Thursday, May 7, 2015

MJÖLNIR - The Open Source Energy Advisor

The interface 0.2
We are glad to announce the stable release 0.2 of our open source energy management system at
Mjölnir provides an open platform where different energy consumption  feedback mechanisms can be implemented and assessed.
The system is one outcome of the MONERGY project, an Interreg research project that explores the use of home energy management systems to foster alteration of consumption patterns and achieve better utilisation of local energy sources. In particular,  we addressed residential settings in Carinthia (Austria) and Friuli-Venezia Giulia (Italy).
We identified common electrical devices and analysed the penetration of renewable energy [1], as well as user's attitude towards smart homes [2]. A measurement campaign was then carried out in 8 selected households, to track power consumption of individual loads at 1Hz for over 1 year. Main outcome was the GREEND dataset [3], openly available here
The energy advisor widget
The dataset was then analysed to gain further insights into energy consumption behaviour in the regions [4]. In particular, policies were formulated to improve energy efficiency, namely: i) shedding of standby losses, ii) postponement to off-peak periods, iii) replacement with more efficient appliances, and iv) operation curtailment.
An estimation of benefits yield by those policies was computed using data from the GREEND dataset, which showed a potential of up to 34% of savings. However, while these policies have a general validity, their benefits can be extended to a larger area by exploiting the functionalities of the Mjölnir framework. To this end, we implemented an energy advisor widget which displays the list of advices and allows users for acceptance and rejection. Each candidate advice is computed based on actual device usage events and energy costs, while a limited number of advices is returned based on user's preferences [5].
The MJÖLNIR system is part of a larger solution consisting of:
  • an aggregate power meter, measuring active power, such as the YOMO open hardware meter [6]
  • an appliance-level monitoring system, such as the OpenEnergyMonitor [7], or a load disaggregation unit [8]
  • the energy management system, consisting of a RESTful webservice and dashboard (Mjölnir) and a mobile application [9]

We expect the tool to be beneficial for both individuals and researchers carrying out field tests on persuasive technologies, whose contribution is particularly encouraged.


  1. A. Monacchi, W. Elmenreich, Salvatore D'alessandro, and A. Tonello. Strategies for domestic energy conservation in Carinthia and Friuli-Venezia Giulia. In Proceedings of the 39th Annual Conference of the IEEE Industrial Electronics Society (IECON 2013). IEEE, November 2013.
  2. T. Khatib, A. Monacchi, W. Elmenreich, D. Egarter, S. D'Alessandro, and A. M. Tonello. European end-user’s level of energy consumption and attitude toward smart homes: A case study of residential sectors in Austria and Italy. Energy Technology & Policy, 1(1):97–105, 2014.
  3. A. Monacchi, D. Egarter, W. Elmenreich, S. D'Alessandro, and A. M. Tonello. GREEND: An energy consumption dataset of households in italy and austria. In Proc. IEEE International Conference on Smart Grid Communications (SmartGridComm'14), Venice, Italy, 2014.
  4. WiTiKee and Lakeside Labs. Validation and analysis of results. Monergy 4th project deliverable, 2015.
  5. A. Monacchi, F. Versolatto, M. Herold, D. Egarter, A. M. Tonello, and W. Elmenreich. An open solution to provide personalized feedback for building energy management. ArXiv preprint arXiv:1505.01311, 2015.
  6. C. Klemenjak, D. Egarter, and W. Elmenreich. YOMO - The arduino based smart metering board. In Proc. Energieinformatik, Zurich, Switzerland, 2014.
  7. OpenEnergyMonitor
  8. D. Egarter, V. P. Bhuvana, and W. Elmenreich. PALDi: Online load disaggregation via particle filtering. IEEE Transactions on Instrumentation and Measurement, pages 1–11, 2014.
  9. A. Monacchi and W. Elmenreich. Insert-coin: turning the household into a prepaid billing system. In Poster Abstract, 5th ACM Workshop On Embedded Systems For Energy-Efficient Buildings. ACM, November 2013.