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Data center industry can help achieving these goals by reducing their carbon footprint and increasing their carbon handprint. (see ICT Climate and Environment Strategy, in Finnish). Using carbon neutral energy and reusing the waste heat from data centers will reduce the footprint.

The carbon handprint refers to the future climate benefits of a product, process or service in terms of emissions reductions for users. This can be seen in the benefits of digitalization, such as the development of the data economy, the reduction of energy used for mobility and, in case of CSC, also in the outcome of the environmental and energy research computed with supercomputers and the impact of various IT services for education. The upcoming European Energy Efficiency Directive will reveal the individual performance of each data center and thus helping the comparison of data centers.

Major by-product, heat

Data center operation creates one major by-product, heat. For years this has only been seen as a waste, but in fact it has vast utilization potential. Let’s review how the LUMI project has been executed and how they estimate the project’s CO2 emissions in different phases of the project.

For any new data center project, one of the most crucial things in terms of future CO2 emissions is the location. The perfect location should have the following features: close to an unlimited supply of power (green power from renewable sources) at low cost, fast time to market, land or existing buildings to support current needs and not limit future scalability, options for excess heat utilization, ability to utilize free cooling all year round, short latency for the end customers and blistering connectivity options to list a few. LUMI landed in Kajaani, Finland after achieving 98/100 points in the assessment of pre-exascale sites. Clearly, the location had strong features since the national supercomputers of Finland had been there now over ten years.

LUMI is built on a former paper mill industry park in Kajaani. Photo: Mikael Kanerva, CSC.

LUMI is built on a former paper mill industry park that has transformed into a Renforsin Ranta business park for energy-intensive industries like data centers. Park supported the use of greenfield and brownfield concepts and for LUMI, the latter was chosen. Not only because it could save up to 1000 tonnes of building time CO2 emissions (see Schneider white paper 66) but because it enabled a faster time to market. Winter in the Nordics can be extremely harsh and limit the ability to start construction projects or at least make it so expensive that you’d run out of budget in no time. Therefore, choosing the utilization of brownfield buildings made sense from a sustainability and economic point of view. We are used to think that you couldn’t get both of these attributes at the same time but hopefully, at the end of reading this article, you will think differently.

Once the data center reaches the operational state the majority of the CO2 emissions are linked to the used power at the facility and how the power was generated. Nordics have vast resources for renewable power production, where a majority of the power is created by hydropower plants. Wind park developments are currently skyrocketing in the Nordics with such a magnitude that the national grids are having difficulties enabling the transformation from the wind parks. Both of these methods have low CO2 intensity and therefore great ways to reduce operational CO2 emissions. The distance between power production and usage makes a difference in terms of transfer losses, the closer the better.

Renewable energy

When looking at Kajaani, we are indulged with renewable energy since the vast majority of the energy in the Kainuu area is close by and from renewables. Data center energy efficiency has been metered with PUE value (power usage effectiveness), meaning the ratio needed for the IT hardware and the need for the whole center’s operations.

For years we could simplify that the closer to value one (1) the better the efficiency. But this can’t be implied anymore because when data centers start to reuse excess heat, e.g., in the case of LUMI to the district heating network of Kajaani. The PUE value will increase because the priming of the heat with heat pumps will consume energy. LUMI’s PUE value with excess heat utilization is 1.24 and without 1.04. This raises the question that why should you utilize excess heat if it increases your PUE. Other option for the data center operator is to provide heat without heat pumps and let the district heating operator prime the water at their end. In this latter option the energy consumption will not be calculated on data center PUE value.

Finnish Data Center Association has been heavily involved in the formulation of the new standard to measure data center energy reuse; the standard is called ERF (energy reuse factor). The standard indicates the percentual value of energy that is being utilized in data centers. With the new standard, you can compare different facilities and see how efficient they are when the excess heat utilization and power usage effectiveness are both taken into account.

Data centers in Finland are eligible for energy tax reduction when the excess heat is utilized. LUMI for example can offset annually ~12 400 tonnes of CO2 emissions and provide 20% of Kajaani’s annual district heat. While contributing back to the local community there is also a financial incentive for excess heat utilization, LUMI gets reimbursement for the delivered heat and this can reduce the electricity cost by up to 40%. It is a truly win-win situation for all the parties. The Community also gets concrete benefits out of data center activities in the area. Close partnership with Kajaani applied science university produces new talent for data center operations and ICT companies. Every new project increases the investments in to the area and strengthens local economy. DC’s are not seen as “takers” but as actual contributors of local wealth.

Green supercomputing

Supercomputers are listed twice a year listed on the TOP500 list for performance and greenest supercomputers. LUMI achieved third (3) place in both categories in the first list of 2022. The Green500 list compares the supercomputers’ energy efficiency with the metric (GFlops / watts), meaning that the more computing power you can have with the least amount of electricity the better. One could still argue that there could be more metrics to support the comparison. For example, the Climate Neutral Data Centre Pact’s metrics measure data center sustainability. There are five (5) main topics; Energy efficiency, use of clean energy, use of water, circular economy, and circular energy system (excess heat utilization).

By HPC data centers use-case, they’re not bound by latency as much as colocation and hyper-scale equivalents. Therefore we should emphasize more the conditions of sustainable and cost-efficient operations when choosing the new site for the next generation of supercomputers. The planned reporting duty of data center sustainability metrics will eventually highlight what are the metrics of each HPC site and how sustainably the operation can be executed. Hopefully, the successful operation of LUMI will act as a reference of Pan-European investment where the actual infrastructure is placed based on sustainability and operational costs than national desire. LUMI received 2023 Green Data Centre of the Year Award in Data Centre World Awards London


1)Schneider white paper 66: “Estimating a Data Center’s Electrical Carbon Footprint” by Dennis Bouley

Writer: Veli-Antti Leinonen, CSC