In a series of articles, also available on request as an eBook, Wattwatchers explores the challenges and opportunities building owners, managers and installers face with electricity metering and monitoring for building code compliance.
ARTICLE 1: Built Environment Compliance Series
‘Metering and monitoring is a central component of good facility management. It can help you manage energy use and costs, report on your energy performance, achieve regulatory compliance and operate your facility more effectively.’ – Fact Sheet: Electricity Metering and Monitoring. NSW Government
To set the scene, electricity metering plays a vital role in delivering on mandatory requirements in the National Construction Code (NCC) Section J8/9.
It’s also crucial for sustainability frameworks including Green Star compliance, that help achieve star ratings in new construction, and NABERS and GRESB that property owners participate in to enhance asset valuations.
Good-quality, readily-available electricity data can be a superpower in keeping building energy costs and carbon emissions down, while increasing property value and identifying issues that operations need to manage.
All of this can now be addressed with smart engineering, and by choosing the right technologies – including cost-effective metering that is ultra-compact, cable-free and cloud-connected.
First, let’s understand the problems that need to be overcome.
Today’s technologies offer new efficiencies compared with traditional metering
Traditional metering technologies are clunky to work with.
Typically, they are cabled using Modbus RTU, feeding into an IP network that connects to a Building Management System (BMS) or Energy Management System (EMS), or for the most part are not connected to any system at all.
Sounds a bit outdated, right?
If you’ve been hands-on with traditional electricity metering technologies you’ll know there’s a number of challenges and inconveniences you’ve just had to live with.
These inconveniences also result in lower utility for the end users, with system potential wasted because data is not used for actually managing building performance.
Let’s drill down.
Old-style setup and installation
Traditionally metering requires cabled communications, where this is supported, which then needs extensive ‘configuration’ and the commissioning of networks.
Drilling holes, running cable conduits, and getting cables to the correct break-out location takes time and materials. In some building types, this is the largest cost in deploying electricity metering.
In addition to the physical cable runs, there’s usually a few layers of communications networks that need to be configured as well: Modbus cables/routers, TCP/IP networks, and BMS/EMS connections.
For electrician installers, this often means getting out your laptop, configuring individual devices by connecting them to your computer with a cable, and working through tedious network settings for Modbus and TCP/IP.
Just getting everything talking is a huge effort! Even before the meter is commissioned and data is flowing!
Awkward to configure and validate
Traditional meters are configured through multi-layered menus on an LCD screen on the front of the meter and push-button, or by connecting them to a laptop, and configuring via an application.
Compared to contemporary technologies – with app-based configuration through wireless connections – the old-style approach seems outdated, and is far less convenient.
The settings that need to be configured are not always as simple as selecting a CT clamp size. You have to pull ‘k-factors’ from specifications of items to set up correctly.
Space and board size
Space in buildings comes at a premium, including for the electricals. More space in a building is more revenue for the owner.
Electrical infrastructure can be optimised if the right technology selections are made, helping to lower build-cost from the outset.
While other technologies have reduced the amount of space required, traditional electricity metering hasn’t really improved in spite of its obvious limitations and inconveniences.
Traditional systems tend to be bulky, requiring significant space allocation for metering. They also use antiquated distributed server architecture and onsite computers, all of which increases the space required when compared with newer, more nimble Internet of Things (IoT) technologies.
Old-style digital meters, with screens on the front and click-buttons to scroll through readouts, require surprisingly large amounts of space in electrical boards.
For new-built, the electrical boards need to be significantly larger to accommodate old-style metering, particularly if you’re shooting for higher than ‘building code compliance’, by putting in more metering to meet Green Star and NABERS requirements.
IoT technologies require significantly less space.
Incorrect Specification
In electricity metering for trade (i.e. billing of kWh in $), there is a Standard called NMI Pattern Approval (NMI stands for National Measurement Institute).
Frequently ‘NMI pattern-approved’ is made a requirement for building energy management, possibly because it is confused with accuracy, when it should not be required at all (because the pattern-approval requirement is only required for actually selling electricity, which usually is not the purpose of metering installed for building code compliance and sustainability performance).
The important thing for managing building energy and meeting NABERS and Green Star requirements is that measurements are accurate, with ‘Class 1’ accuracy of plus or minus one percent being the usual expectation with or without being ‘NMI pattern-approved.
To optimise a metering design and project cost for buildings, the best thing to do is differentiate between the private billing meters required for any on-selling of electricity, such as to tenants, and the monitoring required for energy management (i.e. building code, Green Star etc).
The next article in this series (Article 2) looks at the operational and data downside of traditional electricity metering in the built environment.
James Clements is Director Net Zero Property with Wattwatchers.
