The engineer stood up and walked about. He spotted the nearest wind turbine, pointed to it, and said, "Would you be interested in going up there and seeing for yourself the secrets of being high-power?"

"What do you mean?" Ranran asked, "You mean to show us a generator made of conductive polymers?"

"Yes!" The engineer led them to a hatch at the base of the wind turbine. He pressed a green button, and an elevator next to them was ready. "This is an maglev elevator." He said, "You can come up with me using this, and you won't have to climb the stairs."

"Wow! Great!" William exclaimed.

Soon the elevator took them to the top. "Is it cool at 120 meters high?" Asked the engineer. "Sure!" Natalie replied, "Plus, you can tell from the size that this guy has a lot of power. Photon and Rebecca can both get in."

The engineer took them close to the generator set. Through the transparent glass around them, they could clearly see the three spinning blades and the green plain below them. Next to them was a giant generator about twice their height. It had a shell that was transparent but strong enough to allow a clear and intuitive view of the internal structure. This also laid the foundation for the engineer to judge the fault quickly during maintenance.

"Look," Said the engineer, pointing to the magnet attached to the shaft, "this is a fine Nd-Fe-B magnet with strong magnetism. Those installed have an average magnetic induction intensity of about one Tesla. In addition, new technology has made all the moving parts of windmills made of carbon fiber, so they can withstand higher speeds and are less prone to wear. The design itself that magnets serve as rotors minimizes wear and tear. In this case, the power of each wind turbine can be greatly improved, and the maintenance is more convenient."

He led them to the coil. Through the shell, they could clearly see the intricate winding of the inner coil. "It doesn't look that different from a metal-containing superconductor." Photon said.

"Yes, but merely 'look like'." The engineer said, "Unlike the various metal-containing superconductors we have tried before, this material can easily maintain high conductivity, but those require extremely demanding conditions. To some extent, these conducting polymers are the most suitable 'room-temperature superconductors'."

"Look!" Natalie's keen eyes spotted a small piece of wire lying in the corner. The engineer laughed and said, "Ha ha ha! Yeah, I'm about to take you to see that thing. But you stole a march on me, and I miscalculated!" He pointed to the section of the wire and showed the others the new material. William learned that the blue parts were the camel scientist's latest reinforcements -- additives. These were small organic molecules that could absorb and export electrons that collided with the materials of wires. With them, almost all of the energy that would otherwise be converted into heat was converted into electricity, so these additives had succeeded in delivering high-power, energy-efficient electricity.

"Wow." Rebecca exclaimed, "With all these new technologies, making the planet greener and more habitable is no longer a dream! Sir, the entire planet owes you a debt of gratitude. You're giving them better electricity!"

"Ha ha, thanks for flattering me!" The engineer laughed, "After all, it is the camel scientist who deserves the credit. Without the findings of his new study, wind power might not be as efficient as it is now. Although I have decided to make the generator coils out of the conductive polymers, yet it seems to be more important that he found the additives. Because that will continue to reduce the amount of energy loss. Together with sufficiently advanced UHVDC transmission technology, they allow near-zero energy loss."

"Anyway, you both deserve it!" William said politely, bowing to the engineer.

"Thanks for the compliment. We have now completed the exploration of the high-power generator, but that is not the end." The engineer smiled mysteriously.

"Not the end? Why?" Ranran asked.

"Is there anything else you want to show us?" Photon and Natalie asked together.

"Smart. Come with me." The engineer took them down to the ground in the elevator and went to the plain. Then he led them another 500 meters to a glass tube. "What's this?" William asked curiously.

"Have you ever heard of tube trains?" Asked the engineer.

William replied confidently, "You bet! On my planet, you can see this kind of transportation a lot of times. They are ideal for long trips over 2,000 kilometers."

William made a 3,000-kilometer trip three years ago. He took a tube train.

"That's good." Said the engineer, "This is also a tube train. Except that its tube is high up in the air... It's about the same height as power transmission towers."

"Wow! That's great!" Screamed Rebecca, unable to contain her delight.

"Want to experience it now? Then hurry up and get on! Look, there's a carriage coming." The party looked along the engineer's finger. Something like a capsule had appeared in the distant tube and was slowly approaching them. It came to a steady halt in front of them.

