Solar thermal first

Inaugural IEC publications for solar thermal electric plants

By Catherine Bischofberger

IEC TC 117: Solar thermal electric plants, publishes its first two Technical Specifications (TS) on solar radiation data sets.

STE plant in desert STE plants use reflective material to concentate the sun's heat

Concentrating solar thermal power (CSP) technologies, which employ reflective material to concentrate the sun’s heat to drive steam or gas turbines to produce electricity, are used in solar thermal electric (STE) plants. The number of STE plants is rising around the world, together with the increasing reliance on renewable sources of energy.

According to the Renewables 2017 Global Status Report, from REN21, an international non-profit association which is part of the United Nations environment programme (UNEP), emerging countries with high levels of solar exposure, no or few oil and gas reserves and with a political agenda that favours industrialization and job creation, are increasingly likely to adopt policies favouring the building of such facilities. Most new STE plants can store heat during the day and convert it into electricity at night, making solar thermal attractive for large-scale energy production. As STE plants are situated in sun-drenched areas of the world, they are also a source of predictable and reliable energy.

Spain leads the way

According to the REN21 report, while Spain remains the global leader in installed CSP capacity, new facilities have recently come online in countries including South Africa, China and Morocco. STE projects are on-going in India, Israel and the Middle East.

IEC TC 117: Solar thermal electric plants, was established in 2011, following a proposal from the Spanish National Committee (NC), to draft International Standards in the CSP field. It augured the growth of CSP capacity across the world and the requirement for such Standards. The scope of TC 117 is to prepare International Standards for the conversion of solar thermal energy into electrical energy in STE plants. The Standards are expected to cover current different types of systems in installed plants:

  • Parabolic trough
  • Solar tower
  • Linear Fresnel
  • Dish
  • Thermal storage

Blazing a trail

Simulation studies of plant power production are often required during the various stages of planning, design and building of an STE plant. A standard methodology based on the annual solar radiation (ASR) data set is used to generate data representative of a typical meteorological year and to extrapolate plant production over the long term.

As the Chair of TC 117 Werner Platzer explains: "For the financing of projects, we need a reliable, comprehensive and unambiguous calculation of future generation throughout the lifetime of plants. This can be predicted with representative meteorological data and a precise simulation and prediction of the yield using the meteorological data. The newly published Technical Specifications deal with the question of how to prepare such data sets."

TC 117 has issued its two first publications, IEC Technical Specification (TS) 62862-1-2:2017, Solar thermal electric plants-Part 1-2: General – Creation of annual solar radiation data sets for solar thermal electric (STE) plant simulation and IEC TS 62862-1-3:2017, Solar thermal electric plants – Part 1-3: General - Data format for meteorological data sets.

The first Technical Specification defines the procedures for the creation of ASR data sets used in STE plant simulation. The document also describes the components and parameters of an ASR data set, including factors such as geographic and time identification.

The scope of the second TS is to reduce the efforts involved in preparing data exchange and to avoid misunderstandings rising from the use of different data formats for meteorological data sets. It proposes one format which demonstrates:

  • Suitability for common operation systems
  • Suitability for satellite/model-derived data
  • Suitability for measured data
  • Suitability for combined data sets
  • Suitability for typical meteorological years and forecasted data

The data format proposed has been inspired by the thesaurus on solar radiation proposed at EnvironInfo 2007.

solar tower Tower plants are one type of STE production unit
STE plant in desert STE plants use reflective material to concentate the sun's heat
17193368499_47d473dcf1_b Most new STE plants can store heat at night