Document And Entity Information
Statistical Measurement [Axis]
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 3 - Summary of Significant Accounting Policies
us-gaap_IncomeTaxExpenseBenefit
Income taxes
Income Taxes
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 4 - Fair Value Measurements
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 5 - EverOn Energy Joint Venture and Consolidation of Variable Interest Entity
Trading Arrangements, by Individual [Table]
Note 6 - Other Long-term Assets
Material Terms of Trading Arrangement [Text Block]
Note 7 - Accounts Payable
Note 8 - Accrued Liabilities
Note 9 - Taxes Recoverable and Payable
Note 10 - Convertible and Non-convertible Promissory Notes
Long-Lived Asset, Including Intangible Asset and Goodwill, Impairment and Disposal [Policy Text Block]
Note 13 - Sale of Spanish Subsidiaries
Minimum [Member]
Note 14 - Shareholders' Equity
Note 15 - Segment and Geographic Information
us-gaap_ForeignCurrencyTransactionGainLossBeforeTax
Gain on foreign currency exchange rates
Statistical Measurement [Domain]
Note 17 - Related Party
Maximum [Member]
Note 3 - Summary of Significant Accounting Policies - Summary of Antidilutive Securities (Details)
Note 4 - Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)
Note 4 - Fair Value Measurements - Summary of Fair Value Assumptions (Details)
Litigation Case [Domain]
Note 4 - Fair Value Measurements - Schedule of Fair Value Liabilities With Unobservable Inputs (Details)
Note 4 - Fair Value Measurements - Schedule of Fair Value Liabilities With Unobservable Inputs (Details) (Parentheticals)
us-gaap_MinorityInterestInJointVentures
Noncontrolling Interest in Joint Ventures
Note 5 - EverOn Energy Joint Venture and Consolidation of Variable Interest Entity - Assets Acquired (Details)
Note 5 - EverOn Energy Joint Venture and Consolidation of Variable Interest Entity - Pro Forma Information (Details)
Note 6 - Other Long-term Assets - Schedule of Capitalized Development Costs and Other Long-Term Assets (Details)
Note 7 - Accounts Payable - Schedule of Accounts Payable (Details)
Note 8 - Accrued Liabilities - Schedule of Accrued Liabilities (Details)
Note 9 - Taxes Recoverable and Payable - Schedule of Taxes Recoverable (Details)
Note 10 - Convertible and Non-convertible Promissory Notes - Convertible Notes (Details)
Note 10 - Convertible and Non-convertible Promissory Notes - Schedule of Debt (Details)
Note 10 - Convertible and Non-convertible Promissory Notes - Schedule of Debt Restructuring (Details)
Note 13 - Sale of Spanish Subsidiaries - Summary of Assets and Liabilities in Sale of Subsidiary (Details)
Note 14 - Shareholders' Equity - Summary of Warrant Activity (Details)
Note 15 - Segment and Geographic Information - Schedule of Segment Information (Details)
Note 17 - Related Party - Related Party Transactions (Details)
Notes To Financial Statements
Series D Convertible Preferred stock subject to Put Option
Temporary Equity, Including Noncontrolling Interest
Notes To Financial Statements [Abstract]
Counterparty Name [Axis]
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Effective Income Tax Rate Reconciliation, Percent
Litigation Case [Axis]
Counterparty Name [Domain]
us-gaap_SharesOutstanding
Balance (in shares)
Balance (in shares)
Segment Reporting [Text Block]
Foreign Currency Translation Reserve [Member]
Represents the foreign currency translation reserve.
alce_TotalRevenueIncludingDiscontinuedOperations
Total for the period
Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).
Award Type [Axis]
Segment Reporting [Table Text Block]
Adjustments to reconcile loss from continuing operations to net cash (used in) operations:
Preferred stock
Common shares returned on recission of Liion acquisition (in shares)
Represents the number of shares returned on the rescission of a business acquisition.
Plan Name [Axis]
us-gaap_Liabilities
Total Liabilities
Total for Europe – Continuing Operations
Plan Name [Domain]
Common shares issued for debt issuance costs
Represents the value of shares of stock issued during period that were issued for debt issuance costs.
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]
Common shares returned on recission of Liion acquisition
Represents the value of shares returned on the rescission of a business acquisition during the period.
Common shares issued for debt issuance costs (in shares)
Represents the number of shares issued during the period for debt issuance costs.
alce_NonCashInvestingAndFinancingActivitiesSharesIssuedForStockCompensationToThirdParties
Shares issued for stock compensation to third parties
Represents the value of shares issued for stock compensation to third parties reported as non cash investing and financing activities.
us-gaap_LiabilitiesAndStockholdersEquity
Total Liabilities and Shareholders' Equity
Settlement of payables for common shares (in shares)
Represents the number of shares issued for settlement of payables during the period.
Title and Position [Axis]
Segment Reporting [Table]
Settlement of payables for common shares
Represents the value of stock issued during the period for the settlement of payables.
