Friday, 14 July 2017

Wow, you're making hydrogen from wind and water?

Source: Toyota, 12th July 2017

Do you know what the most abundant element in the universe is? It's hydrogen (H). The intense energy of the sun, like that of all the stars that shine in the night sky, comes almost entirely from hydrogen. So, where would you find hydrogen on Earth? Well, hydrogen is a colorless, odorless gas, practically non-existent in its molecular form. However, as a compound, it exists in virtually endless supply. Among hydrogen compounds found above ground, by far the most common is… water (H2O). Isn't it fascinating to consider that the hydrogen that exists in such vast quantities in outer space takes on the form of water here on Earth?

Have you heard about a unique project that's happening right now in Yokohama? There, in the outskirts of the Minato Mirai district, the harbor gusts affectionately referred to as the "Hama Winds" are being used to generate hydrogen, which is stored and then transported to be utilized as fuel for forklifts. Shall we take a closer look at how this project works?

Here we are at the Mizuho pier in northern Minato Mirai. After passing through the warehouse district right down to end of the pier, we see an area as extensive as a schoolyard. The first thing to catch our eye is a broad pillar. As our gaze travels up its heights, we see a large, white windmill churning the air. It turns out this windmill belongs to a wind power plant called the Hama Wing. The tower is 78 m high and the windmill's massive blades extend across an 80-meter span! Apparently, this allows it to generate roughly 2.2GW of electricity a year, enough to annually power about 500 homes―and all that electricity is now being put to work generating hydrogen!

Let's head to the site. Up close, we hear the hum of the windmill driven by the Hama Winds. Upon approaching the pillar, it almost seems as though we're looking into the boarding bay of a rocket, but it's actually just the entrance to Hama Wing. So why don't we climb the stairs and peek inside? Looking up from within, we see that the tower is hollow right to the top and a ladder clings to the inner wall, rising all the way up. It would seem that maintenance workers are required to climb up to the top decked out in safety gear. Incredible! You need great strength and courage to perform such an arduous task. It makes you wonder if they ever wish for an elevator.

Stepping back outside, we're now in front of facilities resembling huge, white storage sheds. One of them awaits with doors parted like open arms. This calls for a closer look. Inside are black rectangular objects stacked in order… Apparently, they're batteries. In fact, the purpose of these facilities is to store surplus electricity from the Hama Wing in this storage battery system…which is comprised of recycled Prius batteries. There are 180 Prius' worth lined up in there.

Image: Storage Battery System (Toyota Turbine and Systems Inc.)

Now for another kind of storage found next to the Storage Battery System. It's marked with a "TOSHIBA" logo. What on earth could it be? This is the Water Electrolysis System, which produces hydrogen from water. Closer up, we see that tap water is supplied to it near the door on the right. The water is split into its constituent elements using the electricity generated by the Hama Wing and hydrogen is extracted. With a tingling of anticipation, we open the door to find a white, box-shaped object taking up residence within the storage unit. This is the Electrolyzer that extracts hydrogen from the water.

Image: Water Electrolysis System (Toshiba Corporation)

 ★Tap water

Image: Electrolyzer

Let's delve a little deeper. There's just enough room for one person to squeeze through at a time but once we make our way through the passage, we come out behind the Electrolyzer. We can't see into the unit but asking buys us the answer to the question, "From where does the hydrogen come out of?" The answer is that it passes through the silver-colored pipes emerging upward from the Electrolyzer. Light as it is, hydrogen floats up from below. Those are some surprisingly thin pipes.

1The hydrogen generated by the Electrolyzer passes through these pipes.
2This pipe extracts a portion of hydrogen for purity verification.

The next step should be storage of the hydrogen, right? As we look out across the grounds, wondering which facility serves that purpose, we notice a large cylinder near the center of the compound. It must be as tall as 10 meters. Craning our necks back we see the logo of the project emblazoned across the stark white of the cylinder's face. The hydrogen that has been generated is bound for fuel cell (FC)-powered forklifts and, apparently, enough hydrogen is stored in there to power 12 forklifts for two days! Energy can be stored much longer as H2 than as electricity (electricity discharges energy over time)―a longer storage period is one of the merits of hydrogen.

Image: Hydrogen Storage Tank (Iwatani Corporation)

Though we might think that transporting the hydrogen comes next, it turns out another process comes first―compression. We are led to an area with a ceiling surrounded by three walls adjacent to the hydrogen storage tank, where the hydrogen compressor can be found. One might imagine the "compressor" it to be a very large piece of equipment, but it's a surprisingly compact machine at about 2 m in height. Apparently, this is a biaxial vertical hydrogen compressor―a compact design.

Image: Hydrogen Compressor (Iwatani Corporation)

Moving on to the booth beside the compressor, we find a small truck waiting. It's adorned with the same project logo as the hydrogen storage tank. This is the first hydrogen fueling truck introduced for FC forklifts in Japan. The hydrogen compressed in the device we just visited will be transported to sites where FC forklifts will utilize the hydrogen from the hydrogen fueling truck. Enough fuel for six forklifts can be transported at once… It's tempting to wonder if it would be more efficient to deliver more using an even bigger truck but we learn that there are a lot of narrow areas at the site where the forklifts are used, which explains the smaller trucks.

Image: Hydrogen Fueling Truck (Iwatani Corporation)

Let's recap what we've learned about this project: the wind-generated electricity of the Hama Wing is used to extract low-carbon hydrogen from water; the H2 is stored, conveyed, and utilized,―all helping realize a low-carbon hydrogen supply chain model. Seeing the process of Earth-bound hydrogen contained in water being extracted and then transported gives us a peek at a future in which hydrogen will surely be a far more common form of energy.

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