The armoury of an energy manager
Reviewing your operational procedures against energy usage can reveal surprising results. Carmel Corcoran, general manager, SmartEnergy Services at eutility, takes us through the key elements of a good energy data management plan.
As you open the weaponry stronghold of the energy manager, the shining battle- axe at centre stage is data. Standard proponents of energy management monitoring, targeting and verification continually expound on their virtues of these tools, and rightly so, but the route to data management heaven can be a fraught one, even without considering the final outputs and how they are to be used.
The key to good energy data management lies in the planning of such a system and then being modest enough to continually review that system and assess whether it delivers your required objectives. When looking at a monitoring system, understanding the requirements will form the bedrock of your strategy.
ESTABLISHING AN OPTIMAL SOLUTION
The first place to start with a monitoring solution is to review the current equipment on-site and establish what it measures, how frequently and at what intervals. Consider what you need the system for and what reports the system will facilitate. For some sites, data from one main meter and utility bill will be sufficient. For larger or more complex sites it may be useful to have a comprehensive sub-metering system.
BILLING DATA ANALYSIS
The fundamentals need to be adhered to, so checking the rates on each bill is important, or at least check the first bill of each contract to ensure the rates are correct.
Billing systems that incorporate alarms notifying you of unusually large changes in your billing profile can be vital in identifying billing errors and for highlighting changes in your energy profile.
With large premise portfolios, frequent occupancy changes often become overlooked. Using software that can track changes will highlight problems immediately, reducing the time taken to resolve issues and possible overpayments.
Unusual usage or demand patterns appearing in your billing data may alert you to problems, but may not necessarily help you to pinpoint the problem. Interval data can prove invaluable here, especially if linked to daily alerts.
Generally, meters can be categorised into revenue meters, those that supply your energy retailer with data for your bill, and sub-meters.
Utility meter data analysis
Revenue meters are regulated; a site’s energy profile and usage determines the type of meter and data output. Generally, for sites that have an energy contract, electronic data is provided in 15- or 30-minute intervals; the frequency of data is generally day plus one. Retailers and metering providers do have very stringent controls of their data quality, but occasionally anomalies slip through.
Reviewing your operational procedures against energy usage can reveal surprising results. Seeing graphical representations of your energy usage will assist in evaluating the energy being used when the site is not operational. Once established, a quick review of your equipment should reveal whether out-of-hours usage is reasonable. It’s surprising how many lights, compressors, HVAC systems and pieces of IT equipment are left running when the premises are vacant.
Daily alerts and data analysis will assist in implementing behavioural control measures to reduce energy consumption. Alerting a building manager the day after an alert event makes it easier to pinpoint the activity of the previous day. Ensuring this event is not repeated can also ensure that energy management remains a constant consideration.
The network element of a bill can be up to 60 percent of the total cost. The demand element of network charges is significant. Understanding your energy profile, when and how demand charges are implemented is necessary for cost control. Costs can be optimised by comparing site operational procedures against maximum demand in the demand-chargeable hours.
Interval data analysis can identify poor performance of equipment on site. Power- factor (PF) correction equipment controls unnecessary charges related to kVA demand charges, but equipment can fail. Daily alerts and monitoring of the PF at maximum demand will pick up these issues to prevent ongoing excessive charges. In a similar manner, the generation of solar power can also be measured and monitored to ensure the systems perform optimally.
A wide selection of sub-meters exists, with varying costs and functionality for different applications. Understanding what data is required, how the solution will complement other systems on-site and how this achieves your monitoring goals is essential for the optimal solutions. Sub-metering is also vital where it is necessary to obtain real-time data and for data intervals of less than 15 minutes.
These factors all contribute to the cost of the meter. In addition, consideration must be given to a sub-meter’s proposed environment, accessibility, required data frequency, communications, battery life and installation.
Sub-metering applications can be vital in obtaining optimal NABERS ratings, measurement and verification, benchmarking – i.e. Power Usage Efficiency (servers) – equipment performance, control of energy- consuming equipment, internal cost allocation, billing of tenants, demand management and more.
MONITORING AND VERIFICATION
So you have installed energy efficient equipment, started a staff awareness program or changed operational procedures – what are the actual outcomes of the project in terms of costs and energy usage changes?
For monitoring and verification purposes, a common rule of thumb states that, for projects with savings estimated to be greater than 10 percent, site-level data is sufficient. However, if your savings are predicted to be lower than this you will need to consider a sub-metering solution.
There are many sources of power usage which make up the total usage as recorded on your bill. Savings of less than 10 percent will often be ‘lost’ among all the other power usages on-site unless usage is constant and unchanging. Quite simply, this rarely happens.
Normalising variables that cause energy usage to fluctuate – for example, weather, production numbers, occupancy, etc – is done simply by adjusting the figures back to a specific baseline to enable you to compare like with like. There are internationally accepted protocols for measurement and verification (M&V); the most widely accepted is the International Performance Measure and Verification Protocol (IPMVP), which must be performed by a suitably qualified person.
Benefits of M&V include verifying cost savings to management, which can also enhance the profile of energy management and ease the way for future programs.
M&V can also highlight the under- performance of installed hardware. Energy management projects often need fine-tuning by the supplier of the equipment or service, and this provides evidence of the system’s performance. Working closely with the contractor often results in a better relationship and an optimally performing system.
MANAGEMENT AND FUTURE PROOFING
The best system in the world will not help you if data is not acted upon. As with any successful data management program, you must establish what key reports you require out of the system, who is the target of these reports, what action will be taken as a result of the reports, if the data generated can support other reporting functions and, most importantly, who is responsible for the reports.
When looking at energy management software, consider who is in the best place to use the data most advantageously. Is it the building manager, site engineer, sustainability manager or finance director, for example?
What happens if you change your retailer, expand the system or change your software provider? Many retailers provide a service for interval data services, but what happens when you move retailer for a more favourable contract?
Sub-metering companies may offer full-solution contracts for installation, data management and alert systems, but they may also only ‘rent’ the sub-meters to you. In this case, how would you obtain historical data? Would the data compiled be easy to review against billing data?
Energy data management can be a direct improvement to your bottom line; optimally designed data management systems increase the opportunity for direct savings.