Total liabilities sold
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other assets
Stock compensation costs
us-gaap_SellingGeneralAndAdministrativeExpense
Selling, general and administrative
Subsequent Event [Member]
alce_OtherNonoperatingIncomeNet
Other income
Represents the amount of other nonoperating income net of reversals.
Former Director [Member]
Relating to a former director.
Liability for Future Policy Benefit, by Product Segment [Table]
us-gaap_PreferredStockVotingRights
Preferred Stock, Voting Rights
Changes in assets and liabilities, net of effects of acquisitions:
Accounts payable
us-gaap_IncreaseDecreaseInAccountsPayable
Preferred stock, shares issued (in shares)
Preferred Stock, Shares Issued (in shares)
Finite lived intangible assets, useful life (Year)
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Preferred stock, shares outstanding (in shares)
Preferred Stock, Shares Outstanding (in shares)
Warrant liability
alce_WarrantLiabilitiesFairValue
The fair value of the warrant liabilities.
Preferred stock, shares authorized (in shares)
Preferred Stock, Shares Authorized (in shares)
Variable Interest Entity Disclosure [Text Block]
Series D Preferred Stock [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period (in shares)
Series E Preferred Stock [Member]
Series B Preferred Stock [Member]
Series C Preferred Stock [Member]
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
Accrued liabilities
us-gaap_IncreaseDecreaseInAccruedLiabilities
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net increase/(decrease) in cash and cash equivalents
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Balance
Balance
Series A Preferred Stock [Member]
alce_PolicyTable
Effect of exchange rate on cash
Series F Preferred Stock [Member]
alce_ConsultingAgreementInitialTerm
Consulting Agreement, Initial Term (Year)
Represents the initial term of a consulting agreement.
MH02 Note [Member]
Related to MH02 Note.
Capitalized Development and Other Long-Term Assets [Text Block]
Represents the entire disclosure of capitalized development and other long-term assets during the period.
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents beginning of the year
Cash and cash equivalents end of the period
Taxes Recoverable and Payable [Text Block]
Represents the entire disclosure of taxes recoverable and payable during the period.
Antidilutive Securities, Name [Domain]
Comprehensive income/(loss)
alce_TaxesRecoverableAndPayable
Total
Represents the amount of taxes recoverable and payable.
Statement [Table]
Schedule of Taxes Recoverable and Payable [Table Text Block]
Represents the tabular disclosure of the schedule of taxes recoverable and payable during the period.
Operating Activities [Axis]
Continuing Operations [Member]
Consulting fees
Represents the current portion of accrued consulting fees.
alce_ObligationToPurchaseProjectAtMarketValueMinimumPerMegawatt
Obligation to Purchase Project at Market Value, Minimum Per Megawatt
The amount of obligation to purchase project at market value, minimum per megawatt.
Operating Activities [Domain]
Credit Facility [Axis]
Other Payables [Text Block]
Represents the entire disclosure of other payables.
Credit Facility [Domain]
Fair Value, off-Balance-Sheet Risk [Table]
Long-term prepaid expenses
Senior Convertible Note [Member]
Represents a senior convertible note.
Alt Spain Holdco [Member]
Represents Alt Spain Holdco.
us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Line of Credit Facility, Maximum Borrowing Capacity
alce_ContractualObligationMonthlyPayment
Contractual Obligation, Monthly Payment
The monthly payment toward the contractual obligation.
us-gaap_EquityMethodInvestmentOwnershipPercentage
Equity Method Investment, Ownership Percentage
Long-Term Debt, Type [Axis]
Common shares issued to third party for services
Common shares issued to third party for services (in shares)
Stock Issued During Period, Shares, Issued for Services (in shares)
Ownership [Axis]
Ownership [Domain]
Line of Credit [Member]
us-gaap_RepaymentsOfDebt
Payments of debt principal
Proceeds from debt
Proceeds from Issuance of Debt
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)
Measurement Frequency [Axis]
Commitments and Contingencies Disclosure [Text Block]
Statement [Line Items]
Liability Class [Axis]
Private Placement [Member]
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Common Stock, Shares, Issued (in shares)
Common stock, shares outstanding (in shares)
Common Stock, Shares, Outstanding (in shares)
Award Type [Domain]
Common stock, shares authorized (in shares)
Common Stock, Shares Authorized (in shares)
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]
Schedule of Accrued Liabilities [Table Text Block]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Common stock, $0.0001 par value, 2 billion authorized as of June 30, 2026 and December 31, 2025. 724,658 issued and outstanding as of June 30, 2026 and December 31, 2025.
Gain on settlement of debt
The amount of gain on settlement of liabilities.
