Articles

  • Mirka Karra

5 appliances’ unique energy consumption signature

There are many ways to measure the energy consumption of electrical appliances to offer energy insights. One such is with the help of smart plugs. The issue with smart plugs though is that you need to install one behind each appliance you want to measure (Intrusive Load Monitoring). This means that users will need to invest a significant amount of money if they want to measure the consumption of all appliances or selectively choose which appliances they want to measure, thereby losing overall insights from the non-measured appliances.


A more efficient way of acquiring energy insights for end-users is through the NILM (Non-Intrusive Load Monitoring) technology. This is a benchmarking mechanism that takes into account thousands of ground-truth appliances, as well as country-specific information and characteristics, e.g. space heating alternatives in different countries.


NILM uses algorithms that can detect clear and accurate energy consumption patterns in the overall energy consumption at home with the help of 1-10 sec, high data resolution. Each electrical appliance has its own unique signature i.e consumption pattern, which can be recognized by the algorithms. Just like a naked eye can make out the outline of famous sightseeings like the Sacre-Coeur and the Arc de Triomphe in the Paris skyline, so can the algorithms identify the energy consumption of appliances just by looking at their unique signatures



Let’s have a look at some representative consumption signatures of 5 of the most energy-intensive residential appliances. Although one might guess that the consumption signature might be the same for all types of the same appliance, for example, all dishwashers, you would be surprised to know that it is not the case. Consumption patterns vary and can depend on the appliance model, usage and other factors.


Dryer & Oven

A dryer is one of the most energy-intensive appliances in a house. It can consume a great amount of energy and reach consumption peaks of almost 3000 Watts. It contributes a great part to the overall energy consumption and can consume much more energy if it is used for prolonged periods of time. Below, you can see a dryer consumption signature. Though all dryers may perform the same basic functions, it might be dramatically different how various dryers’ signatures can look like.


Figure 1: Consumption Pattern for Dryer


Figure 2 & 3: Consumption signatures of different functionality settings of the same oven


The same is true for ovens. There are different types of patterns, spikes and time frames depending on an oven model (conventional, steam oven, convection oven, etc), functionalities (warmer, oven grill, fan-forced, etc) and temperatures (180C, 200C, 230C, etc).


In Figure 2 and Figure 3, it can be clearly seen that patterns for the same appliance type can differ significantly because of different settings or options selected.


Fridge

Fridge data is difficult to analyze due to the high quality of energy data required for long periods of time, usage habits and room temperature. An old fridge may use up to 2,000 kWh per year by comparison to a new one which may use only 350 kWh annually (1). That's why providing your end-users a way to identify if their electrical home appliances are efficient enough or used in the right way, is an important factor to be reckoned with when utilities are looking for complementary services to enrich their offerings.

Figure 4 & Figure 5: Different types of fridges


Dishwasher & Washing machine

It goes without saying that dishwashers and washing machines are used to a great extent in the household. Even though a user might choose efficient appliances, washing in high temperatures will end up consuming, again, a lot of electricity.


Check out these graphs depicting how different the consumption pattern is for an old dishwasher and a new one!

Figure 6: Consumption pattern for an old dishwasher

Figure 7: Consumption pattern for a new dishwasher


Nevertheless, it’s not just about the energy efficiency of an appliance but also the way it’s being used. Imagine a consumer who recently bought an expensive A+++ washing machine, but for some reason, he or she always washes their clothes at 90 degrees Celsius. This inappropriate use of the washing machine may result in three times higher consumption than expected. On the other hand, regardless of any tips and recommendations, an end-user might follow, he or she can never transform a 30-years old appliance into an efficient one.


With so many changing patterns, how can we identify specific appliances?


Given that there are big changes in energy use, taking place slowly or unpredictably, makes the pattern challenging to model and much harder to identify in real-time. To address this, NET2GRID uses its NILM (Non-Intrusive Load Monitoring) technology, 1-10 sec data and measurements coming from thousands of ground-truth appliances, that have proven to be resilient across different countries and for various electrical appliances over the globe. Taking into account thousands of electrical appliances, benchmarks and regulations, NET2GRID can predict appliance efficiency with 90% accuracy.


Our services can help utility customers to understand how they consume energy and what they can do to be more efficient i.e change their inefficient fridge or shift their energy-intensive habits. Our service providing recommendations and friendly reminders can lead to lower energy bills and higher customer satisfaction.


(1) Source: https://www.directenergy.com/learning-center/how-much-electricity-does-my-refrigerator-use