What Role Does nLighten Play in Data Centre Sustainability?

One of the biggest questions in the data centre industry, as AI demand soars, regulations rise and customer expectations increase, is how can data centres become more sustainable?

One company looking to answer that question is nLighten, one of Europe’s leading data centre operators, which has developed the first Integrated Carbon-Free Energy (ICFEn) scores for its facilities across the UK, Germany and Spain.

Breakthroughs in sustainable data centres

The announcement marks a unique milestone in data centre sustainability measurement as the innovative scoring goes a step beyond regular industry standards, since it captures hourly carbon-free energy matching and heat recovery, all while contributing to grid stability. 

Traditional measurement methods are dependent on annual averages or focused closely on electricity consumption. The ICFEn provides real-time insights that look at how data centres are contributing to decarbonisation through energy reuse and sector coupling.

The ICFEn was created alongside the Fondazione Eni Enrico Mattei (FEEM), with the ICFEn framework highlighting a key shift in how data centres report their environmental impact. 

Chad McCarthy, Chief Technology Officer at nLighten says: “Traditional sustainability metrics have focused on the data centres’ electrical energy profile, but ICFEn integrates the data center into a community energy system accounting both for consumption and contribution. 

“By accounting for heat recovery and real-time renewable energy matching, we’re providing our customers and stakeholders with unprecedented transparency about our actual environmental impact, hour by hour, not just year-end averages.”

How does it work?

The score system uses the 24/7 Carbon-Free Energy concept and builds on it by incorporating three crucial components: hourly-matched renewable electricity mix, heat recovery systems and grid stabilisation contributions. 

It is a comprehensive approach which helps capture the environmental picture of data centre operations in its entirety. The ICFEn aligns with the EU Energy Efficiency Directive and sustainability foundations, which include the Greenhouse Gas (GHG) Protocol and Science Based Targets initiative.

Current results

Results from nLighten’s data centres in the UK, Germany and Spain show strong ICFEn scores through progressive procurement practices in clean energy and heat recovery solutions. 

From April to June 2025 the company’s UK data centres achieved an ICFEn score of 94.61%, significantly outperforming the regional CFE grid average of 56.47%.

nLighten achieves hourly renewable energy matching by placing renewable energy assets within its portfolio and, in real-time, actively assigns different profile productions to data centre operations.

“We’re not just measuring renewable energy consumed, it’s more providing for a quantification of environmental improvement through sustainable projects, for which we transparently share the calculation method,” says Francesco Marasco, VP Energy Operations and Sustainability at nLighten. 

“The ICFEn methodology allows us to demonstrate measurable, system-wide benefits that lower community emissions. We’re actively encouraging other operators to adopt this framework, because raising awareness of data centres benefits everyone.”

Centres are therefore powered by clean energy when it’s actually being used, keeping true even in regions with less favourable grid mixes.

Creating a more sustainable sector

nLighten is looking to drive a sector-wide change with its development, so have published the ICFEn methodology under a Creative Commons license. Operators can therefore use the methodology, free of charge.

The company is planning to roll out ICFEn reporting across its European sites alongside an independent party reviewing the project's hourly energy and heat recovery data to ensure third-party validation.