Net cash proceeds from issuance of Series D convertible preferred shares
Proceeds from Issuance of Convertible Preferred Stock
us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)
Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block]
Accounts payable
Accounts Payable, Current
us-gaap_ProceedsFromIssuanceOfPreferredStockAndPreferenceStock
Proceeds from Issuance of Preferred Stock and Preference Stock
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive income/(loss) attributable to Alternus
Payroll
Legal fees
Subsequent Events [Text Block]
Accrued liabilities
Total
Nonrelated Party [Member]
Related Party [Member]
Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]
Significant Accounting Policies [Text Block]
Schedule of Related Party Transactions [Table Text Block]
Chief Learning Officer [Member]
Chief Learning Officer
Interest on debt
Consolidation, Variable Interest Entity, Policy [Policy Text Block]
us-gaap_LongTermDebtCurrent
Current Maturities net of debt discount
us-gaap_LongTermDebtNoncurrent
Long-term loans and promissory notes, net of debt discount
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]
us-gaap_LongTermDebt
Debt
Movement in fair value
FX movements
us-gaap_LossContingencyAccrualAtCarryingValue
Loss Contingency Accrual
Convertible and other notes measured at fair value
Intangible Asset, Finite-Lived, Class [Axis]
Statement of Stockholders' Equity [Abstract]
Intangible Asset, Finite-Lived, Class [Domain]
Class of Warrant or Right [Axis]
Class of Warrant or Right [Domain]
Statement of Cash Flows [Abstract]
alce_ProceedsFromIssuanceOfPreferredStockAndPreferenceStockNet
Proceeds from Issuance of Preferred Stock and Preference Stock, Net
Proceeds from issuance of capital stock, net of issuance costs, which provides for a specific dividend that is paid to the shareholders before any dividends to common stockholders and which takes precedence over common stockholders in the event of liquidation.
alce_PutOptionAgreementExpirationDate
Expiration date
The expiration debt for put option agreements.
Shareholders’ Equity
Long-Term Debt, Type [Domain]
us-gaap_LossContingencyEstimateOfPossibleLoss
Loss Contingency, Estimate of Possible Loss
Equity Components [Axis]
alce_PutOptionAgreementCovenantMaximumPurchasePrice
Put Option Agreement, Covenant, Maximum Purchase Price
The maximum purchase price for a put option agreement.
alce_PutOptionFairValue
Put Option, Fair Value
The fair value of put options.
Share-Based Payment Arrangement [Policy Text Block]
Convertible Preferred Stock [Member]
Equity Component [Domain]
Convertible and Non-convertible Promissory Notes [Member]
Represents information pertaining to convertible and non-convertible promissory notes.
us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
alce_DebtInstrumentAccruedInterest
Debt Instrument, Accrued Interest
The amount of accrued interest for a debt instrument.
Equity [Text Block]
Fair Value, Inputs, Level 1 [Member]
us-gaap_ClassOfWarrantOrRightOutstanding
Class of Warrant or Right, Outstanding (in shares)
Outstanding, warrants (in shares)
Outstanding, warrants (in shares)
Additional Paid-in Capital [Member]
alce_DebtInstrumentCovenantPercentageOfMembershipInterestPledged
Debt Instrument, Covenant, Percentage of Membership Interest Pledged
The percentage of membership interest pledged for a debt instrument.
Retained Earnings [Member]
alce_DebtInstrumentOriginalIssueDiscountPercentageIncrease
Debt Instrument, Original Issue Discount, Percentage Increase
Represents the percentage increase of the original issue discount of a debt instrument.
alce_ModifiedTermLoansCarryingAmount
Carrying value of modified term loans
The carrying amount of term loans modified during the period.
alce_DebtInstrumentOriginalIssueDiscount
Debt Instrument, Original Issue Discount
Represents the original issue discount percentage related to a debt instrument during the period.
alce_FairValueAdjustmentsNewNotesIssued
Less: Fair value of new Notes
The amount of fair value adjustments for new notes issued.
us-gaap_SettlementLiabilitiesCurrent
Settlement Liabilities, Current
Senior Convertible Notes Converted Into Preferred Stock [Member]
Represents Senior Convertible Notes Converted Into Preferred Stock.
March 2026 Restructuring [Member]
Represents the March 2026 Restructuring.
Subsequent Event Type [Domain]
Subsequent Event [Table]
Subsequent Event Type [Axis]
Sale of Stock [Axis]
Sunrise Development LLC [Member]
Represents Sunrise Development LLC.
SPAC Sponsor Capital Access [Member]
Represents SPAC sponsor capital access.
Subsidiary of LLC or LP [Table]
CFGI LP [Member]
Represents CFGI LP.
Southern Point Capital Corporation [Member]
Represents Southern Point Capital Corporation.
Fair Value Option, Disclosures [Table]
Orrick [Member]
Represents Orrick.
Summary of Troubled Debt Restructuring Note, Debtor [Table Text Block]
alce_SettlementAgreementBeneficialOwnershipPercentageOfCommonStock
Settlement Agreement, Beneficial Ownership Percentage of Common Stock
Represents the beneficial ownership percentage of common stock used in a settlement agreement.
