Note 8 - Derivative Instruments and Hedging Activities

In October 2018, the Company executed two commodity swap contracts with Total Gas & Power North America, an affiliate of TOTAL and THUSA (as defined in Notes 13 and 14), for a total of five million diesel gallons annually from April 1, 2019 to June 30, 2024. These commodity swap contracts are used to manage diesel price fluctuation risks related to the natural gas fuel supply commitments the Company makes in its fueling agreements with fleet operators that participate in the Zero Now truck financing program. These contracts are not designated as accounting hedges and as a result, changes in the fair value of these derivative instruments are recognized in "Product revenue" in the accompanying consolidated statements of operations.

During 2019, the Company entered into fueling agreements with fleet operators under the Zero Now truck financing program. The fueling agreements contain a pricing feature indexed to diesel, which the Company determined to be embedded derivatives and recorded at fair value at the time of execution, with the changes in fair value of the embedded derivatives recognized as earnings in "Product revenue" in the accompanying consolidated statements of operations.

Derivatives as of December 31, 2018 consisted of the following (in thousands):


	Gross Amounts		Gross Amounts		Net Amount
	Recognized		Offset		Presented
Assets:
Commodity swaps:
Current portion of derivative assets, related party	$	1,508	$	—	$	1,508
Long-term portion of derivative assets, related party		8,824		—		8,824
Total derivative assets	$	10,332	$	—	$	10,332

Derivatives and embedded derivatives as of as of December 31, 2019 consisted of the following (in thousands):


	Gross Amounts		Gross Amounts		Net Amount
	Recognized		Offset		Presented
Assets:
Commodity swaps:
Long-term portion of derivative assets, related party	$	3,270	$	—	$	3,270
Fueling agreements:
Prepaid expenses and other current assets		232		—		232
Notes receivable and other long-term assets, net		491		—		491
Total derivative assets	$	3,993	$	—	$	3,993
Liabilities:
Commodity swaps:
Current portion of derivative liabilities, related party	$	164	$	—	$	164
Fueling agreements:
Accrued liabilities		42		—		42
Other long-term liabilities		39		—		39
Total derivative liabilities	$	245	$	—	$	245

As of December 31, 2018 and 2019, the Company had a total volume on open commodity swap contracts of 25.0 million and 21.9 million diesel gallons at a weighted-average price per gallon of approximately $3.18 and $2.30, respectively.

The following table reflects the weighted-average price of open commodity swap contracts as of December 31, 2018 and 2019, by year with associated volumes:


	December 31, 2018			December 31, 2019
	Volumes	Weighted -Average Price per		Volumes	Weighted -average Price per
Year	(Diesel Gallons)	Diesel Gallon		(Diesel Gallons)	Diesel Gallon
2019	3,125,000	$	3.18	—	$	—
2020	5,000,000	$	3.18	4,986,000	$	2.37
2021	5,000,000	$	3.18	5,000,000	$	2.34
2022	5,000,000	$	3.18	5,000,000	$	2.34
2023	5,000,000	$	3.18	5,000,000	$	2.34
2024	1,875,000	$	3.18	1,870,000	$	1.76