“The world’s capacity to generate renewable electricity is expanding faster than at any time in the last three decades,” said the International Energy Agency in a report published earlier this year.
This growth, as per the Paris-based autonomous intergovernmental organization, offers “a real chance of achieving” the goal of tripling global capacity, which was set at the COP28 climate change conference, by the end of this decade.
Renewable capacity has grown significantly over the past decade, with solar energy playing a major role in that. In 2023, renewable sources produced 30% of the world’s electricity, and solar PV accounted for three-quarters of the world’s new renewable capacity additions.
This makes sense, given that the cost of solar energy continues to go down, becoming cheaper than coal. Besides offering economic benefits like cost certainty over a long period, solar energy also boosts resiliency and reduces carbon emissions.
However, despite these benefits and the fact that 50% of global final energy consumption is utilized for heating, solar power usage is still low compared to fossil energy sources.
This is because solar power has its unique limitations, including its unavailability at night, while peak energy use tends to come in the evenings. Then, there’s climate change affecting both its demand and supply.
“We need to think about how climate change will impact the energy system as a whole because, unfortunately, no electricity generating system is immune from the impacts of climate change.”
– Romany Webb, deputy director of the Sabin Center for Climate Change Law at the Columbia Climate School
When it comes to climate impact, more frequent heat waves make solar panels less efficient, while increased demand for cooling strains the grid and negatively affects the system. Hurricanes have actually been found to diminish photovoltaic generation between 18% and 60%, while tropical cyclones can bring down solar radiation by 80%. Extreme weather like wind hazards can further damage solar energy infrastructure.
All these limitations mean that efficient solar energy storage can open up a wealth of possibilities.
Effective storage solutions allow for storing surplus power for peak use when the sun goes down. This way, electric loads can be balanced based on demand and supply and allow for consistent energy flow.
Solar power storage also provides protection during disruptive events like wildfires, during which the energy grid becomes vulnerable to outages.
So, what are these storage solutions? Well, they generally belong to three main categories; battery, mechanical, and thermal. Among these, batteries, especially lithium-ion batteries, are the most common and cost-effective way for solar energy storage.
Researchers, however, are constantly coming up with new innovations. A brand new approach to harvesting and storing solar energy more efficiently involves using underexplored sensitization strategies.
More Efficient Solar Energy Harvesting and Storage
To address the primary problem of limited global solar energy usage—intermittency of its direct availability—researchers at the universities of Johannes Gutenberg University Mainz (JGU) and the University of Siegen have developed molecular systems for storing solar energy.
In contrast to traditional thermal energy storage systems that store energy only for short periods, molecular solar energy storage systems can store it for an extended period, from several weeks to months. This is because solar energy is stored in the form of chemical bonds here.
The way molecular solar energy storage systems work is that specialized molecules or photoswitches first absorb the solar energy and then release it as heat on demand.
Even this system isn’t without its challenges. The key issue with exciting photoswitches is the compromise between efficient absorption of solar light and energy storage capacity. This limits the overall performance of molecular solar energy storage systems.
So, the research team at Mainz and Siegen conducted a study to overcome this problem using a new approach.
The new class of photoswitches was initially introduced at Siegen that showcased incredible energy storage potential in comparison to traditional lithium-ion batteries.
Most widely used battery chemistry, these batteries involve one or many lithium-ion cells in addition to a circuit board. A lithium-ion cell has electrodes, an anode, a cathode, an electrolyte that conducts electricity, current collectors, and a separator. A photoswitch, meanwhile, is a molecule that changes its structural geometry and chemical properties when exposed to electromagnetic radiation.
The novel photoswitch, while having exceptional energy storage potential, their functionality was limited to activation by ultraviolet (UV) light. UV light has wavelengths of 10-400 nanometers and constitutes only a small portion of the solar spectrum.
So, the latest study proposed an indirect light harvesting technique. This one is similar to how light-harvesting works in photosynthesis. Here, a second compound is incorporated, which is a sensitizer that exhibits great visible light absorption qualities. According to Professor Christoph Kerzig of the JGU Department of Chemistry, who led the study along with PhD student Till Zähringer:
“In this approach, the sensitizer absorbs light and subsequently transfers energy to the photoswitch, which cannot be directly excited under these conditions.”
With this new approach, the research teams have enhanced solar energy storage efficiency by more than an order of magnitude. This major step forward in energy conversion opens potential applications for both household heating solutions and large-scale energy storage.