Accounts Payable and Accrued Liabilities Disclosure [Text Block]
Foreign currency translation reserve
Substantial Doubt about Going Concern [Text Block]
Liability for Future Policy Benefit Activity [Table]
us-gaap_AccountsReceivableNet
Accounts Receivable, after Allowance for Credit Loss
Current Liabilities
us-gaap_LiabilitiesCurrent
Total Current Liabilities
us-gaap_TemporaryEquitySharesIssued
Temporary Equity, Shares Issued (in shares)
us-gaap_LongTermDebtFairValue
Long-Term Debt, Fair Value
Product Liability Contingency [Table]
us-gaap_IncomeTaxesPaid
Taxes
Tax Credit Carryforward [Table]
us-gaap_LitigationSettlementExpense
Litigation Settlement, Fee Expense
us-gaap_GainLossOnDispositionOfAssets1
Gain on disposal of subsidiaries
Customer Relationships [Member]
Temporary Equity
Other Commitments [Table]
us-gaap_PreferredStockConvertibleSharesIssuable
Preferred Stock, Convertible, Shares Issuable (in shares)
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Intangible Asset, Finite-Lived, Accumulated Amortization
Intangible Assets, Accumulated Amortization
us-gaap_PreferredStockConvertibleConversionPrice
Preferred Stock, Convertible, Conversion Price (in dollars per share)
us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income/(loss) before provision for income taxes
Loss on extinguishment of debt
Loss on debt Extinguishment
Loss on debt extinguishment
Additional paid in capital
Debt Disclosure [Text Block]
Total Fair Value of Invested Capital
Debt Conversion, Name [Domain]
Noncontrolling interest
Debt Conversion Description [Axis]
Common shares issued to related party
Stock Issued During Period, Value, New Issues
Stock Compensation
us-gaap_DebtInstrumentCarryingAmount
Long-Term Debt, Gross
Common shares issued for conversion of debt
us-gaap_DebtInstrumentFaceAmount
Debt Instrument, Face Amount
us-gaap_StockIssuedDuringPeriodValueAcquisitions
Stock Issued During Period, Value, Acquisitions
Current Assets
us-gaap_AssetsCurrent
Total Current Assets
Stock Compensation (in shares)
Fair Value, Recurring and Nonrecurring [Table]
us-gaap_LitigationSettlementAmountAwardedToOtherParty
Litigation Settlement, Amount Awarded to Other Party
Common shares issued to related party (in shares)
Stock Issued During Period, Shares, New Issues (in shares)
Common shares issued for conversion of debt (in shares)
Stock Issued During Period, Shares, Conversion of Convertible Securities (in shares)
Debt Instrument, Name [Domain]
us-gaap_StockIssuedDuringPeriodSharesAcquisitions
Stock Issued During Period, Shares, Acquisitions (in shares)
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
us-gaap_DebtInstrumentInterestRateStatedPercentage
Debt Instrument, Interest Rate, Stated Percentage
Class of Stock [Domain]
Related and Nonrelated Parties [Axis]
us-gaap_DebtInstrumentUnamortizedDiscount
Debt Instrument, Unamortized Discount
Debt discount
Schedule of Long-Term Debt Instruments [Table]
Debt Instrument [Axis]
Cash Flows from Operating Activities
Cash Flows from Investing Activities:
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net Cash Used in Operating Activities
Cash Flows from Financing Activities:
Net Cash provided by/(used in) Investing Activities
us-gaap_SharesIssuedPricePerShare
Shares Issued, Price Per Share (in dollars per share)
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net Cash provided by Financing Activities
us-gaap_GainsLossesOnRestructuringOfDebt
Gains (Losses) on Restructuring of Debt
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
us-gaap_LitigationSettlementInterest
Litigation Settlement Interest
Troubled Debt Restructuring, Debtor, Current Period [Table]
Settlement of Payables for Shares [Member]
Represents the settlement of payables for shares.
Accounting Policies [Abstract]
Warrant issuance costs
Amount of warrant issuance costs.
Segments [Domain]
Segments [Axis]
Secured Promissory Notes Sold in Subscription Agreements [Member]
Represents secured promissory notes sold in subscription agreements.
alce_BeneficialOwnershipMaximum
Beneficial Ownership, Maximum
The maximum required percentage of beneficial ownership of common stock following the conversion.
us-gaap_IncomeLossFromContinuingOperations
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent
alce_DebtInstrumentCovenantCapitalRaise
Debt Instrument, Covenant, Capital Raise
A debt instrument covenant pertaining to the amount of capital raised.
Measurement Input Type [Axis]
Income Statement [Abstract]
Series C Convertible Preferred Stock [Member]
Represents Series C Convertible Preferred Stock.
alce_PutOptionAgreementCovenantPriceOfRepurchasedShares
Put Option Agreement, Covenant, Price of Repurchased Shares (in dollars per share)
The price of repurchased shares as part of the put option agreement.
Series E Convertible Preferred Stock [Member]
Represents the Series E Convertible Preferred Stock.
Measurement Input, Conversion Price [Member]
Gain on sale of subsidiaries
alce_PutOptionAgreementCovenantEquityRaise
Put Option Agreement, Covenant, Equity Raise
A covenant for the put option agreement detailing the equity raise requirement.
Series D Convertible Preferred Stock [Member]
Represents Series D Convertible Preferred Stock.
