Statistically significant savings at ONS

11th February 2013


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A mixture of big projects and small changes has helped the office for national statistics cut its carbon footprint and operational costs. the environmentalist reports

The cabinet office ranked ONS – the office for national statistics – the “best sustainable performer” across the UK government in 2012. The accolade was the result of several years’ hard work by ONS to reduce the environmental impact of its sites in London, Newport and Titchfield in Hampshire.

Each year, the cabinet office requires central government departments to record the efficiency and environmental sustainability of their administrative offices. The performance data are measured against independent private sector benchmarks, and against government targets and standards.

In 2012, ONS, which collects and analyses economic and other national data, came out on top, noticeably ahead of other departments, making it a leader on sustainability issues across government.

“ONS is subject to a number of government-wide environment targets and milestones – which we have met, exceeded or are on track to reach,” explains Simon Ablitt, head of property projects. “For example, we exceeded the target to cut carbon emissions from government offices by 10% in 2010/11.”

The work it has done to cut CO2 emissions links directly to ONS’s efforts to reduce energy use. It has improved energy consumption by well over 20%, surpassing the government’s 2010 target of 15%.

Secret of success

The secret of ONS’s success is simple: a steady and serious commitment to reducing its environmental impact, initiating both large- and small-scale projects as part of its sustainability strategy.

Some of these initiatives, such as installing biomass boilers at the Newport site (see pictures right), have required significant financial investment and extensive retrofitting of office blocks built in the 1970s. Other projects, like gaining buy-in and encouraging innovation from staff on sustainability issues, have required only the resourcefulness and hard work of the environment team.

ONS has held an ISO 14001 certification for around a decade, so environment priorities are firmly embedded in its operations. Its established environment management system has provided the foundation on which it has built a range of initiatives to reduce its carbon footprint and promote energy savings.

Energy-saving measures

One of the first steps ONS took to improve the sustainability of its premises was to replace the draughty, single-skin windows at its Newport site in 2008/09. Swapping the 2,500 energy-leaking metal windows for new double-glazed ones, and installing cavity wall insulation at the same time was not a small job, and the work was staggered over four years to minimise disruption. The ONS estimates that this initial refurbishment alone has saved more than 75 tonnes of carbon a year.

Other far-reaching changes, attracting even bigger carbon savings, include the installation of automated meter reading (AMR) equipment and a new building management system (BMS). These two initiatives help ONS to closely match energy consumption to the requirements of a building and its occupants.

Before making these changes, Ablitt says that the old heating system was neither efficient nor operated efficiently by its staff. “The heating was left on far longer than necessary sometimes and the data we did collect only enabled us to analyse whole-site electricity and gas consumption, rather than recognise and address any local spikes or anomalies,” he says.

“With the new BMS and AMR we can understand patterns of consumption in detail and align consumption of electricity with occupancy and the use of individual buildings.”

ONS has also installed voltage optimisation equipment from powerPerfector at its Newport and Titchfield offices, saving an estimated 450 tonnes of carbon a year. powerPerfector’s transformers work to optimise the level of the power flowing in to the sites, by lowering voltage levels overall and evening out any spikes in power from the grid.

Duncan Rutter, sustainability manager at MITIE – which provides facilities management services to ONS – explains that levelling out the flow makes the energy usage more effective, by ensuring equipment does not receive more electricity than needed to operate on a day-to-day basis. It also protects expensive equipment against power surges.

In another initiative, ONS has invested around £170,000 in fitting solar thermal systems to heat water at the Newport and Titchfield sites. Reflecting the different needs of the two sites, 42 solar panels have been fitted to the roofs of the offices at Newport and just six at Titchfield.

The effectiveness of the solar thermal heating relies, of course, on the amount of sunlight and the summer of 2012 – the first summer after the panels were fitted – will not be remembered for its long, sunny days. Due to the poor weather, the systems were not as effective as they could have been, although they still contributed a small, but important amount of energy to heat water. Newport’s solar thermal system is designed to be self-sufficient and, in the summer months, the plan is to turn off the site’s biomass boilers and rely solely on solar energy.

Biomass power

Without doubt the largest investment that ONS has made in its sustainability drive and office refurbishment programme is in a pair of 1MW biomass boilers at Newport. These cost £900,000 to install.

Funding for the biomass project was secured because the site’s old gas boilers came to the end of their natural life in 2010. Replacing these with new gas boilers would have been around one-third cheaper than the renewable energy option, but the project was driven by ONS’s environmental agenda and the decision was made to go for the more expensive biomass boilers.

The old gas boilers were inefficient and had a considerable environmental impact. They would heat water to around 108°C, whereas the biomass boilers maintain temperatures at a much more sustainable 70°C–80°C. “The environmental benefit was the main driver, as there was no commercial payback from switching to biomass rather than staying with gas,” confirms Ablitt.

