Analysing the feasibility and impact of data center heat sharing

In the last year or so, there's been a lot of talk about data centers sharing their heat and promoting the circular economy. The practice is widespread in Sweden, Denmark, Lithuania and Estonia and Germany was even exploring making it compulsory for operators to reuse waste heat with a new efficiency law. However, a recent report by the IEA also argued that the decarbonisation potential of district heating is largely untapped. But, just how feasible is this kind of heat sharing, and is it just another form of greenwashing, as some critics have argued?

While in Europe, stories of data center heat sharing are increasingly common, some say that it's unlikely to be repeated in places such as North America, where heat repurposing is difficult to achieve, especially for homes. The proximity of homes to data centers, or lack of proximity, is a particular barrier, and additionally, the heat data centers produce is not always particularly useful. Often, the heat is not as hot as most district heating networks require, making it low-quality and in need of heat pumps, which, in turn, also have high electricity costs to run. Furthermore, it's expensive to capture and transfer. This means that often, it is only a viable option, if subsidies are available. This was partly the reason why the German heat reuse bill was withdrawn - the cost of the required infrastructure was simply too high. That said, liquid-cooling systems are increasingly being looked toward as a way to make heat reuse more feasible.

Another criticism of data center heat sharing is that this contribution doesn't outweigh the potentially damaging impact of facilities on the environment. For example, AWS's Tallaght scheme, which provides waste heat to power south Dublin County Council offices, Tallaght library, part of the TU Dublin campus, and 133 apartments, has received some criticism. Some experts have argued that data centers shouldn't have such a central role in the development of district heating systems, and, further, that this contribution of waste heat is "minimal" compared with energy usage.

However, that's not to say that data center heat sharing is completely unfeasible or not impactful, some argue that with rising energy costs, it could help bolster food security by providing heat to farmers. This has already been demonstrated in Green Mountain's partnership with a trout farm and EcoDataCenter's waste heat projects. Other applications include Deep Green's U.K. swimming pool heating solution, which is helping leisure centers stay afloat by supplying free heat to pools.