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Deep dive into the building of the LUMI data center

The data center for LUMI at Renforsin Ranta business park in Kajaani, Finland, has undergone a complete transformation from an empty former paper mill hall to one of the world’s most ecological data centers, and will soon be ready to welcome LUMI. Despite the complexity of the process and the global pandemic, the data center has been completed on schedule.

Building the premises in a middle of a global pandemic has in many ways been a non-trivial process. The data center project started in June 2019 when the LUMI consortium was selected to host one of the EuroHPC’s flagship supercomputers. The physical building process at the data center began in February 2020 after the tendering rounds for a dozen of sub-projects were completed. Now in spring 2021, the data center is almost complete in its commissioning phase.

– We have built a world-class data center for a world-class supercomputer. On top of that, this data center is one of the world’s most ecological places for supercomputers: LUMI, run with 100% hydropower and with efficient waste heat management, among other benefits, gives it a zero or even a negative carbon footprint, says Jukka-Pekka Partanen, Director for Kajaani data center program at CSC.

Back in 2019, LUMI’s risk management list predicting potential issues that may hinder the process didn’t include one word: pandemic.

– Despite the tight schedule, a large project with a workforce of a dozen contractors plus CSC employees, and the pandemic, we are now in the final stages of the data center construction process. LUMI will be here in no time, Partanen continues.

lumi white space exterior glimpse

A glimpse of the LUMI white space. Jukka-Pekka Partanen, Director for Kajaani data center program at CSC, in front of the white space. Image: Juha Torvinen, CSC

Green, greener, LUMI data center

LUMI is built on world-class environmental sustainability and cost-efficiency. It helps the European ICT sector become greener and more cost-efficient, which is necessary to reach the EU’s ambitious climate targets and pave the way for the green transition.

LUMI will be furnished with liquid circulation cooling. The supercomputer’s waste heat will account for about 20 percent of the district heating in the city of Kajaani and will substantially reduce the entire city’s carbon footprint. Loiste Lämpö has been constructing the district heating connection for the project, and the company will also take care of the utilization of waste heat the computer produces.

The need for cooling is also reduced by the fact that the outdoor temperature and, as a result, the building’s thermal stress is much lower in Kajaani than what it would be in Southern Europe, for instance. The brownfield building solution also decreases LUMI’s carbon footprint.

LUMI’s energy consumption will be covered with power produced 100% with hydroelectricity supplied by Vattenfall.

– Reducing CO2 emissions is a globally critical target. In addition to its other Green Deal objectives, the EU aims to make European data centers climate neutral by 2030. At CSC’s data center, there is no need to wait that long as this objective has already been reached. In terms of sustainability, Kajaani is an ideal place for supercomputers. Additionally, the power grid at the data center is very reliable, and electricity costs are extremely low. The data center is also a crucial part of the high-speed Nordic backbone network, Partanen explains.

Not your average data center

The former paper mill hall has undergone a complete makeover in just over a year: the technical space, including, e.g., cabling, cooling systems, power distribution, and excess heat utilization system, is located under the white space where the HPE (Hewlett Packard Enterprise) Cray EX racks will be located. Moreover, there will be a center for visitors with a balcony for viewing the entire white space from above.

In addition to technical and structural transformations, attention has also been paid to the visual appearance of the data center. LUMI, meaning snow in Finnish, will get a unique shield for the white space resembling snowflakes or a snow blanket. The structure is made of perforated aluminum composite panels which will also be illuminated.

– Inspiration for the design came from the Finnish meaning of the word lumi and also from the northern latitude of the data center. The goal of the project was to create a functional shield for the supercomputer and to wow the visitors of the data center, explains Mikael Haasmaa, CEO of Synopsis Architects Ltd., the principal designer in the LUMI design project.

The aluminium structures were designed with the help of Geometria Architecture Ltd architects using 3D modelling and computational design to help the manufacturing of the complex design of the shield.

lumi white space sketch

Image of how the LUMI data center white space shield will look like. Copyright: Synopsis Architects Ltd. and Geometria Architecture Ltd.

In total, the building process of LUMI has employed around 100 people working in multiple companies.

Now the data center is ready to welcome the LUMI supercomputer to the premises to start its duty to as a world-leading scientific instrument for European scientists.

– We want to thank all involved parties in this data center project: contractors, the LUMI consortium and all employees involved in the project, not forgetting the great collaboration with EuroHPC JU. The data center is now complete; yet this is just the beginning for LUMI! Furthermore, we are looking forward to other research infrastructures to see the eco- and cost-efficiency of the Kajaani data center, and choose it as their future location – we would have space and power left for at least 20 installations of similar capacity, says Dr. Pekka Manninen, the director of LUMI Leadership Computing Facility.

See the making of videos from the LUMI data center:

Part 1:

Part 2:


LUMI will not be alone at Renforsin Ranta business park: CSC’s national supercomputers reside also in the business park, and additionally, there are approximately 40 companies representing various industries. The business park employs more people than the paper mill did at the end of its operations.

LUMI will be one of the world’s fastest computer systems, having theoretical computing power of more than 550 petaflops which means 550 quintillion calculations per second. LUMI will also be one of the world’s leading platforms for artificial intelligence.

LUMI itself will occupy 150m2 of space, thanks to HPE’s high-density hardware installations, which is about the size of a tennis court and it weighs around 150,000 kg.

LUMI is an investment of over 200 million euros, covering the whole lifecycle of the system.

The CSC Kajaani data center is highly scalable for large hardware installations and extensions or other potential infrastructure, making it ideal for building a sustainable data center ecosystem. The reliable and fast data communications networks of the data center are also designed for HPC. In addition, the area has a unique focus on data analytics thanks to the Kajaani University of Applied Sciences and numerous ICT companies.

lumi cabinets

Illustration of the HPE Cray EX cabinets. Copyright: Hewlett Packard Enterprise


Author: Anni Jakobsson, CSC – IT Center for Science, Finland