Shrinking your combined load profile [includes video]

In June, Barbara, our Co-CEO, presented at the Renewable Cities Australia conference at the International Convention Centre in Sydney. The topic of her talk was ‘Reaching ambitious energy efficiency and renewables’.

At the core of her speech was a demonstration of how the combined load profile of a typical metropolitan local council changes after the implementation of energy efficiency and onsite renewable energy.

Please note that a video of the ‘shrinking load profile’ is included at the bottom of this post.

What is a load profile?

A load profile shows how your energy demand changes over a 24-hour period, from meter data that your energy retailer can provide on request or via a web portal linked to your account.

Meter data starts and ends at midnight and is usually in half-hour or 15-minute intervals. The vertical axis shows your energy demand in kilowatts as it changes over this time. The less your energy demand, the lower the curve.

A load profile can also be called ‘interval data’ and is a very useful tool for analysing your energy consumption. For example, a load profile can identify equipment that is running unnecessarily at night or may show you spikes in your energy consumption that hint at inefficient operation of equipment. Changes in your profile from summer to spring or autumn can give you an idea of the energy use needed for cooling in a building.

You use load profiles to help you identify how you can be more energy efficient, and they can also help you to size your solar PV installation.

What is a combined load profile?

A combined load profile adds the demand for all your sites to show you the overall energy demand of your organisation. This information is particularly important when you buy energy via a renewable energy Power Purchase Agreement that is supply-linked.

Building up a combined load profile

In this blog post, we build a combined load profile for a metropolitan local government. Figure 1 shows the combined demand of small sites, like small libraries, amenities blocks, community halls and childcare centres.

Energy demand typically rises sharply in the morning as people start to use these facilities, and it falls as people leave them in the evening. At night there is usually demand for appliances, small servers and emergency and exit lights.

Figure 1: The energy demand of small sites

Now, we are adding the electricity demand for large sites on top of the small sites. Examples for large sites are central administration offices & chambers, depots and aquatic centres. Night demand for depots and offices may be low with good after-hours controls. However, pools are usually heated all the time and can be energy-intensive at night.

Figure 2: The energy demand of large sites

The surprising thing for metropolitan councils is that most of the energy demand happens at night, through streetlighting, which runs from dusk until dawn. Streetlights can consume as much as half of a metropolitan council’s electricity! This creates a combined profile with high demand at night and a big dip in demand during the day.

Figure 3: The energy demand of streetlighting

Lastly, we add parks and sporting fields. Most of the energy demand for sporting fields is lighting and irrigation, so naturally, this demand also occurs from late in the evening (sporting field lights) to early morning (irrigation).

Figure 4: The energy demand of parks, ovals and fields

The impact of onsite energy efficiency and renewable energy measures on the combined demand profile

Now that we have a load profile that aggregates energy demand across all sites, let’s implement onsite abatement measures such as energy efficiency and solar PV.

So that you can see the impact of these measures, we are providing a visual cue to show you where our starting line is, because now we start subtracting.

Figure 5: Implementing onsite measures

Energy efficient lighting for parks and sporting fields

LED lighting replacements and smart controls for parks, ovals and fields can lead to a 40-70% reduction in energy demand. At the same time, you may improve your service provision through better lighting, more activated fields and higher utilisation. The net benefit is shown in Figure 6. A reduction in energy demand brings down the whole load profile from the starting point.

Figure 6: Lighting replacement for parks, ovals and fields

Figure 7 shows the impact of a bulk upgrade to LED lighting for local roads. LED streetlights are 60-80% more energy efficient than older technologies such as Compact Fluorescents or Mercury Vapour.

Figure 7: Streetlighting upgrade for local roads

Figure 8 shows the impact of a bulk upgrade to LED lighting for main roads, with similar levels of savings as local roads. Smart controls such as dimming can further increase savings for streetlights.

Figure 8: Streetlighting upgrade for main roads

Implementing energy efficiency improvements to lights, air conditioning, IT systems, appliances, motor systems and building controls at your facilities can achieve at least a 10% reduction, but more might be achievable. It depends on your individual circumstances and what measures you have implemented in the past.

Figure 9: Energy efficiency at Council sites

Installing onsite solar PV

Figure 10 shows the impact of installing onsite solar PV at your sites. You can see the dip in the load profile in the middle of the day, as the solar energy generation reaches its maximum.

Figure 10: Impact on Solar PV

Battery storage will allow further savings in your electricity and peak demand. Figure 11 illustrates how stored solar energy can reduce a building’s peak demand in the afternoon when peak demand charges might apply, thus reducing power bills.

Figure 11: More Solar PV and battery energy storage

What the load profile was and what it could be

So, we have implemented a number of cost-effective efficiency and renewable energy measures, and we can see that demand has reduced significantly. Figure 12 shows what the load profile looked like before implementation of any actions, and what it could be through energy efficiency and onsite solar PV.

Before you think about switching your electricity supply to offsite renewables (e.g. through a Power Purchase Agreement), you should consider the changes behind-the-meter measures like energy efficiency and solar PV can make to your energy demand, and how this can lower the amount of energy you need to buy over time.

Figure 12: Summary of what load profile is and what it could be

Switching your electricity supply to renewables

Figure 13 shows what remains of your original load profile. The next step will be to switch from conventional electricity supply to 100% renewable energy. This can be staged over time or may be possible all in one go.

Figure 13: Offsite opportunities like PPAs

Goals achieved!

In our experience, by implementing onsite energy efficiency and renewable energy measures, you can save 30-40% in electricity demand. By switching your supply to renewables, you can also achieve 100% renewable energy.

Figure 14: Goals Achieved!

You can watch a video of the shrinking load profile here:

Would you like to see how much you could reduce your load profile?

100% Renewables are experts in helping organisations develop their renewable energy strategies and timing actions appropriately. If you need help with analysing your load profile and with developing your renewable energy plan, please contact  Barbara or Patrick.

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