Nothing Special   »   [go: up one dir, main page]

IDEAS home Printed from https://ideas.repec.org/a/gam/jeners/v10y2017i9p1434-d112284.html
   My bibliography  Save this article

The Economic Feasibility of Residential Energy Storage Combined with PV Panels: The Role of Subsidies in Italy

Author

Listed:
  • Federica Cucchiella

    (Department of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, 67100 L’Aquila, Italy)

  • Idiano D’Adamo

    (Department of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, 67100 L’Aquila, Italy)

  • Massimo Gastaldi

    (Department of Industrial and Information Engineering and Economics, University of L’Aquila, Via G. Gronchi 18, 67100 L’Aquila, Italy)

Abstract
A solar photovoltaic system produces electricity by converting energy from the sun. By the end of 2016, the global installed solar photovoltaic capacity reached 305 GW. Its growth is impressive in the last years; in fact, it was only equal to 41 GW in 2010. However, Europe has installed only 6.9 GW in 2016 (−1.7 GW in comparison to previous year) and this annual power installed is equal to 9% of global one in according to data released by Solar Power Europe. The profitability of PV systems in mature markets depends on the harmonization between demanded energy and produced one residential energy storage when combined with photovoltaic panels is able to increase the share of self-consumption. This work proposes a mathematical model, in which a Discounted Cash Flow analysis is conducted to evaluate the financial feasibility of photovoltaic-integrated lead acid battery systems in Italy. The indicator used is Net Present Value. Furthermore, a break-even point analysis, in terms of an increase of self-consumption, is conducted. The residential sector is investigated and energy storage system investment is incentivized by fiscal deduction and regional subsidies. The analysis provides several case studies, determined by combinations of the following variables: photovoltaic plant size, battery capacity, the increase of the share of self-consumption, and the useful lifetime of energy storage system. The same case studies are proposed also in four alternative scenarios, where is the modified the structure of subsidies. Results confirm that the profitability can be reached in presence of subsidies.

Suggested Citation

  • Federica Cucchiella & Idiano D’Adamo & Massimo Gastaldi, 2017. "The Economic Feasibility of Residential Energy Storage Combined with PV Panels: The Role of Subsidies in Italy," Energies, MDPI, vol. 10(9), pages 1-18, September.
  • Handle: RePEc:gam:jeners:v:10:y:2017:i:9:p:1434-:d:112284
    as

    Download full text from publisher

    File URL: https://www.mdpi.com/1996-1073/10/9/1434/pdf
    Download Restriction: no

