Tetra Tech’s Kathryn Barker, air quality specialist, discusses the importance of planning ahead for a data centre emergency, and the role a robust air quality management plan (AQMP) will play.
With so many aspects of our economic, commercial and social lives now online, data centres have become one of the most important classes of infrastructure. With increasing concerns about power blackouts over the coming winter, our data centres must be designed and built for resilience, efficiency and security.
Environmental impact of backup generators
A backup power source for a data centre is essential. On-site emergency back-up power generation provides a short-term solution to cover the grid during brief fluctuations or prolonged outages.
Typically, backup generators will be fuelled by diesel stored on-site and need to be tested regularly throughout the year. And when they are, they emit potentially harmful pollutants into the air. The installation of a backup generator therefore triggers the need for an air quality impact assessment to accompany a planning application, or environmental permit.
The need for robust air quality management plans
Regulators require operators to prepare an air quality management plan (AQMP) outlining the response measures they will take during a grid failure. The response measures in the plan will need to be tailored to reflect the likely air quality impact for surrounding land users. The plan must also include details of the local conditions during a grid failure that might influence the response required. For example—weather conditions or time of day.
The assessment results provide valuable information to help estimate the weather conditions that are most likely to affect certain nearby land users. Pollutant concentrations at nearby locations are predicted using an atmospheric dispersion model for five years of hourly meteorological measurements (over 43,800 hours).
From that, operators can be advised of the likely wind direction that may lead to a potentially significant air quality effect for each of the nearby land users. This can be used within the AQMP to allow nearby land users to take appropriate action which might include:
- Move and/or stay indoors
- Close windows and doors
- Reduce physical exertions as far as practicable
- For a prolonged emergency, relocate
Routine testing and maintenance
As trusted data centre advisors, we undertake air quality assessments to accompany a planning application or an environmental permit application at the beginning of a project. These assessments consider the impacts of the potentially harmful pollutants emitted into the air when the backup generators are tested and maintained regularly throughout the year.
The air quality impacts are relatively straightforward to predict in this situation, as we generally know the frequency and duration of testing.
How to assess in an emergency
The short-term impacts are usually much greater during an emergency as all the generators may need to be deployed simultaneously, with testing and maintenance carried out on only one generator at a time.
However, assessing the air quality when the generators are used in an emergency is more difficult, as it’s unknown when this might happen, or for how long backup power will be needed.
What can be done is assessing the probability of a significant effect by predicting pollutant concentrations at nearby locations for a wide range of weather conditions. That gives a good indication of the types of weather conditions that could affect land users surrounding any particular data centre. This will allow the operator to take focused action to warn the community at the most critical times.
How we can help
Early consideration of the likely air quality impacts allows appropriate mitigation to be built into the design of a data centre. This can be a key factor in a successful planning application or an environmental permit.
If permission is granted, the predictions in the assessment, undertaken to accompany the application, can provide valuable information to assist in the development of an AQMP. Its content will be informed by the results of the air quality assessment.
Working in partnership, we can support you right from project inception; from clarifying regulations, defining targets and steering you through the planning process, to identifying and mitigating environmental impacts such as air quality, addressing biodiversity net gain, through to cost effective and pragmatic advice for design and operation.
About the author
Kathryn Barker
Kathryn Barker is an air quality consultant specialising in air quality, odour, and dust assessments.
She has over 10 years experience supporting planning and permitting applications across a range of sectors including residential, commercial, renewable energy, waste facilities, data centres, industrial installations, power generation, short-term operating and carbon capture facilities. She has prepared assessments to support EIA and DCO developments and undertaken monitoring of dust, air quality and odour.
She has an MSc is Environmental Pollution Control from the University of Southampton and a BSc (Hons) in Environmental Science from the University of Leeds. She is a member of the Institute of Air Quality Management and the Institution of Environmental Sciences.