The advantage of using a sustainable energy source is easily quantifiable in carbon terms: the old gas heating system emitted around 700 tonnes of CO2 annually, while the biomass system produces less than 70 tonnes over 12-months.

The biomass project was a significant undertaking for ONS, with the installation taking about six months. There are often teething problems with such systems and the Newport project was no exception. During the Christmas office shutdown in 2010, a problem developed with the fuel-feed mechanism. Since the system is duel feed and can run on gas, ONS temporarily switched to gas while the fault was resolved. However, the gas safety interlocks did not operate properly, causing the system to overheat. The contractor repaired the fault and the biomass boilers have been running satisfactorily since.

The biomass system requires little manual intervention and is linked to the BMS at Newport for monitoring purposes. It uses 23 tonnes of wood pellets a month on average, rising to 60 tonnes in the winter. The pellets arrive in 14-tonne lorry loads from an Avonmouth supplier. Initially ONS used recycled wood pellets as the fuel source, but has since switched to sustainable virgin forest pellets, which, Ablitt says, burns with very little ash.

ONS was keen to replicate the success of its biomass boiler project at Newport at other sites. It investigated the possibility of introducing one at the Titchfield office, for example. However because of the site’s location, it could not receive wood pellet deliveries and so the project was not viable.

Water savings

Alongside tackling CO2 and improving energy efficiency, ONS has been working to cut its water consumption. Installation of sensor taps and other water-saving features have helped, but it is the rainwater harvesting initiative at Newport that really excites the environment team.

The £230,000 project was possible because the site sits on land with a high water table. ONS has been able to turn this natural habitat to its environmental advantage by setting up a rainwater harvesting system.

Rainfall and groundwater that infiltrate the surface water drainage system over the seven-hectare site are collected in a subterranean tank that sits behind the onsite multi-storey car park. Runoff from the car park passes through an oil interceptor before entering the tank, which can hold around 110 cubic metres (m3), and fills at a rate of 5–120m3 an hour, depending on the weather.

Instead of pumping all the water offsite to the local River Ebbw, a proportion is extracted, filtered and pumped back into the buildings to flush the toilets. The system uses around 25m3 a day and has saved 25,000m3 of mains water since it was installed in 2010.

As with the biomass boilers at Newport, ONS also investigated the potential for installing rainwater harvesting at Titchfield but, again, this was not possible as there was no suitable location for the water tanks.

Encrypted video-conferencing

Another successful ONS initiative has been the installation of encrypted video-conference facilities for its media function, which has dramatically reduced the need for staff to travel offsite to meetings. Although ONS already had a well-used video-conferencing system in place for the whole organisation, the introduction of an ultra-secure system now allows confidential material generated by the statistical service to be safely communicated.

The organisation gives many “locked-in” media briefings to journalists eager for its latest statistical releases where previously this would have involved extensive travel to London by the media team. With the installation of sophisticated, secure video and audio conferencing facilities, face-to-face briefings are now rarely necessary.

“As well as reducing the environmental impact of our travel, by holding remote briefings and meetings we save valuable work time and make significant financial savings,” says media relations officer Martin Nicholls. “The feedback from journalists has been very positive as there is still the opportunity for interaction with ONS statisticians through the high-definition video-link.”

Workforce commitment

Gaining commitment from managers and staff to follow environmental principles is high on ONS’s sustainability agenda. Ablitt says that buy-in from managers is now ingrained, due to the organisation operating within the government’s long-standing framework of corporate social responsibility targets.

ONS encourages wider employee engagement with environmental issues through a variety of methods, including education, training and one-off events, such as its support and activities around Britain’s annual climate week – this year running 4–10 March (

The environment team is also keen to encourage suggestions and project ideas from staff and, to this end, uses “Idea Street”, an innovation management platform for the public sector that was developed by the work and pensions department.

Idea Street is an online tool enabling frontline staff to post their ideas for change on a website, as well as vote and comment on other ideas. It encourages innovative thinking in a social media format and is hosted on a sustainable development intranet site at ONS. Staff can post ideas on the site and, if there is enough “buzz” around them, the suggestion will be considered by one of the environment team.

Shared services

ONS shares its Newport site with the intellectual property office (IPO), which helps inventors protect their creations, and is keen to share the fruits of its sustainability work with other central government departments. “We already share some services with IPO and our biomass system has the capacity to provide enough hot water for our neighbour too – we just have to work out how to connect two independent systems,” says Ablitt.

ONS also plans to extend its innovative rainwater harvesting system to the part of the Newport site that is occupied by IPO.

“Our top ranking by the cabinet office is a clear indication that the money we invest in environment and sustainable projects is money well spent,” says Ablitt. “If we can extend the benefits of these projects to other government departments, that creates even better value. ONS intends to build on this success by continuing to find innovative ways of improving its environmental performance.”


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