    File URL: https://www.mdpi.com/1996-1073/10/9/1434/
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Beck, T. & Kondziella, H. & Huard, G. & Bruckner, T., 2017. "Optimal operation, configuration and sizing of generation and storage technologies for residential heat pump systems in the spotlight of self-consumption of photovoltaic electricity," Applied Energy, Elsevier, vol. 188(C), pages 604-619.
    2. Georgios C. Christoforidis & Ioannis P. Panapakidis & Theofilos A. Papadopoulos & Grigoris K. Papagiannis & Ioannis Koumparou & Maria Hadjipanayi & George E. Georghiou, 2016. "A Model for the Assessment of Different Net-Metering Policies," Energies, MDPI, vol. 9(4), pages 1-24, April.
    3. Lai, Chun Sing & McCulloch, Malcolm D., 2017. "Levelized cost of electricity for solar photovoltaic and electrical energy storage," Applied Energy, Elsevier, vol. 190(C), pages 191-203.
    4. Vieira, Filomeno M. & Moura, Pedro S. & de Almeida, Aníbal T., 2017. "Energy storage system for self-consumption of photovoltaic energy in residential zero energy buildings," Renewable Energy, Elsevier, vol. 103(C), pages 308-320.
    5. Orioli, Aldo & Di Gangi, Alessandra, 2016. "Five-years-long effects of the Italian policies for photovoltaics on the energy demand coverage of grid-connected PV systems installed in urban contexts," Energy, Elsevier, vol. 113(C), pages 444-460.
    6. Ramírez, F. Javier & Honrubia-Escribano, A. & Gómez-Lázaro, E. & Pham, Duc T., 2017. "Combining feed-in tariffs and net-metering schemes to balance development in adoption of photovoltaic energy: Comparative economic assessment and policy implications for European countries," Energy Policy, Elsevier, vol. 102(C), pages 440-452.
    7. Diouf, Boucar & Pode, Ramchandra, 2015. "Potential of lithium-ion batteries in renewable energy," Renewable Energy, Elsevier, vol. 76(C), pages 375-380.
    8. Han, Xiaojuan & Zhang, Hua & Yu, Xiaoling & Wang, Lina, 2016. "Economic evaluation of grid-connected micro-grid system with photovoltaic and energy storage under different investment and financing models," Applied Energy, Elsevier, vol. 184(C), pages 103-118.
    9. Oh, Jeongyoon & Koo, Choongwan & Hong, Taehoon & Jeong, Kwangbok & Lee, Minhyun, 2017. "An economic impact analysis of residential progressive electricity tariffs in implementing the building-integrated photovoltaic blind using an advanced finite element model," Applied Energy, Elsevier, vol. 202(C), pages 259-274.
    10. Hoppmann, Joern & Volland, Jonas & Schmidt, Tobias S. & Hoffmann, Volker H., 2014. "The economic viability of battery storage for residential solar photovoltaic systems – A review and a simulation model," Renewable and Sustainable Energy Reviews, Elsevier, vol. 39(C), pages 1101-1118.
    11. Nan Zhou & Nian Liu & Jianhua Zhang & Jinyong Lei, 2016. "Multi-Objective Optimal Sizing for Battery Storage of PV-Based Microgrid with Demand Response," Energies, MDPI, vol. 9(8), pages 1-24, July.
    12. Kumar Sahu, Bikash, 2015. "A study on global solar PV energy developments and policies with special focus on the top ten solar PV power producing countries," Renewable and Sustainable Energy Reviews, Elsevier, vol. 43(C), pages 621-634.
