The TikTok data centre under construction in Lahti, southern Finland, has received an environmental permit, but the decision has renewed controversy over the authorities’ refusal to disclose certain environmental documents, citing trade secrets.
The permit was granted on 5 October by Finland’s Licensing and Supervision Agency (Lupa- ja valvontavirasto, LVV). It covers the operation of backup generators and fuel storage at the facility in the Kiveriö district.
The data centre is being developed by Singapore-based DayOne, with TikTok as its main tenant. Construction is already underway, and operations are expected to begin in 2027.
The project is part of TikTok’s wider expansion in Europe, with the company announcing a €1 billion investment in Lahti earlier this year.
Why the TikTok data centre documents are disputed
According to Finnish public broadcaster Yle, the licensing authority has withheld parts of the environmental permit application on the grounds that they contain commercially sensitive information.
The confidential documents include detailed emissions data and stormwater management plans, which explain how rainwater and surface runoff will be handled at the site.
The decision has been questioned by Tomi Voutilainen, professor of public law at the University of Eastern Finland, who argued in May that the authorities’ approach could undermine residents’ ability to participate in decisions affecting their local environment.
Yle’s investigation also revealed that some plans classified as confidential by LVV had been provided without redactions by the City of Lahti during the construction permit process.
The concerns are not limited to external legal experts. LVV’s own public-interest oversight unit raised objections during the environmental permit procedure.
The unit argued that emissions information cannot generally be withheld simply by invoking trade secrets, referring to Finnish environmental protection legislation and the public’s rights to access information, participate in environmental decision-making and challenge decisions.
In response, the company applying for the permit submitted a table summarising noise and air emissions. However, more detailed information, including the fuel capacities of backup generators and the quantities of fuel stored, was provided confidentially to the authority.
DayOne maintains that the withheld documents contain commercially valuable technical information. LVV has defended its decision, stating that confidentiality was based on its own assessment rather than simply accepting the company’s request.
Noise restrictions for a data centre close to homes
The transparency dispute is particularly relevant because the facility is being built around 50 metres from the nearest residential buildings.
Some residents have already complained about noise from construction work, raising concerns about the impact of the facility once it becomes operational.
Under normal conditions, the data centre will use electricity from the local grid. Its backup generators, powered by light fuel oil, will operate mainly during testing or electricity outages.
The environmental permit establishes noise limits of 55 decibels during the day and 50 decibels at night at affected locations. Generator testing must take place during daytime hours on weekdays.
The facility will also have 48 water-cooling units installed on its roof, surrounded by noise barriers. The authorities have required further assessments of emissions and noise levels once operations begin.
According to LVV, stormwater must be monitored before discharge into waterways. The facility will not use surface water for cooling, while plans are being developed to recover waste heat for district heating.
Finland’s growing debate over data centres
The Lahti project comes amid increasing scrutiny of Finland’s rapidly expanding data centre industry.
In September, a citizens’ initiative demanding stricter regulation collected the 50,000 signatures required to bring the proposal before Parliament in just three days.
The initiative calls for stronger conditions on electricity grid connections, greater use of waste heat and a dedicated fee reflecting the environmental impact and resource consumption of data centres.
For TikTok, the Lahti investment forms part of Project Clover, its European data protection programme, which also includes another Finnish data centre project in Kouvola.
The Lahti permit application was processed under a priority procedure for green-transition projects. The authority has also authorised operations to begin in accordance with permit conditions even if the decision is appealed.
The environmental permit remains open to legal challenges until 11 November 2026, leaving the dispute over public access to environmental information unresolved as construction continues.
