Floor Area · reported
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Reading listings, research log, and source-health evidence.
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Municipal district-heating plant blasted into Åbykullen at Mölndal, placed in service in 1964 after nearly a decade of planning, with 1,000 m² / 10,764 ft² floor area, roughly 15 m height and initial capacity for about 2,000 households.
Floor Area · reported
Published date and precision preserved
Published date and precision preserved
Unit-attributed from its source article
Functional recreation of the documented facility in Sweden using current construction methods and 2026 prices, preserving the documented capacity, protection, autonomy and redundancy. Ex VAT; excluding land, financing, remediation, classified mission equipment and data-centre hardware.
Provisional audited central concept screen; expected-risk calibration is pending. It is not yet a risk-adjusted expected cost.
Method, scope and confidence →21 photographs sourced from the original article, with captions where available.
Published, calculated and proxy dimensions are deliberately separated. Missing evidence stays visible instead of becoming zero.
Rock in place removed before bulking; the excavation-pricing quantity.
Internal airspace; not the amount of rock removed.
Blasted material after bulking; the haul and disposal quantity.
These cubic metres are not interchangeable.
Usable, floor or footprint area; the label is preserved because these are not always interchangeable.
Floor Area · reported · Publisher articleRock in place removed before bulking; the quantity used to price excavation.
Published 1000 m² / 10,764 ft² floor and roughly 15 m internal height imply a 15000 m³ minimum envelope; base/high add explicit crown, wall and access geometry. · Prior model input reviewed by auditInternal air or chamber volume. It is not solid excavation without overbreak, access and support geometry.
No usable quantity in the reviewed source · Evidence gapBlasted material after bulking, or its handled mass. No swollen cubic metres are inferred when only tonnes are modelled.
Published 1000 m² / 10,764 ft² floor and roughly 15 m internal height imply a 15000 m³ minimum envelope; base/high add explicit crown, wall and access geometry. Mass uses an assumed Swedish hard-rock density o… · Reviewed mass-handling modelLength alone is insufficient; a costable tunnel also needs width, height or cross-sectional area.
No usable quantity in the reviewed source · Evidence gapPublished chamber or arch geometry used to test volume and support assumptions.
Internal Height · Publisher articleRock surface requiring bolts, mesh or shotcrete, preferably measured in square metres.
No support-area quantity is published · Audited excavation scopeCounts and dimensions of access, transfer, utility and emergency interfaces.
Industrial rock access is required; exact portal arrangement is unpublished. · Reviewed base modelCast inner structures and linings, kept separate from excavated rock and reinforcement mass.
Reported facility floor/shelter area is used as the screening usable-area basis. Archetype concrete factor is 0.6 m³ per usable m². · Reviewed base modelGroundwater, inflow, drainage, pumping and moisture-control evidence affecting construction and operation.
Initial Hot Water Boilers · Publisher articleThe headline answers the current replacement question. Historic cost, CPI and construction-index comparisons remain separate because they answer different questions.
Different specifications receive different estimates; they are not used as the upper and lower limits of one answer.
Preserves documented capacity, protection, autonomy and redundancy using current construction methods.
Requires a modern structural, fire, protection and supplier performance brief.
Requires IT load, cooling topology, grid capacity, redundancy and autonomy. Server hardware is excluded.
No representative facility construction cost selected
General purchasing-power comparison—not a construction quote
Broad BKI proxy—not a bunker-specific rebuild price
Scope lock. Functional recreation of the documented facility in Sweden using current construction methods and 2026 prices, preserving the documented capacity, protection, autonomy and redundancy. Ex VAT; excluding land, financing, remediation, classified mission equipment and data-centre hardware. The article supports an industrial cavern commissioned in 1964 with 1,000 m² / 10,764 ft² floor area and roughly 15 m clear height, initially two hot-water boilers and a third added in 1969. It records a serious 1980 fire, closure in 1984, and an approximatel…
Audit revision sweden-replacement-audit-2026.08.15. The central WBS below incorporates the 61-article review. The former deterministic low/base/high cases remain available only as sensitivities and revision history.
Direct works + owner / design / investigation + legacy concept contingency
Central quantities × current installed-rate screen.
Not yet probability-weighted. The current legacy concept contingency remains separate.
22% applied to the direct-work screen.
