Fuel Cells as a Potential Solar Energy Storage Solution | APT

When it comes to solar energy, storage is incredibly important. This is primarily because solar systems are heavily reliant on the sun, which means that if it’s nighttime or even if it’s cloudy, they will be rendered useless. So, if you want to maximize the purpose of a solar energy system, then you would need a form of solar storage to store the excess energy produced by the solar array, thus allowing you to use that stored energy during night-time or during power outages.

Unfortunately, solar batteries are usually expensive, and they can only store enough energy to back up the grid for a few hours at most. In other words, there is a massive need to improve the current solar energy storage solutions that we have now. Luckily, there is a new technology that can help provide a solution to this solar storage problem. And that technology is also known as the fuel cell.

What Is a Fuel Cell?

Components

Essentially speaking, a fuel cell is an electrochemical energy conversion device that converts hydrogen and oxygen into electricity, heat, and water. In a way, it is very much like a battery because it can produce electricity while being recharged at the same time.

Moreover, even though fuel cells are similar to batteries in that they convert chemical energy into electrical energy, they also have their own differences. The primary difference is that fuel cells produce electricity from external supplies of fuel (on the anode side) and oxidant (on the cathode side), and these react in the presence of an electrolyte.

The primary components of a fuel cell are electrolytes, which are also the reactors that keep the reagents from mixing together. The other important components of a fuel cell are electrodes, which are the pieces that act as catalysts for the electrical chemical reaction. Basically, what happens is that the reactants flow in and reaction products flow out while the electrolyte remains in the cell. Then there is a bi-polar plate, called a separator, which is a way to collect the current and build voltage from the cells. Because of all this, fuel cells can operate virtually and continuously as long as the necessary flows persist.

Fuel for Fuel Cells

Simply put, fuel cells can use a wide array of fuels. Some of the most commonly used ones are hydrogen, ethanol, methanol, and other various acids and alkalines (bases).

Out of these, hydrogen is known to work the best for fuel cells, but it’s also the one that is incredibly difficult to source. As of right now, there are two ways in which hydrogen can be sourced for fuel cells. The first is digging out fossil fuel and converting it into a hydrogen-rich stream (but one has to reform the stream first and clean up the gases a bit). And the second is using an electrolyzer to split water into its constituent parts of hydrogen and oxygen. Both processes are complicated and difficult to accomplish.

How Can Fuel Cells Help Fix the Renewable Energy Storage Problem?

Because of all the problems that batteries for renewable energy offer (such as a mismatch in the electricity generated by the array to the grid power demand, the high cost, and the short amount of time that the stored energy can be used), there is a dire need for an alternate solution. And one alternative that developers have found is the water electrolysis technology.

Basically, with water electrolysis technology, devices called electrolyzers split water into its oxygen and hydrogen gas. Then the second set of devices — the fuel cells — can convert that hydrogen back to electricity to power cars, trucks, and buses, or to feed it to the grid.

Hydrogen gas has the largest energy content of any fuel, thus making it a very good vehicle for holding and distributing energy. In fact, it has the ability to hold 120 MJ/kg, which means that a relatively small amount of hydrogen is needed to store significant amounts of energy. Additionally, the stable chemistry of hydrogen also means that energy can be stored for far longer than any other medium. Because of all this, this technology is considered as a solution to the storage problems that the renewable energy industry is facing today.

What Are the Benefits of Fuel Cells?

The most notable benefit of fuel cells, especially those that are running on pure hydrogen, is the fact that they are pollution-free, giving only electricity, water, and heat. In fact, the potential for fuel cells to provide zero or near-zero emissions has been a prominent force in the development of technology over the past three decades. And as of right now, it is still drawing increasing attention to the fuel cell technology.

To elaborate even further, because of the fact that there is no combustion in a fuel cell, fuel is then converted to electricity more efficiently than any other electrical generating technology available today. There are also no moving parts in a fuel cell stack, thus making them more reliable and quieter than generators. Even the ancillary systems, such as fans, pumps, controls, etc., in a complete fuel cell unit, are relatively mature and simple technologies that should prove to be reliable.

Additionally, fuel cell reactions do not degrade over time and can theoretically provide continuous electricity. This is unlike batteries considering that batteries must be disposed of once their chemicals are used up. Fuel cells can also achieve higher efficiencies at any scale, making them perfect for small portable, residential, and transportation uses. This is an advantage over traditional power plants since power plants have to be large in order to gain efficiency.

There are more benefits that fuel cells offer. For one thing, fuel cells can be located almost anywhere because they are clean and efficient at any size. And for another, they can offer an alternative to building new power lines while also reducing the dependency on foreign oil. And, last but not least, on an economic point of view, fuel cells represent a prudent path to provide the country’s electric power because they can be installed quickly, are fuel flexible, and can be put in place incrementally, thus mitigating the need for more expensive and sweeping changes.

What Are the Disadvantages of Fuel Cells?

The obvious disadvantage of fuel cells is the fact that they are large and extremely expensive to manufacture. However, this is expected to change just like how the prices for computers dwindled down once they were mass-produced. As of right now, there are already a lot of fuel cell companies that are investing millions of dollars to gear up for mass manufacturing. At the same time, these companies are also trying to begin to develop a variety of markets for their fuel cell products.

However, even though that disadvantage seems solvable in the near future, fuel cells still have another disadvantage. And that is the fact that as of right now, there is no hydrogen infrastructure to supply coast-to-coast delivery of hydrogen fuel. Technologies are currently being developed to provide alternative fuel storage and delivery methods. SOFCs, MCFCs, and PAFCs can internally reform natural gas, thus providing the perfect solution for industrial use. But MCFCs and PAFCs are too large for home and transportation use, and SOFCs still have years in development.

Aside from that, PEMs and AFCs can use fuel reformers to convert hydrocarbons, like gasoline and natural gas, into hydrogen, but this technology can lower the overall efficiency of the fuel cell by 25% and can release small amounts of pollutants. And onboard fuel storage and conversion solutions are also being developed, but they are still years from being perfected.

Takeaway

As the name suggests, solar energy depends heavily on the sun’s light — a fact that proves to be a problem at times. This is because if it’s nighttime or a cloudy day, the solar arrays are forced to be idle. Thus, in order for the solar system to be maximized, there must be a form of energy storage that can store excess energy for future use.

Solar batteries do exist, but they are costly and can only store enough energy to back up the grid for a few hours at most. Plus, batteries also exhibit an intermittency problem where the energy generated by the arrays does not match with the grid power demand. So, with all this, the solar industry is actively looking for an alternative to solar batteries.

Luckily, there is actually an alternative, and that is the fuel cell. A fuel cell is essentially an electrochemical energy conversion device that converts hydrogen and oxygen into electricity, heat, and water. And it’s primarily used alongside the water electrolysis technology, which is a process that splits water into its constituent parts of hydrogen and oxygen.

Using fuel cells as storage for energy proves to be extremely beneficial. For one thing, hydrogen can store a large amount of energy for a long period of time. And for another, fuel cells that are running on hydrogen are notably pollution-free. Basically, fuel cells are an ideal solution to the storage problems that the renewable energy industry is facing today.

However, fuel cells come with their own share of disadvantages. To begin with, they’re not cheap since they’re not yet mass-produced. Plus, their technologies are still being developed, and this development might take a long time for them to become perfect. Basically, there is still a long way to go for fuel cells to become fully integrated into the solar energy industry. But on the bright side, all that will definitely happen in the near future.

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