CASE STUDY UNDERGROUND GAS STORAGE PROJECT “YELA”                      ENAGAS S.A. Brussels, 24th May 2007

MAIN FEATURES YELA

MAIN FEATURES YELA 2002 2007 2011 2020 Promoter: ENAGAS S.A Type: Aquifer Location: <100 km. from Madrid Capacity Data: Working Volume: >1.000 Mcm Withdrawal: ~ 15 Mm3/day Injection: ~ 5 Mm3/day YELA PROJECT SCHEDULE GEOLOGY AND GEOPHYSICS TESTS + PERMITS & PERMISSIONS GEOLOGICAL EXPLORATION IN SPAIN CONSTRUCTION & FIRST START-UP BUILD-UP 2002 2007 2011 2020

INVESTMENT/REMUNERATION/TARIFFS INVESTMENT/FINANCING Facilities  ~ 150 - 200 M€ Cushion Gas  ~ 250 - 300 M€ (10 years) 400 - 500 M€ Financing Option  Corporate Finance REMUNERATION (Regulated Activity) Based on  properly Audited Costs (Cost-Based) ROR  at least WACC + 3 % TARIFFS Design  Total Cost / service Type  pure r-TPA

FUTURE (Mandatory Planning) Storage/Residential Demand ratio IMPACT ON THE SPANISH STORAGE 106 TWh LNG STORAGE CAPACITY + 81 % UNDERGROUND STORAGE 43 TWh + 185 % FUTURE (Mandatory Planning) 2007 Storage/Residential Demand ratio 83 % 134 %

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