Look before you leap

Although renewable energy technologies have been given a significant number of column inches, maximising the effectiveness of an existing building energy management system (BEMS) should be at the top of the list of ways to optimise energy use and save money.

In light of rising costs of energy and growing pressure to use it more wisely, building owners and managers need to think hard about their consumption. In recent years the focus has been on generating energy via technologies such as solar photovoltaic (PV) panels and while they have their place, there are more immediate energy and financial savings to be achieved by optimising a Building Energy Management System (BEMS).

The Department of Energy and Climate Change (DECC) has set out plans for achieving the reductions in carbon emissions stated in the Climate Change Act 2008, which outlines the transition to a low carbon economy in the UK through emissions reduction targets. When compared to 1990 levels this equates to a reduction of at least 34% by 2020 and at least 80% by 2050.

Responsible for 17% of the UK’s carbon emissions, the nation’s 1.8 million non-domestic buildings are central to meeting this challenge and given the massive amounts of publicity that renewable energy technology has been given, it is no surprise that it has proved popular.

While the attractive Feed-In-Tariffs (FITS) on offer initially helped drive adoption, sentiment towards FITs has changed in the last couple of years due to the government reducing the payments to those installing solar PV from 43.3p per kWh to 15.44p for schemes up to 4kW in size. All of a sudden investing in renewables has become slightly less appealing due to much longer return on investment (ROI) periods.

Silver lining

This situation has encouraged end users to focus on maximising the energy saving potential of their existing infrastructures and the role that a Building Energy Management System (BEMS) can play in optimising energy usage. Given that up to 84% of a building’s energy usage can be under the control of this type of system, taking control of an asset most building owners and users already have at their disposal is the logical thing to do.

It is currently estimated that 80% of the buildings that will be in the UK in 2020 are already built and it is important to take control of these first. It makes sense to reduce energy bills immediately utilising systems that are already installed, before thinking about investing in new or additional energy sources.

For the average company, energy accounts for around 1% of its annual costs and by maximising the potential of an existing BEMS, energy savings of 10-20% are easily achievable which could equate to a 0.1-0.4% saving on a company’s total cost base. What’s more, a reduction of this size can be made in a way that is not only cost effective, but brings with it other additional benefits in terms of productivity and improved comfort conditions for those who occupy these buildings.

With organisations such as the UK Green Building Council (UK-GBC) calling for the rollout of Display Energy Certificates (DECs) to all non-domestic buildings, the use of a BEMS and the information that can be gathered from it will be useful in achieving the best rating possible.

Made to measure

The government’s Low Carbon Construction IGT report found that the property sector is not routinely measuring accurate operational energy use and carbon emissions from commercial buildings. And, as the saying goes, ‘if you can’t measure it, you can’t manage it’.

When a BEMS is first commissioned it is configured around an existing building layout and occupancy patterns. These can change over time and incorrectly configured time clocks and set points, new layouts, repartitioning, and the addition or moving of equipment can lead to some areas being too warm or too cold – all of which has a massive effect on the energy consumption.

In order to rectify such a situation, it is advisable to undertake an audit that ascertains what can be achieved by reviewing the way a building is used and identifying energy saving opportunities. In most cases adjustments can be made to the operation of the BEMS that deliver immediate savings of between 5-10%, while items such as boilers, chillers, air conditioning and pumps can be checked to make sure they are working correctly. In short a BEMS can only work to its full potential if it is correctly set up and then maintained regularly.

Renewable technologies clearly have a key part to play in reducing the UK’s energy usage but they should not be viewed as a panacea to this issue. A properly specified, installed and maintained BEMS will ensure that building services operate in strict accordance with demand, while the data produced will allow better analysis, understanding and improvement of a site’s energy usage and costs for long term management and control.

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