A lot of hot air?

19-03-2012 - John Hatcher

It goes without saying that the cost and reliability of power supplies sits alongside data connections as the number one priority for data centre developers and operators. Reducing the carbon footprint (and associated cost) probably comes in at number two. Those who can successfully apply innovative solutions to improve reliability, reduce cost and reduce carbon will obtain a competitive edge over their peers. However, at present, there is little appreciation in the industry of just how much combined heat and power ('CHP') technology can contribute.

To help bridge the gap in understanding, law firm Nabarro LLP co-hosted a seminar with the Combined Heat & Power Association ('CHPA') to bring the data centre and CHP industries together. In this article, John Staheli, of Nabarro's dedicated data centres group, reviews some of the highlights of the meeting.

Craig Dennett of the CHPA kicked off the morning's proceedings with an overview of the technology and economics of CHP.  Craig explained that the CHPA represents the developers, operators and installers of combined heat and power plant, tri-generation and district heating systems. Of particular relevance, tri generation technology enables power to be generated and heat to be converted into cooling, making it a real contender for improving data centre performance. District heat and cooling systems even provide opportunities for waste heat from data centres to be exported and monetised, generating an additional revenue stream.

Christopher Stanwell, a planning partner at Nabarro, then explained how the UK's town and country planning regime has evolved to include green planning conditions as standard. These obligations apply equally to developers of new data centres as they do to developers of other commercial buildings or housing. CHP is often seen as the means of discharging green planning requirements at the lowest capital outlay. Christopher observed that developers are no longer so resistant to such conditions because they provide opportunities to differentiate projects, provide security of supply and create additional income. The benefits of CHP plant include making a significant contribution towards meeting on-site power and heat/cooling requirements together with the potential to provide heating (and possibly cooling) to surrounding buildings. When fuelled with biomass or biogas, CHP can not only reduce carbon but is also considered 'renewable'. The energy efficiency of CHP, as compared with other renewable technologies, helps local planning departments meet policy objectives and offers significant opportunities for local authorities to meet their own heating and cooling requirements. Christopher illustrated his point with the Leeds low carbon energy centre, which includes both a biomass boiler and CHP system in a single building in the centre of Leeds.

All speakers acknowledged, however, that there is no one-size-fits-all solution. Barry Knight, speaking on behalf of the Carbon Trust, noted that CHP plant, although highly efficient, is also bulky and heavy. You need to have the space to install CHP and that is not always easy given the constraints of many data centre locations. Given the demanding air quality requirements of the modern data centre in a city location, there may be tensions between the desire to reduce CO2 emissions to zero (through bio-fuels) versus the need for cheap, easily-sourced and particulate-free fuel (natural gas). Whilst liquid biomass might prove attractive in terms of sustainability credentials, Barry emphasised that such plant requires rigorous maintenance and biogas presents another set of challenges.

But how does the data centre industry approach power and efficiency? Future-Tech has successfully applied CHP to a number of data centre projects achieving award-winning performance on energy efficiency and market-leading operating cost reductions. James Wilman talked through some real life examples, explaining how Future-Tech has achieved Power Usage Effectiveness ratings ('PUEs') as low as 1.16. Tri-generation plants can achieve a cooling co-efficient of performance ('COP') of 0.7, which means that a one mega watt IT load data centre, powered by CHP, can work within design optimum parameters and with compressor-free cooling all year round. The result is substantially reduced operating costs and a much lower carbon footprint.

After the formal presentations, questions from the audience demonstrated a real hunger for further information about the benefits of CHP to the data centre industry and a clear need for closer co-operation between the two sectors. If you would like copies of the presentations referred to in this article, please contact either Craig Dennett of the Combined Heat & Power Association or John Staheli of Nabarro.