Value chain · CLM-1310
In plain terms
The 2016 guidelines recommend default lifetime, wear-out and performance numbers for a ground solar energy-return study, and list 16 facts every study must report. An SBSP figure can be checked against the same list to see whether it is comparable.
The claim as recorded
For PV net energy studies the guidelines give default figures: a 30-year life for modules, supporting structure, transformers, cabling and large inverters and 15 years for small inverters; a performance ratio of 0.75 for rooftop and 0.80 for ground-mounted systems; and linear degradation of 0.7 per cent a year by default with 0.5 per cent as a sensitivity case. Irradiation is to reflect actual orientation, shading and site. Reporting 16 items is mandatory, including PV technology, system type, module efficiency and degradation (if not in the performance ratio), module and balance-of-system lifetimes, location, irradiation and yield, whether EROI_el or EROI_PE-eq is used and the grid efficiency assumed, goal, system boundary, any non-process method, LCA database and software with versions, primary energy factors, and input-material assumptions.
Evidence behind this: T3: an IEA-PVPS Task 12 methodology guideline with named authors. Its defaults are recommendations; not the normative-instrument (T1) case, as ruled for SRC-187 on 2026-09-11.
Scope and limits
The defaults are for terrestrial PV. They say nothing about cell degradation in orbit, where radiation damage applies, so they cannot be carried over to SBSP. This record does not check any SBSP figure (CLM-0145, CLM-1038) against the 16 items. The averaging arithmetic is the register's own. The companion document cited on PDF p.22 is the 2016 3rd edition of the guidelines held as SRC-187 (2020, 4th edition). The 4th edition (SRC-187 PDF p.10 to 12) keeps the performance ratios and the 0.7 and 0.5 per cent degradation rates, but gives large inverters 30 years with 10 per cent part replacement every 10 years and ground-mounted metal supports 30 to 60 years, and puts the average yield loss over 30 years at 10.5 per cent at 0.7 per cent a year and 7.5 per cent at 0.5 per cent. The net energy guidelines' 2021 second edition (IEA-PVPS T12-20:2021) has not been read.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.22: the defaults as stated; "assume linear yearly degradation rates of 0.7% (default)"; details deferred to the companion LCA guidelines, cited in their 2016 3rd edition (PDF p.32), sections 3.1.1 to 3.1.4 (paraphrase). PDF p.16 footnote 4: the performance ratio is "assumed to include age-related degradation", so the worked example in CLM-1307 carries degradation inside PR 0.75 rather than applying it separately (our reading). PDF p.30: items 1 to 16 listed as mandatory, items 1 to 6 to appear in figure and table captions (paraphrase); repeated in the summary on PDF p.3-4. Our arithmetic: linear degradation from year 0 averages 1 - 0.007 x 14.5 = 0.899 of first-year output over 30 years at 0.7 per cent, and 0.928 at 0.5 per cent (assumes first-year output undegraded; the document does not state this calculation).
Basis: years of life; performance ratio in MJ/MJ; linear degradation in per cent a year
Related records
- Answers question
- QST-021 not published in this release
Cite this
energyaperture.com/c/clm-1310
CLM-1310, Energy Aperture, as of 2016-01.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-187
- CLM-0316In 2009 three researchers guessed that, once the energy to deliver and use it is counted, an oil-based fuel must return at least about 3...
- Also from SRC-646
- CLM-0316In 2009 three researchers guessed that, once the energy to deliver and use it is counted, an oil-based fuel must return at least about 3...CLM-1307An "energy return" figure for solar power can be stated in two ways, counting the electricity itself or counting the fuel a power station...CLM-1308"Energy payback time" and "energy return" are two views of one calculation and can be converted only when the lifetime and counting method...CLM-1309A fair energy-return comparison of SBSP with ground solar counts the same things for both: the energy to build, run and scrap each...