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
alce_PutOptionAgreementCovenantSharesRepurchased
Put Option Agreement, Covenant, Shares Repurchased (in shares)
The number of shares that may be repurchased as part of the put option agreement.
Measurement Input, Expected Dividend Rate [Member]
Measurement Input, Expected Term [Member]
Income Tax Contingency [Table]
Conversion of Notes into Series C Convertible Preferred Stock [Member]
Represents the conversion of notes into Series C Convertible Preferred Stock.
Fair value movement in warrant liability
Fair value movement of warrants
Fair value movement of warrants
Nicholas Parker [Member]
Represents Nicholas Parker.
alce_OwnershipPercentage
Ownership Percentage
Percentage of ownership.
Measurement Input, Discount for Lack of Marketability [Member]
us-gaap_NetIncomeLoss
Net income/(loss)
Net Income /(Loss)
Measurement Input, Price Volatility [Member]
alce_ClassOfWarrantOrRightIssued
Class of Warrant or Right, Issued (in shares)
The number of warrants or rights issued.
Favorable Contracts [Member]
Represents favorable contracts.
us-gaap_AmortizationOfIntangibleAssets
Intangible Asset, Finite-Lived, Amortization Expense
Subscription Agreements [Member]
Subscription Agreements
Operating Expenses
Measurement Input, Share Price [Member]
Measurement Input Type [Domain]
Measurement Input, Risk Free Interest Rate [Member]
Derivative liability, measurement input
Derivative liability, measurement input
us-gaap_DebtConversionOriginalDebtAmount1
Debt Conversion, Original Debt, Amount
Accredited Debt Holder [Member]
Represents accredited debt holder.
us-gaap_DebtConversionConvertedInstrumentAmount1
Debt Conversion, Converted Instrument, Amount
Convertible Debt [Table Text Block]
us-gaap_DebtInstrumentMeasurementInput
Risk-free rate
us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Debt Conversion, Converted Instrument, Shares Issued (in shares)
Morgan Franklin Consulting LLC [Member]
Represents Morgan Franklin Consulting LLC.
us-gaap_CostsAndExpenses
Total operating income/ (expenses)
alce_NoncashInvestingAndFinancingActivitiesSharesIssuedInSettlementOfDebtAndOtherLiabilities
Common shares issued for settlement of debt
The shares issued in the settlement of debt and other liabilities for noncash investing and financing activities.
Income Tax Disclosure [Text Block]
Risk-free rate
us-gaap_WarrantsAndRightsOutstandingMeasurementInput
alce_EquityOfferingMaximumAmount
Equity Offering, Maximum Amount
Maximum amount of equity offering.
Restricted Stock [Member]
Accounting Standards Update and Change in Accounting Principle [Table]
Non-cash investing and financing activities:
Approximate [Member]
Represents approximate.
Related party transactions
us-gaap_RelatedPartyTransactionAmountsOfTransaction
Related Party Transaction, Amounts of Transaction
Related and Nonrelated Parties [Domain]
Related Party Transaction [Table]
Related Party Transactions Disclosure [Text Block]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Alternus Energy Group Plc [Member]
Represents Alternus Energy Group Plc.
Sale of Subsidiaries [Text Block]
Represents the entire disclosure of the sale of subsidiaries during the period.
Short secured debt
Represents the amount of short term secured debt included in the liabilities of a disposal group.
Disposal Group, Not Including Discontinued Operation, Assets and Liabilities of Subsidiary Sold [Table Text Block]
Represents the tabular disclosure of the assets and liabilities of a subsidiary sold that is reported as a disposal group that is not a discontinued operation during the period.
Fair Value Hierarchy and NAV [Domain]
Operating leases, current liabilities
Represents the current portion of operating lease liabilities included in the liabilities of a disposal group.
Measurement Frequency [Domain]
alce_DisposalGroupNotDiscontinuedOperationCostsAssociatedWithSale
Disposal Group, Not Discontinued Operation, Costs Associated with Sale
Represents the amount of costs associated with the sale of a disposal group that is not considered a discontinued operation during the period.
us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableCurrent
Accounts payable
Total assets sold
Other income/(expense):
Statement of Financial Position [Abstract]
Convertible and other notes measured at fair value
us-gaap_ConvertibleDebtFairValueDisclosures
us-gaap_NonoperatingIncomeExpense
Total other income/(expenses)
Operating leases, non-current liabilities
Represents the non current portion of operating lease liabilities reported under the liabilities of a disposal group.
Net (gain)/loss on sale of net assets
Represents the amount of gain (loss) on the sale of the net assets of a disposal group.
Supplemental Cash Flow Disclosure
us-gaap_OtherAssets
Other Assets
Variable Interest Entity [Table]
Fair Value, Recurring [Member]
us-gaap_OtherAssetsNoncurrent
Total
Nonmonetary Transaction Type [Domain]
Nonmonetary Transaction Type [Axis]
Four Current Independent Directors [Member]
Represents four current independent directors.
