Saying NO to “Plug Load” in the fight against climate change


Buildings are a major contributor to climate change, accounting for over a third of global CO2 emissions, a number projected to double by 2060 if left unchecked. In response, world leaders at COP28, the 2023 United Nations Climate Change Conference, have set a bold target to achieve "near-zero emissions and resilient buildings by 2030" for 28 countries, writes John Ridgeway.

However, if we are to meet this ambitious goal, it will require a multi-pronged attack on building energy consumption. Traditionally, the focus has been on improving HVAC systems and lighting efficiency, but a new study has shed light on a significant and often overlooked aspect – it’s called plug load.

This refers to the energy used by electronics and appliances plugged into outlets throughout a building, that are doing little if any useful work and which can contribute up to 30% of a building’s energy use. These seemingly small energy draws add up quickly and need to be addressed.

Groundbreaking research

A groundbreaking study by researchers from Carnegie Mellon University and NASA Ames Research Centre offers hope for tackling this challenge. Led by Dr. Chaitanya Poolla, the research has looked into some innovative strategies for managing plug load in commercial buildings.

The study explored two key approaches, highlighting strategies that shift energy consumption patterns to align with peak grid capacity. By strategically adjusting plug load usage during high-demand periods, occupants can contribute to a more stable and efficient electricity grid. The study has also investigated how occupants' awareness and behaviour can impact energy use.

The researchers conducted meticulously designed experiments in two distinct settings - a government office and a university environment. They examined the impact of two interventions on plug-load energy consumption which involved installing dashboards displaying real-time energy consumption data. Occupants could see their energy usage, giving them a tangible sense of their impact. In some cases, they received financial rewards for reducing their plug load usage.

The results were impressive. Implementing the real-time visual feedback alone resulted in a significant reduction in plug load energy use - 9.52% reduction in the government office setting and a 21.61% reduction in the university environment.

Financial incentives

The addition of variable monetary incentives further boosted reductions in the university setting, leading to an average drop of 24.22%. Importantly, these results were statistically significant, meaning they were not just a fluke, with all of the findings published in the prestigious journal, Sustainable Cities and Society.

However, this study goes beyond simply demonstrating the effectiveness of feedback and incentives. A crucial aspect of the research lies in its statistical analysis of the observed data. The researchers developed time-series models to predict energy savings based on the interventions. These models, accounting for the inherent unpredictability of human behaviour, were surprisingly accurate – 75-80% accurate to be precise.

This highlights the power of occupant-in-the-loop control architectures for commercial buildings and underscores the remarkable potential of combining technology and human behaviour to optimise energy efficiency in a predictable manner.

"Engaging occupants effectively through feedback and incentives can not only motivate significant energy savings but can also generate awareness about inefficient devices and energy hogs," explains Dr. Poolla, the study's lead author.

This research has significant implications for the future of building energy management and demonstrates the effectiveness of empowering occupants to manage energy use through real-time feedback. This approach can significantly contribute to a more decentralised demand response strategy, easing pressure on the electricity grid during peak demand periods.

By providing real-time feedback and incentives, the study also shows how occupants can become active participants in reducing building energy consumption. This fosters a sense of ownership and environmental consciousness, leading to long-term behavioural shifts.

Accurate predictions

More importantly, the study's development of accurate predictive models underscores the potential for building managers to confidently implement these interventions, knowing the expected energy savings. This can support cost-benefit analyses and encourage widespread adoption.

Looking ahead, these findings point toward a future where buildings are not just energy-efficient but also engage occupants in the energy-saving process. By harnessing the power of information, incentives and human behaviour, we can transform buildings from climate culprits to climate champions.

However, while this research paves the way for significant advancements, further exploration is vital. Future studies could investigate the long-term effects of these interventions and explore their applicability to different building types and demographics. Additionally, research into gamification and personalised feedback systems could offer even more engaging ways to encourage occupant participation.

While the Carnegie Mellon and NASA study focused on commercial buildings, the principles of occupant engagement and behaviour modification can be applied to any setting, including homes, schools and even small businesses.

That said, there is no doubt that the study is a beacon of hope, demonstrating the immense potential for occupant engagement in reducing building energy consumption. By empowering occupants with real-time feedback and incentives, we can unlock a powerful force for change.

This research, coupled with individual and collective action, can pave the way for a future where buildings are not just sustainable but actively contribute to the fight against climate change. As Dr. Poolla aptly states, "Engaging occupants effectively, can not only motivate significant energy savings but can also generate awareness about inefficient devices and energy hogs."

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