    13. Kaschub, Thomas & Jochem, Patrick & Fichtner, Wolf, 2016. "Solar energy storage in German households: profitability, load changes and flexibility," Energy Policy, Elsevier, vol. 98(C), pages 520-532.
    14. Khalilpour, Kaveh Rajab & Vassallo, Anthony, 2016. "Technoeconomic parametric analysis of PV-battery systems," Renewable Energy, Elsevier, vol. 97(C), pages 757-768.
    15. Christoph Goebel & Vicky Cheng & Hans-Arno Jacobsen, 2017. "Profitability of Residential Battery Energy Storage Combined with Solar Photovoltaics," Energies, MDPI, vol. 10(7), pages 1-17, July.
    16. Battke, Benedikt & Schmidt, Tobias S. & Grosspietsch, David & Hoffmann, Volker H., 2013. "A review and probabilistic model of lifecycle costs of stationary batteries in multiple applications," Renewable and Sustainable Energy Reviews, Elsevier, vol. 25(C), pages 240-250.
    17. de Oliveira e Silva, Guilherme & Hendrick, Patrick, 2016. "Lead–acid batteries coupled with photovoltaics for increased electricity self-sufficiency in households," Applied Energy, Elsevier, vol. 178(C), pages 856-867.
    18. Giovani Almeida Dávi & José López de Asiain & Juan Solano & Estefanía Caamaño-Martín & César Bedoya, 2017. "Energy Refurbishment of an Office Building with Hybrid Photovoltaic System and Demand-Side Management," Energies, MDPI, vol. 10(8), pages 1-24, August.
    19. Federica Cucchiella & Idiano D’Adamo & Massimo Gastaldi, 2017. "Economic Analysis of a Photovoltaic System: A Resource for Residential Households," Energies, MDPI, vol. 10(6), pages 1-15, June.
    20. Nyholm, Emil & Goop, Joel & Odenberger, Mikael & Johnsson, Filip, 2016. "Solar photovoltaic-battery systems in Swedish households – Self-consumption and self-sufficiency," Applied Energy, Elsevier, vol. 183(C), pages 148-159.
    21. Aldo Orioli & Vincenzo Franzitta & Alessandra Di Gangi & Ferdinando Foresta, 2016. "The Recent Change in the Italian Policies for Photovoltaics: Effects on the Energy Demand Coverage of Grid-Connected PV Systems Installed in Urban Contexts," Energies, MDPI, vol. 9(11), pages 1-31, November.
    22. Lai, Chun Sing & Jia, Youwei & Lai, Loi Lei & Xu, Zhao & McCulloch, Malcolm D. & Wong, Kit Po, 2017. "A comprehensive review on large-scale photovoltaic system with applications of electrical energy storage," Renewable and Sustainable Energy Reviews, Elsevier, vol. 78(C), pages 439-451.
    23. Holger C. Hesse & Rodrigo Martins & Petr Musilek & Maik Naumann & Cong Nam Truong & Andreas Jossen, 2017. "Economic Optimization of Component Sizing for Residential Battery Storage Systems," Energies, MDPI, vol. 10(7), pages 1-19, June.
    24. Riccardo Squatrito & Filippo Sgroi & Salvatore Tudisca & Anna Maria Di Trapani & Riccardo Testa, 2014. "Post Feed-in Scheme Photovoltaic System Feasibility Evaluation in Italy: Sicilian Case Studies," Energies, MDPI, vol. 7(11), pages 1-19, November.
