Will Perovskite Solar Panels Be Better for LEED Buildings?

LEED architects earn credit for using strategies such as designing buildings to be highly energy efficient, water efficient or by using building materials that contain recycled content.

With the launch of LEED v4, LEED changed radically from its prior version with its addition of Life-Cycle Analysis (LCA), also known as Life-cycle Assessment, and Environmental Product Declarations (EPD) as core aspects of the Materials and Resources (MR) credit category.

A Life-Cycle Analysis (LCA) traces the origins of a particular building material or product, from the mining of its raw materials until the end of its life.

With LEED v4, LEED project teams are now rewarded for conducting a whole building LCA of the project’s structure and enclosure.

Using energy efficiency strategies, such as on-site renewable energy through solar PV, and using materials that are documented to have less environmental impact from cradle to grave is congruent with the spirit of MR Credit Building Life-Cycle Impact Reduction.

Also, using Perovskite-based solar panels could arguably qualify the design team to be awarded an Innovation point for addressing a design strategy that LEED v4 does not specifically address.

LEED v4 MR Building Life-Cycle Impact Reduction Credit

The aim of the Life-Cycle Impact credit option is to measure the impact of the product on the environment throughout the product’s entire lifecycle.

Project teams pursuing the LCA option will have a better understanding of the cumulative energy use and other environmental consequences resulting from all phases of the building’s life. The LCA will also help the project team determine which materials best fit the project’s needs throughout the building’s lifetime.

To achieve this option the proposed building must demonstrate at least a 10% reduction in global warming potential and a 10% reduction of two of five other impact areas, such as “depletion of nonrenewable energy resources” or “ozone depletion potential” (each is discussed in the LEED BD+C Reference Guide) when compared to a baseline building, without increasing any measure by more than 5%.

Perovskite Solar Panels

Perovskite is not only one of Earth’s most abundant minerals (calcium titanium oxide), it can also be used to make efficient solar panels.

Consensus among solar industry experts is that perovskite boasts both low cost and high power conversion efficiency, promising attractive economic and technological performance improvements in renewable energy in the years to come.

Indeed, in 2013 Science magazine listed perovskite solar cells as one of the year's ten biggest breakthroughs. "A new breed of materials for solar cells burst into the limelight this year", the citation stated.

The pace at which new technical advancements are being made in perovskite energy production efficiency is breathtaking, especially when compared to the efficiency of silicon based panels. As can be seen in the chart to the right, advances in perovskite PV productivity have happened extremely fast, compared to silicon materials, which are the industry standard.

Perovskites are cheap, easy to make, and already capable of converting 15% of the energy in sunlight to electricity.

The most important aspect of perovskite, however, may be its affordability.

A report by Kevin Bullis in the MIT Technology Review indicated:

"Researchers developing perovskite technology say that it could lead to solar panels that cost just 10 to 20 cents per watt. Solar panels now typically cost about 75 cents a watt, and the U.S. Department of Energy says 50 cents per watt will allow solar power to compete with fossil fuel."

Perovskite Cells Have Less Environmental Impact

A new study by the U.S. Department of Energy’s Argonne National Laboratory published in the journal Energy & Environmental Science and the Royal Society of Chemistry indicates that perovskite solar technology slashes the energy used in making solar panels.

The team performed Life-Cycle Analyses on two types of perovskite solar modules, including all of the components used in the modules. The team measured impact variables such as “Energy Pay Back Time” (EPBT) and CO2 emissions.

The EPBT of solar panels is defined as the time it takes for panels to produce electricity equivalent to sum of all the energy needed to mine, process and purify raw materials, and to manufacture and install the final product.

Perovskite solar modules have an 'energy pay back time' (EPBT) of just two to three months.

Silicon solar panels, the most commonly used today, may take between 30 months to four years to 'pay back' the energy used in their manufacture. Another type of solar panel defined as amorphous silicon comes out slightly better at under two years of EPBT.

While perovskites currently lag behind silicon in conversion efficiency, they require much less energy to be made into a solar module.

So perovskite modules pull ahead with a substantially shorter EPBT - the shortest, in fact, among existing options for solar power.

While solar modules manufactured from perovskite are still being researched and developed in labs, and have not yet been commercialized, when they are ready solar PV made from perovskite may offer another option for LEED project teams seeking on-site renewable energy with less environmental impact.

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Centerpoint Solar photo credit Rob Freeman via Flickr