REVENUEDisaggregated Revenue
The following table presents the Company’s revenue, disaggregated by source (in thousands):
| | | | | | | | | | | |
| Year Ended December 31, |
| 2024 | | 2023 |
| Product revenue | $ | 4,795 | | | $ | 5,103 | |
| Service revenue | 132 | | | 183 | |
| Other revenue | 1,368 | | | 2,254 | |
| Total revenue | $ | 6,295 | | | $ | 7,540 | |
The majority of the Company’s revenue is derived from product sales of energy storage systems. During 2024 other revenue included engineering services related to product site deployment, customer reimbursements for freight, travel, and other expenses, and revenue earned for work performed to date under project contracts that were ultimately terminated. See Note 2, Significant Accounting Policies for further information regarding revenue recognition.
Contract Balances
Contract assets relate to unbilled amounts resulting from contract arrangements in which the related revenue recognition performance obligations have been satisfied, however invoicing to the customer has not yet occurred. Deferred revenue (or contract liabilities) relates to consideration received from customers in advance of the Company satisfying the revenue recognition performance obligations under the related contractual arrangements. Contract balances are reported in a net contract asset or deferred revenue liability position on a contract-by-contract basis at the end of each reporting period. Contract assets are included in prepaid expenses and other current assets and deferred revenue is presented separately on the balance sheets.
The following table provides information about contract assets and deferred revenue from contracts with customers (in thousands):
| | | | | | | | | | | |
| December 31, 2024 | | December 31, 2023 |
| Contract assets | $ | 332 | | | 253 | |
| Deferred revenue | 19,637 | | | 20,781 | |
Contract assets increased by $79 thousand during the year ended December 31, 2024 due to the recognition of revenues for which invoicing had not yet occurred. Deferred revenue decreased by $1.1 million during the year ended December 31, 2024, reflecting $1.0 million in customer advance payments, offset by the recognition of $2.1 million of revenue that was included in the deferred revenue balance at the beginning of the period.
Deferred revenue of $5.2 million is expected to be recognized within the next 12 months and non-current deferred revenue of $14.4 million related to the non-refundable deposit discussed in Note 18, Related Parties, is expected to be recognized thereafter as firm orders are received and fulfilled. Additionally, contracted but unsatisfied performance obligations that had not yet been billed to the customer or included in deferred revenue were $13.7 million as of December 31, 2024.
About Revenue Disclosures
Revenue disclosures under ASC 606 explain how a company identifies performance obligations, allocates transaction prices, and determines when revenue is recognized. This section is essential for understanding whether reported revenue reflects genuine economic activity or aggressive accounting choices. Analysts examine the mix of point-in-time versus over-time recognition, which directly affects revenue timing and comparability.
Key signals: rising contract liabilities (deferred revenue) suggest strong future revenue visibility, while declining contract assets may indicate slowing project milestones. Watch for variable consideration estimates — rebates, returns, and performance bonuses that require management judgment. Significant changes in disaggregated revenue by geography or product line can reveal shifting business mix before it appears in headline numbers. Compare revenue growth against contract liability growth to assess sustainability, and scrutinize any changes in the timing of recognition that coincide with earnings pressure.