Reliability Concerns Associated with PV Technologies (2009)

Nick Bosco. (S. Kurtz) 2010.Reliability Concerns Associated with PV Technologies. National Renewable Energy Laboratory,^[1]

• This document is a non-comprehensive summary of known reliability concerns for PV technologies. It has 3 parts:
  1. List of reliability concerns with corresponding references
  2. Reference list
  3. Prioritization of failures
• Several technologies listed

Solar panel costs 'set to fall (2009)

Anon. 2009.Solar panel costs 'set to fall' ,BBC, November 30, sec. Science & Environment.^[2]

• "EU Energy Institute have found that 90 percent of solar panels last for 30 years or longer, a considerable leap from the 20 years generally recognized by banks and lenders."
• Dr Ossenbrink says 40-year panels will be on the market soon.

Dr. Heinz Ossenbrink presents 22nd EU PVSEC Technical Highlights

• cannot find report?

PV Durability and Reliability Issues (2009)

Allen Zielnik, Atlas Material Testing, 2009. PV Durability and Reliability Issues,Photovoltaics World Magazine, Nov/Dec 2009 - Volume 1 Issue 5,December 3, 2009^[3]

• While there are initial PV qualification tests, such as the IEC and UL requirements, among others, they are neither intended to, nor capable of, predicting long-term performance. As a result, there has been an evolution in the application of accelerated life testing (ALT) and accelerated environmental testing (AET) to the service life prediction (SLP) of PV modules and systems.
• no test program can predict with 100% certainty that a module will properly perform in an environment for 25+ years (except for real-time 25 year testing, of course)

History of accelerated and qualification testing of terrestrial photovoltaic modules: A literature review (2009)

Osterwald, C. R., and T. J. McMahon. 2009. History of accelerated and qualification testing of terrestrial photovoltaic modules: A literature review. Progress in Photovoltaics: Research and Applications 17, no. 1: 11-33.^[4]

• An important facet of this subject is the standard module test sequences that have been adopted by national and international standards organizations, especially those of the International Electrotechnical Commission (IEC). The intent and history of these qualification tests, provided in this review, shows that standard module qualification test results cannot be used to obtain or infer a product lifetime. Closely related subjects also discussed include: other limitations of qualification testing, definitions of module lifetime, module product certification, and accelerated life testing.

Module 30 Year Life: What Does it Mean and Is It Predictable/Achievable? (2000/ 2008)

T. McMahon, G. Jorgensen, R. Hulstrom,2000 "Module 30 Year Life: What Does it Mean and Is It Predictable/Achievable?," National Renewable Energy Laboratory,Conference: National Center for Photovoltaics Program Review, Denver, CO (US), 04/17/2000--04/19/2000. 2000 Apr 11^[5]

• The authors define what they mean by a 30-year module life and the testing protocol that they believe is involved in achieving such a prediction. However, they do not believe that a universal test (or series of tests) will allow for such a prediction to be made. They can test for a lot of things, but they believe it is impossible to provide a 30-year certification for any PV module submitted for test. They explain their belief in this paper.
• Reprinted in: T. McMahon, G. Jorgensen, R. Hulstrom, "Module 30 Year Life: What Does it Mean and Is It Predictable/Achievable?," National Renewable Energy Laboratory, Reliability Physics Symposium, 2008 (IRPS 2008); IEEE Inter., April 27, 2008-May 1, 2008 pp.: 172–177.

The Results of Performance Measurements of Field-aged Crystalline Silicon Photovoltaic Modules (2009)

***Artur Skoczek, Tony Sample and Ewan D. Dunlop, The Results of Performance Measurements of Field-aged Crystalline Silicon Photovoltaic Modules, Progress in Photovoltaics: Research and Applications, Volume 17 Issue 4, 2009, Pages 227 - 240^[6]

