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News article19 March 2019

European Solar Test Installation activities in support of European renewable energies policy

ESTI indoor
© European Union / European Union

The Joint Research Centre (JRC)'s expertise in Photovoltaics (PV) is based on the work carried out, since more than 35 years, at the European Solar Test Installation (ESTI). This independent European reference laboratory validates electrical performance and lifetime (power and energy generation) of photovoltaic devices. A new technical report supports the EU political objective of increasing the share of renewable energy in the market.

A Clean Planet for all: European strategic long-term vision

PV is expected to make a major contribution to achieving European and global climate change mitigation goals. It is the renewable energy technology with the largest scope for cost reduction and efficiency gains, as well as exploiting the largest resource. The JRC works together with policy makers, industry and the research community to monitor the progress of PV technology and helps develop the solutions for the future.

Traceability of solar irradiance, reference materials and validation of PV products and measurement methods

For the first time a technical report collects and summarises all ESTI activities in the fields of:

• traceable measurement of solar irradiance (legal requirements),

• international inter-comparison with other reference laboratories

• establishing the traceability, stability and conformity of ESTI calibration measurements

• the generation of PV reference materials to be used by secondary measurement laboratories

• the verification of exceptional performance of PV products

• the ongoing development of improved and new measurement methods to validate their implementation into the ESTI quality system and ISO/IEC 17025 accreditation scope

A particular focus in 2018 was on establishing a quantitative measurement and correction procedure for the non-linearity of PV reference cells. This is important in the context of energy rating, as the latter requires the reliable measurement of PV devices at a large range of solar irradiance. Within this activity, ESTI developed for the first time a fully quantitative analysis method for the two-lamp method, and used the results so obtained to provide a quantitative correction for non-linearity effects. This will contribute to a tenfold reduction of measurement uncertainties for solar irradiance at non-standard conditions, namely from 2% to 0.2%.


PV are required achieve the goal of transition to a low carbon energy system. PV solar energy is fundamental in order to realise European and global climate change mitigation goals over the coming 35 years. PV is the renewable energy technology with the largest scope for cost reduction and efficiency gains, as well as exploiting the largest available energy resource: the sun. In order to prepare the PV products to meet this challenging task high quality of PV products and reliable measurement protocols are required. This report describes the activities of JRC scientist in supporting the European Commission goal of becoming the world number one in renewable energies. The JRC plays a prominent role in developing, validating and implementing such measurement protocols, exploiting more than 35 years of expertise developed in ESTI, the European Commission’s reference laboratory to validate electrical performance and lifetime of PV devices.

ESTI is an ISO/IEC 17025 accredited calibration laboratory for PV devices. To guarantee reliable results and international equivalence, ESTI regularly performs comparison with peer laboratories around the world and acts as a reference to secondary national or regional laboratories. The knowledge gained is implemented into international standards harmonising the assessment of the electrical performance of PV products globally.

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Publication date
19 March 2019