Noise assessment for planned Keswick data centre flags 72 rooftop chillers

"Very high" and "in line with existing background levels" can both be true, because they describe two versions of the same building. The first comes from the noise assessment, which found the site has the "potential to generate very high levels of noise to the surrounding area" and would need extensive mitigation ^[2]. The second is the developer's description of the finished design, measured at surrounding sensitive locations ^[12]. The gap between the two is the mitigation scheme. The BBC's account does not include decibel figures or the background readings that comparison depends on.

Most of the noise would come from the 72 chiller units on the roof ^[3]. The company's water case rests on cooling too. It says air cooling means no water is required for cooling, with water used only for staff facilities and none taken from nearby rivers or marshes ^[4]. Chillers are cooling plant. The design choice that answers the water objection is therefore the same equipment the assessment names as the main noise source ^[13]. Work to quieten the chillers is work on the system the company cites to show the site needs no cooling water.

The company is just as firm on wildlife. "Our environmental assessments conclude the data centre will not harm nearby designated wildlife sites," a spokesperson said ^[5].

Whether noise decides the application is a separate question. So far the record points to scale. Daniel Elmer, who leads South Norfolk Council for the Conservatives and represents Keswick on the county council, has said he will lodge a formal objection ^[7]. "My personal view, is that it is just too damned big for the site it would be on," he told the Local Democracy Reporting Service ^[8]. "It is right next to the marshes and the southern edge of Norwich, while it is near a listed church," he said ^[9]. According to the BBC, the petition's signatories are worried mainly about the neighbouring wildlife sites. Water use, noise and the effect of the building's scale on the landscape are also cited ^[6].

I think the technical argument will concentrate on noise. It is the one topic where the developer's own submission concedes a large effect before mitigation ^[2]. The objection from the council's leader concerns the size of the building on that site ^[8].

The developer's case also includes up to 150 permanent jobs and planting and landscaping to screen the building ^[10]. The site is close to an electrical substation for North Sea offshore wind farms, from which the centre could draw power ^[11].