Investment Agreement with Apache

To:
BUENOS AIRES STOCK EXCHANGE
ARGENTINE SECURITIES COMISSION
Your Offices

Ref.: Relevant Event. Pampa Energía and
Apache partner to develop
unconventional gas fields

(Prot/BCBA y CNV/RB/fv/PESA Nº 111)

Dear Sirs,

In my capacity as Responsible of Market Relations for Pampa Energía S.A. (“Pampa” or the “Company”), I address to the Argentine Securities Commission and to the Buenos Aires Stock Exchange in relation to the relevant event published on August 5th of this year.

Regarding to that reference, I am pleased to inform that on the date hereof Pampa has, through its subsidiaries Petrolera Pampa S.A., celebrated an investment agreement with Apache Energía Argentina S.R.L. (“Apache”) to jointly engage in the development and exploitation of unconventional gas repositories.

The partnership with Apache would allow the production of an additional 700,000 m3/day of non conventional natural gas from reservoirs with low permeability at the Anticlinal Campamento and Estación Fernández Oro blocks, in the provinces of Neuquén and Río Negro, respectively. Pampa would invest approximately US$20 million during the next three years, representing 15% of the necessary investments for the development of this gas production, allowing Pampa to obtain its proportional participation in the production.

Simultaneously, we inform that Central Térmica Loma de la Lata S.A., subsidiary of Pampa, has signed a contract to acquire 595,000 m3/day of Gas Plus from Apache for a three year period, which corresponds to Apache’s 85% participation stake in the before mentioned production.

The previously mentioned agreements along with the purchase of 800,000 m3/day of Gas Plus from Apache for a three-year period informed on August 5th, guarantee the supply of 1,500,000 m3/day of Gas Plus assigned to consumption of the recently inaugurated Central Térmica Loma de la Lata.

Kind Regards,

Romina Benvenuti
Responsible for Market Relations