An introduction to non-domestic energy meters and data collection

May 14th, 2013 by

Gas and electricity meters may lack excitement and glamour but they are central to understanding how your organisation uses gas and electricity and how to cut consumption.

Here is a quick guide to non-domestic energy meters and methods of collecting consumption data.

The key points

  • All gas and electricity meters are designed to show the total consumption over a given period, but some meters can show you how your consumption varies over time. Typically these show how much energy has been used during each half-hour period of time.
  • Half-hour consumption data allows you to build up a picture of your consumption over a 24hour period and is extremely useful in working out how to cut consumption.
  • The type of meter installed on your site is normally determined by how much gas or electricity you use over the course of a year. Large consumers generally have access to half-hourly meters.
  • Where half-hourly meters are not installed there are other options. These include:
    – Negotiating with your supplier to see if they will provide this.
    – Installing additional meters or data loggers to provide this information.
    – Getting a third party company to provide data on your energy consumption.
  • By 2014 many businesses are due to have SMART meters installed which will provide half-hourly consumption data.
An introduction to non-domestic meters and data collection

Exciting? Perhaps not. Useful? Yes. Pulsed output meters allow variations in energy use over time to be recorded.

Introduction

Though the design of electricity and gas meters varies considerably they are all designed to measure power or “volume flow”.

Gas consumption is measured from the volume of gas delivered to a site. Electricity consumption is measured by the number of kilowatt hours passing “through” the meter.

Whatever type of meter you have the data collection and billing arrangements remain the responsibility of the supplier. That said there may be scope to negotiate over the exact metering arrangements for your site when tendering for a supply contract.

Electricity

Metering electricity consumption

Electricity metering has developed considerably over the last 10 years, meaning there now a number of choices available to consumers. Some of these are determined by the classification of your business site (whether it is a Code 5 or non-Code 5 site) and others are optional.

Sites which are classified as Code 5 will have their electricity consumption measured every half-hour.

Sites which are classified as non-Code 5 do not normally have half-hour meters installed (though the supplier my offer this as an option at additional cost). However, if the Profile Class of the supply to your site is 05 to 08 then by 2014 you should have a SMART meter installed which will provide half-hourly data as a built-in function of the meter.

Getting hold of half-hourly electricity data

For Code 5 sites with half-hourly meters installed energy suppliers will normally provide data on your electricity consumption via their website. Some also provide software which enables you to interrogate this data, find out what it means, look for trends and to produce reports and spreadsheets.

Some half-hourly meters also incorporate a device to show your consumption in real time. These can be useful showing how much energy is being consumed at a moment in time and in spotting spikes in demand. Increasingly real time displays can be connected to computer networks and TV monitors so that information can be displayed in other parts of the site or anywhere for that matter using the internet.

Collecting half-hour data

If the peak load of your site is over 100kW you can nominate who collects half-hourly data on your behalf – in other words you are not obliged to have the data collected by your energy supplier. The cost of providing this service will vary according to suppliers and the services offered. To arrange for half-hourly data collection by a third-party, firstly you will need to make a request to your supplier.

Key point: One thing to bear in mind is that it is the supplier who owns your consumption data. For this reason it is important that the supplier agrees to make the data available to a third party company charged with collecting your half-hourly data.

Options for sites without half-hour metering

If your site does not have half-hourly metering there are several options open to you:

  • You can askĀ  your supplier to reclassify the site and install one. There will usually be additional charges for data collection and settlement so this can be expensive. For these reasons this is likely to be most suitable for larger companies which can take advantage of bulk electricity purchase tariffs.
  • You can consider leasing or purchasing a half-hourly meter as a replacement for the existing meter or the services of a consultant to monitor your consumption for you.
  • You can build up a pattern of your energy use by taking your own regular (hourly or daily meter readings) from your existing meter.

Gas

Metering gas consumption

Daily metering (DM)

Sites with an annual gas consumption of 58,600MWh or more are classified as Daily Metered (DM) sites. DM sites have a gas meter which is designed to communicate gas consumption to the supplier so that consumption can be tracked against time.

For non-DM sites it is possible to request a DM classification if the gas consumption in excess of 73.2MWh/year. However, by requesting that the site becomes DM the business must also sign up to an interruptible gas supply tariff. This means is that the supplier has the option of switching off the gas supply for up to 30 days per year. (This enables the supplier to balance requirements during periods of peak demand. But it also means that you can usually negotiate cheaper tariffs).

Non-DM sites

For sites with consumption which between 73.2MWh and 58,600MWh for whom an interruptible supply is not suitable and for sites with much lower consumption it may be possible to arrange the gas meter so that it provides half-hourly data on gas consumption.

Many gas meters are pulse meters meaning they produce a pulse output which can be measured with a data logger and communication equipment to record half-hourly consumption. (Rule of thumb: If the meter was installed within the last 15 years and the meter reference number begins with an “A” then it is likely to have a pulse output).

A note about data loggers

The most common method of counting pulses is to use a battery powered data logger with integrated GSM communications facility.

National Grid UK specifies that for obvious reasons these must be specified to be suitable for “zone zero” conditions, meaning they provide a specified level of protection against ignition.

In addition the loggers themselves must be approved by the SIRA accreditation agency and can only be fitted by an accredited installer.

Loggers are normally designed to send an SMS text message with consumption data, often from the previous 48 hours.

Options for non-pulse meters

There are three options where the meter does not have a pulse output:

i) An optical reader can be placed over the dial of the meter and programmed to take a reading every half-hour.

ii) The meter can be replaced (you will need permission from the supplier). The data can then be collected automatically or by a company specialising in data collection.

iii) A sub-meter can be installed on the site to measure consumption on the whole or part of the site.

One further point to note is that by 2014 all customers with gas consumption in excess of 732MWh should have a SMART meter installed. As with electricity SMART meters these will show “interval consumption” i.e half-hourly consumption.

Safety note

Any work to gas meters including the installation of sub-meters and data loggers must be qualified and Gas Safe registered technician.

Written by

Environmental consultant, facilitator, founder & Director of Climate Works Ltd.