Carbon footprint and energy payback
Abstract : Heliotrop has completed a life cycle analysis of a 2MW plant with its high concentration photovoltaic modules with the help of professors from Mines ParisTech : thanks to the very limited use of semiconductors (10cm² of cells per m² !) as well as recyclable materials the results obtained are excellent. The carbon footprint is 12.5 gCO2eq/kWh and the plant produces in six month as much energy as the total energy needed for its fabrication.
Heliotrop is the French manufacturer of high concentration photovoltaic modules (HCPV), third generation technology specially adapted to areas under high irradiance. Thanks to the use of Fresnel lenses, the sunlight concentrates onto small yet very efficient solar cells (triple-junction). Heliotrop modules are almost twice as efficient as classic PV systems, thus allowing substantial cost reductions.
The modules are manufactured in France with industrial partners from the automotive sector which take advantage of their production lines and use electricity with little carbon. With the same power, the needed semiconductor surface is 2 000 times less than what would be required for classic PV (Heliotrop data). Moreover, the Heliotrop HCPV modules use long lasting and recyclable materials such as glass, aluminum and steel.
We have considered the following scenarios: manufacturing of the modules and trackers in France for a 2MWp plant in the south of France (Direct Normal Irradiation of 1850 kWh/m²/yr) or in Portugal (1950 kWh/m²/yr) with a durability of 30 years. We have considered a producible of 3.4 GWh/yr on the base of 1850kWh/m²/yr and an efficiency of 27%.
The ADEME Bilan Produit database 2008 [1] has been used to evaluate the impact of materials contained in modules (principally aluminum and glass) and trackers (galvanized steel and concrete). For 2MWp, this would represent 110 tons of aluminum, 30 tons of glass, 270 tons of steel and 1600tons of concrete. Module and tracker transportation using trucks from France to the site has also been considered. Finally, for more complex parts (triple-junction cells, inverters, motors, tracker control boxes, cables) we have used existing life cycle analyses that takes into account the manufacturing processes [2],[3]&[4]. We have also taken into account the end of life (disposal and recycling) of the various components.
We have not taken into account the flows between suppliers for the transportation of assembled modules and trackers, as it is already almost negligible. For the same reasons, we did not take into account the installation and dismantling either.repliky hodinek
The obtained carbon footprint is of 12.5 gCO2eq/kWh for a 30-year lifetime and the plant displays an energy payback time of 6 months (including parts that will need to be replaced such as inverters for instance). The results are identical within 1% between the south of France and Portugal.
Emissions breakdown – HCPV plant Heliotrop.
Sources : [1],[2],[3],[4] & Heliotrop study
Source: EDF [9], Heliotrop study
Source : [5],[6],[7],[8], Heliotrop study
Source : [5],[6],[7],[8], Heliotrop study
We would like to thank Mr Marchio Dominique (professor at Mines ParisTech), Mr Duplessis Bruno (project leader at Mines ParisTech), Mr Adnot Jérôme (professor at Mines ParisTech) as well as Mr Gabarrou Sylvain (PhD student on the life cycle analysis in PV), for their advices on this project.
References :
[1] Bilan Produit ADEME 2008.
[2] Life Cycle Assessment of the 33 kW Photovoltaic System on the Dana Building at the University of Michigan: Thin Film Laminates, Multi-crystalline Modules, and Balance of System Components Sergio Pacca, Deepak Sivaraman and Gregory A. Keoleian Center for Sustainable Systems
[3] Energy Payback Time of the High-concentration PV System FLATCON®Gerhard Peharz and Frank Dimroth*,Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrasse 2, 79100 Freiburg, Germany
[4] Energy Payback Time of a SolFocus Gen1 Concentrator PV System Artin Der Minassians Rouin Farshchi, Jimmy Nelson, Corinne Reich-Weiser, Teresa Zhang, 2006
[5] Solar as an environmental product: Thin-film modules – production processes and their environmental assessment
[6] Energy Payback Time of the High-concentration PV System FLATCON®Gerhard Peharz and Frank Dimroth*,Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrasse 2, 79100 Freiburg, Germany
[7] Energy Payback Time of a SolFocus Gen1 Concentrator PV System Artin Der Minassians Rouin Farshchi, Jimmy Nelson, Corinne Reich-Weiser, Teresa Zhang, 2006
[8] http://www.amonix.com/content/sustainability
[9] EDF, Méthode d’élaboration de l’indicateur d’émission de CO2, 2005
