This workshop introduces an improved framework for rating the performance of PV modules in real-world conditions. It overviews the need for a new approach, introduces the concept of an ‘energy rating’ and discusses how it can provide a fairer comparison between different PV technologies to benefit both manufacturers and customers.

Aimed at energy consultants, developers of photovoltaic systems, test labs and the R&D community, the workshop will feature a range of industry and research speakers, equip attendees with an accessible, useful and economical framework for comparing PV, and provide a forum for networking with key stakeholders in the photovoltaic community.

Background

Traditionally, PV modules are sold based on the power they produce under standard test conditions (STC). However, this artificial metric does not reflect real-world conditions; temperature, irradiance, angle-of-incidence, spectrum and wind-speed all cause deviations in annually-averaged module efficiencies of up to 20 %. The result is that modules are optimised and selected for STC, not the conditions under which they will actually operate. It also impedes the uptake of emerging and innovative technologies, such as modules optimised for moderate light levels or high temperatures.

An alternative method is to rate the output of solar modules based on a metric that takes into account these real world factors.

A new set of standards, IEC 61853, provides a framework for energy rating of PV, including measurement, modelling and reference meteorological data. These have been developed through the large European research project, PhotoClass, which aims to:

Enhance capability across Europe for the accurate and traceable characterisation of PV modules under different conditions, including developing new techniques to reduce costs
Provide open-access meteorological data and models for evaluating energy rating and uncertainty
Complete the formulation of energy rating standards IEC 61853 and promote of their uptake across the value chain

Uptake of the energy-based metric over traditional power rating will better align the interests of the manufacturer and customer. By encouraging the collection of more data on module performance under different conditions, it enables a fairer comparison between different PV technologies, and improves the accuracy of energy-yield estimates and financial models.

This workshop will explain the new energy-rating standards for PV modules, enabling attendees to make use the standards, understand in more detail the potential benefits to the industry, meet key stakeholders and feedback to identify priorities for future work.

Agenda
09:30 Registration, networking and coffee

10:00 Welcome and meeting aims James Blakesley, NPL

10:15 Session 1: Drivers for accuracy and comparability
Drivers for PV energy rating standards: The IEC perspective
Ralph Gottschalg, CREST, Loughborough University, UK
The value of accuracy in energy-yield forecasting
TBC
Overview of the Photoclass project and current status
Stefan Winter, PTB, Germany
Indoor and outdoor measurements of PV module performance
Markus Schweiger, TÜV Rheinland Energy, Germany
Session and panel Q&A chaired by Fernando Castro

12:00 Lunch

13:00 Session 2: Energy-rating explained
Open-access meteorological data and the energy rating model
Thomas Huld, Joint Research Centre, European Commission
Accurate indoor data for energy rating
Jochen Hohl-Ebinger, Fraunhofer Institute for Solar Energy, Germany
Performance of PV modules under different irradiances and temperatures
Harald Müllejans, Joint Research Centre, European Commission
Session and panel Q&A chaired by Stefan Winter

14:15 Coffee

14:45 Open discussion session on priorities for metrology and standardisation
Session chaired by Harald Müllejans

15:30 Session 3: Future of energy rating and PV performance standards
Requirements of performance standards for BIPV
Steve Pester, BRE, UK
Measurement of current-voltage characteristics of bifacial photovoltaic devices
Nicolas Bassi, Pasan SA, Switzerland
Impact of degradation on long-term energy yields
TBC
Session and panel Q&A by Ralph Gottschalg

16:30 Close

Getting Here
NPL is well served by public transport.
See how to get here for more details.

Energy Rating for Photovoltaics: evaluating real-world performance