There is no land more than 10 meters above sea level in the waters of Tuvalu, and the highest place at present is only the buildings in the urban units where the main project of the Special Administrative Region has just been completed.

The height of the fifteen-story steel structure house is only about 50 meters above sea level, which is a drop and a limited area, and the energy storage method realized by gravity such as pumped storage does not play much role at all.

In addition, the energy density and scale of flywheel energy storage, thermal energy storage and battery energy storage cannot be compared with pumped hydro storage methods.

Suffice it to say, there are no suitable conditions for the current energy storage methods in the entire Tuvalu Sea.

Shuguang Group issued a demand for energy storage projects through Minsheng Company, and all interested companies could only choose to leave with regret after learning about the situation in the Tuvalu Special District.

Because, according to such a geographical environment, they simply do not have the ability to build a large or medium-sized storage power station, and they cannot even find sufficient conditions to build a small storage power station.

But Wei Minsheng didn't believe in this evil, since the way of gravitational potential energy didn't work, why couldn't he use buoyancy?

In the vast sea, gravity and buoyancy are almost the same except that the direction of the force is opposite.

If you can come up with a way to carry the air to the bottom of the sea and lock it in, the sea is a natural pressure vessel under the pressure of the seawater.

When in use, the compressed air is slowly released, and the generator is driven by the air motor to achieve stable power output.

In this process, there are no technical obstacles to pressing the air to hundreds of meters of the ocean floor with a compressor.

The challenge is how to lock the compressed air on the seabed and release it in a controlled manner without leakage.

Due to the electrochemical corrosiveness of seawater to conductive metals, ordinary metal containers are definitely not good.

Otherwise, the energy storage device built with a lot of money and manpower will be completely damaged and lose its energy storage function in a short time.

In addition to metals, rubber or plastic products can also act as a seal in the air.

However, the strength and weight of these materials simply cannot bear the heavy responsibility of locking the compressed air on the seabed, and they may float from the seabed as soon as they are inflated.

Moreover, hundreds of meters of seabed, a bubble the size of a ping-pong ball, when it rises to the surface of the sea, the volume will increase at least tenfold.

In such a situation, these plastic or rubber containers are sure to burst.

If this energy storage problem cannot be solved, Tuvalu SAR can only use the distributed energy storage method of battery and UPS uninterruptible power supply to store these unstable energy sources.

The service life of the battery and the pollution it can cause to the environment are obviously not the ideal choice for the City of Hope.

Wei Minsheng issued a survey mission, surveyed the waters around Tuvalu, and found that most of the surrounding continental shelf was 70 to 80 meters deep, and a little further away from the Tuvalu Islands, those low-lying areas were 2 to 300 meters deep.

At 70 to 80 meters under the sea, the water pressure is equivalent to seven or eight atmospheres.

With such a large pressure, it only needs to be slightly adjusted to directly drive the pneumatic motor to work.

Such a large pressure produces a compressed air pressure that is higher than the working pressure of an ordinary steam turbine.

At a depth of two or three hundred meters, the pressure reaches twenty or thirty atmospheres, which can completely drive a large turbine unit.

As long as the problem of compressed air storage can be solved, Wei Minsheng can build a compressed air storage power station, using 25 to 50 megawatts of turbine units, arbitrarily combined into a power station with greater power generation.

Wei Minsheng read a lot of information and finally found inspiration from the caisson construction process of the bridge pier.

This large cabinet made of reinforced concrete structure is like a rectangular cabinet that is upside down in the water, with no bottom underneath, and the air pressure in the box is used to drain the water below, so as to obtain a space for people to work freely under the surface of the water.

The world's largest caisson has reached a weight of 2,000 tons in the seventies of the last century, and the top area has reached the scale of thousands of square meters.

But no matter how large these caissons are, they are not used underwater at a depth of more than thirty-five meters at most.

After careful study, Wei Minsheng found that this was not because the caisson structure could not withstand greater water pressure, but because no matter how deep it was, the people working in the caisson could not withstand such a large air pressure.

The caisson is a special structure that allows thousands of tons of concrete elements to float on the water.

In order to allow the caisson to sink smoothly, some auxiliary passages and valves are also needed, and the method of discharging the air in the caisson is used to achieve the purpose of sinking to the designated place.

But Wei Minsheng is interested in the caisson's ability to store high-pressure gas, anyway, his caissons don't need people to work, so putting them deeper will not affect the use.

Since the bottom of the caisson is directly connected to the seawater, the pressure on the inner and outer walls of the caisson is the same.

In this case, there will be no lateral shear force to damage the caisson structure, and the only thing that can cause damage to the caisson structure is the direct pressure on the concrete.

The concrete structure, which can reach the C30 strength standard, is enough to ensure that the caisson will not be damaged at a depth of 300 meters, and it will be used on the seabed at about 200 meters, without any problems at all.

The gas storage space of Wei Minsheng's customized caisson is a rectangle with a length and width of 50 meters and a height of 20 meters.

In order to increase the stability of its structure, some beams were added to the rectangular space.

In order to increase its air tightness and anti-corrosion, Wei Minsheng required that a layer of protective agent be coated on the inside and outside of the caisson, so that some small gaps could not affect the gas storage performance of the caisson.

Nine of these large caissons are arranged in a group of nine squares on a specially constructed platform twenty meters deep underwater.

The top of the caisson space is slightly arched, and at the top of the arched structure, two high-pressure corrugated hoses with a diameter of 50 cm are installed horizontally.

A high-pressure corrugated hose connects the storage spaces of the nine caissons for greater storage capacity.

Each of the two caissons at the beginning and end of each set is left with a hose that acts as an exhaust pipe for the compressed air, which will pass through these two pipes to propel the turbines on the sea surface for power generation.

When the exhaust pipe is not closed and the air in the storage space can flow freely, the air in the caisson is completely emptied by seawater, and the caisson of thousands of tons is firmly rested on the platform, ready for the next step.

Under the condition of ensuring the stability of the nine caissons, the nine caissons are connected into a whole by cast-in-situ of reinforced concrete structure.

At the same time, a five-meter-high reinforced concrete fence was poured over its edge, creating a space on top of the caisson where sand and gravel could be stacked.

When the maintenance period of the cast-in-place structure is up, the exhaust duct is closed and the seawater in the caisson is discharged with compressed air.

Under the action of buoyancy, this large caisson structure can be easily pulled to the designated place with a towing boat.