    25. de Oliveira e Silva, Guilherme & Hendrick, Patrick, 2017. "Photovoltaic self-sufficiency of Belgian households using lithium-ion batteries, and its impact on the grid," Applied Energy, Elsevier, vol. 195(C), pages 786-799.
    26. Luthander, Rasmus & Widén, Joakim & Nilsson, Daniel & Palm, Jenny, 2015. "Photovoltaic self-consumption in buildings: A review," Applied Energy, Elsevier, vol. 142(C), pages 80-94.
    27. Pyrgou, Andri & Kylili, Angeliki & Fokaides, Paris A., 2016. "The future of the Feed-in Tariff (FiT) scheme in Europe: The case of photovoltaics," Energy Policy, Elsevier, vol. 95(C), pages 94-102.
    28. Branker, K. & Pathak, M.J.M. & Pearce, J.M., 2011. "A review of solar photovoltaic levelized cost of electricity," Renewable and Sustainable Energy Reviews, Elsevier, vol. 15(9), pages 4470-4482.
    29. Rodrigues, Sandy & Chen, Xiaoju & Morgado-Dias, F., 2017. "Economic analysis of photovoltaic systems for the residential market under China's new regulation," Energy Policy, Elsevier, vol. 101(C), pages 467-472.
    30. de Oliveira e Silva, Guilherme & Hendrick, Patrick, 2016. "Pumped hydro energy storage in buildings," Applied Energy, Elsevier, vol. 179(C), pages 1242-1250.
    31. Rita Pinto & Sílvio Mariano & Maria Do Rosário Calado & José Felippe De Souza, 2016. "Impact of Rural Grid-Connected Photovoltaic Generation Systems on Power Quality," Energies, MDPI, vol. 9(9), pages 1-15, September.
    32. Brusco, Giovanni & Burgio, Alessandro & Menniti, Daniele & Pinnarelli, Anna & Sorrentino, Nicola, 2016. "The economic viability of a feed-in tariff scheme that solely rewards self-consumption to promote the use of integrated photovoltaic battery systems," Applied Energy, Elsevier, vol. 183(C), pages 1075-1085.
    33. Peters, Jens F. & Baumann, Manuel & Zimmermann, Benedikt & Braun, Jessica & Weil, Marcel, 2017. "The environmental impact of Li-Ion batteries and the role of key parameters – A review," Renewable and Sustainable Energy Reviews, Elsevier, vol. 67(C), pages 491-506.
    34. Luis Ramirez Camargo & Judith Franco & Nilsa María Sarmiento Babieri & Silvina Belmonte & Karina Escalante & Raphaela Pagany & Wolfgang Dorner, 2016. "Technical, Economical and Social Assessment of Photovoltaics in the Frame of the Net-Metering Law for the Province of Salta, Argentina," Energies, MDPI, vol. 9(3), pages 1-21, February.
    35. Koumparou, Ioannis & Christoforidis, Georgios C. & Efthymiou, Venizelos & Papagiannis, Grigoris K. & Georghiou, George E., 2017. "Configuring residential PV net-metering policies – A focus on the Mediterranean region," Renewable Energy, Elsevier, vol. 113(C), pages 795-812.
    36. Ramli, Makbul A.M. & Hiendro, Ayong & Sedraoui, Khaled & Twaha, Ssennoga, 2015. "Optimal sizing of grid-connected photovoltaic energy system in Saudi Arabia," Renewable Energy, Elsevier, vol. 75(C), pages 489-495.
    37. Mariaud, Arthur & Acha, Salvador & Ekins-Daukes, Ned & Shah, Nilay & Markides, Christos N., 2017. "Integrated optimisation of photovoltaic and battery storage systems for UK commercial buildings," Applied Energy, Elsevier, vol. 199(C), pages 466-478.
    Full references (including those not matched with items on IDEAS)