As he got on, the engineer explained to the others, "This carriage came out of the depot. It went through an underground tube and is about to climb high into the air. Then the tube will be combined with the power transmission towers."

"Oh! So why did you do it this way?" Ranran asked.

"Because this is actually the tube train I take to repair the towers." The engineer had solved the mystery.

"Wow! Such treatment is unthinkable on my planet!" Said William, "In my country it's OK; maintenance workers have adequate safety measures. But in some of the less developed countries it's not always so! Workers are always at risk of falling, electric shock and so on!"

"It seems that on your planet, international cooperation is a required course." The engineer joked. At the same time, the train started, climbing slowly. In front of them was a tall power transmission tower, where the transmission lines started. The tube passed through a gap in the center of the tower, allowing the passengers inside the train to see the thick wires overhead.

"That's another part of the exploration." The engineer pointed to the tube train.

"Is there more?" William's eyes sparkled with excitement.

"Oh dear, no, no. How interested you are in exploration!" Laughed the engineer.

"Certainly. I've been to many different places! And are these wires made of the same material as the generator coil we just looked at?"

"Yes. It's just that the additives are a little bit worse, because wires aren't as demanding as generators in terms of energy loss. And we get cold snaps here once in a while. In this case, the temperature will drop and ice may form on the wires. Although these conductive polymers are even stronger than metal-containing superconductors, overloading them is never a good thing. So I will increase the current a little bit so that the heat will be enough to melt the ice. When the temperature is moderate or high, no deicing will be required. I will switch to a lower current so there won't be too much lost power."

"It seems that the power of wisdom is endless!" Ranran said, and the party laughed.

The engineer added, "Maintaining wires and towers in this tube train is much better than being exposed to high altitude. One reason is that it's a glass tube; glass itself is an insulating material, and the insulation suit I'm wearing reduces the risk of electric shock. The other is that I don't need to tie a strong rope, and I don't have to pay attention to falling."

"The tube train is a clever idea." Photon said.

"You can do the maintenance more safely while enjoying the beautiful views." Natalie took his words, "But what if the tube train also needs maintenance?"

"See the platform under the track?" The engineer pointed right under the seat, "That's an automatic aisle. If a part needs to be repaired or replaced, the glass doors in the appropriate location will open automatically for me to enter. The tube train is operated by the intelligent operating system, so the failure rate is relatively low. And it's highly integrated, all-in-one, avoiding the trouble of having too many parts."

William was full of praise for all this. He thought of Earth before he set out. He had a good experience that time on the tube train, but the maintenance was no easier than this one. He was reminded of Guidelines on protecting the safety of maintenance personnel in high-voltage transmission systems issued by China State Council in May, which mentioned the idea of a dedicated tube train for maintenance, and that work was underway. But it wouldn't be ready until at least around next year's Spring Festival. And the tube train he was riding right now was similar to those he would experience on Earth in the future. It was an early taste of the future, and how exciting!

When they finished their sightseeing, the tube train took them back to the ground and made its way back to the depot. Another day on this planet had passed before they knew it, but having just rested at the mushroom pianist's, they were not sleepy. After a few more words with them, the engineer stood at the villa door to see them off.

"It's an honor to meet you! By the way, I don't yet know your name, Sir." William said.

"I am Hans," Said the engineer, "and almost everyone on this planet knows who I am. The chance to meet you aliens... Oh, except Rebecca," and he could not help laughing at the sweetness of her feigned anger. He continued, "It's really good. I hope you will visit me again some day."

"Farewell, Mr Hans!" The party bade him farewell with one voice.

"Goodbye..." The engineer stood in the doorway and watched them in the direction they were going, until the largest plane was out of sight. Then he returned to the villa, ate some food, and sat down at his computer to monitor each of his wind turbines. For about six hours he had not noticed the state of his favourite windmills because of the arrival of these aliens.

"I wonder whether you are able to be away for long." The engineer said to his robot.

"I can't be away for long, Sir," Interrupted his robot, before the engineer could finish, "but I can watch all day."

He said earnestly, "Then it is necessary for me to change. After all, it takes a lot of energy to monitor myself all day long. But you can only take my place. You cannot appreciate how much I love these windmills and this clean planet."