@gastar.com