Environmental Matters (Tables)

12 Months Ended

Dec. 31, 2017

Environmental Remediation Obligations [Abstract]

Schedule of Environmental Loss Contingencies by Site [Table Text Block]



	Current Liabilities				Non-Current Liabilities
In thousands	2017		2016		2017		2016
Portland Harbor site:
Gasco/Siltronic Sediments	$	2,683	$	869	$	45,346	$	43,972
Other Portland Harbor	1,949		1,970		4,163		4,148
Gasco/Siltronic Upland site	13,422		10,657		47,835		49,183
Central Service Center site	25		73		—		—
Front Street site	1,009		906		10,757		7,786
Oregon Steel Mills	—		—		179		179
Total	$	19,088	$	14,475	$	108,280	$	105,268

Environmental Regulatory Table [Table Text Block]



In thousands	2017			2016
Deferred costs and interest ⁽¹⁾	$	45,546		$	53,039
Accrued site liabilities ⁽²⁾	126,950			119,443
Insurance proceeds and interest	(94,170		)	(98,523		)
Total regulatory asset deferral⁽¹⁾	$	78,326		$	73,959
Current regulatory assets⁽³⁾	6,198			9,989
Long-term regulatory assets⁽³⁾	72,128			63,970


⁽¹⁾	Includes pre-review and post-review deferred costs, amounts currently in amortization, and interest, net of amounts collected from customers.


⁽²⁾	Excludes 3.32% of the Front Street site liability, or $0.4 million in 2017 and $0.3 million in 2016, as the OPUC only allows recovery of 96.68% of costs for those sites allocable to Oregon, including those that historically served only Oregon customers.

⁽³⁾

Environmental costs relate to specific sites approved for regulatory deferral by the OPUC and WUTC. In Oregon, we earn a carrying charge on cash amounts paid, whereas amounts accrued but not yet paid do not earn a carrying charge until expended. We also accrue a carrying charge on insurance proceeds for amounts owed to customers. In Washington, a carrying charge related to deferred amounts will be determined in a future proceeding. Current environmental costs represent remediation costs management expects to collect from customers in the next 12 months. Amounts included in this estimate are still subject to a prudence and earnings test review by the OPUC and do not include the $5 million tariff rider. The amounts allocable to Oregon are recoverable through utility rates, subject to an earnings test.