Metering to make energy management work
Meters are an essential tool in the drive towards reducing energy consumption and CO2 emissions and make buildings greener. Mark Rimell of Carlo Gavazzi explains how to develop an effective metering strategy to benchmark energy use and pinpoint waste.
Many businesses and homeowners have once again had to experience the misery of severe flooding as the UK was battered by heavy downpours and gales this winter. Do we blame it on climate change or the effects of El Niño? The jury’s out, but developed countries around the world are committed to achieving massive cuts in their emissions of greenhouse gases such as carbon dioxide (CO2) in an effort to slow global warming.
Here in the UK, we are already a long way down that road. The UK Government has committed to legally binding targets to reduce carbon emissions by a staggering 80% by 2050, with an interim target of 34% by 2020.
While low-energy new builds grab all the headlines, that revolution in energy use will only be achieved if we can significantly reduce energy consumption in our existing building stock. According to the Building Research Establishment, 60% of the buildings that will be standing in 2050 are already built. Carbon emissions from the UK’s non-domestic buildings are responsible for 18% of the UK’s total.
Part L of the Building Regulations is the central legislative plank used to bring about change. This is backed by measures such as the Carbon Reduction Commitment Energy Efficiency Scheme (CRC) for large energy users, fiscal penalties such as the Climate Change Levy and the use of Display Energy Certificates (DECs) where poor energy performance can damage the reputation of building owners.
2015 also saw the introduction of the Energy Savings Opportunity Scheme (ESOS), a new piece of EU legislation which requires member states to introduce a mandatory programme of energy audits for ‘large enterprises’. This means over 9000 of Britain’s biggest companies will be required to comply; the initial audits were due to be undertaken by 5 December 2015.
It’s not all stick, of course. Carrots include incentives such as Enhanced Capital Allowances, Feed-in Tariffs and the Renewable Heat Incentive. Another carrot is reduced operational costs through improved energy consumption via monitoring and targeting. A green image with the public doesn’t do any harm to reputations either.
In the search for energy savings within a commercial building, identification of wasted energy is the single largest way to reduce operating costs, cut CO2 emissions and deliver greener buildings.
Data gathered from an effective monitoring system can transform the way a building is run. It is estimated that up to 70% of a building’s total CO2 emissions are associated with heating, cooling, ventilation and hot water systems. Re-commissioning and optimisation of a BMS system to reflect a building’s current and actual usage can reduce a building’s CO2 emissions by up to 20%. Metering data will provide visibility of excessive consumption and identify opportunities for savings through simple BMS strategy adjustments that doesn’t involve large capital expenditure.
Regulatory requirements have provided a structure for metering systems that should encourage consistency of design and, therefore, provide meaningful data in our drive for monitoring, targeting, benchmarking and energy reduction. Part L applies to both new (L2A) and existing (L2B) buildings. The Regulations call for metering systems to enable the following.
• At least 90% of the estimated annual energy consumption of each fuel to be assigned to end-use categories as detailed in CIBSE’s TM39 guidance on building energy metering.
• The output of any renewable system to be separately monitored.
• Automatic meter reading and data collection facilities in buildings with a floor area greater than 1000 m².
TM39 advises that in new buildings specifiers should consider the metering requirements early on in the design process — while the supply and distribution network is being planned out. This saves time, effort and money later on.
The first step is to consider all energy that is imported or exported — including main incoming supplies and renewables.
The second step is to identify all sub-main circuits requiring meters: i.e. for end users, tenants and various activity areas.
The third step is to provide metering that enables consumption loads to be identified in all key categories, such as heating, hot water, lighting, small power, ventilation, pumps etc.
Metering strategies for existing buildings can be particularly challenging, as boards and risers designed years ago may not lend themselves to current metering requirements. In such circumstances metering should provide sufficient ‘evidence’ to pinpoint avoidable wastage without requiring expensive and time-consuming detective work.
Specifiers need to be aware of the EU Measuring Instruments Directive (MID) for any meter to be used in conjunction with the re-sale of electricity. This legislation became effective on 30 October 2006, with a 10-year transition period, and replaces Ofgem’s Schedule 7 of the Electricity Act 1989. Any new meter to be used directly for billing must be MID approved after October 2016.
Metering in itself however, does not save energy. It is action taken as a result of installing meters and using the information that can achieve quantifiable energy savings. Metering should be designed to facilitate performance benchmarking as detailed in CIBSE’s TM46 and Guide F. To do that, data needs to be exported to a user-friendly interface where graphical displays are engaging, educational and meaningful.
If this is done correctly, the data can be interrogated by the user — be it a building owner, occupier or facilities manager — to identify baseline consumption and benchmark against similar building types, to identify BMS strategy errors, plant operation conflicts, automate CRC reporting and, importantly, assess return on investment of renewable technology introduced or CAPEX projects such as plant replacement and lighting upgrades. It is imperative that users act on the data and develop a system of continuous improvement.
In summary, metering can provide so much more than a tick in the box to meet with legislation if designed, installed and commissioned effectively. Metering provides a powerful management tool that will reduce operating costs and CO2 emissions to deliver greener buildings. After all, if you can’t monitor it, you can’t manage it.
Mark Rimell is regional sales manager with Carlo Gavazzi.
