Rising energy costs and warnings from the major suppliers that we could suffer future energy blackouts really emphasise the need to be aware of what energy we are using and where it is being wasted.
When it comes to performing an energy audit, you need to start with the basics. A lot of information can be gleaned in no time at all, simply by reviewing your electricity bill. From there you will have an understanding of what is being used and when, giving you a starting point.
There are several ways to measure and quantify your energy consumption and how much you could save over the course of time. In 2013, Instrotech ran a series of Energy Saving seminars in conjunction with Fluke and this article considers some of the key points that were addressed.
How to start an Energy Audit
The first thing you need to understand when carrying out an energy audit is how much are you currently spending, so get a copy of a recent electricity bill and review the charges.
For users on domestic tariffs, the cost per kWh doesn’t vary, you pay a fixed price for the units you use and there are no extra charges outside your tariff.
For users on commercial tariffs, there are various factors that can impact on your energy costs and penalties that can be applied for extra demand caused by poor power quality. Key areas to consider are:
- How much does your electricity cost?
- Are you being penalised?
- How much are you consuming?
Your bill will show you maximum demand and fixed demand charges, along with any additional penalties for demand that has exceeded the maximum allowed. Reviewing your bill is a great way to build a profile of your energy usage and you will often find that some savings can be made instantly, simply by making some changes to shift patterns, or when equipment is powered up or down.
What Factors Can Cause Increases in Energy Usage?
There are several factors that can impact on your energy usage and therefore increase your costs. Three of the main causes are as follows:
Peak Demand
If your peak demand goes above the level set by your supplier you will incur a penalty, because the supplier will have to either install new infrastructure, or limit other loads on the network.
Power Factor
Power factor represents the efficiency of a circuit. If a circuit is operating at 100% efficiency, then demand = power. With a circuit operating below 100% efficiency, the Power Factor is the difference. A power factor below .95 is inefficient and will often result in penalty charges from the utility.
Harmonics & Unbalance
Bad harmonics cause an increase in power needed, yet the power is unusable as it is not converted to actual work. Harmonics can also cause other issues such as current flowing in the neutral, a decrease in the life of motors & transformers and reduced transformer efficiency.
Negative harmonics rotate in the opposite direction and in addition to heating, they create a magnetic field that works against the normal rotation of motors, trying to move them in the opposite direction which reduces the efficiency and the life of the motor.
The third type of harmonic are triplens (multiples of three). Whereas positive and negative harmonics cancel each other out, triplens do not. The result is the current flowing to neutral continually adds up, increasing both the current and heat in the neutral, which can lead to more serious problems.
Monitoring Power Quality Issues & Energy Consumption
In order to find out what energy is being used and where, you need to conduct a load study, using the right meter for the job.
A basic load study, looking at power consumption over a period of time, is great to get a general idea of what is being used and if there are any phase imbalances that could be corrected. The Fluke 1730 energy logger is an ideal tool for carrying out this type of energy audit.
For those who want an in-depth analysis, including details of harmonics, or who want to question their electricity supplier about their bill, the Fluke 435-II is the best meter for the job. The Fluke 435-II is one of the most advanced analysers available and has a preset to measure power quality to the same standard that the energy suppliers use.
In addition, the Fluke 435-II can be programmed with your kWh costs, including the times when it switches from peak and off peak rates. This information is then combined with all the power quality issues detected to provide an annual cost for consumption. This allows you to clearly see the areas where you can make savings by implementing the right correction measures.
A thermal camera is a great tool for carrying out analysis of electrical systems and the actual building itself to determine where issues are and improvements can be made.
Faulty electrical components will typically generate excessive heat when under load, which shows up clearly on a thermal survey. Unbalanced phases can be quickly spotted too and a good quality thermal camera will give you a lot of useful data that can be combined with a load study to pin-point areas of concern and make the necessary cost saving improvements.
An audit of your building is also a good way to find areas for improvement. There are several areas that contribute to heat loss, such as missing, damaged or under-specified insulation, faulty window seals, air leaks and more.
Once you have collected your measurement data, you can then analyse the results and put forward recommendations for improving your systems and thus saving money. All Fluke meters are supplied with intuitive software for post analysis and report creation.
You may be pleasantly surprised in how easy it can be to make savings through making minor changes to your working practice. Other solutions may be required to improve system performance, however if ongoing annual savings outweigh the cost to implement corrective solutions, it becomes much easier to justify.
The Fluke 435-II analyser features an energy cost calculator. This is a patented technology that will tell you how much your power quality issues are costing you.
More Information
Throughout this article we have touched briefly on some of the areas that cause power issues and how to locate them. There is a host of information available on this subject as detailed below:
Free guides on Power Quality Measurement & Thermography
We have a number of application guides covering the use of thermal cameras for electrical and building inspections, as well as a power quality measurement DVD. Fill in our online form to request your free copy.
Application Notes
Click any of the links below to download Fluke application notes:
Basic Power Quality Methodology
Cutting Costs with Energy Auditing
Energy Saving Case Study in a Hospital
Most Common Wastes in an Electrical System
