You can only manage what you measure
One of the biggest challenges of any building energy efficiency program can be deciding where to start. This can be tough if you’re talking about one property, and particularly tricky for managers of large portfolios.
To set off on the right track, data can be your biggest friend. If analysed and presented correctly, it can be hugely powerful, both in terms of identifying where to begin on your energy efficiency quest, as well as providing the means to track and quantify performance improvements over time.
Buildings are our biggest energy consumers – research by the U.S Department of Energy, and results are similar in Australia, found that “buildings consume more energy than the transportation or industrial sectors, accounting for nearly 40% of total energy use.”
As always in discussions around building (in)efficiency, when it comes to costs we need to consider both the environmental and the financial
The environmental cost is pretty easy to work out. In Australia, each kilowatt-hour of electricity poured into an empty building generates around 0.9kg3 of greenhouse gas emissions. Of course, you might be subsidising your wasted electricity through some onsite renewables, such as solar, but remember that the majority of this out of hours consumption is going to occur at night when your PV can’t help.
The financial cost is trickier to calculate as it will depend on the tariff for each building. In order to explore the cost question a little further, and at the same time to illustrate the value in understanding your building’s energy profile, the graphic below illustrates how significant out of hours consumption can be to the financial bottom line.
It compares the average weekly energy consumption for three office buildings. The buildings are located within a few kilometres of each other in a major Australian city, are of very similar size, have very similar operating hours and perform the same function. In many ways they are typical examples of office buildings.
Despite the similarities in form and function, the amount of energy going into these buildings during out of hours periods varies hugely, with correspondingly significant implications in terms of operating costs. Even the ‘best’ performer here is spending over $100,000 a year powering an empty building!
What the graphic also shows is that, while bench marking can put the out of hours performance of each building in context, taking a seven day view of resource consumption is extremely useful in understanding when that energy is being used.
A bit of data digging will help identify the biggest contributors to your building’s out of hours energy use. Some questions to kick things off could be:
1. What’s our biggest out of hours opportunity?
Is our main energy user plug loads, lighting, HVAC or maybe the server room?
2. If plug loads (most likely), what are the biggest offenders?
3. Are there any devices that are left on but not used at night? Can we upgrade, use a power saving mode or simply turn them off?
4. Armed with this information, which building occupants and champions should we engage to see the biggest results?
5. What data will people need to be aware of and how can we provide it in an engaging way?
6. What other relevant information can we provide to educate and motivate people? Remember to always frame any data you’re sharing in a way that your staff can easily understand and relate to.
7. How else can we encourage behaviour change? e.g. an energy saving competition or a tie-in with an event such as Earth Hour or the Global Corporate Challenge.
All these suggestions are straightforward enough and, best of all, shouldn’t cost much if anything to implement.
For those aspiring to improve the energy efficiency of their buildings, getting to grips with out of hours consumption is an obvious, and often rewarding, place to start.
By focusing on one particular element of building performance, it helps bring direction and clarity to your efficiency program. All you need to get going is some decent quality interval data and the ability to analyse it in a way that helps you determine how much of your precious and increasingly expensive energy is going into empty buildings. The results will be startling and should provide all the incentive you need to start tracking down those savings.