Abstract This paper presents the results of electrical performance measurements of 204 crystalline silicon-wafer based photovoltaic modules following long-term continuous outdoor exposure. The modules comprise a set of 53 module types originating from 20 different producers, all of which were originally characterized at the European Solar Test Installation (ESTI), over the period 1982-1986. The modules represent diverse generations of PV technologies, different encapsulation and substrate materials. The modules electrical performance was determined according to the standards IEC 60891 and the IEC 60904 series, electrical insulation tests were performed according to the recent IEC 61215 edition 2. Many manufacturers currently give a double power warranty for their products, typically 90% of the initial maximum power after 10 years and 80% of the original maximum power after 25 years. Applying the same criteria (taking into account modules electrical performance only and assuming 2·5% measurement uncertainty of a testing lab) only 17·6% of modules failed (35 modules out of 204 tested). Remarkably even if we consider the initial warranty period i.e. 10% of Pmax after 10 years, more than 65·7% of modules exposed for 20 years exceed this criteria. The definition of life time is a difficult task as there does not yet appear to be a fixed catastrophic failure point in module ageing but more of a gradual degradation. Therefore, if a system continues to produce energy which satisfies the user need it has not yet reached its end of life. If we consider this level arbitrarily to be the 80% of initial power then all indications from the measurements and observations made in this paper are that the useful lifetime of solar modules is not limited to the commonly assumed 20 year. Copyright © 2008 John Wiley & Sons, Ltd.

• Very detailed study

Reliability of PV Systems, Reliability of Photovoltaic Cells, Modules, Components and Systems (2008)

J. Wohlgemuth, "Reliability of PV Systems, Reliability of Photovoltaic Cells, Modules, Components and Systems," edited by Neelkanth G. Dhere, Proc. of SPIE,Vol. 7048, 704802-1, (2008).^[7]

According to John Wohlgemuth (BP Solar), "Today, BP Solar offers a 25-year warranty on most of its crystalline silicon PV modules…while the modules have to last for 25 years of outdoor exposure, we cannot wait 25 years to see how they perform… no BP/Solarex module has been in the field longer than ten years. Even the oldest 20-year warranty modules have only been in the field 15 years."

• "Examples of accelerated stress tests of use for PV include:
• Thermal cycling;
• Humidity-freeze;
• Damp heat;
• Mechanical load both static and dynamic, and
• Ultraviolet exposure"

The Performance of Crystalline Silicon Photovoltaic Solar Modules after 22 Years of Continuous Outdoor Exposure (2005)

Ewan D. Dunlop and David Halt, 2005."The Performance of Crystalline Silicon Photovoltaic Solar Modules after 22 Years of Continuous Outdoor Exposure", PROGRESS IN PHOTOVOLTAICS: RESEARCH AND APPLICATIONS, DOI: 10.1002/pip.627

• the majority of modules exceeding the level of 92% of Pmax after 20 year, the actual lifetime of these products is significantly more than 20 years.
• Figure 1. Relative power degradation of silicone-encapsulated PV modules after 22 years

20 years of life and more: where is the end of life of a PV module (2005)

Dunlop, E.D.; Halton, D.; Ossenbrink, H.A.;20 years of life and more: where is the end of life of a PV module?, Photovoltaic Specialists Conference, 2005. Conference Record of the Thirty-first IEEE Proceedings 2005, Page(s): 1593 - 1596.^[8]

• no visible evidence that degradation rate is increasing with time
• no defined "end of life" if assume constant continuous degradation, such that life time is well beyond 20 years

Long Term Photovoltaic Module Reliability (2003)

John H. Wohlgemuth, 2003.Long Term Photovoltaic Module Reliability,NCPV and Solar Program Review Meeting 2003, NREL/CD-520-33586 pp 179-183.^[9] Abstract:The reliability of crystalline silicon PV modules has improved dramatically over the years. Module warranties of 25 years are now common. Extension of the warranties to 25 years was based on excellent field results for modules with 10 year warranties and on extensive accelerated testing. Since none of the 25 year warranty modules have been in the field that long, we do not know how or when they will eventually fail. It is important for the PV industry to know this, because it impacts the ultimate useful life of our PV systems, it provides critical input for future improvements in module reliability and it provides important data on the long term wear out or failure of today's crystalline silicon PV modules.

