Posted by: Nigel Collins
You may have read my previous article, Mean and Lean Before You Go Green in which I described the three stage approach to energy management.
Assuming that you have your energy procurement under control (stage 1 – Mean), you should have access to billing data. From this and especially if you have access to half hourly data, you can gain a basic understanding of where energy is being used and possibly identify anomalies such as high out of hours usage. The aim of an energy audit is to understand in more detail how this energy is being used and look at ways of reducing consumption.
Depending on the size of the premises or organisation, when undertaking an energy audit, I recommend a 3-stage approach:
- Level 1: Opportunity – this includes a walk through survey with wide scope. The aim is to identify items for further investigation
- Level 2: Detail – at this stage, rough cost estimates can be arrived at and firm recommendations are made
- Level 3: Investment Grade – the scope will have been narrowed down to a specific project (or projects). Quotations for implementation with risk evaluation and a plan for measuring and verifying savings will be included in the subsequent energy audit report.
Breaking the audit down in this way reduces the risk of abortive work as you can gauge commitment at each stage.
A lot of the ground work is done at Level 1. The energy audit checklist I use has 109 items split into 15 headings. Access to billing and preferably half hourly data makes this more effective as you need to be able to benchmark current energy usage and expenditure. For ROIs to be established and post implementation savings to be proven from undertaking capital projects (e.g. LED lighting, voltage optimisation), being able to measure usage is essential. You cannot manage what you cannot measure. Ongoing monitoring can also flag up sudden changes due to for example, an equipment fault or a thermostat having been tampered with.
The other useful outcome from even a Level 1 audit can be that potential no cost or low cost savings can be identified. This could be as simple as switching of plant at night, fine tuning timer control settings or turning heating down or off in unoccupied areas.
Where there are multiple sites, an audit could be the first stage towards training and setting up energy champions as one of many similar sites can be used as a pilot.