The Mainz-based research team also conducted thorough spectroscopic analyses to explore the complex system in order to understand the underlying mechanism.
Gaining a detailed comprehension of how the system operates will help “push the light-harvesting limit substantially,” said first author Zähringer, adding that it could also improve light’s conversion efficiency into stored chemical energy.
In operational conditions, each photon that is absorbed is able to trigger a chemical bond formation process. This is seldom observed in photochemical reactions as a result of several energy loss channels.
Researchers successfully validated the robustness of the system’s practicality by cycling between the energy storage and release state numerous times using solar light, highlighting the system’s potential for real-world applications.
Latest Developments in Solar Energy Harvesting & Storage
Given the big role solar plays in the renewable energy mix, it has been the growing focus among researchers, companies, and government initiatives, which are trying to gain a deeper understanding of how it all works and develop better solutions to harvest the energy and its storage.
New research from NC State University has focused on providing a deeper understanding of what occurs in organic cells as sunlight converts to electricity. To visualize the interfaces where light energy converts to electrical charges, researchers developed a novel method, scanning-probe microscopy, and used it to improve solar cell efficiency.
Made of carbon-based polymer materials, organic solar cells have the potential to be used for flexible and lightweight solar applications as well as semi or full-transparent window applications, but they are not as efficient as perovskite or silicon solar technologies at converting light into electricity.
This is because these cells are made of a mixture of two materials; one of them harvests electrons (donor) but then has to interact with the second one to pass them (acceptor), and interfaces between the two are responsible for a voltage loss, hence, limiting organic solar cells efficiency.
The latest study found that both energy differential between constituent donor and acceptor materials, as well as energetic disorder along interfaces, drive voltage loss.
According to co-author Aram Amassian, professor of materials science and engineering at NC State University, selecting materials with minimal energy offsets reduces voltage losses. Solvent and processing parameters that diminish interfacial disorder can further reduce energy losses.
Another recent study took the task of reliably estimating the capacity of household energy storage systems to get an idea of the future deployment of effective residential PV systems.
For this, researchers introduced a scalable capacity estimation technique, which involves three key steps: determining when a storage system is at full capacity and when it is empty and calculating capacity between these two states.
It was then used to measure 21 lithium-ion batteries-based systems in private households in Germany over eight years. The analysis revealed that, on average, the systems lost 2-3% of their capacity annually.
Notably, the method can be used by manufacturers and solar energy companies to estimate the capacity of their energy storage systems. Moreover, researchers published an extensive dataset, which comprises 14 billion data points from over 100 years, that can be used to conduct additional studies or train computational models.
Earlier this year, in June, researchers also developed an innovative light-harvesting system that can “absorb a great deal of light energy in a relatively thin layer,” much like natural light-harvesting systems.
By having a band structure that is similar to inorganic semiconductors, it can absorb light panchromatically across the whale visible range, while using high absorption coefficients of organic dyes allows it to absorb a lot of energy.
The system has four different merocyanine dyes that are folded and stacked closely together, enabling ultra-fast and efficient energy transport within it. The system has been found to be able to convert 38% of the irradiated light energy.
For efficient storage of solar energy and reducing conversion loss, researchers from around the world also came together earlier this year to study the dynamics of photo- and electrochemical transformation to design a better-suited molecule for the desired functions.
The researchers are looking into norbornadiene for this, which is a hydrocarbon isomer having two molecule rings and, when exposed to UV light, results in its conversion to a more highly strained quadricyclane.
Given the pure energy density of the norbornadiene-quadricyclane system is comparable to a lithium-ion battery, if its reversal conversion can be controlled reliably, that can achieve an efficient solar module that is also suitable for storing electricity.
Focusing on hydrocarbon molecules offers a cost-effective method that doesn’t require any rare metals and can be easily recycled or disposed of. All these recent developments in the sector are a testament to the growing focus on increasing solar energy adoption worldwide.
Companies Positioned to Benefit from the Advancement
Now, we’ll look into two of the most prominent names that can benefit from or offer such a molecular solar energy storage system. These two names are NextEra Energy, Inc. (NEE +0.36%) and Enphase Energy, Inc. (ENPH +2.84%), both of which are US-based companies and actively involved in renewable energy.
1. NextEra Energy (NEE +0.36%)
Known for its investments in renewable energy technologies, NextEra Energy can benefit from such technology in terms of storage efficiency.
Having a market cap of $161 billion, NextEra shares are currently trading at $78.37, up over 29% this year so far. The company has an EPS (TTM) of 3.37 and a P/E (TTM) of 23.24, while it pays a dividend yield of 2.63%.
