Revenue

12 Months Ended

Dec. 31, 2022

Revenue

Revenue

18. Revenue

Disaggregation of revenue

The following table provides information about disaggregation of revenue (in thousands):

Major products/services lines
	Year Ended December 31,
	2022		2021		2020
Sales of fuel cell systems	$	207,691	$	225,229	$	(55,091)
Sales of hydrogen infrastructure		141,528		135,055		(43,391)
Sales of electrolyzers		28,463		16,667		4,187
Sales of engineered equipment		93,489		7,571		—
Services performed on fuel cell systems and related infrastructure		35,280		26,706		(9,801)
Power Purchase Agreements		47,183		35,153		26,620
Fuel delivered to customers and related equipment		57,196		46,917		(16,072)
Sales of cryogenic equipment		87,761		8,255		—
Other		2,849		789		311
Net revenue	$	701,440	$	502,342	$	(93,237)

Contract balances

The following table provides information about receivables, contract assets, and contract liabilities from contracts with customers (in thousands):

	December 31,		December 31,
	2022		2021
Accounts receivable	$	129,450	$	92,675
Contract assets		104,287		38,757
Deferred revenue and contract liabilities		229,898		183,090

Contract assets relate to contracts for which revenue is recognized on a straight-line basis, however billings escalate over the life of a contract. Contract assets also include amounts recognized as revenue in advance of billings to customers, which are dependent upon the satisfaction of another performance obligation. These amounts are included in contract assets on the consolidated balance sheet.

The deferred revenue and contract liabilities relate to the advance consideration received from customers for services that will be recognized over time (primarily fuel cell and related infrastructure services). Deferred revenue and contract liabilities also include advance consideration received from customers prior to delivery of products. These amounts are included within deferred revenue and other contract liabilities on the consolidated balance sheet.

Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands):

Contract assets
	December 31, 2022		December 31, 2021
Transferred to receivables from contract assets recognized at the beginning of the period	$	(33,394)	$	(14,638)
Contract assets assumed as part of acquisition		—		9,960
Contract assets related to warrants		26,455		—
Revenue recognized and not billed as of the end of the period		72,469		25,246
Net change in contract assets	$	65,530	$	20,568

Deferred revenue and contract liabilities
	December 31, 2022		December 31, 2021
Increases due to cash received, net of amounts recognized as revenue during the period	$	200,347	$	182,052
Contract liabilities assumed as part of acquisitions		10,011		35,727
Revenue recognized that was included in the contract liability balance as of the beginning of the period		(163,550)		(110,974)
Net change in deferred revenue and contract liabilities	$	46,808	$	106,805

Estimated future revenue

The following table includes estimated revenue included in the backlog expected to be recognized in the future (sales of fuel cell systems, equipment, and hydrogen installations are expected to be recognized as revenue within one year; sales of services, PPAs, and fuel are expected to be recognized as revenue over five to ten years) related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period, including provision for common stock warrants (in thousands):

	December 31,
	2022
Sales of fuel cell systems	$	38,234
Sales of hydrogen installations and other infrastructure		31,876
Sales of electrolyzers		303,038
Sales of engineered equipment		18,500
Services performed on fuel cell systems and related infrastructure		126,814
Power Purchase Agreements		375,802
Fuel delivered to customers and related equipment		93,798
Sales of cryogenic equipment		193,644
Total estimated future revenue	$	1,181,706