PGEs Humboldt Bay HBPP Diablo Canyon DCPP Power

PG&E’s Humboldt Bay (HBPP) & Diablo Canyon (DCPP) Power Plants Decommissioning process and replacement power April 14, 2011 Loren Sharp

History of HBPP Unit 3 • Humboldt Bay Unit 3 was designed for a g load of 0. 25 (considered a reasonable value in 1960) • G value exceeded in 1975 Ferndale earthquake • Plant shutdown in July 1976 for refueling and seismic upgrades – Many geotechnical evaluations performed over next four years • A 1980 report proposed 0. 5 as the new g load, but this report was never accepted by NRC • Decision was made to remain in shutdown, and enter SAFSTOR and recently start decommissioning the plant – Uncertainty over what g value was going to be accepted – Expense of other safety modifications required as a result of the Three Mile Island event versus power benefit 2

HBPP Unit 3 Decommissioning Status • Spent fuel removed from pool December 2008 • Started Systems removal May 2009 • High Pressure Turbine removed Oct 2010 • Low Pressure Turbine removed Oct 2010 • Upper Condenser Removed Nov 2010 • Lower Condenser removed Dec 2010 3

DCPP Operation • DCPP produces approximately 18, 000 GWh per year of energy – With 2, 200+ MW of net qualifying capacity toward PG&E’s reliability requirements – Currently, operating costs are approximately $50/MWh 4

DCPP Replacement Power – Generation Sources • Combined Cycle Generation • Energy Efficiency • Renewable Generation • Coal-Fueled Integrated Gasification Combined Cycle and Carbon Capture and Sequestration • Combined Heat and Power Generation 5

DCPP Replacement Power – Estimated Alternative Costs 6