Schedule of property plant and equipment (Details) € in Thousands	6 Months Ended
Jun. 30, 2026 EUR (€)
IfrsStatementLineItems [Line Items]
At 1 January 2026	€ 1,233
At 30 June 2026	1,403
Assets under construction [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	412
At 30 June 2026	122
Machinery [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	357
At 30 June 2026	834
Office equipment [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	23
At 30 June 2026	24
Right-of-use assets [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	441
At 30 June 2026	423
Gross carrying amount [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	2,601
Additions	238
Disposals	(30)
Transfers
Exchange differences	79
At 30 June 2026	2,888
Gross carrying amount [member] \| Assets under construction [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	412
Additions	154
Disposals
Transfers	(464)
Exchange differences	20
At 30 June 2026	122
Gross carrying amount [member] \| Machinery [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	1,502
Additions	17
Disposals
Transfers	464
Exchange differences	42
At 30 June 2026	2,025
Gross carrying amount [member] \| Office equipment [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	26
Additions	3
Disposals
Transfers
Exchange differences	1
At 30 June 2026	30
Gross carrying amount [member] \| Right-of-use assets [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	661
Additions	64
Disposals	(30)
Transfers
Exchange differences	16
At 30 June 2026	711
Accumulated depreciation and amortisation [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	(1,368)
Disposals	30
At 30 June 2026	(1,485)
Charge for the period	(108)
Exchange differences	(39)
Accumulated depreciation and amortisation [member] \| Assets under construction [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026
Disposals
At 30 June 2026
Charge for the period
Exchange differences
Accumulated depreciation and amortisation [member] \| Machinery [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	(1,145)
Disposals
At 30 June 2026	(1,191)
Charge for the period	(14)
Exchange differences	(32)
Accumulated depreciation and amortisation [member] \| Office equipment [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	(3)
Disposals
At 30 June 2026	(6)
Charge for the period	(3)
Exchange differences
Accumulated depreciation and amortisation [member] \| Right-of-use assets [member]
IfrsStatementLineItems [Line Items]
At 1 January 2026	(220)
Disposals	30
At 30 June 2026	(288)
Charge for the period	(91)
Exchange differences	€ (7)

Depreciation charge property plant and equipment.

No definition available.

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Namespace Prefix:	HTOO_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Gains losses on exchange of property plant and equipment.

+ References

No definition available.

+ Details

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Namespace Prefix:	HTOO_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Increase decrease through transfers property plant and equipment including rightofuse assets exchange differences.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The amount of additions to property, plant and equipment including right-of-use assets other than those acquired through business combinations. [Refer: Total for all business combinations [member]; Property, plant and equipment including right-of-use assets]

+ References

+ Details

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- References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
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-URIDate 2025-03-27

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) in property, plant and equipment including right-of-use assets resulting from transfers. [Refer: Property, plant and equipment including right-of-use assets]

+ References

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period. Note that right-of-use assets are not included. [Contrast: Property, plant and equipment including right-of-use assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of property, plant and equipment including right-of-use assets whose underlying assets would be presented as property, plant and equipment if they were owned. [Refer: Property, plant and equipment; Right-of-use assets]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=HTOO_AssetsUnderConstructionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=ifrs-full_MachineryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis=ifrs-full_OfficeEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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- Details

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