Large-scale investments bring jobs and tax revenue, but they also raise questions about environmental impacts. How do data centres and their construction affect nature and the climate, and how are these impacts experienced by local residents? Environmental Manager Hanna Pasonen from Mikkeli Region Environmental Services provides the answers.
According to Pasonen, the impacts of data centres should be examined from both a local and a wider perspective.
”The most visible impacts are land use, construction-related traffic and noise. On a broader scale, the most significant environmental concern is energy consumption and how the electricity used by the data centre is generated,” says Pasonen.
Data centres require large sites. During construction, trees and undergrowth are cleared, land is reshaped and surfaces are paved. In addition, data centres require upgrades to the electricity network, new cabling and a range of technical systems.
”The need for land is the most visible environmental impact. The environment changes when vegetation is removed and land is taken into development use. That is why careful zoning and site selection are critically important from the outset of a project and throughout its development.”
According to Pasonen, Mikkeli has certain advantages when it comes to planning and zoning. The city has suitable areas available for development, meaning facilities do not need to be located as close to residential neighbourhoods as they often are in more densely populated areas of Southern Finland.
Energy consumption determines climate impacts
The use of renewable energy reduces a data centre’s carbon footprint, but even renewable energy sources are not entirely impact-free.
”For example, wind and solar power also require land. That is why the environmental impacts of data centres must be assessed as a whole,” Pasonen emphasises.
One way to reduce climate impacts is to utilise waste heat. Data centres generate significant amounts of heat, which can be recovered and fed into district heating networks. In Mikkeli, plans are being developed to make use of data centre waste heat for district heating.
Noise is a key concern for local residents
Noise during the construction phase is one of the most common concerns raised by residents. Questions have also been raised about the noise levels of operational data centres.
”We have received questions about how noise might carry towards residential areas,” says Pasonen.
In data centres, cooling systems are typically the most significant source of noise. The actual impact depends on factors such as the size of the facility, the cooling technology employed and the surrounding environment.
”In a quiet area, noise is naturally more noticeable than it would be near a busy road.”
Heavy construction traffic has also attracted attention.
”It has been one of the concerns raised by residents. That is why haulage routes and temporary traffic arrangements should be planned carefully to minimise disruption for local communities.”
What about impacts on water resources?
The impacts of data centres on waterways and groundwater are assessed on a case-by-case basis. The data centres planned and currently under construction in Mikkeli are not located within groundwater protection areas.
”The storage of fuels and other chemicals is strictly regulated, and such materials must be kept in properly protected areas. This is standard practice in construction projects,” Pasonen stresses.
However, development increases the amount of impermeable surfaces, resulting in greater volumes of stormwater and snowmelt run-off.
”Stormwater management must be carefully planned before construction begins. It is equally important to ensure that the planned measures are implemented and that their effectiveness is monitored.”
During construction, the most significant impacts generally relate to surface waters. Earthworks can increase sediment run-off and water turbidity, which is why appropriate water management measures are required on construction sites.
Water is also needed for cooling
Data centres use water in their cooling systems. In many cases, closed-loop water circulation systems are used, allowing the same water and cooling agents to circulate continuously within the equipment.
Although the water consumption of a single data centre is unlikely to create challenges for local water services, the overall picture may change if several large facilities are established within the same area.
”In the future, water consumption should also be considered from a cumulative perspective if more data centres are located in the region.”
Environmental impacts can be mitigated
Pasonen emphasises that minimising environmental impacts begins at the planning stage. Site selection, careful zoning, noise mitigation, stormwater management and energy solutions all influence the final outcome.
One future opportunity, according to Pasonen, is the wider use of ecological compensation schemes adopted by businesses.
”Impacts on nature can be mitigated through ecological compensation. It is an approach whose use could be further developed in the future, including here in Mikkeli.”
Data centres are an increasingly important part of a digital and AI-driven society, and their significance continues to grow. At the same time, the need to ensure that these investments are carried out in an environmentally sustainable manner is becoming ever more important.
”From an environmental standpoint, data centres are not fundamentally different from many other major industrial developments. The key is to identify impacts at an early stage and address them through careful planning,” Pasonen concludes.