The PLANET Project: A Tool for Flexibility in the Energy Transition

Renewable energy resources offer immense prospects to mitigate greenhouse gas emissions and combat climate change, whilst addressing the growing energy demand. In recent years, owing to falling costs and supportive policies, the integration of renewable energy has expanded significantly. Nevertheless, challenges to its further expansion are raised due to the inherent variability of renewable energy production (‘vRES’) coupled with grid stability considerations, which – if not properly addressed – shall lead to vRES generation curtailment. The latter would cause renewable capacity expansion to decelerate, reductions in the capacity factors of vRES technologies and subsequent economic losses, to name a few.

Against this backdrop, PLANET has developed a holistic decision support system for utilities, network operators and policy makers to help them implement optimal grid planning and management solutions compatible with complete decarbonization of the energy system. To that end, the project leverages energy conversion and storage technologies, such as Power-to-Gas, Power-to-Heat, Combined Heat and Power, Thermal storages and Virtual Energy Storage. These technologies have been deemed very promising to address issues related to the integration of renewables in the electricity grid, by enabling coordination of the electricity, heat and gas sectors towards revealing the maximum potential of network flexibility, a vital prerequisite for ensuring security of supply.

The PLANET project commenced in November 2017 with the participation of 11 partners from 7 different countries: Italy, Finland, Greece, UK, Germany, France and Belgium including technical universities, research centers and associations, consultancy firms, utilities and information technology companies.

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Cross-Cutting Technologies for Developing Innovative BIPV Systems in the Framework of the PVadapt Project

Trends in the total population worldwide show a decline in the share of population living in rural areas of the total population, while towns and cities experience a smooth and constant increase. In Europe, the level of urbanization is expected to increase to approximately 83.7% by 2050. While being responsible for a high level of energy consumption and, therefore, generating about 70% of global GHG emissions, cities are also particularly vulnerable to the impacts of climate change. Thus, it is difficult to envision a sustainable future without transforming the urban environment by applying powerful renewable energy technologies. A new and promising way is to integrate solar technologies in the constructed environment (e.g., buildings), as solar energy is the most abundant energy source in both direct and indirect forms in comparison to all the other renewable sources.

Building integration of photovoltaics replaces traditional elements (windows, cladding, roofs, or accessories) with a functional component able to generate energy. When active heat recovery is combined with building-integrated photovoltaic (BIPV) systems, either in a closed loop (like PV-T with liquid loop) or in an open loop with forced air, they are designated as “building-integrated photovoltaic–thermal” (BIPVT) systems. As a market, the BIPV sector is expected to keep growing from a 3 billion euro market in 2015 to 26 billion by 2022, bringing 20 years of R&D into fruition [2]. However, while market growth of BIPVs might inspire confidence for the future, this market share will only be 7% of the total PV market by 2020, as opposed to the current share of 3%. Combining functional building elements with solar energy technologies leads to the BIPV market comprising a wide array of products with corresponding variations in price range: integrated roof systems are priced between 200 and 600 €/m2, whereas tiles cost between 350 and 500 €/m2. A baseline assumption shows that the consumer will invest between 5.02 and 5.72 €/W on roof-based systems. For façade systems, the situation is similar with options available from 100 to 150 €/m2 but featuring low efficiency thin-film PV technology to high end sophisticated BIPV systems at 750 €/m2.

Despite the promising outlook for the BIPV sector, there are still barriers regarding prefabrication, modularity, smartness, and recyclability, impeding widespread adoption. In Europe, the ageing building stock and low rate of new construction have led to initiatives to increase the rate of refurbishment by 1.5% to 3%. The current low rate of refurbishment adversely affects BIPV adoption, since the largest contributor to the market is rooftop systems, and roofs are usually replaced as part of deep refurbishment.

