The Solar Energy Multiverse Keeps Expanding: Perovskites, Shape-Shifting Molecules, & More
For all the activity in the solar energy marketplace, PV technology has barely even begun to hit the global economy in full force. Huge solar arrays filled with rows of super-efficient silicon solar panels are just one piece of an expanding universe. With that in mind, here are 4 new developments that could kick the slow pace of change into high gear.
1. Distributed Solar Energy
Distributed renewables are a big deal for the US Department of Energy and other solar energy planners, but they generally don’t catch the media spotlight. That’s because they tend to be small. On an individual basis, distributed energy resources range down to the kilowatt scale. They are easily eclipsed by huge multi-million megawatt PV arrays.
However, when distributed resources are totaled up, the results can be stunning.
The latest example comes from New York State, where Governor Kathy Hochul has just announced a new distributed solar program aimed at 10 gigawatts by 2030.
The public-private plan is significant because it builds on the successful NY-Sun PV afforadability program, which aims at filling a huge, gaping hole in the small-scale solar marketplace that limits access by wide swaths of the economy.
If all goes according to plan, by 2030 the expanded NY-Sun program will provide disadvantaged communities and low-to-moderate income households in New York State with a solar power boost of at least 1,600 megawatts.
The plan also involves a commitment to assign at least 450 megawatts to Con Edison’s service territory in New York City and Westchester County, and another 560 megawatts to Long Island through the Long Island Power Authority. If you have any idea how they’re going to wedge thousands of new PV panels into a region already saturated with infrastructure, drop us a note in the comment thread.
As for the cost of the expanded NY-Sun plan, the Governor’s office expects that the average residential bill will go up by only $0.71 per month.
2. More Good News About Solar Energy, With Perovskite
Both the cost and the siting aspects of the NY-Sun solar distributed energy plan could be upended in the next few years, but in a good way, by new organic thin film technology. In contrast to stiff, bulky silicon solar cells, thin film is lightweight and flexible, providing a far greater range of opportunities to collect solar energy on existing infrastructure.
Thin film is also relatively inexpensive. The “organic” part of the name refers to the use of carbon polymers, aka plastics. Manufacturing and application costs are also a factor. Thin film can be produced at high volumes and sprayed, painted or printed onto surfaces, both of which help push down the total installed cost of solar energy.
There being no such thing as a free lunch, earlier iterations of thin film did not come close to matching the solar energy conversion efficiency of silicon solar cells.
More recently, researchers have come up with a series of record-setting twists on the technology. That includes deploying perovskites, a class of finicky materials with superior optical properties. With the rough edges sanded off, perovskites can be deployed to boost the conversion efficiency of organic thin film.
The challenge for fans of the organic-perovskite tandem solar cell mashup is trying to get the two substances to work together. From a solar conversion perspective, it’s like trying to fit a piece of one puzzle into another.
Last month, a research team in Germany came up with a new solution to the organic-perovskite problem. As reported by the University of Cologne, the researchers built their project on previous research indicating that tandem solar cells are a promising pathway. Specifically, they added a tweak to tandem cells that deploy organic semiconductors to harvest solar energy in the form of ultraviolet and visible light, and perovskite to harvest near-infrared light.
They got impressive results from inserting a nano-thin layer of indium oxide into the cell, reporting a solar conversion efficiency of 24% compared to a previous record of 20% for solar cells of that type.
That’s even more impressive when you consider that perovskites were first investigated for PV applications in 2009, with a reported conversion efficiency of just 3%. That’s an incredibly rapid pace of improvement for new solar technology.
3. Floating Solar
Floating PV is another new field that’s taking off like a rocket. As the name indicates, the idea is to float solar panels onto a body of water, typically a reservoir or other human-made structure. Quarry lakes have become another target.
The floating solar field provides a workaround for conflicts with agriculture and other land use issues. When attached to an existing hydropower dam, they can also take advantage of existing transmission infrastructure. Developers are also attracted by the idea of saving money on construction, because there is no need to prep the underlying ground.
It looks like water treatment plants are next on the floating PV list. Earlier this year, The Times of India reported on one such project that indicates many more could be in store. The plant operators point out that situating the solar array on the untreated side of the facility enables them to recycle the water used for washing dust and grime from the panels.
The explosive growth of the offshore wind industry is adding yet another twist, making it possible to situate solar panels out at sea.
4. Long Duration Energy Storage
Energy storage is the key that unlocks the full potential of solar energy, but as of now the technology for storing large amounts of solar energy for long periods of time is practically non-existent. The go-to technology mainly consists of lithium-ion batteries, which only provide for a few hours at a time. That can fit many use cases, but a global economy that relies on intermittent energy harvesting will require new technologies that can provide for days, weeks, and seasons of storage.
Much of the attention around long duration solar energy storage has been turning to various forms of kinetic or gravity-enabled devices.
Another approach is illustrated by a team of researchers from Chalmers University in Sweden, in collaboration with a team in Shanghai. Last month, Chalmers reported progress on its “Molecular Solar Thermal Energy Storage Systems,” which deploys a shape-shifting molecule.
5. The Hydrogen Connection
Of course, no mention of solar energy is complete without taking note of the green hydrogen trend, where much of the activity involves using solar or wind energy to push hydrogen gas out of water. Hydrogen fuel cells have been slow on the uptake regarding the passenger car market, but otherwise there are plenty of other ways to apply sustainably sourced hydrogen in the modern industrial economy, including agriculture and food processing as well as medicines, toiletries and other goods.
Hydrogen is also an energy storage enabler. Its role in that area could expand if the Chalmers project pans out, because the shape-shifting molecule that forms the heart of the MOST system is composed of carbon, hydrogen and nitrogen. It is activated by sunlight, which transforms it into an energy-infused isomer of itself.
“The isomer can then be stored in liquid form for later use when needed, such as at night or in winter,” Chalmers University explains, adding that “The researchers have refined the system to the point that it is now possible to store the energy for up to 18 years.”
This is just a small sample of the solar news that splashes across the CleanTechnica radar every day. Global decarbonization is within reach. The only question is how fast the world economy can pivot into a sustainable model. Researchers and innovators are doing their jobs. Now it’s time for policy makers to do theirs.
Follow me on Twitter @TinaMCasey.
Photo: Solar energy conversion efficiency improved with new tandem solar cell featuring perovskite (BEST chart courtesy of National Renewable Energy Laboratory).
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