Warrant [Member]
us-gaap_WarrantsAndRightsOutstanding
Warrants and Rights Outstanding
Document Type
Document Information [Line Items]
Document Quarterly Report
us-gaap_RestructuringCosts
Restructuring Costs
Document Information [Table]
Antidilutive securities (in shares)
us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Revenue
us-gaap_BusinessAcquisitionsProFormaRevenue
Antidilutive Securities [Axis]
Entity Interactive Data Current
Document Transition Report
Weighted-average common stock outstanding, diluted (in shares)
Convertible Debt, Fair Value Adjustment
Convertible Debt, Fair Value Adjustment
Fair value movement of convertible debt
Represents the amount of adjustment to convertible debt during the period.
Basic & diluted loss per share of common stock:
Conversion of Note Into Common Stock [Member]
Represents the conversion of a note into common stock.
Net Income / (loss)
us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Weighted-average common stock outstanding, basic (in shares)
us-gaap_DebtInstrumentTerm
Debt Instrument, Term (Year)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Total income/(loss) per share of common stock, basic (in dollars per share)
us-gaap_StockIssued1
Fair value of Series C Convertible Preferred shares issued for settlement of liabilities
Term loans and promissory notes, net of debt discount
Title and Position [Domain]
alce_ProceedsFromIssuanceOfDebtExpected
Proceeds from Issuance of Debt Expected
Represents the amount of proceeds from the issuance of debt expected during the period.
Earnings Per Share, Policy [Policy Text Block]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Intangible assets, net
Intangible assets
Amortization of debt discount
Amortization of Debt Discount (Premium)
us-gaap_FiniteLivedIntangibleAssetsNet
Intangible Asset, Finite-Lived, after Accumulated Amortization
Depreciation, amortization and accretion
Depreciation, amortization, and accretion
Document Fiscal Period Focus
Corporate Joint Venture [Member]
Conversion of Debt Into Series E Convertible Preferred Stock [Member]
Represents conversion of debt into series E convertible preferred stock.
us-gaap_FiniteLivedIntangibleAssetsGross
Intangible Assets, Gross
Private Placement Warrants [Member]
Represents private placement warrants.
Document Fiscal Year Focus
Investment, Name [Domain]
us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Stockholders' Equity Note, Stock Split, Conversion Ratio
Series C convertible preferred shares issued for debt restructuring (in shares)
Number of new stock issued for debt restructuring during the period.
Conversion of Debt Into Series D Convertible Preferred Stock [Member]
Represents conversion of debt into series D convertible preferred stock.
Amendment Flag
Series C convertible preferred shares issued for debt restructuring
Less: Fair value of Series C Convertible Preferred Stock
Equity impact of the value of new stock issued for debt restructuring during the period.
Common Stock [Member]
Goodwill
Goodwill
Goodwill
Series D Convertible Preferred shares issued for debt
Represents the conversions of liabilities with fair value measurements with unobservable inputs during the period.
Document Period End Date
Warrant Liability [Member]
Represents a warrant liability.
Legal Entity [Axis]
Alt Spain Hold Shares [Member]
Represents Alt Spain Hold Shares.
us-gaap_FinancialLiabilitiesFairValueDisclosure
Total
Audit Fees
Represents current accrued audit fees.
Tax penalties
Represents current accrued tax penalties.
Business Combination [Domain]
Entity File Number
Entity Tax Identification Number
Business Combination [Axis]
Reverse Stock Split [Member]
Represents a reverse stock split.
Entity [Domain]
Entity Central Index Key
Entity Registrant Name
Software, Internally Developed [Member]
alce_PreferredStockSharesDesignated
Preferred Stock, Shares Designated (in shares)
Represents the number of preferred stock shares designated.
Foreign currency translation adjustment
us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
Foreign currency translation adjustment
Entity Current Reporting Status
Business Combination [Table]
alce_ConsultingMonthlyFee
Consulting Monthly Fee
Represents the amount of a consulting monthly fee.
Entity Incorporation, State or Country Code
alce_SharebasedCompensationArrangementBySharebasedPaymentAwardVotingRightsPercentage
Share-Based Compensation Arrangement by Share-Based Payment Award, Voting Rights, Percentage
Represents the percentage of voting rights under a share-based payment arrangement.
alce_PreferredStockVotesPerShare
Preferred Stock, Votes Per Share
Represents the number of votes per share of preferred stock.
Twenty Twenty Three Equity Incentive Plan [Member]
Represents the 2023 equity incentive plan.
Business Combination, Pro Forma Information [Table Text Block]
Current Fiscal Year End Date
alce_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantPercentageOfSharesOutstanding
Share Based Compensation Arrangement By Share Based Payment Award, Number of Shares Available for Grant, Percentage of Shares Outstanding
Represents the percentage of shares outstanding under a share based compensation arrangement.
Put Option Liability (Series D)
Amount of put option liability.
alce_ClassOfWarrantOrRightExpiredDuringPeriod
Expired, warrants (in shares)
Represents the number of warrants or rights expired during the period.
