China's Tongwei Group Plans World's Biggest Solar-Cell Plant (5GW/yr)

[kristopher]

16. Are you saying you expect your panels to suddenly go kaput in 3 years?

Just as 3 years means nothing about the life of an automobile, 25 years is a warranty figure that bears no known relationship to the actual expected life of silicon solar panels.

Solar Panels Creating Electricity for Much Longer than 20 Years
December 27th, 2011 by Zachary Shahan

As indicated in a study Josh wrote on just a couple weeks ago, the lifespan of a solar power system is far longer than the 20 years most analysts use to calculate solar power costs. Last November, Susan featured one that was going strong at 30 years. A Facebook fan notes that solar panels at the Technical University of Berlin have been in operation for 31 years. Similarly, Kyocera, one of the oldest solar panel manufacturers in the world, recently posted on the fact that a number of its early installations continue to generate electricity reliably nearly 30 years after installation.

I would also note that technology has improved, solar panels have become more durable, and if early solar panels produce electricity for far more than 20 (or even 25) years, what to expect of today’s solar panels?!

Here are a few case studies Kyocera highlighted in its recent article on the matter:

- In 1984, Sweden’s first grid-connected photovoltaic system was built in Stockholm. Since its installation, the façade-mounted 2.1kW system has been continuously and reliably providing the residents of an apartment building with environmentally-friendly electricity. The modules’ average annual power generation performance is still reliable — with no significant change since the system was installed 27 years ago.

- Also in 1984, Kyocera established its Sakura Solar Energy Center just outside of Tokyo. At the time, the Center was equipped with a 43kW solar power generating system which to this day continues to generate a stable amount of power for the facility.

- In 1985, Kyocera made a donation of a 10kW solar power generation system to a small farming village with no electrical infrastructure located at an elevation of 2,600m (8,500ft) in Gansu Province, China. In 1993, the area received electrical infrastructure, and the solar modules were moved to a regional research facility for clean energy, where after more than 25 years, they are still producing consistent levels of electricity.

http://cleantechnica.com/2011/12/27/solar-panels-creating-electricity-for-much-longer-than-20-years/

Or if you prefer a more analytic approach:

National Renewable Energy Laboratory

Photovoltaic Degradation Rates — An Analytical Review
Dirk C. Jordan and Sarah R. Kurtz

Abstract
As photovoltaic penetration of the power grid increases, accurate predictions of return on investment require accurate prediction of decreased power output over time. Degradation rates must be known in order to predict power delivery. This article reviews degradation rates of flat- plate terrestrial modules and systems reported in published literature from field testing throughout the last 40 years. Nearly 2000 degradation rates, measured on individual modules or entire systems, have been assembled from the literature, showing a median value of 0.5%/year. The review consists of three parts: a brief historical outline, an analytical summary of degradation rates, and a detailed bibliography partitioned by technology.

1. Introduction
The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Two key cost drivers are the efficiency with which sunlight is converted into power and how this relationship changes over time. An accurate quantification of power decline over time, also known as degradation rate, is essential to all stakeholders—utility companies, integrators, investors, and researchers alike. Financially, degradation of a PV module or system is equally important, because a higher degradation rate translates directly into less power produced and, therefore, reduces future cash flows [1]. Furthermore, inaccuracies in determined degradation rates lead directly to increased financial risk [2]. Technically, degradation mechanisms are important to understand because they may eventually lead to failure [3]. Typically, a 20% decline is considered a failure, but there is no consensus on the definition of failure, because a high-efficiency module degraded by 50% may still have a higher efficiency than a non-degraded module from a less efficient technology. The identification of the underlying degradation mechanism through experiments and modeling can lead directly to lifetime improvements. Outdoor field testing has played a vital role in quantifying long-term behavior and lifetime for at least two reasons: it is the typical operating environment for PV systems, and it is the only way to correlate indoor accelerated testing to outdoor results to forecast field performance.
Although every reference included in this paper contains a brief to slightly extensive summary of degradation rate literature, a comprehensive review could not be found. This article aims to provide such a summary by reviewing degradation rates reported globally from field testing throughout the last 40 years. After a brief historical outline, it presents a synopsis of reported degradation rates to identify statistically significant trends. Although this review is intended to be comprehensive, it is possible that a small percentage of the literature may not have been included...

http://www.nrel.gov/docs/fy12osti/51664.pdf