• Failure modes covered

MTBF - PVm, Mean Time Before Failure of Photovoltaic modules (2003)

Antonella Realini, 2003. "MTBF - PVm, Mean Time Before Failure of Photovoltaic modules",Final report BBW 99.0579, June 2003,58 pages^[10]

• Extensive MTBF project under Solarec. Very detailed study.
• Results after 20 year study (indoor)

▪ 59% of the modules exhibited a decrease lower than -10% to the stated nominal power ▪ 35% of modules exhibited a decrease between -10% and -20% ▪ only the 6% of modules showed a decrease greater than -20%.

• The perspective to produce commercial modules with lifetimes of 30 years Italic textor more is so realizable, trying to avoid the degradation mechanisms which could compromise modules efficiency and lifetime (in particular encapsulant delamination and hot-spot formation).

Life Expectancy of Solar Panel

Life Expectancy of Solar Panels

• Andy Black, one of the leading solar financial analysis experts and instructor, recently published his report on the lifespan of solar panels. His analysis showed that the first solar panels manufactured about 40 years ago are still creating power at about 80% of their original power. From that study combined with his other analysis, he concluded that most solar panels will lose about a half percent a year in efficiency.

*Mono-crystalline Silicon

Sustainability of photovoltaics: The case for thin-film solar cells (2009)

Vasilis Fthenakis, Sustainability of photovoltaics: The case for thin-film solar cells, Renewable and Sustainable Energy Reviews, Volume 13, Issue 9, December 2009, Pages 2746-2750,^[11]

Abstract: To ensure photovoltaics become a major sustainable player in a competitive power-generation market, they must provide abundant, affordable electricity, with environmental impacts drastically lower than those from conventional power generation. The recent reduction in the cost of 2nd generation thin-film PV is remarkable, meeting the production milestone of $1 per watt in the fourth quarter of 2008. This achievement holds great promise for the future. However, the questions remaining are whether the expense of PV modules can be lowered further, and if there are resource- and environmental-impact constraints to growth. I examine the potential of thin-films in a prospective life-cycle analysis, focusing on direct costs, resource availability, and environmental impacts. These three aspects are closely related; developing thinner solar cells and recycling spent modules will become increasingly important in resolving cost, resource, and environmental constraints to large scales of sustainable growth.

*Amorphous Silicon

*In Ga N

*CIGS

Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate

Ham et al. Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate. Nature Chemistry, 2010; DOI: 10.1038/nchem.822 Plants are good at doing what scientists and engineers have been struggling to do for decades: converting sunlight into stored energy, and doing so reliably day after day, year after year. Now some MIT scientists have succeeded in mimicking a key aspect of that process. New Self-Assembling Photovoltaic Technology Repairs Itself, ScienceDaily Sept. 6, 2010.

Preliminary Situation Analysis: Advances in Photovoltaic Technologies (2010)

Energetics Incorporated, 2010. Preliminary Situation Analysis: Advances in Photovoltaic Technologies, Workshop on Grand Challenges for Advances in Photovoltaic Technologies and Measurements, Denver, Colorado, May 11-12, 2010.

• Standards, market challenges, measurement issues, contacts fo various PV researchers

PV Status Report 2009 - Research, Solar Cell Production and Market Implementation of Photovoltaics (2009)

European Commission Joint Research Centre (EU JRC), 2009,PV Status Report 2009 - Research, Solar Cell Production and Market Implementation of Photovoltaics,JRC Scientific and Technical Reports (EUR collection)

• The current solar cell technologies are well established and provide a reliable product, with sufficient efficiency and energy output for at least 25 years of lifetime.
• The average lifetime of a residential home is 25 to 35 years and corresponds well with the lifetime of solar modules.
• feed-in tariffs and other incentives covered
• One of the research issues is ensuring module lifetime >35years

Accelerated Aging Testing and Reliability in Photovoltaics Workshop II (2008)

U.S. Department of Energy, Accelerated Aging Testing and Reliability in Photovoltaics Workshop II, Summary Report, April 1 & 2, 2008.