Entity Ex Transition Period
Expired, weighted average exercise price (in dollars per share)
Represents the weighted average exercise price of warrants or rights expired during the period.
Entity Filer Category
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Business Combination, Recognized Asset Acquired, Asset
alce_OwnershipSoldPercentage
Ownership Sold Percentage
Represents the percentage of ownership sold.
Common shares issued under 3a(10) settlement (in shares)
The number of shares issued during the period to settle litigation.
Entity Shell Company
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
Business Combination, Recognized Liability Assumed, Liability
Issuance cost of put option liability with Series D convertible preferred shares
The amount expense on derivative issuance.
Entity Emerging Growth Company
Entity Small Business
Hover [Member]
Represents Hover.
Common shares issued under 3a(10) settlement
The value of stock issued during the period for legal settlements.
Measurement Input, Probability of Qualifying for PIPE [Member]
The measurement for the probability of qualifying for PIPE.
us-gaap_OperatingIncomeLoss
Income/(loss) from operations
Measurement Input, Probability of Liquidation [Member]
The measurement input for the probability of liquidation.
Issued, weighted average exercise price (in dollars per share)
Class of Warrant or Right, Issued During Period, Weighted Average Exercise Price (in dollars per share)
Represents the weighted average exercise price per share of warrants or rights issued during period.
Put Option Liability (Series D)
alce_PutOptionLiabilityFairValue
The fair value of the put option liability.
Preferred Equity Financing [Member]
Represents preferred equity financing.
Issuance cost put option liability (Series D)
Issuance cost put option liability (Series D)
The amount of issuance costs for the put option liabilities.
Europe Segment [Member]
Relating to the Europe segment.
United States Segment [Member]
Relating to the United States segment.
Other current liabilities
us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentLiabilities
alce_ClassOfWarrantOrRightOutstandingWeightedAverageExercisePrice
Outstanding, weighted average exercise price (in dollars per share)
Outstanding, weighted average exercise price (in dollars per share)
Represents the weighted average exercise price for outstanding warrants or rights.
Measurement Input, DOLM [Member]
The measurement input representing the DLOM.
us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets
Other current assets
Measurement Input, Holding Period [Member]
The measurement input representing the holding period.
Measurement Input, ALCE Closing Price [Member]
The measurement input representing the ALCE closing price.
Issued, warrants (in shares)
Class of Warrant or Right, Issued During Period (in shares)
Represents the number of warrants or rights issued during period.
Measurement Input, Face Value of Preferred Shares [Member]
The measurement input representing the face value of the preferred shares.
us-gaap_InterestExpenseDebt
Interest Expense, Debt
Exercisable, warrants (in shares)
Represents the number of warrants or rights exercisable during the period.
Entity Address, State or Province
alce_ClassOfWarrantOrRightIssuedDuringPeriodWeightedAverageRemainingContractualTerm
Class of Warrant or Right, Issued During Period, Weighted Average Remaining Contractual Term (Year)
Represents the weighted average remaining contractual term of warrants or rights issued during the period.
Entity Address, City or Town
Outstanding, weighted average remaining contractual term (Year)
Represents the weighted average remaining contractual term of warrants or rights outstanding.
us-gaap_InterestExpenseNonoperating
Interest expense
Interest expense
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Entity Address, Address Line One
Exercisable, weighted average exercise price (in dollars per share)
Represents the weighted average exercise price of warrants or rights exercisable.
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
City Area Code
Local Phone Number
Entity Address, Postal Zip Code
Exercisable, weighted average remaining contractual term (Year)
Represents the weighted average remaining contractual term of warrants or rights exercisable.
Preferred Stock [Member]
Title of 12(b) Security
Capitalized Contract Cost [Table]
Trading Symbol
us-gaap_EquitySecuritiesFvNiMeasurementInput
Equity securities FVNI, measurement input
Convertible and Non-convertible Notes [Member]
Represents Convertible and Non-convertible Notes.
Additional Warrants to an Accredited Investor [Member]
Represents Additional Warrants to an Accredited Investor.
Class of Stock [Axis]
Related Party Transaction [Domain]
Entity Common Stock, Shares Outstanding
Related Party Transaction [Axis]
Four Accredited Investors [Member]
Four Accredited Investors
Two Accredited Investors [Member]
Two Accredited Investors
Chief Executive Officer [Member]
Director [Member]
Loss attributable to noncontrolling interest
Net Income (Loss) Attributable to Noncontrolling Interest
alce_NoncashInvestingAndFinancingActivitiesSharesIssuedForIssuanceCosts
Common shares issued for debt issuance costs
The shares issued to cover debt issuance costs for noncash investing and financing activities.
One Accredited Investor [Member]
One Accredited Investor
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Net income/(loss) for the period
Consolidated Net Income / (Loss)
us-gaap_LitigationReserveCurrent
Estimated Litigation Liability, Current
Three Accredited Investors [Member]
Three Accredited Investors
alce_PreferredStockStatedValue
Preferred Stock, Stated Value (in dollars per share)
Represents the stated value of preferred stock.
