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Autonomous cleaning robot for large scale photovoltaic power plants in Europe resulting in 5% cost reduction of electricity

Final Report Summary - PV-SERVITOR (Autonomous cleaning robot for large-scale photovoltaic power plants in Europe resulting in 5 % cost reduction of electricity)

Executive summary:

The PV-SERVITOR project focused on concepts for a fully autonomous cleaning robot for ground-mounted large-scale photovoltaic (PV) power plants. The PV-SERVITOR is able to automatically clean glass surfaces of solar modules arranged in long rows in an unrestricted way. Its application will increase the electricity output of the PV plant at a lower service cost, thus resulting in a user-benefit by cost reduction of the electricity yield. The quantification of the user-benefit requires specialised research and measurement capabilities for each individual plant.

Europe's largest PV companies active in the main European PV markets such as Germany and Spain strongly supported this small and medium-sized enterprise (SME) project as end-users and granted access to their large scale PV power plants in Germany and Spain. This end-user involvement will also help to secure the SMEs a market success after the completion of the PV-SERVITOR project.

Tasks for research were lightweight construction, automated cleaning of glass surfaces, the synchronisation of technical and economic lifecycles, sustainable outdoor mobility including the challenge to replace rechargeable batteries with a long life energy supply system, unrestricted navigation and cognitive vision systems for pollution detection and cell inspection.

PV-SERVITOR was a research project supported by the European Commission (EC)'s Seventh Framework Programme (FP7). The proposal was submitted on 11 April 2008 and the project started on 1 September 2009 with a duration of 24 months. Further information can be found in several languages such as Chinese, English, German and Spanish, at the project website:

Project context and objectives:

According to an EU publication PV is the most capital-intensive renewable source of electricity. Currently, the generation costs of grid-connected PV electricity in Europe range from EUR 0.25 / kWh to EUR 0.65 / kWh, depending on both local solar irradiation and market conditions. The average market price of electricity at the European Energy Exchange in the first quarter 2008 was EUR 56.20 / MWh, which is EUR 0.056 / kWh and more or less a still valid price as per today (19 September 2011).

The PV-SERVITOR project focused on the reduction of the generation cost of grid-connected PV electricity in Europe by 5 % through automated add-on services. The automated service of a PV power plant was planned to result in an increase of energy output of 8 % and at a cost 3 % of the installation value of the PV power plant, resulting in a benefit of 5 % for the PV power plant operating company.

The potential users are all free terrain PV-project operating companies in Germany and other countries such as Spain and Italy with a German Renewable Energy Act (EEG)-type income from PV energy production for the public-grid. The EEG is a very successful German law which states the obligation of the grid-operator to pay for renewable energy being fed into the public-grid.

Project results:

The project achieved five patent applications to the European Patent Office (EPO). After positive feedback for the first patent applications which was submitted ahead of the others internationalisation of the first patent application commenced to China, India, Israel, Korea and the United States.

However the key question of how to replace rechargeable batteries with a long life energy supply system remains to be solved in the future.

Potential Impact:

The SMEs originally planned direct utilisation of the knowledge after the research project through a product PV-SERVITOR. However the research prototypes would require a development phase before they reach an industrial prototype status. Therefore the time to market is still some years ahead. After a training session on 25 and 26 January 2011 at EPO organised by the European Patent Academy about 'Patents in Business' MS changed the plan for the use of foreground to include licensing.

The potential impact depends on the benefit of cleaning.

For the final test the most polluted free-field installation under service contract of the end-users was searched anywhere within Europe. The PV power plant Extremadura I in Castuera, SPAIN was selected. At first glance a power loss of around 6 to 8 % of the nominal installed power was expected due to the visual impression of pollution. An astonishing result was the fact that at this PV power plant Castuera cleaning of PV modules with clearly visible pollution only increased their power in the order of about 3 %.

Substantial user benefit might therefore be rather limited to arid areas found outside of Europe. The problem of pollution depends significantly on the location and further research on this topic is needed.

The SMEs created and updated the project specific website early in the project, well ahead of the plan in the description of work. In a team effort Robotnik supported the translation into Spanish and Shadow checked the MS translation into English. The main domain is:

Three language specific subdomains are: German (see online), English (see online), Spanish (see online).

The language selection reflects the native languages spoken by the SMEs MS, Robotnik and Shadow.

Following the internationalisation of dissemination two more language specific subdomains were created in an update of the project specific website:

Chinese (see online), Hebrew (see online)

The translation to Chinese was organised by MS at the end of the project. A final check and minor correction was completed with the help of Shadow and their Chinese distributor shortly after project end. However the translation to Hebrew remained a task for the future.