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

2 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

3 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

4 DCPP Operation DCPP produces approximately 18,000GWh 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

5 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

6 DCPP Replacement Power – Estimated Alternative Costs