Molecular hydrogen is becoming a key player in cleaning up our energy systems to meet emission reduction targets outlined in agreements like the Paris Agreement. One promising method to produce hydrogen sustainably is through water splitting using renewable energy sources. Among these, the production of hydrogen energy from solar energy stands out as a widely accessible and cost-effective option, with over 520 GW of capacity installed globally as of 2018. This makes hydrogen production using solar energy the go-to choice for generating the clean electricity needed to produce green hydrogen. Although there are alternative methods like photocatalytic reactions and direct photo-electrochemical water splitting, current technology primarily focuses on PV-electrolysis (PV-E) systems for efficient hydrogen production.
The efficiency of converting solar hydrogen (STH efficiency) plays a crucial role in determining the size and effectiveness of PV and electrolyzer plants. Silicon photovoltaic (PV) cells are nearing their maximum efficiency potential at around 30%, leaving limited room for improvement in solar-to-hydrogen (STH) efficiency using silicon PV technology. In contrast, concentrator photovoltaic (CPV) cells, which utilize III–V group elements, have already achieved much higher efficiencies, reaching approximately 47% with the potential to exceed 80% theoretically. Recent advancements have demonstrated CPV modules with efficiencies as high as 43.4%, and projections suggest they could reach 47% efficiency by 2035. Additionally, CPV systems can operate effectively under high light concentrations, exceeding 1000 suns, which helps offset their higher manufacturing costs.
An Experiment was Conducted to Show the Potential of CPV Cells
The experiment illustrates that Concentrated Photovoltaic (CPV) cells can attain notable Solar-to-Hydrogen (STH) efficiency, followed by an analysis of how efficiency and economies of scale impact the cost of hydrogen.
- In the experiments, they used triple junction (3J) InGaP/InGaAs/Ge CPV cells connected to alkaline electrolyzers.
- Without a DC-DC converter, they achieved an impressive solar-to-hydrogen (STH) efficiency of 28% under 41 suns along with alkaline electrolyzers.
- This marks the highest reported efficiency shown by PV cells.
- Building upon this achievement, they conducted a Techno-Economic Analysis (TEA) to assess the cost of hydrogen production.
- They assumed a commercial CPV farm with a module efficiency of approximately 41%, and added an alkaline electrolyzer plant operating at around 70% efficiency, resulting in a 28% overall plant or STH efficiency.
- Under these conditions, the levelized cost was estimated to be around $5.9 per kilogram, with the potential to decrease to $5.6 per kilogram with a 31.5% STH efficiency.
- In contrast, using silicon PV modules with an efficiency of around 17.5%, the cost of hydrogen is approximately $4.9 per kilogram.
- Furthermore, they projected the future cost of trackers, CPV modules, and associated hydrogen production based on cumulative installed capacity.
- Assuming a learning rate of 18%, the cost of hydrogen from solar CPV-E setups could plummet to $2.65 per kilogram if the cumulative installed capacity exceeds 100 gigawatts, similar to silicon PV cells.
The Results of the Experiments Conducted
This research demonstrates the possibility of achieving a stable system with a solar-to-hydrogen (STH) efficiency of 28% by optimizing the configuration of CPV cells, which are around 40.7% efficient, along with available alkaline electrolyzers with an efficiency of 70%. Through detailed Techno-Economic Analysis (TEA), they found that despite the higher cost of CPV cells, the Levelized Cost of Hydrogen (LCOH) from CPV solar farms can now rival that of conventional c-Si solar farms. – As the commercial viability of c-Si solar cells has nearly peaked, we conducted a sensitivity analysis on various factors affecting both CPV and alkaline electrolyser systems. – Our findings suggest that when the installed capacity of CPV technology matches that of silicon, and when electrolyser’s operating current density reaches around 0.7 A cm−2, the levelized cost of hydrogen from CPV-electrolysis systems could drop below $2 per kilogram. – Currently, the cost of hydrogen from steam methane reformers with CO2 sequestration ranges between $1.2 and $2.8 per kilogram. – Hydrogen production from water can be highly efficient and productive. The significant increase in efficiency showcased in the experiment shows STH efficiency on par with other practical energy sources. – Like any emerging technology, the cost of implementing CPV-electrolysis systems is expected to decrease over time, especially with increased usage and support. – Just as the silicon PV industry experienced a substantial price drop, mainly due to subsidies, CPV has faced challenges due to a lack of a dedicated supply chain. – We hope that our findings and cost analysis will inspire researchers, governments, and companies to explore CPV-electrolysis for commercial hydrogen production. – While immediate financial gains may not be the primary driver, the environmental benefits could serve as a powerful incentive, eventually leading to progress and prosperity. By using hydrogen solar panels you might also be able to sell the H2 produced and earn something extra from your solar system.
Producing Green Hydrogen by Using Renewable Energy
Currently, the majority of hydrogen, totaling around 70 million tons annually, comes from fossil fuels, contributing to about 2% of coal demand and 6% of the total natural gas consumption worldwide. Are you wondering “What is green hydrogen energy”? It is a growing opportunity to produce hydrogen using electrolyzers powered by solar and wind energy as the costs of renewable energy generation are declining. This approach offers a clean and cost-effective alternative, even when factoring in the hydrogen solar energy storage for transportation to end-users. 3,600 terawatt-hours (TWh) of electricity will be needed to produce 70 million tons of electrolytic hydrogen every year. According to insights from the International Energy Agency, this surpasses the European Union’s combined yearly power generation. Yet, there is untapped potential in renewable capacity, as some solar and wind power is lost due to constraints in transmission and distribution grids. Grid operators, in their efforts to maintain stability, sometimes have to limit the amount of renewable energy transmitted through overloaded lines. This situation often leads to renewable energy being sold at very low prices during periods of high wind and sunlight, and in some cases, generators are forced offline to balance the system. For instance, Northern Ireland and the Republic of Ireland aimed to generate 40% of their power from renewable energy by 2020. However, the grid has struggled with stability issues, resulting in wasting some of the solar and wind energy.
Transportation can be Powered by Green Hydrogen
Hydrogen holds significant promise in the transportation sector, particularly for larger vehicles facing challenges with battery weight and driving range. This shift is crucial for countries striving to meet zero-emissions targets, as transportation accounts for a substantial portion of carbon emissions. Hydrogen solar panel refueling offers faster turnaround times than recharging batteries, making it appealing for frequent road users. Several car models powered by hydrogen fuel cells, like the Toyota Mirai, are already on roads in various countries. Moreover, hydrogen can be converted into various fuels like ammonia, methanol, and synthetic methane, offering additional options for transportation. If you are betting for hydrogen vs solar mix then you are the clear winner. After looking at the experiments and real-time examples, we hope you understand the huge revolution solar-generated Hydrogen will bring. So, be prepared to invest before the change happens or hug it when it becomes a norm.