Taking into account the gap in the current market for modular and prefabricated BIPV, especially in the area of PV cooling and heat recovery, the main objective of the PVadapt H2020 project is to develop a BIPVT turn-key system with an exceptionally high level of modularity, applicability, sustainability, and cost efficiency. The overall concept aspires to deliver the following to the market: (i) deep refurbishment BIPVT modules designed for wall and roof replacement, (ii) shallow refurbishment BIPVT systems for replacing or adding building accessories (e.g. shaders and parapets), and (iii) new construction systems designed for residential or commercial applications as well as auxiliary buildings. Moreover, PVadapt will implement a circularity approach to the life cycle for all components and materials applied, following the principles of sustainable construction. Until now, six articles have been published in international journals and proceedings of international conferences to present the outcome of PVadapt as well as its contribution to BIPV market.

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PVadapt: Integration of innovative bipv solutions on micro chp plants

 In the last two decades, the energy consumption has been increased by approximately 58% (Enerdata, 2018). Both residential and commercial sectors are responsible for the consumption of 40% of U.S. and Europe total energy. Moreover, buildings are responsible for 36% of GHG emissions (E.C. 2016). For a more sustainable future, due to global warming and the exhaustion of fossil resources, research is conducted in order to create energy production systems more efficient and environmentally friendly (J. Twidell and T. Weir 2015). Today 55% of the world’s population lives in urban areas, a proportion that is expected to increase to almost 70% by 2050 (Kiss et al. 2015). 

It is more than obvious that a sustainable future cannot be achieved without transforming the urban environment by applying powerful energy production technologies based on renewables. Currently, more that 18% of the global energy consumption is delivered from renewable energy sources. To that end, modern BIPV and BIPV/T technologies consist the core for urban sustainability. Photovoltaic solar thermal hybrid system considered as CHP systems since they produce both electricity and heat from one energy source (solar) (Kolanowski 2011). A distributed generation using renewable energy can be a solution in order to reduce greenhouse gas emissions and to increase the supply security (Pepermans et al. 2005). 

One of the main challenges is the development of solutions able to induce reduction of total energy consumption and to achieve the greatest possible integration of renewable energy systems into the building envelope. The use of renewable energy sources as part of the building envelope could potentially provide a promising solution, transforming buildings from “energy consumers” to “energy producers”. For the PV technology in particular, the introduction of a PV panel that is not just the mean for producing energy but also a building element with enhanced properties, can become a smart, multifunctional and cost effective solution not only for new constructions but also for the retrofitting of old, even traditional buildings. 

In this aspect, The “Construct PV” FP7 European research project aspired to confront all the technical and architectural barriers of PV technology with a holistic approach of Building Integrated Photovoltaics (BIPV), by installing PVs for energy harvesting in the opaque surfaces of a building. The developed PV module introduces modern wire bonding and heterojunction technologies that lead to increase in active area and minimization of shading losses. As a result, the new PV panels achieve a higher efficiency of up to 7% when comparing with conventional solar panels (Peppas et al., 2017). For the evaluation of the new PV panel, a rooftop demo grid-connected BIPV system of 15 KWp has been installed in the roof of the building that hosts the School of Mining and Metallurgical Engineering of NTUA at Zografou Campus in Athens, Greece. The performance evaluation of the new PV modules has been done according to IEC 61724 Standard. Based on the results, it is more that evident that cell temperature significantly affects performance and the overall conversion efficiency of PV panels. More specifically, during summer, the cell temperature reached a maximum of 78oC leading to a performance degradation of up to 15% (Peppas et al., 2018). 

Thus, PV cell cooling techniques will not only increase PV’s efficiency but also will exploit the thermal content that is generated. On this direction, solar-thermal collectors can be combined with photovoltaic (PV) modules to produce hybrid PV-thermal (PV-T) collectors. These can deliver both heat and electricity simultaneously from the same installed area and at a higher overall efficiency compared to individual solar-thermal and PV panels installed separately. Hybrid PV-T technology provides a particularly promising solution when roof space is limited or when heat and electricity are required at the same time. 


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