Author: David McAuley, R&D programme manager, Sustainable Energy Authority of Ireland Ireland currently houses 135MW of data centres. This accounts for about 3% of national electricity demand and is growing rapidly. The ICT industry worldwide is no stranger to the connection between energy and sustainability, and actively seeks to include renewable supply and efficiency in its portfolio of solutions. So, how can Ireland leverage its proven advantages in these areas to become the leading centre for sustainable ICT? [login type="readmore"] ENERGY NEEDS ICT It is evident that ICT has a lot to offer the energy industry in terms of solutions. In buildings, for example, we have for many years used building management systems (BMS) in commercial properties, but the new challenge is to integrate the BMS into everyday devices, enhancing the possibilities for monitoring and control. In transport too, many applications are now available to assist with urban mobility, be it live timing for Dublin Bus or car sharing using social networks. The ‘smart grid’, by definition, leverages ICT to help make intelligent decisions concerning the optimisation of supply and demand. This is especially important in Ireland, where high penetration of wind on the electrical grid means that the system must have enhanced flexibility. Data communications is also important for emerging energy technologies, such as marine energy. The SmartBay project, based in Galway Bay, demonstrates the collection of marine acoustic data that will be used to identify any affect of marine devices on the ecosystem. An expansion of this idea is the ‘smart city’, which encompasses energy, transport, water and ICT, as well as planning and forecasting for the optimum operation of municipal systems. Companies such as IBM and Intel are pioneering these ideas in Ireland. SUSTAINABLE DATA CENTRE The Sustainable Data Centre is a concept marrying renewable energy supply with efficient operation, sustainable buildings and reactive data-routing to achieve the minimum carbon impact. The carbon footprint of a data centre varies depending on the prevailing weather conditions, the electricity grid carbon content at that time, the data throughput and the amount of locally generated power. The ‘embedded carbon’ in the building and the IT devices is a static value, so can only be addressed at the design stage. LEED or BREEAM certification can be used to assess the sustainability credentials of buildings, and includes life-cycle assessments. When specifying energy-using equipment, refer to the Sustainable Energy Authority of Ireland’s (SEAI’s) Accelerated Capital Allowance list, which includes servers, power management and cooling equipment for data centres. For a logical approach to the design of industrial sites, see SEAI’s energy-efficient design methodology. This outlines a process whereby all disciplines have some responsibility for energy in the design, but an overall coordinator is assigned, ensuring that energy use is optimised in the final design. EFFICIENT DATA CENTRES At its most basic level, the core energy service of a data centre is to process data. Servers and devices draw electrical energy to do this. From an energy balance perspective, most of the energy is converted to heat, which must then be removed to prevent overheating of devices. Ancillary services such as uninterruptable power supplies (UPS), power conditioning and office operations also consume power. The term ‘power and cooling’ covers all these areas and is the subject of much research. A measure of power and cooling efficiency developed by the Green Grid is PuE (power-use effectiveness) and it is expressed as a ratio of IT equipment power to ancillary power. Values as low as 1.12 have already been reported for some large operators. Smaller operations face different challenges, so will find these values harder to achieve. The EU's data centre code of conduct provides a similar reporting structure. PuE is a useful metric, but it does not directly address energy use in the IT equipment itself. If, for example, a server became inefficient during operation, it could have the effect of improving the PuE, masking the problem. It is important to monitor the performance of all critical energy using equipment. Keep an eye out for new metrics too. For certified energy management, ISO 50,001 is a proven approach to continuous improvement of energy performance. Many of Ireland's biggest energy users have already been certified to this international standard, which takes energy beyond the boiler house to the boardroom. TECHNICAL SOLUTIONS While it is important to have efficient cooling equipment, it is more important to ensure this cooling is not being used in a wasteful manner. The principle of working outwards from the core energy service often yields the best possible results from an efficiency perspective. Taking this approach puts a priority on the software design. This is followed by server internal layout and temperature tolerances; then rack layout, airflow management, hot and cold aisles, room design and coolant distribution; and finally the cooling system. The power delivery and backup systems should also be addressed. IT equipment ultimately uses DC power, but many devices are designed to receive AC power, necessitating several conversion stages and wasting energy. It might appear that the re-use of the waste heat is the simplest solution, but this is not always feasible. How much heat is available and when? Is there an end user for this heat? Is it feasible to use a heat pump? With regard to operating temperature set points and ranges for server equipment, there is a trend towards widening the acceptable operating bands for ICT equipment, leading to a reduction in demand for cooling. The days of the chilled server room are gone. Ireland's low-temperature conditions currently offer the advantage of free cooling, and we already have a number of data centres operating completely using free-aircooling. Heat profiles and tolerances must also be considered. If you were designing the server yourself, then placing the more sensitive components closer to the cold side of the airflow makes more sense. With rising energy costs, it is clear that Irish-based ICT organisations have addressed the question of efficient data centres. Not all solutions will work in all situations, but some examples are listed below: • Energy-efficient design • Ongoing energy management • Virtualisation • Efficient servers • Temperature and RH setpoints • Hot and cold aisle segregation • Free air-cooling • Direct DC power • UPS forward stability monitoring • Liquid cooling RENEWABLE ENERGY SUPPLY Ireland has set an ambitious target for renewable electricity supply of 40% renewables by 2020. Already by 2011, some 18% of energy came from renewables, most notable wind. Because wind is a variable resource, on some days, over 50% of electrical demand is met by wind. This variability may offer new opportunities for sustainable data centres. Energy storage might be a solution, allowing data centres to generate or purchase low-carbon energy when it is available, storing it for use when needed. Data centres already do this when using UPS systems, so designing out traditional UPS systems with new forms of storage could make this approach economically viable. Storage may also take virtual forms, such as demand response. LAST WORD Comparing the sustainability of data centres is a complex task and the result will be transient. How will sustainable data centres stand out? How can discerning users be guaranteed their data and processes are housed in the most sustainable facilities available at that time, and are they willing to pay for such green credentials? A validated network of sustainably built and managed data centres, fed with renewable energy, would go a long way towards attracting this growing market.