Raw model SEK 511.1m · rounded for Confidence D.
Transitional limitation. SEK 86,917,500 is still a blanket concept contingency, not probability-weighted expected risk. This is why the amount is labelled provisional. The audited industrial rock WBS remains the central scope ledger.
No subject caveat recorded.
68/100 article-geometry completeness. Detailed source extraction is available in the original-article audit.
Confidence D · geometry completeness 68/100
Largest active lines in the audited central component schedule.
The workbook publishes one revised central schedule. Its prior low and high stress cases are retained only under sensitivities; no line-level probability distributions are implied.
Hydrogeology, drainage, pumping and moisture control · SEK 10,800,000
Hydrogeology, drainage, pumping and moisture control · SEK 10,800,000
Integrated testing, commissioning and public-safe documentation · SEK 8,900,000
| Change | Scope | Audited base | Quantity / rate basis | Provenance |
|---|---|---|---|---|
| Retained | 01Industrial cavern excavation and supportCivil Rock | SEK 135,000,000 | 18,000 Solid Design m³ × SEK 7,500 / Solid Design m³Derived From Published quantity · Assumption ratePublished 1000 m² / 10,764 ft² floor and roughly 15 m internal height imply a 15000 m³ minimum envelope; base/high add explicit crown, wall and access geometry. | Existing archive WBS |
| Retained | 02Rock mass handlingMass Handling | SEK 4,770,000 | 47,700 T × SEK 100 / TDerived From Published quantity · Derived ratePublished 1000 m² / 10,764 ft² floor and roughly 15 m internal height imply a 15000 m³ minimum envelope; base/high add explicit crown, wall and access geometry. Mass uses an assumed Swedish hard-rock density of 2.65 t/m³. | Existing archive WBS |
| Retained | 03Concrete floors and inner structuresStructural | SEK 4,200,000 | 600 m³ × SEK 7,000 / m³Derived From Published quantity · Assumption rateReported facility floor/shelter area is used as the screening usable-area basis. Archetype concrete factor is 0.6 m³ per usable m². | Existing archive WBS |
| Retained | 06Protection and resilient site systemsProtection | SEK 18,000,000 | 1 Project × SEK 18,000,000 / ProjectAssumption quantity · Assumption rateOne protection package per 2000 usable m² / 21,528 ft², subject to a 1-package minimum. | Existing archive WBS |
| Retained | 07Portal and utility interfacesSite And Access | SEK 6,000,000 | 1 Project × SEK 6,000,000 / ProjectClass Proxy quantity · Assumption rateIndustrial rock access is required; exact portal arrangement is unpublished. | Existing archive WBS |
| Retained | 10Industrial process plantProcess And Support | SEK 160,000,000 | 1,000 m² / 10,764 ft² × SEK 160,000 / Process Floor m²Derived From Published quantity · Assumption rateReported facility floor/shelter area is used as the screening usable-area basis. Fit-out factor is 1 times the reference scale. | Existing archive WBS |
| Added | R165Hydrogeology, drainage, pumping and moisture control | SEK 10,800,000 | 8% of supported-rock scope as a class-screening allowance | Class assumption — site investigation/RFQ required |
| Added | R166Integrated testing, commissioning and public-safe documentation | SEK 8,900,000 | 5% of MEP/protection/mission-system scope | Class assumption — commissioning plan required |
Active base WBS SEK 347,670,000 · owner/design and contingency are added in the scenario cards above · 12 removed rows across the archive remain visible as change history.
The three inputs most likely to move the current screen.
These deterministic stress cases simultaneously vary quantities, rates, scope allowances and contingency. They are not confidence intervals and no longer serve as the headline answer.
Links support a rate, scope boundary or method. Context-only sources are not represented as quotations.
Gryaab February-2024 long-tunnel benchmark: SEK 5,513/design m³ for excavation plus support. Low case is lightly currentized; base/high add small, constrained, non-repetitive bunker uncertainty.
Gryaab February-2024 long-tunnel benchmark: SEK 5,513/design m³ for excavation plus support. Low case is lightly currentized; base/high add small, constrained, non-repetitive bunker uncertainty.
Skanska's Ostlanken order value is SEK 240m for handling 2.0m tonnes of rock and 0.4m tonnes of soil, excluding options. The base is the observed blended benchmark; bounds are assumptions.
