The old adage “if you can’t measure it you can’t manage it” remains as true as it always has been. Rising energy and water prices; increasing environmental pressures; and a conscious decision by many organisations to demonstrate corporate social responsibility are all driving greater attention to improving the efficiency with which we use utility services.
At the heart of this drive is the need for modern metering methods to ensure we have information in a form that can be easily acted upon. Advanced metering in process control and energy management, as part of monitoring and targeting, holds the key to reduced costs and a lower environmental footprint.
Advanced metering is a combination of a technology and management process to read meters on a frequent (e.g. halfhourly) basis, by fixed line or wireless means, and automatically transmit information to be monitored and analysed. It is commercially available, but prior to the Carbon Trust’s trial of advanced metering for energy savings it had not been widely used in the UK, despite appearing to be cost-effective.
Desk studies and commercial cases have proved that in the small and medium enterprise (SME) commercial and industrial sectors, advanced metering – used as a demand management tool – reduces energy consumption (and costs) by between 10% and 15%. (It also provides a check on the billing meter, which can be very useful indeed if you are in a part of the world with less reliable billing systems.) In addition, the better data available from advanced metering helps underpin effective energy and carbon management. Frequent metering of energy consumption within companies is intrinsic to achieving energy management and carbon reductions on an ongoing basis. This is, of course, the primary interest of the Carbon Trust – hence the decision to run its current project to promote the wider take-up of advanced metering systems in SMEs.
Finally, it is possible that advanced metering can help electricity companies reduce the amount of generation required to guarantee meeting a given electricity demand. This is because it may be possible to reduce the amount of ‘spinning reserve’ required at peak demand. By knowingenergy consumption profiles and the opportunities to reduce demand, energy suppliers may choose to use demand side management as a tool to reduce trading uncertainty and avoid paying premium prices for peak power from the generators.
However, in spite of these opportunities the UK market has been slow to take up the technology because of a number of barriers.
• Market research identified low awareness and demand among likely end users, who generally did not appreciate the benefits and potential in their operations.
• Limited supply push. Whereas energy suppliers are ideally positioned to drive a rapid take-up of the technology, they had not identified advanced metering as a priority and consequently were not promoting it. Their decisions were complicated by the availability of low risk revenue through the regulatory asset value mechanism and worries about possible stranded costs. Meanwhile, the suppliers of advanced metering systems tend to be small players who do not have the capacity to greatly impact the market.
• Regulation that is unclear makes it difficult and expensive for energy users and their agents to access data on their own consumption from billing meters.
The case for running the advanced metering project rested on its ability to deliver:
• A step reduction in energy consumption by end users.
• A critical tool to allow ongoing improvement in energy and carbon management.
• Eventually, the reduction of spinning reserve through better supply-demand forecasting and balancing.
OBJECTIVES OF THE METERING PROJECT
The aim of the project is to show how good quality, usable data can be acquired to manage utility services in business. In so doing, we also seek to help stakeholders effect change through removal of barriers to market diffusion of advanced metering, and thereby enable market growth and carbon savings. The primary objectives are:
1. To stimulate market demand and help to make advanced metering in process control and energy management widespread and common practice.
2. To identify regulatory impediments and work with stakeholders to remove them and thereby create a level playing field for service delivery.
3. To help service providers demonstrate their products and penetrate the market.
The project programme began in January 2004 and is due to finish in June 2006. An Official Journal of the European Union (OJEU) tendering process was required, leading to contracts with seven supply consortia. These contracts include the recruitment of 575 SME or SME-like sites and the installation of advanced metering there.
The consortia collect the half-hourly data from each site remotely and aggregate it before uploading to a web-based database that is common to all consortia. The consortia then analyse the usage profiles for opportunities to make energy savings, and report results to the site and the Carbon Trust.
