**EXHIBIT 15.(b).1****Valuation and Qualifying Accounts and Reserves**                     Amount in NOK million     Additions          Balance at  Charged to  Charged to      Balance at   beginning of  costs and  other      end of Description period  expenses  accounts1)  Deductions 2)  period   Year-end 31 December 2005                    Allowance for doubtful accounts  891   225   (99)  (233)  784 Valuation allowance for deferred tax assets  967   1,054   570   —   2,591 Asset retirement obligation 3)  6,281   404   1,365   (356)  7,694                      Year-end 31 December 2004                    Allowance for doubtful accounts  922   200   39   (269)  891 Valuation allowance for deferred tax assets  1,047   (25)  (55)  —   967 Asset retirement obligation  5,235   351   914   (219)  6,281                      Year-end 31 December 2003                    Allowance for doubtful accounts  685   737   138   (638)  922 Valuation allowance for deferred tax assets  945   22   80   —   1,047 Asset retirement obligation 4)  4,538   306   504   (113)  5,235    1) Includes amounts recognized in business combinations and foreign currency translation adjustments. 2) Deductions primarily represent uncollectible accounts charged against the allowance for doubtful accounts and expenditures related to and reductions of asset retirement obligations. 3) Hydro implemented FASB Interpretation (FIN) No. 47 Accounting for Conditional Asset Retirement Obligations beginning 31 December 2005. FIN 47 is aninterpretation of SFAS 143 Accounting for Asset Retirement Obligations which refers to legal obligations to perform asset retirement activities.FIN 47 requires an entity to recongnize a liability for the fair value of a conditional asset retirement obligation, if the fair value of the liabilitycan be reasonably estimated, even if timing and/or method of settlement is conditional on a future event that may not be within the control of the entity.FIN 47 implementation mainly relates to brick-lining used in primary aluminium production within Metals. The implementaion of FIN 47 resulted in an increase ofasset retirement obligation liabilities by NOK 223 million. According to FIN 47 prior year amounts should not be restated. 4) Effective 1 January 2003, Hydro implemented the accounting standard for asset retirement obligations, such as decommissioning and abandonment of oil and gas productionplatforms, facilities and pipelines [SFAS 143]. The accounting standard requires that the fair value of future asset retirement obligations be recorded in the Company’sbalance sheet in the period it is incurred; accordingly, obligations for oil and gas installations should be recognized at the start of production. Asset retirement costs arecapitalized as part of the asset’s original cost and depreciated over the asset’s useful life, while changes to the present value of the obligations are charged to earnings. Thechanges resulted in an increase in the capitalized value of fixed assets by NOK 1,089 million. The increase in the original cost of fixed assets was NOK 1,918 million andrelated accumulated depreciation was NOK 829 million. In addition, liabilities for asset retirement obligations increased NOK 2,407 million to NOK 4,538 million.