Public ready-mix material check only; installed underground rates require RFQ.
Public sources establish specialized tested products but not project prices.
Bomb-protected municipal production of district heat and hot water.
Almost ten years of proposals, negotiations and siting discussions preceded construction.
B004Construction began after Åbykullen was selected.
B004Plant entered service.
B003Municipal district-heating operation with 1969 expansion and 1980 fire/repair.
B003,B008,B009District-heating network expanded and a third hot-water boiler was disassembled, brought underground and rebuilt in place.
B008Night fire disabled the entire plant; three mobile boiler units served during repairs.
B009Heating operations moved to Riskulla and the cavern became unused.
B003Unused cavern largely preserved as left.
B003Mölndals Energi planned to strip the cavern and install district cooling.
B010Proposed strip-out and district-cooling conversion; execution not established by this source.
B01020 reviewed claims. Evidence locators resolve against the stored article hash or archived snapshot.
| Subject | Claim | Value | Date | Evidence | Certainty |
|---|---|---|---|---|---|
| milestone | Event | Almost ten years of proposals, negotiations and siting discussions preceded construction. | mid-1950s to early 1960s | B004 | Reported |
| milestone | Event | Construction began after Åbykullen was selected. | early 1960s | B004 | Reported |
| milestone | Event | Plant entered service. | 1964 | B003 | Reported |
| milestone | Event | District-heating network expanded and a third hot-water boiler was disassembled, brought underground and rebuilt in place. | 1969 | B008 | Reported |
| milestone | Event | Night fire disabled the entire plant; three mobile boiler units served during repairs. | 1980-02 | B009 | Reported |
| milestone | Event | Heating operations moved to Riskulla and the cavern became unused. | 1984 | B003 | Reported |
| milestone | Event | Mölndals Energi planned to strip the cavern and install district cooling. | 2015 planned | B010 | Reported |
| lifecycle summary | Event | Municipal district-heating operation with 1969 expansion and 1980 fire/repair. | 1964–1984 | B003,B008,B009 | Reported |
| lifecycle summary | Event | Unused cavern largely preserved as left. | 1984-article era | B003 | Reported |
| lifecycle summary | Event | Proposed strip-out and district-cooling conversion; execution not established by this source. | 2015 planned | B010 | Reported |
| quantitative observation | Initial Household Capacity | 2,000 households | — | B003,B007 | Reported |
| quantitative observation | Planning Duration | 10 years | — | B004 | Reported |
| quantitative observation | Internal Height | 15 m | — | B004 | Reported |
| quantitative observation | Floor Area | 1,000 m² / 10,764 ft² | — | B004 | Reported |
| quantitative observation | Initial Hot Water Boilers | 2 boilers | — | B007 | Reported |
| quantitative observation | Boilers After 1969 | 3 boilers | — | B008 | Reported |
| technical system | Heat Generation | Two hot-water boilers initially, expanded to three in 1969. | — | B007,B008 | Reported |
| technical system | District Network | Initially intended for Idrottshuset and nearby schools, then expanded to additional neighbourhoods. | — | B007,B008 | Reported |
| technical system | Emergency Continuity | Three mobile boiler centres substituted after the 1980 fire. | — | B009 | Reported |
| protection | Rock Siting | Chosen partly to protect municipal heat supply against possible Cold War bombing and partly to conceal an unattractive industrial plant. | — | B005 | Reported |
Programme, sale, operating and component figures remain visible but are not silently relabelled as facility construction cost.
| Scope | Stage | Nominal | CPI 2025 | BKI 2025 | Date / evidence |
|---|---|---|---|---|---|
| Estimated scrap value said to offset strip-out cost; value, not expenditure and not construction cost. {"amountBound":null,"nonAdditive":true,"publisherLegacyEquivalentSek":null,"publisherLegacyEquivalentBasis":null} | Estimate | SEK 700,000 | SEK 933,792 | — | 2015 plannedB010 |
| Removal of remaining cavern equipment before proposed district-cooling reuse; not original construction cost. {"amountBound":null,"nonAdditive":true,"publisherLegacyEquivalentSek":null,"publisherLegacyEquivalentBasis":null} | Contract | SEK 700,000 | SEK 933,792 | — | 2015 plannedB010 |