Workshop Proceedings of the "1st International Workshop Thin Films in the Photovoltaic Industry (2005)

European Commission Joint Research Centre (EU JRC), 2005,Workshop Proceedings of the "1st International Workshop Thin Films in the Photovoltaic Industry" 10/11 November 2005,JRC Scientific and Technical Reports (EUR collection)

• The various thin film technologies (TF) have the highest cost reduction potential of all PV technologies in middle and long term. Equally, competitive technologies are amorphous/microcrystalline Silicon, CdTe and the material family of Cu (In,Ga)(Se,S)2. thin films.
• summary of presentations, lifetime prediction still a challenge
• PV System Assessment in Performance - Towards Maximun Output

SolarCity [Canada]

http://web.archive.org/web/20160402150549/http://www.solacity.com:80/pricingcad.htm

• The Eoltec Scirocco and Power-One electronics come standard with 5 years of warranty. There is an extended warranty available for the Aurora inverter, PVI-6000-OUT-US-W, taking the Aurora inverter to 10 years total warranty. See the list for pricing.

Example:

• Power-One 3kW Aurora inverter PVI-3.0-OUTD-US: $2,275
• Power-One 3kW Aurora inverter /w DC disc. PVI-3.0-OUTD-S-US: $2,695
• Power-One 15 year warranty option for PVI-3.0-OUTD-US: $910
• Power-One 20 year warranty option for PVI-3.0-OUTD-US: $1,595

PV Powered Commercial Inverters

• PV Powered has always included an industry leading 10-year standard warranty with all their commercial

inverters sold anywhere in the US and Canada. Now PV Powered raises the bar again by offering an option to extend the standard 10-year warranty to a full 20 years for just 20% of the original sales price. Ask for the 20/20 Warranty the next time you buy a commercial inverter.

Prolonging PV module life by improving inverter maintenance and manufacturing

Module Behavior, Apr 1, 2009 12:00 PM, By Beck Ireland, Staff WriteR- Prolonging PV module life by improving inverter maintenance and manufacturing

• "In comparison to the decades-long warranty for the cells, mean time to first failure (MTFF) for inverters is estimated to be between five and 10 years (see Reasons Inverters Fail below)."- Reasons inverters fail in the article
• "Luckily, there are maintenance procedures that can extend the life span of the inverters. "Electricity performs better under cool conditions," Haney says. "By cleaning off the heat sinks, you allow it to run cooler, which is more efficient." "
• An issue that energy output of PV drops below that required by the inverter and it muct be changed
• "The inverter accounts for 10% to 20% of the initial system cost, according to a report from the National Renewable Energy Laboratory (NREL), Golden, Colo., in conjunction with Navigant Consulting, Inc. (NCI), Burlington, Mass. However, because inverters generally need to be replaced every 5 to 10 years, they result in investment in a new inverter three to five times over the life of a PV system. "

SolarBuzz Inverter Price Indicies

As of Sept 2010: US$0.72/W continuous =>2.5kW ~ US$1800

Extended Warranties for Fronius PV Inverters

• http://www.fronius.com/cps/rde/xbcr/SID-7239D476-365FE811/fronius_espana/Extended_warranties_for_Fronius_PV_inverters_EN_126951_snapshot.pdf
• Warranties from 10 to 20 available: Cost is variable- contact sales

Xantrex Inverters via Solar Direct

• http://www.solardirect.com:80/pv/inverters/xantrex-gt5.htm
• 5 year standard, 10 year extended warranty
• Cost depends on estimate- contact sales

Solar PV Projects

Solar PV Projects, Gennadi Saiko,15 Sept.

• "For inverters, the industry standard is 5 years on parts and labour. It is well known that the typical life span of an inverter is around 15-20 years; so the possibility that you will have to change the inverter during the 20 year timeframe (e.g. span of FIT contracts in Ontario) is not unlikely. For this reason, you may consider buying extended warranty or inverters with warranty above the industry standards (clearly these will cost more). "