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Wang, Yue & Das, Ridoy & Putrus, Ghanim & Kotter, Richard, 2020. "Economic evaluation of photovoltaic and energy storage technologies for future domestic energy systems – A case study of the UK," Energy, Elsevier, vol. 203(C).
    2. Paulo Rotella Junior & Luiz Célio Souza Rocha & Sandra Naomi Morioka & Ivan Bolis & Gianfranco Chicco & Andrea Mazza & Karel Janda, 2021. "Economic Analysis of the Investments in Battery Energy Storage Systems: Review and Current Perspectives," Energies, MDPI, vol. 14(9), pages 1-29, April.
    3. Iolanda Saviuc & Herbert Peremans & Steven Van Passel & Kevin Milis, 2019. "Economic Performance of Using Batteries in European Residential Microgrids under the Net-Metering Scheme," Energies, MDPI, vol. 12(1), pages 1-28, January.
    4. Francesca Andreolli & Chiara D'Alpaos & Peter Kort, 2023. "Does P2P Trading Favor Investments in PV-Battery Systems?," Working Papers 2023.02, Fondazione Eni Enrico Mattei.
    5. Castellini, Marta & Menoncin, Francesco & Moretto, Michele & Vergalli, Sergio, 2021. "Photovoltaic Smart Grids in the prosumers investment decisions: a real option model," Journal of Economic Dynamics and Control, Elsevier, vol. 126(C).
    6. Lai, Chun Sing & Locatelli, Giorgio, 2021. "Economic and financial appraisal of novel large-scale energy storage technologies," Energy, Elsevier, vol. 214(C).
    7. Berrada, Asmae, 2022. "Financial and economic modeling of large-scale gravity energy storage system," Renewable Energy, Elsevier, vol. 192(C), pages 405-419.
    8. Federica Cucchiella & Idiano D’Adamo & Massimo Gastaldi & Vincenzo Stornelli, 2018. "Solar Photovoltaic Panels Combined with Energy Storage in a Residential Building: An Economic Analysis," Sustainability, MDPI, vol. 10(9), pages 1-29, August.
    9. Pervez Hameed Shaikh & Zohaib Hussain Leghari & Nayyar Hussain Mirjat & Faheemullah Shaikh & Asif Raza Solangi & Tariqullah Jan & Muhammad Aslam Uqaili, 2018. "Wind–PV-Based Hybrid DC Microgrid (DCMG) Development: An Experimental Investigation and Comparative Economic Analysis," Energies, MDPI, vol. 11(5), pages 1-37, May.
    10. Lai, Chun Sing & Locatelli, Giorgio & Pimm, Andrew & Tao, Yingshan & Li, Xuecong & Lai, Loi Lei, 2019. "A financial model for lithium-ion storage in a photovoltaic and biogas energy system," Applied Energy, Elsevier, vol. 251(C), pages 1-1.
    11. Rômulo de Oliveira Azevêdo & Paulo Rotela Junior & Luiz Célio Souza Rocha & Gianfranco Chicco & Giancarlo Aquila & Rogério Santana Peruchi, 2020. "Identification and Analysis of Impact Factors on the Economic Feasibility of Photovoltaic Energy Investments," Sustainability, MDPI, vol. 12(17), pages 1-40, September.
    12. Barbara Mendecka & Lidia Lombardi & Paweł Gładysz & Wojciech Stanek, 2018. "Exergo-Ecological Assessment of Waste to Energy Plants Supported by Solar Energy," Energies, MDPI, vol. 11(4), pages 1-20, March.
    13. Andreolli, Francesca & D’Alpaos, Chiara & Moretto, Michele, 2022. "Valuing investments in domestic PV-Battery Systems under uncertainty," Energy Economics, Elsevier, vol. 106(C).
    14. Jos? ?ngel Gimeno & Eva Llera Sastresa & Sabina Scarpellini, 2020. "Determinants and barriers of PV self-consumption in Spain from the perception of the installers for the promotion of distributed energy systems," ECONOMICS AND POLICY OF ENERGY AND THE ENVIRONMENT, FrancoAngeli Editore, vol. 0(1), pages 153-169.
    15. Sofiane Kichou & Nikolaos Skandalos & Petr Wolf, 2020. "Evaluation of Photovoltaic and Battery Storage Effects on the Load Matching Indicators Based on Real Monitored Data," Energies, MDPI, vol. 13(11), pages 1-20, May.
    16. Mohamad Kharseh & Holger Wallbaum, 2018. "How Adding a Battery to a Grid-Connected Photovoltaic System Can Increase its Economic Performance: A Comparison of Different Scenarios," Energies, MDPI, vol. 12(1), pages 1-19, December.
    17. Lazzeroni, Paolo & Moretti, Francesco & Stirano, Federico, 2020. "Economic potential of PV for Italian residential end-users," Energy, Elsevier, vol. 200(C).
    18. Aragón, Gustavo & Pandian, Vinoth & Krauß, Veronika & Werner-Kytölä, Otilia & Thybo, Gitte & Pautasso, Elisa, 2022. "Feasibility and economical analysis of energy storage systems as enabler of higher renewable energy sources penetration in an existing grid," Energy, Elsevier, vol. 251(C).

