Why do humans love to use electricity?

01

Did you know that the third new aircraft carrier being built in our country will adopt "all-electric propulsion" or "integrated all-electric propulsion system" as the ship's power source?

Imaginary picture of China's new aircraft carrier

What does it mean? In short, the main engine generates electricity first, and then the electricity is supplied to the motor for propulsion . The benefit is that aircraft carriers will be equipped with "power-intensive" electromagnetic catapults. If the main engine is dedicated to generating electricity, the problem of electromagnetic catapult power consumption can be solved at the same time.

Schematic diagram of electromagnetic catapult

Looking at the list, the following ships are using all-electric propulsion systems in the world:

The benefits of all-electric propulsion: more agile speed changes, more powerful push-back feeling, which is very similar to electric cars. For military ships, high-power radars, electromagnetic catapults, and electromagnetic guns and laser weapons that will appear in the future are all large power consumers, so all-electric systems naturally have advantages.

Advanced kinetic killing weapon-electromagnetic gun

Since electric propulsion is so good, shouldn’t all ships in the world use electric propulsion a long time ago? In fact, as early as World War I, the United States tried to use electric propulsion on large battleships: large battleships such as the New Mexico class, Tennessee class, and Colorado class all used electric propulsion systems one after another, and this was even in the 1920s.

Colorado-class battleship

However, in World War II, all types of main battleships of the United States returned to the method of using the main engine to directly drive the propeller through a long shaft. Why is this? The reason is that the main engine is used to generate electricity first, and then the electricity drives the motor to convert the mechanical energy into electrical energy, and then the electrical energy is converted into mechanical energy. There will be inevitable energy loss, which reduces the overall energy utilization rate. It is not as refreshing and efficient as a few large gears + a large shaft mechanical transmission. Therefore, most of the ships, tanks, and cars of later generations still use simple and direct mechanical transmission.

Mechanical transmission structure diagram

So why is the concept of "all-electric propulsion" revived now? It is nothing more than the result of the game between the rigid demand of the new equipment "big electricity users" mentioned above and other benefits such as performance flexibility, and the disadvantages caused by the loss of energy conversion back and forth.

02

When it comes to "electric propulsion", the rapid development of consumer-grade civilian electric vehicles in recent years is definitely an unavoidable topic. In fact, large electric buses have been popularized in our cities earlier without anyone noticing.

Beijing's "China Red" pure electric buses run on Chang'an Avenue

But when it comes to personal cars, people will seriously examine its "cost-effectiveness" (after all, it is their own money that is being spent). With the progress in battery, control and other technical fields, as well as the subsidy support of the country's "low-carbon and environmental protection" policy, today's booming development has emerged.

State Grid Electric Vehicle Charging Station

When it comes to "low-carbon and environmental protection", the following question may come to everyone's mind: electric cars "burn" electricity and do not emit carbon, but the main method of power generation in our country is still coal-fired power generation, so isn't carbon still being emitted?

Well, we can only say that you should first connect the energy use of your private car to the power grid, and then optimize the power generation mode at the source of the power grid, and gradually replace traditional thermal power with clean energy such as nuclear power, wind power, solar power, and biomass. Only by connecting to the grid first can we make overall optimization more convenient~

In fact, this model of network optimization has already begun as early as the last industrial revolution. Let me ask you, what was the iconic technology of the "Second Industrial Revolution" that took place in the second half of the 19th century? It was electricity and the internal combustion engine.

Working diagram of a four-stroke three-cylinder engine

In fact, Dr. Porsche of Germany had built an electric racing car as early as the beginning of the 20th century, but electric cars did not become popular because of this. The internal combustion engine still occupied the core position of power for various vehicles on land, sea and air. This shows that its energy utilization efficiency and convenience on a single vehicle are better than electricity. So what are the advantages of electricity? Networking!

03

If we look down at the Earth from outer space, what is the most intuitive sign of human civilization? It is the bright lights that cover the earth, and the main source of these lights is cities.

China night light distribution map

Along with the "Second Industrial Revolution", urbanization and electrification were carried out simultaneously. As people gradually gathered in cities, it was no longer necessary for every household to install a generator, but to use a shared power grid. In addition, the water supply, sewage, transportation, logistics and other elements that were synchronized with it appeared in the city. The network effect of aggregation and sharing has greatly improved people's living standards and even life expectancy.

New York street scene at night in the 1930s

Electricity, which travels at the speed of light, is extremely efficient whether it is used as a carrier of energy or information. Moreover, electric current is like water flow, which has excellent versatility. The network system built using electricity, from a car to a ship to a city, the larger and more complex the system is, and the more functions it needs to achieve, the more obvious the advantages of electricity will be.

Shanghai Bund Night View

In the steam age, humans tried to build a general-purpose computer, but failed. In the electric age, we finally succeeded! This proves that electricity is indeed the best networking tool that humans have discovered so far. But conversely, we can also understand that the reason why humans like to use electricity so much is that they have a strong tendency to network various systems. In terms of technical details, such as electric motors and internal combustion engines, electric transmission and mechanical transmission, the latter once had an advantage in single-unit competition, but with the upgrading of technology, as long as the two sides can tie, the networking advantage of electricity makes people tend to use electricity.

Power line inspection using LiDAR

In summary, people use electricity to "go online". This is not only true in the Internet age, but also in the advent of the electricity age. It's just that now people are networking information, and then they networked the use of energy. Now the popularity of electric vehicles is also further networking the use of energy.

So, life lies in "using electricity" and "going online"~O(∩_∩)O~

Yingda Media China Electric Power Press Co., Ltd. Design and Production Center Wu Di