Sustainable Sunshine: A New Standard for Environmentally-Friendly Solar Panels

by | May 24, 2019

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Solar photovoltaics (PV) are a key technology in the global clean energy transition. PV generates no use-phase emissions and can reduce electric grid emissions by displacing emitting generators. However, PV still entails up- and downstream environmental impacts during its life-cycle. In particular, PV modules – the panels that encase the conductive materials used to convert sunlight into electricity – entail upstream impacts during materials mining and manufacturing and downstream impacts from end-of-life disposal.

These environmental impacts may become more salient as more PV is deployed: the International Energy Agency projects that global PV capacity will grow from about 400 gigawatts today to about 2,000 gigawatts by 2040 under existing policies and could exceed 4,000 gigawatts in 2040 under a more ambitious global clean energy policy regime. Addressing the up– and downstream environmental impacts of PV modules will be a key challenge as the industry scales.

Some PV module manufacturers have already integratedsustainability into their manufacturing processes. For instance, some manufacturers take back their modules for end-of-life recycling or have conflict-free mineral sourcing policies. However, it is currently difficult for PV buyers to identify PV modules with sustainability attributes. Further, until recently there was no standard to verify the sustainability of different modules. But that has begun to change.

In 2015 the Green Electronics Council initiated a process to develop an objective, verifiable standard to define high sustainability performance for PV module manufacturing and disposal. Following American National Standards Institute rules, a standard-development committee was formed, comprising a balanced mix of manufacturers, researchers, and users. In December 2017, the committee finalized and published the “Sustainability Leadership Standard for PV Modules” (SLS-PV). The SLS-PV defines sustainability criteria and scoring for PV modules across seven performance categories:

management of substances;
preferable materials use;
life-cycle assessment;
energy efficiency and water use;
end-of-life management and design for recycling;
product packaging; and
corporate responsibility.

(More information is available here.)

As the ink dries on the SLS-PV, several processes are moving forward in parallel to prepare industry to incorporate the new standard. First, the SLS-PV will be added to the well-known EPEAT Registry of sustainable electronic products used by large buyers like the US federal government and corporations. Once in EPEAT, PV modules can be certified to three levels of performance—bronze, silver, and gold—depending on how many SLS-PV criteria are met by the modules. Second, module manufacturers have begun to pursue SLS-PV certification. To our knowledge, at least three manufacturers are currently exploring certification. Third, to meet stakeholder demand, the SLS-PV is being expanded to include PV inverters (devices that “invert” the direct current output of PV modules to alternating current used by our electric devices).

The long-term impact of SLS-PV remains uncertain. In part, this uncertainty stems from a chicken-and-egg problem: PV manufacturers will only certify if there is sufficient market demand for SLS-certified modules, and PV buyers will only buy SLS-certified modules if there are enough certifying manufacturers to support a competitive market.

Researchers at the National Renewable Energy Laboratory (NREL) have begun to research this dilemma. Preliminary results suggest that enough latent demand for sustainable modules may exist to drive manufacturers to certify. Our research suggests that the SLS-PV could align well with existing procurement initiatives. For instance, currently, U.S. federal government agencies are required to procure EPEAT-registered electronic products. Once the SLS-PV is added to the EPEAT Registry, federal procurement officers may have a rationale if not a requirement to buy SLS-certified modules for federal PV purchases.

In the corporate sector, well over 100 corporations have committed to buying renewable energy under various initiatives such as RE100. Corporate buyers and other stakeholders expressed interest in SLS-PV during interviews with NREL and suggested that SLS-PV could play into these various corporate PV procurement initiatives. Several utilities expressed similar interest, stating that SLS-PV certification could be added as acriterion for selecting vendors during utility PV power procurement.

The development of the SLS-PV could represent a significant milestone for the PV industry. For the first time, PV buyers will be able to consult an objective, verifiable, consensus-based standard for sustainable PV modules, and identify conforming products in a public registry. Depending on the demand for and supply of SLS-certified modules, the standard could help mitigate the up– and downstream environmental impacts of PV modules as the industry scales from hundreds to thousands of gigawatts.

By Eric O’Shaughnessy (Analyst), David Smith (Business Intern) and Garvin Heath (Senior Scientist), National Renewable Energy Laboratory


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