NextEra Energy, Inc. (NEE +0.36%)
The energy infrastructure company recently reported the financial results for 3Q24, revealing that its net income jumped to $1.85 billion, compared to $1.29 billion in Q3 of 2023. Adjusted earnings per share meanwhile increased by 10% year-over-year. These results, according to its CEO John Ketchum, show “continued solid financial and operational performance.”
Meanwhile, NextEra Energy-owned Florida Power & Light Company (FPL) had $1.29 bln in net income, while its capital expenditures were $2 bln, and regulatory capital employed increased by 9.5% year-over-year. Talking about its Floridian customers being affected by Hurricanes Helene and Milton, Ketchum noted that FPL’s “investments in hardening and smart-grid technology prevented hundreds of thousands of outages.
Now, NextEra Energy Resources, for the second consecutive quarter, added about 3 gigawatts of new renewables and storage projects to its backlog. It also announced agreements with two Fortune 50 customers for renewables and storage project development, totaling up to 10.5 gigawatts till 2030.
“The continued strong performance of our businesses and our scale, experience, and technology will allow us to capitalize on the opportunity that increased power demand is bringing to our sector.”
– Ketchum, NextEra Energy CEO
Last week, the leading clean energy company entered into an agreement to sell $1.5 billion worth of its equity units to major financial institutions, including Goldman Sachs, J.P. Morgan, and Mizuho. The funds will be used for investments in AI-related energy and power projects and to repay its outstanding commercial paper obligations.
As AI mania leads to rising demand for power from AI data centers and the company focuses on growing its renewable energy business, NextEra Energy is also conducting studies and having discussions with federal regulators about restarting the Duane Arnold nuclear power plant in Iowa.
2. Enphase Energy, Inc. (ENPH +2.84%)
Specializing in solar inverters and storage, Enphase Energy could also potentially expand to include innovative molecular storage if commercially viable to enhance energy resilience and efficiency for its consumers.
Having a market cap of $11.8 billion, Enphase shares are currently trading at $87.46, down 33.87% this year. The company has an EPS (TTM) of 0.44 and a P/E (TTM) of 198.82. For Q3 2024, the global energy technology company reported revenue of $380.9 million and a non-GAAP gross margin of 48.1%. During this period, Enphase shipped more than 1.73 million microinverters and 172.9 MWh of Batteries.
Enphase Energy, Inc. (ENPH +2.84%)
The world’s leading supplier of micro inverter-based solar and battery systems meanwhile ended the quarter with $161.6 million in free cash flow while cash, cash equivalents, and marketable securities were $1.77 billion.
During this period, Enphase launched AI-based software to optimize energy use by integrating solar and consumption forecasting with electricity tariffs in order to help consumers maximize savings.
In October, the company started shipping IQ8™ Microinverters to support newer, high-powered solar panels in select countries, expanded its support for grid services programs (or virtual power plants) in select US states, and launched IQ8X Microinverters with the longest standard residential warranty of 25 years in Australia.
In the two months prior to that, it launched its most powerful Enphase Energy System to date, announced a solution for expanding legacy net energy metering (NEM) solar energy systems in California without penalty, launched NACS connectors for IQ EV Chargers, and shipped IQ8 Microinverters to support newer, high-powered solar modules in select countries throughout Europe. It also introduced IQ Energy Management to enable support for dynamic electricity rates and the integration of third-party EV chargers and heat pumps in the Netherlands.
The company is now preparing for the launch of the 2nd gen IQ® EV charger, the 3-Phase IQ Battery with backup, and the IQ® Balcony Solar Kit for the European market while its fourth-generation energy system, featuring the IQ® Meter Collar, 10 kWh IQ Battery, and enhanced IQ® Combiner, will debut in the US early next year.
Overall, Enphase’s sales in Europe dropped 15% from Q2 due to “further softening in European demand,” while inventory returning to normal levels sent its US revenue up by 43% sequentially.
Conclusion
Amidst the global push for renewable energy, solar power has emerged as a prominent player in offering a clean and abundant solution. However, its worldwide adoption is affected by cost, more efficient solutions, and lack of infrastructure, among other factors.
Recent advancements, ranging from molecular solar storage to organic solar cell innovations, offer great potential in making solar energy more efficient, help meet global power demand, even during adverse conditions, and pave the way for a sustainable future.
Click here for a list of top solar power stocks.
