Nuclear exit and the restart question · Maanshan 2 shut 17 May 2025, licence renewal under review
Where it stands: Licence renewal applications under staged review by the Nuclear Safety Commission
Taiwan became nuclear-free on 17 May 2025 when the Maanshan Unit 2 operating licence expired, four decades after the unit started up. A 2025 amendment to the nuclear regulation law reopened the possibility of licence renewal, a national referendum on restarting Maanshan failed to clear the statutory approval threshold, and the Nuclear Safety Commission is now running a four-part licence renewal review.
The problem
Taiwan legislated a nuclear-free homeland and let its reactor licences run out one by one: Chinshan, then Kuosheng, whose Unit 1 licence expired on 27 December 2021, then Maanshan, whose Unit 1 licence expired on 27 July 2024 and Unit 2 on 17 May 2025. The policy was set when Taiwan expected flat demand and cheap LNG. It collided with three later facts: electricity demand rose sharply with semiconductor investment and data centres, the 2050 net-zero target made replacing 8 to 10 percent of generation with gas awkward, and the island's reserve margin and LNG storage cover left it exposed to supply interruption with no interconnection to fall back on. The original licensing law also made the question difficult to reopen, because it did not contemplate renewing a licence that had already expired and required decommissioning to begin.
What it does
The Legislative Yuan amended the nuclear reactor facility regulation legislation in 2025 to allow operators of reactors whose licences had expired, or were about to, to apply for renewal and to permit extended operating periods, removing the automatic path to decommissioning that the earlier law implied. A national referendum on restarting the Maanshan plant was then held in 2025; affirmative votes outnumbered negative ones, but the result did not pass because the affirmative vote fell short of the statutory threshold of one quarter of the electorate required under the Referendum Act, so it created political momentum without legal effect. Taipower has since filed for operating licence renewal and the Nuclear Safety Commission has established a dedicated restart review programme. That review runs in four parallel workstreams, each fed by staged submissions from Taipower: a restart plan review, a review of the report on the execution results of that plan, a safety technical report review, and a review of the technical and management capability and financial basis report. The Commission publishes regulatory dynamics, a chronology, monthly regulatory information and the record of its regulatory meetings for each plant under review, and maintains separate pages for Maanshan and Kuosheng; the programme pages were last updated on 26 August 2026. Both Maanshan units are formally recorded as in decommissioning status while the renewal review proceeds.
Market effect
Removing the nuclear fleet moved Taiwan's marginal generation decisively toward imported LNG and, on tight days, coal, which raised both the average cost of electricity and the carbon intensity of every corporate renewable buyer's residual grid supply. It also tightened the reserve margin in a system with no interconnection and limited LNG storage, so the value of demand response, reserve contracts and new gas-fired capacity rose, as did the risk premium in long-dated industrial supply negotiations. The restart question is now the largest single uncertainty in Taiwanese power fundamentals. If licence renewal succeeds at Maanshan and later at Kuosheng, several gigawatts of low-marginal-cost baseload return, LNG import volumes fall and the merit order shifts down, which would reduce Taipower's fuel bill and ease the tariff pressure. If it fails, the 2030s depend on offshore wind, solar, gas and the demand-side. For gas infrastructure investors the asymmetry matters: terminal and pipeline capacity sized for a nuclear-free system becomes surplus if reactors return. Regulatory risk runs both ways, since the Nuclear Safety Commission is independent and a restart requires it to be satisfied on safety, technical and management capability and financial basis, none of which a referendum or a statute can compel.
Key numbers
- Maanshan Unit 1 licence
- 27 July 1984 to 27 July 2024
- Maanshan Unit 2 licence
- 18 May 1985 to 17 May 2025; Taiwan nuclear-free from that date
- Kuosheng Unit 1 licence
- 28 December 1981 to 27 December 2021
- 2025 statutory change
- Nuclear Reactor Facilities Regulation Act Article 6 amended — passed by the Legislative Yuan 13 May 2025, promulgated 23 May 2025, six days after Maanshan 2 shut
- What the amendment did
- Removed the bar on renewing an already-expired licence: an operator may now apply after expiry, subject to the regulator confirming no safety concern; original licences run a maximum of 40 years and a renewed licence a maximum of 20 years from its effective date
- Referendum case 21, 23 August 2025
- Agree 4,341,432 (74.17% of valid votes) against disagree 1,511,693 (25.83%) — a 3-to-1 majority in favour of restart
- Why it failed anyway
- Agree votes were 21.70% of the 20,002,091-strong electorate, short of the one-quarter threshold of 5,000,523; turnout was 29.53%
- Restart review structure
- Four reviews: restart plan, restart plan execution results, safety technical report, and technical, management and financial capability
Who gains and who pays
- Taiwan Power Company (mixed): Carries the decommissioning cost and the restart application; a successful renewal would cut its fuel bill materially.
- LNG importers and terminal developers (costs): Infrastructure sized for a nuclear-free system becomes surplus if reactors return.
- Industrial and semiconductor customers (gains): Restart would ease reserve-margin risk and slow tariff increases in a system with no interconnection.
- Renewable developers (mixed): Returning baseload lowers residual demand but also lowers the grid carbon factor and the urgency of procurement.
- Nuclear Safety Commission (obligation): Must complete four separate reviews before any restart, independent of political direction.
Implementation
Nothing restarts without the Nuclear Safety Commission. Taipower submits documents in stages against a published review plan; the Commission reviews each workstream, holds regulatory meetings, publishes monthly regulatory information and a chronology for each plant, and can require further analysis, plant modification or ageing-management measures before it will issue a renewed licence. Because the units are formally in decommissioning status, some equipment has been laid up or defuelled and restoration is itself a project with cost and schedule risk that Taipower must fund from a balance sheet already under strain. Fuel procurement, spent-fuel storage capacity on site and the low-level waste question at Lanyu, which the Electricity Act itself addresses in Article 95, are all live constraints. Politically the referendum result gives the restart case momentum without a mandate, so the decisive events are regulatory rather than electoral: the completion of the four reviews and any licence renewal decision, followed by the same question at Kuosheng.
Concerns
- Units are formally in decommissioning status, so restoration is itself a costly and uncertain project
- The referendum created political pressure but no legal obligation to restart
- Spent fuel storage capacity and the low-level waste question remain unresolved
- Taipower must fund restoration from a balance sheet already strained by fuel costs
- Regulatory independence means the Nuclear Safety Commission can refuse renewal regardless of policy
Dates to watch
- 2027: Expected completion of the Nuclear Safety Commission's Maanshan licence renewal reviews
- 2027: Progress of the parallel Kuosheng restart review programme
Sources
- Nuclear Reactor Facilities Regulation Act (核子反應器設施管制法), consolidated text, Laws & Regulations Database of the Republic of China (Taiwan), Ministry of Justice (official text)
- 114年全國性公民投票第21案投票結果 (Result of national referendum case 21, 2025), Central Election Commission, Taiwan
- 114年全國性公民投票第21案投開票結果表 (Case 21 count table), Central Election Commission, Taiwan
- Nuclear Safety Commission (核能安全委員會), Nuclear Safety Commission, Taiwan
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