On Monday March 26th 2018, an open workshop about “Energy flexible buildings” was organized by IREC, in the building of the Palau Robert in the heart of Barcelona. The objective of the workshop was to disseminate the ideas behind energy flexible buildings to a wider audience, and raise the awareness of local engineers, designers, architects and any other citizens interested in this engaging topic. Energy flexible buildings constitute a key asset in the future energy system, and could help tackle the challenges raised by an increasing penetration of renewables in the grids. To succeed and increase the users’ acceptance, it is however important to educate building owners, operators and occupants (i.e. everyone!) to the needs and reasons behind such research, which was one reason for organizing this open session. The workshop also served as a prelude to the Annex 67 biannual meeting, who was hosted by IREC and took place in Barcelona the days following the workshop.
Jaume Salom opened the workshop, whose organization was supported by INCITE, Comunitat Energia RIS3CAT & ICAEN. Søren Østergaard Jensen, from the Danish Technological Institute, started as the first speaker to introduce the IEA EBC Annex 67. The International Energy Agency (IEA), within its programme for Energy in Buildings and Communities (EBC), manages large scale projects named Annexes. The Annex 67, with around 50 experts participating from 16 countries, especially focuses on the study of Energy flexible buildings, covering all the related aspects: characterization of their potential, development of control strategies, business cases and user acceptance, lab tests and good examples from field study cases. As the operating agent, Søren presented the reasons behind such Annex project: the increased penetration of variable renewable energy sources calls for demand-side management options, and the energy loads of buildings (such as heating, cooling, ventilation, white goods) can offer some flexibility to the grid in this regard. Since this field of study is relatively recent, there are still debates on specific topics, such as the quantification and key performance indicators of energy flexibility: these were also discussed during the presentation.
Next, Cristina Corchero from IREC presented the work carried out in another framework of the IEA, the Hybrid and Electric Vehicle (HEV) programme, and more specifically Task 28, titled “Home grids and V2X technologies”. This task aims at using electric cars as storage elements and for other purposes than powering the vehicle, starting from the statement that EVs are not utilized during 52% of the time. Different applications are investigated in Task 28, such as vehicle-to-grid (V2G), vehicle-to-load (V2L), vehicle-to-vehicle (V2V) or vehicle-to-home (V2H). All these applications make a flexible use of the battery of the EVs to improve the management of the power grid and provide additional services.
The following presentation was given by Albert Cot from COMSA about REFER. In this local project, the objective is to implement demand-side management strategies in a network of public libraries. A smart energy management system (EMS) is developed to supervise all the electrical energy flows, from the PV generation, the HVAC systems use and a second life EV battery. This concept will be tried on one test site, a public library situated in Montgat, Spain. If the flexibility is accumulated at an upper level, for instance at the scale of the libraries network in the REFER project, the aggregator can offer such flexibility to potential markets. Analyzing this economic potential was the object of the next presentation by Mattia Barbero from IREC, who reviewed the markets to trade with aggregated energy flexibility. Mattia stated that our conventional energy system is challenged by the apparition of prosumers and decentralized energy generation. In the new schemes of the power grid, aggregators could play an important role to gather prosumers and offer flexibility to the market, for balancing services acting at different time scales. However, the legislation for such operation varies significantly from country to country within Europe, with for example aggregators already commercially active in France, the UK or Switzerland, while such market is closed in Spain, Portugal or Italy.
Cristina Corchero gave a second speech to present SABINA, a European H2020 project. SABINA (which stands for SmArt BI-directional multi eNergy gAteway) aims to develop new technology and financial models to connect, control and actively manage generation and storage assets to exploit synergies between electrical flexibility and the thermal inertia of buildings. The latter is considered as one of the cheapest possible sources of flexibility, and thus is particularly targeted by the project. The concepts of SABINA are tested in three demonstration sites in Greece, Denmark and Spain, where the two laboratories (electrical and thermal) of IREC will be connected to create a full test bed.
Kyriaki Foteinaki, a PhD student from the Technical University of Denmark then presented some results from her external stay as a visiting researcher in IREC. Within the EnergyLab Nordhavn project, her work focuses on the flexibility potential of the district heating network of Copenhagen, in a neighborhood of newly-constructed energy-efficient buildings, therefore she brought a different perspective to the topic of energy flexibility. The highly insulated buildings of the Nordhavn quarter possess a high thermal inertia and therefore can efficiently be utilized for load-shifting. Through a close collaboration with the utility company managing the district heating network, Kyriaki’s work aims at reducing the costs of operating the network and limiting the use of peak-load boilers for the heat production, thus also providing environmental benefits. Different scenarios of set-point modulations for shifting the heating loads depending on the varying marginal cost of heating production were presented and discussed.
Up next, Thibault Péan, PhD student in IREC, presented his work carried out in the framework of the INCITE project. His thesis revolves around the development of innovative control strategies to enhance the energy flexibility of buildings, and especially for heat pump systems. Heat pumps supplied with renewable electricity represent an excellent combination for decarbonizing our energy grids, and they also provide potential for unlocking the energy flexibility of building thermal loads, if controlled in a smart manner. Thibault thus first presented a short review of the existing control strategies in this domain, mainly separated between rule-based control strategies and model predictive control. As a first step, a strategy of set-point modulation according to the varying electricity price was introduced, but other signals could as well be used (share of renewables, CO2 emissions etc.). Some results applying and tuning such strategy for Catalan building typologies were presented, as well as graphical representation of the flexibility potential according to the hour of the day for such buildings.
Closing the workshop, Lluís Morer i Forns, Head of Energy Efficiency at ICAEN presented the vision of this institution regarding the role of buildings in the energy transition of Catalonia. The energy mix of this region highly depends on nuclear and fossil fuels, but the authorities aim to at least fulfill the European targets set in the “2030 Climate and Energy Package”: 27% of renewable electricity and an improvement of 30% of the energy efficiency. Buildings present a great potential for this last action, given their important share in the global final energy use. To achieve the energy efficiency targets, the actions will first focus on the public buildings owned by the region and the municipalities.
Following the workshop, the 6th working meeting of the Annex 67 took place in the UPC in Barcelona and was organized by IREC. One of the recent developments of the Annex was the submission of a position paper as an input to the revision of the European Performance of Buildings Directive (EPBD). The position paper can be found here on the Annex 67 website. One of its goals was to inform the EU consortium which develops a “Smart Readiness Indicator for Buildings” about the vision shared by the Annex 67 participants. In particular, it is remarked that the current EU climate and energy policy targets for 2030 greatly emphasize energy efficiency and savings. However, the studies carried out in the Annex 67 suggest that energy flexibility strategies can sometimes go against these declared goals (i.e. they can result in higher energy use), even though they finally provide greater benefits in terms of CO2 emissions or RES share. The focus should therefore be shifted towards “CO2 emissions efficiency” and not only on energy efficiency. Following these observations, the experts of the Annex 67 suggest to take into account energy flexibility as a key component of smart buildings, which together with energy efficiency measures will help make our energy grids more sustainable. Furthermore, the current discussions about the Smart Readiness Indicator revolve solely around the counting and rating of smart devices present in the buildings. The Annex 67 proposes in its position paper a more qualitative approach which also takes into account the impact of the building operation on the grid, rather than considering only the components separately. Overall, it is hoped that the position paper will value the outcome of 3 years of collaboration work within the Annex, and its ideas be utilized for developing the upcoming building regulations in the EU.