11. GAS RESERVES

NW Natural has invested approximately $188 million through the gas reserves program in the Jonah Field located in Wyoming as of September 30, 2018. Gas reserves are stated at cost, net of regulatory amortization, with the associated deferred tax benefits recorded as liabilities in the consolidated balance sheets. The investment in gas reserves provides long-term price protection for utility customers through the original agreement with Encana Oil & Gas (USA) Inc. under which NW Natural invested approximately $178 million and the amended agreement with Jonah Energy LLC under which an approximate additional $10 million was invested.

The cost of gas, including a carrying cost for the rate base investment, is included in the annual Oregon PGA filing, which allows NW Natural to recover these costs through customer rates. The investment under the original agreement, less accumulated amortization and deferred taxes, earns a rate of return.

Gas produced from the additional wells is included in the Oregon PGA at a fixed rate of $0.4725 per therm, which approximates the 10-year hedge rate plus financing costs at the inception of the investment.

The following table outlines net gas reserves investment:



	September 30,				December 31,
In thousands	2018		2017		2017
Gas reserves, current	$	16,916	$	16,218	$	15,704
Gas reserves, non-current	170,391		171,318		171,832
Less: Accumulated amortization	99,835		83,442		87,779
Total gas reserves⁽¹⁾	87,472		104,094		99,757
Less: Deferred taxes on gas reserves	19,377		29,298		22,712
Net investment in gas reserves	$	68,095	$	74,796	$	77,045


⁽¹⁾	The net investment in additional wells included in total gas reserves was $5.0 million, $6.0 million and $5.8 million at September 30, 2018 and 2017 and December 31, 2017, respectively.

The investment is included in the consolidated balance sheets under gas reserves with a maximum loss exposure limited to the investment balance.