New solar radi­a­tion dataset published

In order to keep our pow­er grid sta­ble and to mar­ket solar pow­er on the stock exchange, pre­cise pro­jec­tions and fore­casts of pho­to­volta­ic gen­er­a­tion are becom­ing increas­ing­ly impor­tant. To improve this, the Fraun­hofer Insti­tute for Solar Ener­gy Sys­tems ISE and the trans­mis­sion grid oper­a­tor TransnetBW have set up a net­work of mea­sur­ing sta­tions in the “PV-Live” project, with which the cur­rent irra­di­a­tion con­di­tions in the grid area are record­ed every minute. These data are also very valu­able for solar ener­gy mete­o­rol­o­gy research.
The project part­ners are now mak­ing the first qual­i­ty-con­trolled data sets with mea­sured val­ues since Sep­tem­ber 2020 pub­licly available.

For “PV-Live”, the Fraun­hofer ISE research team devel­oped a mea­sur­ing sta­tion which uses pyra­nome­ters to record the glob­al radi­a­tion on the hor­i­zon­tal and the tem­per­a­ture as well as — with three dif­fer­ent­ly ori­ent­ed sil­i­con ref­er­ence cells — the radi­a­tion on inclined sur­faces as the basis for sim­u­lat­ed PV pow­er val­ues. In the con­trol area of the Baden-Würt­tem­berg trans­mis­sion sys­tem oper­a­tor TransnetBW, a total of 40 of these mea­sur­ing sta­tions were installed at inter­vals of 15 to 35 kilo­me­tres by March 2019. The sta­tions are locat­ed at project part­ners and com­pa­nies, but also at munic­i­pal util­i­ties of cities in Baden-Würt­tem­berg. The radi­a­tion val­ues are trans­mit­ted from the mea­sur­ing sta­tions in real time every minute, qual­i­ty con­trolled at Fraun­hofer ISE, con­vert­ed into PV pow­er and made avail­able to TransnetBW. The col­lect­ed data is com­bined with satel­lite-based irra­di­a­tion val­ues to pro­vide a spa­tial­ly and tem­po­ral­ly high-res­o­lu­tion pic­ture of the cur­rent PV gen­er­a­tion and thus the result­ing feed-in to the pow­er grid.
“The nov­el con­cept for the mea­sur­ing sta­tions and data acqui­si­tion was devel­oped in close coop­er­a­tion between Fraun­hofer ISE and TransnetBW,” explains Dr. Flo­ri­an Dinger, head of spe­cial tasks Algo­rithms and Fore­casts at TransnetBW. “We see the coop­er­a­tion between indus­try, sci­ence and soci­ety as an impor­tant pil­lar of the ener­gy tran­si­tion. Accord­ing­ly, we are mak­ing the new high-res­o­lu­tion dataset avail­able to the pub­lic research com­mu­ni­ty of solar ener­gy meteorology.”

Qual­i­ty con­trolled minute val­ues of solar irra­di­a­tion for dif­fer­ent­ly inclined surfaces

The dataset of read­ings tak­en every minute since Sep­tem­ber 2020 has now been pub­lished. Before pub­li­ca­tion, the irra­di­ance and tem­per­a­ture data go through a qual­i­ty con­trol scheme with algo­rithms spe­cial­ly adapt­ed for this data set. The auto­mat­ed real-time data pro­cess­ing and qual­i­ty con­trol were set up togeth­er with Mon­das GmbH, a spin-off of Fraun­hofer ISE. The datasets are avail­able for use by researchers and oth­er inter­est­ed par­ties. Mea­sure­ment data will con­tin­ue to be col­lect­ed and reviewed and pub­lished as month­ly updates.
“Thus, for the first time, research in solar ener­gy mete­o­rol­o­gy has a tem­po­ral­ly high­ly resolved mea­sure­ment data set of solar irra­di­ance at its dis­pos­al, which cov­ers the entire area of Baden-Würt­tem­berg. This allows inves­ti­ga­tions of spa­tial and tem­po­ral fluc­tu­a­tions and smooth­ing effects, which are very impor­tant for feed­ing solar elec­tric­i­ty into the pow­er grids,” explains Dr. Elke Lorenz, Group Leader Ener­gy Mete­o­rol­o­gy at Fraun­hofer ISE.
Anoth­er spe­cial fea­ture of “PV-Live” is the simul­ta­ne­ous mea­sure­ment of solar radi­a­tion with dif­fer­ent­ly ori­ent­ed sen­sors. While mete­o­ro­log­i­cal mea­sur­ing net­works usu­al­ly mea­sure in the hor­i­zon­tal plane, these inclined sen­sors record the solar radi­a­tion as it impinges in prac­tice on solar mod­ules installed on roofs or in ground-mount­ed sys­tems. This is rel­e­vant, for exam­ple, for the devel­op­ment and val­i­da­tion of mod­els for radi­a­tion at the lev­el of the solar module.

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