Energy saving: how it to manage it

With no strategy to measure energy use, when it comes to efficiency managers are at best stumbling around in the dark, hoping to bump into a solution, or at worse simply ignoring one of today’s biggest challenges to competitiveness, argues Loic Moreau of LEM:

London - Often energy usage is a major proportion of an organisation’s costs, so any improvements in efficiency will not only benefit the environment, but also substantially benefit the bottom line. Despite this fact, many organisations spend a large amount of time minimising the purchase cost, but pay no attention to the running costs. For equipment that consumes power this is a big mistake! For example, 95% of the costs of a motor may be the energy it consumes, with maintenance accounting for 3% and the motor’s price accounting for only 2% of the total lifetime costs.

The need to reduce consumption, control costs and minimise the impact on the environment means that organisations need to understand where and how energy is being used if they are to identify opportunities for reducing energy use. The importance of measurement is not new: over 100 years ago, Lord Kelvin stated, “If you can measure it, you can manage it". Sadly most organisations still fail to do enough to monitor their energy consumption, inevitably meaning they are unable to identify and realise potential savings.

Energy monitoring is a key factor for compliance with a whole range of regulations being enacted throughout the EU. By legislating, Governments not only hope to achieve carbon dioxide emission targets, but also to make businesses in their countries more competitive. In the UK the carbon reduction commitment requires large organisations to monitor energy use and report on their equivalent carbon dioxide (CO2) emissions, whilst Part L2 of the Building regulations requires new commercial buildings to be able to record at least 90% of the energy usage by function.

Simple energy sub-metering can enable significant savings, with typical reductions in overall consumption of 5-10%. The more detailed the measurement, however, the clearer the picture and ultimately the greater the savings that are possible. For example identifying that pumps are unnecessarily left on 24 hours a day, seven days a week can result in energy savings of 60%.

As most organisations lack a good picture of how and where they consume energy, they need to start measuring without delay. The benefits are clearly both important and well proven, so why is it not being used to its full potential? The principle reason is the association of monitoring with conventional sub-meters, which means many people believe installation is still difficult, disruptive and expensive.

The concerns are valid with conventional solutions, but new approaches address all these issues. Modern wireless energy meters offer a simple, low-cost and flexible approach that allows organisations to acquire detailed measurement data, providing facilities managers the information they need to track and allocate energy costs to particular activities, allowing them to identify areas where energy is being wasted.

In many cases, the root cause of wasted energy is very simple – a heating controller may have been incorrectly set or a lighting control sensor covered up by a poster. Wastage can also be caused by equipment defects such as a faulty thermostat, or by poor configuration such as heating and air conditioning systems operating simultaneously in the same room, something that may not be immediate apparent to the room’s occupants. Simply measuring the energy used will shine a light on these problems.

Measuring energy consumption can be particularly useful in industrial applications where it can be used, for example, to benchmark one production cell against another. Any major discrepancy indicates a need for investigation, which may reveal problems such as motors using too much energy because they have worn bearings, or equipment that is operating inefficiently because it is in need of lubrication or other maintenance. Identifying such issues not only eliminates energy wastage, it also helps to prolong the life of machines and equipment by highlighting potential problems so they can be remedied before developing into full scale failures.

Widespread adoption of energy metering relies on the availability of solutions that do not suffer from the same drawbacks as conventional sub-meters. The latest systems can , for example, measure electricity consumption and communicate the data over a wireless mesh network, removing the need for extensive cabling that is usually associated with energy monitoring systems. The technology makes installation faster and easier, as well as greatly reducing equipment and deployment costs. Other features that simplify deployment include the use of split-core transducers, which clip around the cables, unlike ring-type transducers that require the cable to be disconnected before being passed through.

Wireless communication is suitable for installations in existing buildings, allowing deployment with little or no disruption to the organisation using the premises. It also enables measurement of energy use to be implemented in applications such as historic properties, where installation of additional cabling is not permitted and therefore monitoring usage would previously have been difficult or impossible.

The process of minimising energy consumption typically follows a cycle of plan-do-check-act (also known as a Deming or Shewhart cycle). This iterative approach often means systems measuring energy use need to be modified to allow for more detailed investigation of potential wastage, or to accommodate changes to the internal layout of a building.

Wireless transducers can be moved around as needed, with minimal disruption and very little cost. New technologies mean that no reconfiguration of the equipment is required as the transducers automatically recognise and communicate with the nearest repeaters and gateways. This also ensures exceptionally reliable operation, as the system can reconfigure the network to bypass equipment that has failed. The latest devices also offer an RF output power of 10mW, providing a long range within the building, even when transmitting through walls.

Unlike conventional sub-meters, modern energy monitoring systems can provide detailed information on parameters such as active and reactive power, current and voltage in real time. Understanding short-term changes gives greater insight into the way energy is used and helps organisations reduce peaks in consumption, which are often linked to higher tariffs.

Modern energy management solutions give organisations the opportunity to integrate their measurement of energy use by monitoring other utilities such as gas and water as well as environmental information such as temperature and humidity. This approach provides much richer measurement data that can often make it easier to identify problems. For example if a heating system is operating on a warm summer day, there is clearly a problem that needs immediate investigation.