This subtask aims at establishing and demonstrating that PV systems are environmentally friendly and that future very large-scale implementation will provide clear environmental benefits.

 

This will be accomplished by the following activities: 

• Compare the environmental impact profiles of PV technologies with those of  other energy technologies

• Show the trends in PV environmental profiles by certain indicators (e.g., EPBT, GHG emissions, environmental impacts, waste reduction, materials’ recycling and recovery).

• Continue showing such progress in annual updates over the course of Task 12 (5 years).

• Valuate the environmental benefits of PV by showing avoided impacts or avoided “external” costs. 

• Credible communication and dissemination of results.

 

These activities have started with developing guidelines for a consistent methodological approach in LCI (Life Cycle Inventory) databases and Life Cycle Assessment (LCA), enabling well-balanced and transparent comparisons among PV and other energy technologies.

The results of this subtask may continue to benefit the PV industry by developing tools to monitor and report progress on process EH&S and product sustainability, and potentially benchmark the performance of individual companies. 

At this time the technical experts who participate in this task plan to study the following technologies: Mono and multi- c-Si; Ribbon c-Si; a-Si; CIGS; CdTe;  Concentrator PV, and production of Si feedstock.  In addition, incorporation of data in Ecoinvent v2.01.is planned.

 

Planned Workshops:

- Two expert workshops aimed at exchanging views on methods and approaches, discussion of LCA results, identification of important research issues;

- One industry workshop, aimed at discussing LCA approaches, data quality, LCA results, benchmarking and Environmental Product Declarations (EPDs) with PV industry representatives.

 

The first experts’ workshop was held in Boston and New York in November 2007, in conjunction with the Materials Research Society Symposium on LCA of new Energy Conversion and Storage Options. The result of the workshop was a draft of guidelines for a consistent methodological approach which is currently being refined (the draft is shown as Annex C)

The “Guidelines for a Common Approach in Photovoltaics Life Cycle Inventory and Life Cycle Assessment” are being finalized and are expected to be ready in the spring of 2009. Once they are approved by the ExCo, they will be printed and disseminated.

The Next version of ecoinvent data v2.1 will be ready incorporating updates of thin-film GaAs modules and updated figures on BOS components. It will also include Metallurgical grade silicon production:

• include microsilica as by-product
• refine CO2 emissions
• include emissions of PAHs and dioxin

Task 12 participants from Brookhaven National Laboratory (BNL), University of Utrecht, the Energy Research Centre of the Netherlands (ECN), Stuttgart University and Elkem Solar are engaged on ongoing LCA projects on LCA.  These investigators presented papers in the 23^rd EU PVSEC in Valencia, Spain, in September 2008, and also submitted several articles to major journals.

 

Datasets of the Ecoinvent database have been updated on behalf of the European Photovoltaics Industry Association and the Swiss Federal Authority for Energy. Data that have been collected by Utrecht University, ECN, BNL and others were provided to this project.  The information is used to elaborate a life cycle inventory from cradle to grave for the PV electricity production in grid-connected 3kWp plants in Switzerland, in the year 2005. Work on this project continues with the aim to update the CdTe and mounting data.

An LCA model of silicon production was developed by Elkem Solar with support from ECN. The LCA model’s work aims at disseminating results on environmental impact and energy use for the Elkem Solar process to produce solar grade silicon (or Elkem Solar Silicon – ESS™). This includes entities like Energy Pay Back Time and CO₂ Pay Back Times. In addition, models for competing processes will be set up and compared to the ESS – process.

Expert meetings were  held in Boston and  New York in  November 2007, that established guidelines for assumptions to be used in conducting and communicating comparative life cycle assessments across different PV technologies and in comparing the environmental impacts of PV systems with those from other energy technologies.  The first version of the “Guidelines for a Common Approach in Photovoltaics Life Cycle Inventory Analysis and Life Cycle Assessment” was produced and is included in Annex C.

Task 12 participants from Brookhaven National Laboratory (BNL), University of Utrecht, Energy Research Centre of the Netherlands (ECN), Stuttgart University and Elkem Solar are engaged on ongoing projects on LCA.  These researchers presented papers in the 23^rd EU PVSEC in Valencia, Spain, in September 2008, and also submitted several articles to major journals

 

Studies on LCA have been carried out for different Concentrated PV products and for the Solar grade silicon through a metallurgical route (Elkem Solar Silicon – ESS™) based in a low energy production process. 

In 2008, a complete LCA model for estimating climate impact and energy consumption was finished. Results from this were disseminated at the "SCSI IX - Silicon for chemical and solar industry" at Holmen Fjordhotel in Asker Norway (June 2008). The models were upgraded with sensitivity analysis on the re-use of waste heat internally and externally in the production process. These results were presented at the 23rd  PVSEC - European Photovoltaic Solar Energy Conference and Exhibition in Valencia, September 2008.

 

Update of the life cycle inventories of selected BOS components and of the GaAs modules embedded in the life cycle assessment database ecoinvent

 

A draft of the “Guidelines for a Common Approach in Photovoltaics Life Cycle Inventory and Life Cycle Assessment” was presented during the experts meeting in Valencia, September 2008 and afterward, several discussion have taken place to agree on the assumptions. The work in this area is now advancing quickly and the final version is expected to be ready by March 2009.    

 

A number of papers related to life cycle assessments and other environmental aspects have been published during 2008 and can be found at the Publications and Reports Area.