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Federica Cucchiella & Idiano D’Adamo & Massimo Gastaldi & Vincenzo Stornelli, 2018. "Solar Photovoltaic Panels Combined with Energy Storage in a Residential Building: An Economic Analysis," Sustainability, MDPI, vol. 10(9), pages 1-29, August.
    2. Han, Xuejiao & Garrison, Jared & Hug, Gabriela, 2022. "Techno-economic analysis of PV-battery systems in Switzerland," Renewable and Sustainable Energy Reviews, Elsevier, vol. 158(C).
    3. Schopfer, S. & Tiefenbeck, V. & Staake, T., 2018. "Economic assessment of photovoltaic battery systems based on household load profiles," Applied Energy, Elsevier, vol. 223(C), pages 229-248.
    4. Bruno Domenech & Gema Calleja & Jordi Olivella, 2021. "Residential Photovoltaic Profitability with Storage under the New Spanish Regulation: A Multi-Scenario Analysis," Energies, MDPI, vol. 14(7), pages 1-17, April.
    5. Tervo, Eric & Agbim, Kenechi & DeAngelis, Freddy & Hernandez, Jeffrey & Kim, Hye Kyung & Odukomaiya, Adewale, 2018. "An economic analysis of residential photovoltaic systems with lithium ion battery storage in the United States," Renewable and Sustainable Energy Reviews, Elsevier, vol. 94(C), pages 1057-1066.
    6. von Appen, J. & Braun, M., 2018. "Interdependencies between self-sufficiency preferences, techno-economic drivers for investment decisions and grid integration of residential PV storage systems," Applied Energy, Elsevier, vol. 229(C), pages 1140-1151.
    7. Federica Cucchiella & Idiano D’Adamo & Massimo Gastaldi, 2017. "Economic Analysis of a Photovoltaic System: A Resource for Residential Households," Energies, MDPI, vol. 10(6), pages 1-15, June.
    8. Rômulo de Oliveira Azevêdo & Paulo Rotela Junior & Luiz Célio Souza Rocha & Gianfranco Chicco & Giancarlo Aquila & Rogério Santana Peruchi, 2020. "Identification and Analysis of Impact Factors on the Economic Feasibility of Photovoltaic Energy Investments," Sustainability, MDPI, vol. 12(17), pages 1-40, September.
    9. Bertsch, Valentin & Geldermann, Jutta & Lühn, Tobias, 2017. "What drives the profitability of household PV investments, self-consumption and self-sufficiency?," Applied Energy, Elsevier, vol. 204(C), pages 1-15.
    10. Petrollese, Mario & Cau, Giorgio & Cocco, Daniele, 2018. "Use of weather forecast for increasing the self-consumption rate of home solar systems: An Italian case study," Applied Energy, Elsevier, vol. 212(C), pages 746-758.
    11. Pena-Bello, A. & Barbour, E. & Gonzalez, M.C. & Patel, M.K. & Parra, D., 2019. "Optimized PV-coupled battery systems for combining applications: Impact of battery technology and geography," Renewable and Sustainable Energy Reviews, Elsevier, vol. 112(C), pages 978-990.
    12. Khezri, Rahmat & Mahmoudi, Amin & Aki, Hirohisa, 2022. "Optimal planning of solar photovoltaic and battery storage systems for grid-connected residential sector: Review, challenges and new perspectives," Renewable and Sustainable Energy Reviews, Elsevier, vol. 153(C).
    13. O'Shaughnessy, Eric & Cutler, Dylan & Ardani, Kristen & Margolis, Robert, 2018. "Solar plus: A review of the end-user economics of solar PV integration with storage and load control in residential buildings," Applied Energy, Elsevier, vol. 228(C), pages 2165-2175.
    14. Andreolli, Francesca & D’Alpaos, Chiara & Moretto, Michele, 2022. "Valuing investments in domestic PV-Battery Systems under uncertainty," Energy Economics, Elsevier, vol. 106(C).
    15. Holger C. Hesse & Michael Schimpe & Daniel Kucevic & Andreas Jossen, 2017. "Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids," Energies, MDPI, vol. 10(12), pages 1-42, December.
    16. Luthander, Rasmus & Nilsson, Annica M. & Widén, Joakim & Åberg, Magnus, 2019. "Graphical analysis of photovoltaic generation and load matching in buildings: A novel way of studying self-consumption and self-sufficiency," Applied Energy, Elsevier, vol. 250(C), pages 748-759.
    17. Freitas Gomes, Icaro Silvestre & Perez, Yannick & Suomalainen, Emilia, 2020. "Coupling small batteries and PV generation: A review," Renewable and Sustainable Energy Reviews, Elsevier, vol. 126(C).
    18. Coria, Gustavo & Penizzotto, Franco & Pringles, Rolando, 2019. "Economic analysis of photovoltaic projects: The Argentinian renewable generation policy for residential sectors," Renewable Energy, Elsevier, vol. 133(C), pages 1167-1177.
    19. Bai, Bo & Xiong, Siqin & Song, Bo & Xiaoming, Ma, 2019. "Economic analysis of distributed solar photovoltaics with reused electric vehicle batteries as energy storage systems in China," Renewable and Sustainable Energy Reviews, Elsevier, vol. 109(C), pages 213-229.
    20. de Oliveira e Silva, Guilherme & Hendrick, Patrick, 2017. "Photovoltaic self-sufficiency of Belgian households using lithium-ion batteries, and its impact on the grid," Applied Energy, Elsevier, vol. 195(C), pages 786-799.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:gam:jeners:v:10:y:2017:i:9:p:1434-:d:112284. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: MDPI Indexing Manager (email available below). General contact details of provider: https://www.mdpi.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.