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Getting real value from an energy audit

It is now widely accepted that the majority of industrial and commercial sector organisations can make significant and worthwhile savings in energy consumption by implementing energy efficient practices.

In addition, the facilities managers and engineers in these organisations are often aware of the techniques for making energy savings. The problem seems to be (i) how to convince senior management that savings with short paybacks can be made and (ii) how does an organisation implement energy saving.

The most common objection to considering an energy audit is that there is a perception that implementation is going to be costly. In the experience of Environmental Efficiency this is not so. First, the majority of recommendations - about two-thirds - will have a financial payback of less than 18 months (data from Environmental Efficiency's own energy audits). Secondly, there is good financial assistance by way of Grant Aid from Sustainable Energy Authority of Ireland (SEAI) and the Accelerated Capital Allowances Scheme (ACA). This SEAI scheme offers grant aid of between €20,000 and €500,000 for eligible projects.

Another common objection is the belief that an energy audit will not come up with a level of savings which would be sufficient to adequately justify the fee payable.

Environmental Efficiency has always given an undertaking that, if a minimum of 10% savings, based on impartial best practice, are not identified, then there is no charge. Where this is likely to be the case, Environmental Efficiency will be able to determine this early in the process.

The first step in achieving real energy savings is to understand how energy is presently being used in the organisation. Environmental Efficiency has carried out over 500 energy audits in Ireland and has good data on what energy costs should be for each sector and what constitutes best practice. This data is supplemented by third party data. Where energy consumption is higher than expected for the sector, the scale of possible energy savings can estimated. This review is normally carried out as part of an energy audit. Having an adverse energy benchmarking comparison against your competitors should be enough to get decision makers' attention at a board meeting.

Once the manner in which energy is being used has been reviewed, the next step is an energy audit.

To be meaningful, an energy audit should cover the entire site and all systems and should rank these by energy efficiency. These systems include lighting, AHUs, boilers, refrigeration, space heating, compressed air and production equipment. Those areas or systems that are the worst performing should then be concentrated upon. For example, if the review of energy efficiency identifies that kitchen lighting or compressed air is particularly inefficient, further investigation could be to measure light levels and occupancy patterns or data log air compressors.

In addition to concentrating on the worse performing systems, any item or system that is potentially a large energy user should also be data-logged.

During a recent audit of a large maintenance facility, the air compressors were data-logged even though these were brand new highly efficient units. The findings were surprising - air consumption at 04:00 hours was almost the same as that at 10:00 hours, even though there was no night shift. Air leaks were suspected and a follow-up leak survey by Environmental Efficiency using ultra sonic leak detection revealed over 100 leaks, many of them significant.

Once the energy audit is completed, it should be presented in person by the auditor to allow the recommendations to be discussed. An implementation plan should be agreed upon and an energy team set up to run the programme - ideally, the auditing organisation should be part of the team as they will have had much experience in driving through such projects in other organisations. If the organisation chooses to go it alone with an energy team, having the auditor on call for technical support can be useful.

With monthly meetings of the energy team, most recommendations can be implemented with a 12-month timeframe. The more difficult task is then to ensure that the savings are permanent and that poor energy efficiency practices do not reappear.

The main method in maintaining savings and identifying further saving opportunities is by monitoring energy consumption on a regular basis. This could be undertaken by reading utility meters daily and plotting the results on a graph. Consumption patterns should soon become apparent and abnormalities spotted. More sophisticated techniques would be to plot energy use against some variable such as degree days for space heating or level of production. Techniques such as control charts can then be used to monitor and aid control of variations in energy consumption.

For large sites, sub-metering of energy consumption to give a more detailed view of energy usage may be necessary. For example, each boiler in a plant room could be monitored for energy use. Steam boilers could also have steam meters fitted, thus enabling kWh/tonne steam to be monitored. For larger organisations, an Energy Management System to EN 16001 will ensure that energy costs are effectively managed.

Environmental Efficiency has carried out over 500 energy audits in Ireland, mainly in the industrial and commercial sectors. All energy audits include 12 months free implementation support via the company's help desk. Environmental Efficiency can offer advice to energy teams in implementation, training and monitoring of energy use - and also has significant experience of implementing Energy Management Systems and has assisted NSAI in auditing such systems.

The material in this article has been condensed from over 20 years of energy auditing experience. Please contact Environmental Efficiency for more information on any aspect of this article. Alternatively, visit the company's website to discover more about energy audits or more about Environmental Efficiency itself.