Scenario [Axis]
EBITDA
Adjusted EBITDA
Represents earnings before interest, taxes, depreciation and amortization (EBITDA).
Equity, Capital Unit or Share [Table]
Scenario [Domain]
alce_ShareholderOwnershipPercentage
Shareholder Ownership, Percentage
Represents the percentage of shareholder ownership.
Series D convertible preferred shares issued for cash (in shares)
The number of shares of stock issued during the period explicitly for cash.
Series D convertible preferred shares issued for cash
The value of stock issued during the period explicitly for cash.
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share (in dollars per share)
Investment, Name [Axis]
Debt restructuring costs
Debt restructuring costs
The amount of debt restructuring costs.
New notes issued in period
us-gaap_OtherLiabilities
Other Liabilities
Basis of Accounting, Policy [Policy Text Block]
Schedule of Other Assets, Noncurrent [Table Text Block]
Hoover [Member]
Related to Hoover.
us-gaap_OtherNonoperatingIncomeExpense
Other Expense
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]
us-gaap_OtherNonoperatingExpense
Other expense
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements
Convertible Preferred shares issued for debt
alce_LossOnSettlement
Stock issued for debt settleent costs
The amount of loss from settlement.
Sale of Stock [Domain]
alce_ValueOfRestitution
Value of Restitution
The value of restitution.
Convertible Note Warrants [Member]
Related to convertible note warrants.
us-gaap_Assets
Total Assets
Total for Europe
alce_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityExtinguishments
Gain on settlement of debt
Amount of extinguishments of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.
April 2025 Warrants [Member]
Related to April 2025 warrants.
Cash and cash equivalents
Cash and Cash Equivalent
OID Notes [Member]
Related to OID Notes.
Professional Consulting Agreement [Member]
Represents a professional consulting agreement.
Consulting Agreement [Member]
Represents a consulting agreement.
alce_IncreaseInProfessionalFeesPerMonth
Increase in Professional Fees Per Month
Represents the amount of increase in professional fees per month during the period.
Total Notes [Member]
Related to total notes.
April and October Convertible Notes [Member]
Represents the April and October convertible notes.
Represents Remuneration in Respect to Long-Term Incentive Schemes with Restricted Shares [Member]
Represents remuneration in respect to long-term incentive schemes with restricted shares.
Remuneration in Respect of Services of Directors [Member]
Represents remuneration in respect of services of directors.
Total income/(loss) per share of common stock, diluted (in dollars per share)
alce_AccruedLegalFees
Accrued Legal Fees
Represents the amount of accrued legal fees.
us-gaap_InvestmentOwnedBalanceShares
Investment Owned, Balance, Shares (in shares)
Term Loans [Member]
Relating to term loans.
Payable to related party
The increase (decrease) during the reporting period in the aggregate amount of obligations to be paid to (received from) the following types of related parties: a parent company and its subsidiaries; subsidiaries of a common parent; an entity and trust for the benefit of employees, such as pension and profit-sharing trusts that are managed by or under the trusteeship of the entities' management; an entity and its principal owners, management, or member of their immediate families, affiliates, or other parties with the ability to exert significant influence.
alce_GainLossOnDebtSettlements
Gain (Loss) on Debt Settlements
Gain on debt settlement
Represents the amount of gain (loss) on debt settlements during the period.
The 2024 Convertible Notes [Member]
Relating to the 2024 Convertible Notes.
Director's Remuneration [Member]
Relating to directors' remuneration.
us-gaap_FinitelivedIntangibleAssetsAcquired1
Finite lived intangible assets
Consolidation, Policy [Policy Text Block]
Fair Value by Liability Class [Domain]
Disposal Group Name [Domain]
us-gaap_InterestPaidNet
Interest (net of capitalized interest of $0 and $568 respectively)
us-gaap_NoncontrollingInterestInVariableInterestEntity
Noncontrolling Interest in Variable Interest Entity
Schedule of Long-Term Debt Instruments [Table Text Block]
Comprehensive loss attributable to noncontrolling interest
us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
Comprehensive income/(loss)
Liability for Catastrophe Claims [Table]
us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Total Shareholders’ Equity
Balance
Balance
Disposal Group Name [Axis]
Other payables
Other Payables, Current
Represents the amount of other current payables.
Alt Alliance Llc [Member]
Represents Alt Alliance LLC.
alce_TaxesRecoverable
Taxes recoverable
Represents the amount of taxes recoverable.
us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Disposal Group, Including Discontinued Operation, Consideration
Parent [Member]
EverOn Energy LLC [Member]
Represents EverOn Energy LLC.
Noncontrolling Interest [Member]
us-gaap_StockholdersEquity
Shareholders’ Equity attributable to Alternus Clean Energy, Inc.
us-gaap_ValueAddedTaxReceivableCurrent
Taxes recoverable
us-gaap_PaymentsForLegalSettlements
Payments for Legal Settlements
Consolidation, Less-than-Wholly-Owned Subsidiary, Parent Ownership Interest, Effect of Change [Table]
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Revenue
Revenues