The public sector is leading the UK’s response to net zero. At the last count, 63 local authorities have committed to achieve net zero council emissions by 2030, and wider community emissions by 2045.
NHS Trusts are also working at a pace to help meet the NHS goal of net zero by 2040.
The most successful carbon reduction strategies start with a clear understanding of when and where energy is being used, and to achieve this level of insight, we’re helping many of our public sector clients to implement sub-metering across their estates.
Sub-meters are separately installed meters downstream of the main meters that measure the individual consumption of plant and equipment, on a half-hourly basis. They give a more detailed picture of what makes up the total consumption figure on your energy or water bill.
They can either be location based, for example used to measure the energy and water use of each floor or occupier. Or they can measure the consumption of separate assets, such as lighting, heating and cooling. This gives energy managers much greater detail on their consumption – how, where and when energy is being used – and highlights potential areas of waste.
Sub-metering: where to start
The first step to a successful sub-metering strategy is to undertake an audit of the site, to document where sub-meters would be most useful. An audit should identify where sub-meters are already installed, whether they are working correctly, and whether the infrastructure is in place to read and collect the data. This helps to avoid common pitfalls: many estates managers are surprised to learn of legacy sub-meters you didn’t know existed.
Once everything is documented, we can carry out a sub-metering trial – where we install sub meters and then monitor the consumption. We use the data to make recommendations on where savings could be made.
For example, in the case of a hospital: could the use of certain energy-intensive equipment such as MRI scanners, be restricted to off peak times (when energy costs are cheaper)? In the case of council buildings: are lights and air conditioning being left on overnight when the building is shut? Could timers be installed on equipment to ensure they are switched off out of hours? We often find there is tremendous scope for savings – and the process can very quicky pay for itself.
Once we know what the typical sources of energy waste are, we can go further by producing an energy saving checklist for staff – that lists the things to switch off at the end of the day: lighting, heating etc. It’s a simple exercise, but one that reaps huge savings.
Engaging staff in energy reduction
One of the key benefits of sub metering is that it can be used to empower staff to get involved in carbon and energy reduction.
In the case of some hospitals that we’re working in, we see great results when separate sub meters are installed for each ward, and each ward is then appointed a “green champion”. We put a dashboard in place that shows staff where and when energy is being used, and crucially, what impact their energy saving efforts are having. This visibility over energy use – and the positive results achieved – is a very powerful motivation tool.
Long-term savings
It would be easy to assume that sub-metering strategies only yield big ticket savings in the short term, once the major sources of energy waste have been identified and fixed. But the biggest savings occur when sub-meter data is interrogated on a continual basis. We can monitor day-to-day activity remotely, looking for anomalies. Our Energy Alarms use half-hourly data and highlight anything that appears unusual in real time. A team of experienced data analysts can then work out what is going on and suggest changes.
This process of monitoring, analysing, giving feedback and continually improving is how we can save public sector clients millions of pounds every year.
Sub-metering has the potential to be a powerful tool within an organisation’s net zero strategy. But, data is no use unless it’s interrogated and used as a springboard for action. BiU can help you establish a robust sub-metering strategy and harness your data to drive real cost and carbon savings in your organisation. If you’d like advice, contact hello@biu.com.