A CASE STUDY – TIVERTON HIGH SCHOOL
Tiverton High School is located on the outskirts of Tiverton, Devon. It is a mixed, 11 to 18 comprehensive school with 1,000 students. “This system is all part of our approach to our environmental principles and part of our belief that we should practise what we teach,” says Acting Head Teacher Mr Kaye. “This case study examines the benefits to the school of measuring its gas, electricity and water supplies with ½ hourly remotely read meters.
“Thanks to the enthusiasm of its Bursar, Steve Downe, the school already had the lowest electricity use per pupil in the county. It has built on that by achieving substantial reductions in gas and water usage. The school has:
• Saved approximately £24,000 p.a.
• Improved heating efficiency.
• Identified and isolated a water leak from an underground pipe serving three outbuildings that were no longer used.
• Identified a heating control fault that may be occurring in other Devon County schools.
• Reduced electrical power consumption.
“Like most secondary schools, Tiverton School only had access to 30 minute data for its electricity consumption, and then only up to a month after the event. There was no way to obtain detailed profile data for gas and water, or information about the outside air temperature and other factors that were driving variations in energy consumption.”
A meter reading system was installed in February 2004, during school hours, with no disruption to normal activities. The system reports through a software package on Steve Downe’s PC, and can also be dialled up remotely.
School hours are 9am to 4pm, with additional evening and weekend use of certain rooms. Cleaners and maintenance staff are in the building from 8am to 7pm. The school is closed for 13 weeks of the year.
ENERGY SAVINGS IDENTIFICATION
“The system immediately showed a baseline water consumption of 900 litres per hour. This warranted a more thorough investigation, and the leak was traced to an underground pipe serving three prefabricated classrooms. Only one of the three was still in use, and that one had no need for running water. The annual water cost saving was £20,000, with annual carbon savings of 3,469 kg.
The electricity profile shows a good ‘aspect ratio’ with low overnight usage.
The gas profile shows the effect of turning off and restarting the optimising heating controller.
The water profile from the first week that the system operated shows a high base load.
“With the start of the new heating season in September 2004, we discovered that the control system was starting the main boilers at midnight or earlier, to warm the school up for the following day. The fault was found to be on an ‘optimum start-stop’ controller”. The controller was turned off and restarted, and the heating ran for six hours less per day –but within a few days the fault recurred.
To investigate the fault further, the school purchased another radio transmitter with an embedded temperature sensor. Mr Downe then placed it overnight at various locations around the school, to record how long it actually took to reach a comfortable temperature. This showed that the heating did not need to start any earlier than 6am, even in the depths of winter. Heating has therefore been put on a fixed time schedule, pending a permanent fix for the optimum start-stop fault.
The water graph shows the effect of isolating the leak during the 2004 Easter break. There is now no water consumption ouside operating hours.
The gas graph shows the immediate effect of shutting down and restarting the heating controller. The operating time is reduced by six hours p/d.
THE FINANCIAL CASE
Annual water cost saving was 7,884 cubic metres, saving £20,000 and 3,469 kg CO2 per annum. Annual gas saving was 216,000kWh, worth £3,456 and 41,000 kg of CO2 annually. The total cost of the original meter reading system was £5,075, and the additional transmitter cost £180. The system has paid for itself in three months on water savings alone.
Once a site has acted upon the energy saving suggestions, the consortium reports the savings achieved and any further potential to make savings. Towards the end of the project, each consortium will produce case studies on its sites. This process is audited independently to understand the effectiveness of advanced metering.
All the sites have now been recruited and data is being received from over 400. The first reports proving that energy savings have been made are now available, and on average they show savings per site are approximately £2,500 p.a. –about 10% cost saving, as well as 14 tonnes of carbon dioxide. Savings of electricity, gas and water have been identified, and the first case study has just been published. Once the advanced metering trial is complete, the case studies and recommendations in the final report will be used to promote advanced metering by other Carbon Trust programmes specifically to encourage:
• Carbon emissions reductions
• Cost savings
• Benchmarking data to identify areas for further action.