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Step 7 Guide 1: How to understand your bills

This is the seventh of 20 steps in the in the Energy Management Action Programme (Energy MAP).
Learn about Energy MAP and what it can do for your business.

In a nutshell

The process of collecting data from your bills is a good opportunity to understand your bills, and check if you are on the right tariff or if there are any unusual charges. We frequently find significant savings that can be achieved with very little effort. This guide will help you.

Are you on the most appropriate gas tariff?

For business customers Bord Gáis has a number of tariffs and the appropriate one is easily checked:

  • Standard commercial: Less than 450,000kWh/yr
  • Demand and commodity tariff 1: 450,000 to 2,400,000kWh/yr
  • Demand and commodity tariff 2: 2,400,000kWh/yr to 5,300,000kWh/yr
  • Large energy users: over 5,300,000kWh/yr (i.e. 5.3GWh/yr)

Are you on the most appropriate electricity tariff?

This question isn’t easily answered. One possible clue is if the Average Unit Price (AUP) appears too high. If you have multiple sites, you can compare AUPs. If you don’t, a crude approach is to compare your facility AUP to the AUP in your home. The larger your facility the cheaper it should be relative to domestic costs.

There are a range of tariffs, the three main categories being:

  • General purpose business tariffs - best suited to small industrial or commercial type business premises with an electrical capacity connection (MIC) less than 50kVA.
  • Maximum demand business tariffs - best suited to large industrial or commercial type business premises with an electrical capacity connection (MIC) greater than 50 kVA.
  • Residential business tariffs - These tariffs apply to small business premises where there is an attached residence and there is just one electricity metering point. This is a restricted tariff and is only available to existing customers who are currently on this tariff.

Unless the pattern of site use has changed substantially, of the site circumstances are such that they do not naturally fit into one of the generic categories (e.g. a wastewater pumping plant), it is unusual to be on an inappropriate electrical tariff.

However, if you are on the General Purpose tariff, consider the GP Nightsaver option. Being on the GP Nightsaver tariff increases your standing charges slightly, but significantly reduces the cost per unit of electricity consumed between 11pm and 8am. It is generally recommended that if more than 15% of your electricity is consumed between 11pm and 8am, you should be on a Nightsaver tariff.

If you are on the Maximum Demand tariff, you will already have lower cost night electricity.

If, after reading this, you think you may be on the wrong tariff then contact your electricity supplier who can use your historical profile to simulate the cost of alternative tariffs.


Do you consume much power at night and is this as you would expect?

It is worth sense-checking your night usage. The traditional approach is to calculate your Night Load.

Night Load (%) = night units per billing period / total units per billing period

Because there are 9 “night” hours per 24 hours, if your electrical load at night is the same as during the day your Night Load will be 37.5%. If it is lower than 37.5%, your electrical load during the day is higher than at night. One generally expects a higher electrical load during the day, i.e. a Night Load of less than 37.5%.

Night units are cheaper. If your energy management practices are good, and you intentionally shift usage to the night (11pm to 8am) from the day, then a high Night Load is a good thing.

However, we frequently find high night usage is not an indication of good energy management, but of substantial waste through unnecessary usage at night. Do you expect to consume much power at night?


Are you incurring any power factor/wattless power charges?

A low power factor results in wattless charges. These can be eliminated by the installation of power factor correction capacitors. If you are incurring wattless charges (and companies frequently do) it is likely that you already have power factor correction capacitors installed, but they may be damaged or the controls may require tuning. You should contact your electrical contractor to confirm power factor correction capacitors are installed and are operating correctly.


Are you actively participating in the Winter Demand Reduction Incentive (WDRI) scheme, and is this delivering savings?

This applies to those on Maximum Demand tariff only.

Traditionally, national demand for electricity is at its highest on winter weekday evenings between 5pm and 7pm. The capacity of the electricity generators to meet the overall national demand is stretched at this time. For this reason MD customers are encouraged to make a special effort to consistently reduce demand during this interval by offering a Winter Demand Reduction Incentive from late October to early March.


What you can do

You can reduce demand at these times by deliberate scheduling of building services plant and production equipment. Identify electrical loads that can be shut off during the energy survey (next step). If you have a backup generator it may be possible to use this for “peak shaving”. In our experience, it always pays to run the backup generator to participate in the scheme where this is technically feasible.


What to do next

If your electricity is supplied by ESB Customer Supply, then your tariff is already structured to deliver substantial savings if you consistently reduce your load between 5pm and 7pm from November to February.

If your electricity is supplied by another electricity supplier, then you need to register to participate in the WDRI scheme. Contact your supplier for details of the scheme.

If you are already participating, you can quickly confirm if it is delivering savings by checking your average unit price for the different billing periods. It should be lower in the winter months. If it is not delivering savings then the reason is most likely that you are not consistently reducing demand between 5pm and 7pm.

If you want to actively participate in the scheme, the application process will help you establish how much you can reduce your load by and value the savings.


Is your Maximum Import Capacity (MIC) appropriate to your current and future needs?

This applies to those on Maximum Demand tariff only.

Each electrical meter supply has a specific capacity contract (agreed between the business owner and ESB Networks), for the amount of electricity that can be safey used at any time. If your contract does not reflect your present requirement then you will be incurring unnecessary costs.

Inappropriate MICs are common, expensive, and straightforward to fix.

If your MIC is below your actual requirements, then you will be incurring Excess Capacity charges. Check what your annual Excess Capacity charge is.

If your MIC is above your actual requirements, then your standing charges will be high.


What you can do

To find out if you are using the correct MIC you should check your bills for the last year and write down your MIC and Maximum Demand levels.

The electrical capacity of your premises (MIC) should be compared with your Maximum Demand (MD) to ensure that you have the appropriate capacity. As a guide, use the following formula to determine the MIC that you should be using:

Correct MIC = (Maximum Demand / 0.95) x 1.1


What to do next

If your MIC is significantly higher or lower than your MD, and you do not anticipate your MD changing in the near future (e.g. an extension will increase your MD), then contact your electricity supplier to discuss.

For references and more information on electricity charges see the related links box in Step 6:

Return to Step 6

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