PNNL NILM User Group

The Pacific Northwest National Laboratory (PNNL) has set up on online NILM user group via the Conduit platform. The user group consists of a monthly call, followed by an online summary and discussion. The group aims include:

• vetting NILM metrics and test protocols
• exploring utility use cases –mapping NILM characteristics and performance levels to each use case
• better understanding non-US products and use cases;
• maintaining a list of NILM products, including overviews on new products
• sharing field test results
• informing future NILM projects, including surveys to provide feedback on projects

The first call was on 6th November 2015, and gave an overview of PNNL's recent analysis of the performance of a number of NILM vendors in the Northwest Energy Efficiency Alliance's NILM field study. Challenges with evaluating the performance were also highlighted along with planned next steps to overcome these challenges and potentially accelerate the development of NILM technologies. EPRI also gave an overview of the NILM segment of their EE Symposium. The full webinar is available to watch on demand.

The user group welcomes any researchers who wish to join and contribute to the discussion. See you on the next call!

EPRI's 2015 NILM workshop

The Electric Power Research Institute (EPRI) has been a long term research player in the field of NILM since beginning development of NIALM systems in the 1980s. In conjunction with its efforts of laboratory and field trials, EPRI has been attempting to facilitate an industry effort to develop “consensus based” performance metrics, create protocols to test metric impacts and demonstrate the need for product labels. To this end, EPRI hosted a NILM workshop on 13 November 2015 in Orlando, FL, to follow on from the previous 2013 EPRI NILM workshop in Palo Alto, CA. The event was attended by disaggregation vendors, utilities, universities, a U.S. Department of Energy National Lab and research organisations and covered topics such as current EPRI research, use cases, utility and consultant experiences with NILM and product labelling (see full slide deck). One of the key outcomes of workshop was the recognition of gaps related to NILM metrics and how to address them as an industry through collaborative efforts. Specifically the need to define an analytical framework to understand metric characterisation, their impact on the representation of NILM device performance and ways to assess these impacts.

The meeting was conducted for the following two-fold objectives:

• Facilitate a collaborative dialogue between product manufacturers, utilities and other stakeholders such as national labs and researchers for identifying gaps and new opportunities that enable adoption of NILM technologies.
• Propose a set of “straw man” metrics to stimulate discussion and focus efforts to create working groups and follow-on activities to address identified gaps.

The discussions covered four key areas:

• Value of end use load data to utilities and new use cases
• Current research
• Practitioner experiences
• Quest for metrics and product labels

The collaborative industry group arrived at the following conclusions and expressed interest in the following activities for the future:

• Non-intrusiveness is a significant attribute of the technology that makes it appealing for both utilities and customers.
• Customer interfaces such as mobile apps and web dashboards play a decisive role in persuading customers to use the technology and benefit from the information reported
• Metrics and product labels can improve the credibility, visibility and confidence for use of these products both in utility and customer applications.
• Automatic load labelling is a must for high-value utility applications, and this characteristic may well be the “deal breaker” for some utilities.
• Metrics need to be simple and articulate so that utility customers can derive tangible benefit. EPRI’s set of metrics is a good start and lays the ground work for future work to assess metric characteristics and impacts on performance representation
• Other industry stakeholders such as PNNL’s NILM user group effort should coordinate their efforts to represent industry interest and requirements. (more on this soon!)

The following next steps are proposed:

• Identify use cases that can lend themselves well to the use of AMI data and demonstrate customer integration case studies.
• Start engaging with NILM vendors and interested utilities for pilots targeting the commercial sector by building type.
• AMI meter manufacturers are interested to develop embedded NILM solutions which can be included as part of the meter hardware and software. Partner with AMI meter manufacturers to define requirements for such apps for various use cases.
• Continue to track the NILM market space and understand product performance and features.
• Engage utilities and vendors through laboratory trials and field assessments as newer technologies become available 
• Continue to assess NILM metrics and test protocols. By virtue of the metrics proposed at the meeting, EPRI should work to create analytical frameworks to assess impact of metrics on performance representation.
• Exploring utility use cases, map NILM characteristics and performance levels to each use case
• Informing of future utility and research projects and release the data to vendors for algorithm development and refinement.

Many thanks to Chris Holmes and Krish Gomatom for contributing most of the material for this post!

REFIT analysis using NILMTK converter

I recently wrote a NILMTK converter for the REFIT data set, which allowed me to do a quick piece of analysis over the data set which I wanted to share. See my post on the release of the data set for further details about REFIT.

Below is a plot showing the duration of data recorded from each of the 20 houses. We can see that the installations took place between September 2013 and March 2014, and data continued to be collected until July 2015. The data set is pretty complete, apart from a gap of one or two months during early 2014, and a few small gaps mid 2015.



Below is a bar graph showing the number of instances of each appliance category across the data set. It can be seen that the television is monitored in all 20 houses (while the washing machine is monitored once in 18 houses, and twice in one house), while other common kitchen appliances, such as the microwave, dish washer and fridge freezer, were monitored in most houses. However, no lighting or oven/hobs were monitored in the data set, since only plug monitors were used.



Below is a histogram showing the proportion of the total electricity that was also sub-metered by the plug-level monitors. It can be seen that only 30-50% of the electricity was sub-metered in 16 out of the 20 houses, while no houses managed to sub-meter greater than 65% of the electricity consumption. This is likely due to a range of appliances which hardwired into the ring main consuming a large amount of energy, which could not be measured using plug-level monitors.



Below is a scatter plot showing the average daily energy consumption of each appliance instance in the data set. It can be seen that white goods often consume the most energy, with the dish washer, fridge freezer, tumble dryer and washing machine all consuming large amounts of energy. However, it should be noted that I've limited the y-axis to 2.5 kWh/day, despite one fridge freezer consuming nearly 6 kWh/day and one dishwasher consuming more than 3 kWh/day.

From Southampton to London

This week I finally said goodbye to Southampton as I started my new full-time role as a Data Scientist at British Gas Connected Homes. I'm definitely a little sad to be leaving my academic life behind me, but I'm also excited about the new challenges that lie ahead. The Connected Homes team are a fantastic group of people, and are the ones responsible for products such as the Hive thermostat and the My Energy dashboard. I'm still hoping to continue writing this blog and to stay in contact with the NILM community, though I doubt I'll be writing as many papers. Fingers crossed I'll still make it to Vancouver though for NILM 2016!

Below is a photo I shared this time last year of the Connected Homes' London office, which is probably not what you might expect from the UK's largest gas and electricity supplier!