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Why AC Power REALLY Won the Current Wars

April 14, 2022

Imagine what life would be like if we didn't have access to electricity? Maybe some of you think you could handle it, and maybe you could.

But if you have a job that requires an internet connection, a cell phone to call your family or friends, or a coffee addiction (like myself), you may find it difficult to let go of electricity. Even if you gave up all your devices, electricity is still what powers light and heat in your building (not to mention indoor plumbing).

people working on many electronic devices
People working on their many devices

Electricity as a technology is something that can be very easily taken for granted. We're often so focused on our daily lives, that we forget how much of our activities rely completely on electricity. In fact, we'll become even more reliant on electricity as our daily lives continue to become even more entwined with technology.

With this in mind, did you know there are two different types of electricity? Both alternating current (AC) and direct current (DC) power were discovered, and then inventions and technologies were developed with respect to each of them. Coincidentally or not, innovations were made almost in parallel to each other as the two types were developed independently. However, in the late 1800s, it was time for the world to decide which type of electricity would be standardized in modern infrastructure to power the world. AC electricity came out on top, winning the co-called War of the Currents. This historical event was just as dramatic as it sounds, in fact there was a whole movie made about it starring Tom Holland, Benedict Cumberbatch, and Nicholas Hoult (you should check it out!).

In a previous article we covered the scientific reason why AC electricity was chosen as the more practical option between AC and DC electricity (in one word: transformers). Check out that article here: 4 Reasons Power Grids Still Distribute AC Electricity.

However, we can’t talk about why the world is powered with AC electricity without discussing the War of the Currents

The War of the Currents

The War of the Currents was essentially a competition between Nikola Tesla and Thomas Edison (or Westinghouse and Edison Co.) to determine who’s inventions would contribute to powering the modern world. Although there are many scientists that can be attributed with helping to develop the technologies necessary to transmit AC electricity, Tesla may be the most famous. Tesla invented the first practical alternating current (AC) motor and developed AC generation and transmission technology. Tesla's rival, (and former employer) Thomas Edison, improved on the invention of the incandescent lightbulb in the late 1870s so that it would be long-lasting enough to be practical for widespread use. This achievement led to his desire to develop DC electricity generators so that homes and businesses could use his lightbulb. According to Ernest Freeberg (a historian at the University of Tennessee), Edison’s genius was taking a new technology that someone else had pioneered, and developing a superior way of doing the same thing. Freeberg says:

“An invention not only has to work fairly well, but it has to be something that the market wants and can afford to buy. Edison understood that as well as anyone in his day".

Edison opened his first power plant in New York City in 1882. Two years later, Nikola Tesla was hired to work for Edison. Tesla had been working on his own invention: an AC motor. But, after being slighted by Edison, Tesla quit working with him, and in 1888 he sold his patents relating to AC electricity to George Westinghouse. This was a direct affront to Edison, as Westinghouse could be considered Edison’s rival and closest competitor. One reason Tesla might've wanted to work with Edison's closest competitor was because Edison had broken his word to Tesla. Edison said he would pay Tesla $50,000 to improve the design of his DC dynamos, so Tesla worked on a solution to Edison's problem for months, and then presented a solution to Edison. But Edison shrugged him off, saying: 

"Tesla, you don’t understand our American humor."

When Tesla sold the patent for his AC motor to Westinghouse, and started working with him, Edison became even more driven to prove to the world that DC electricity was the superior technology. To do this, he decided to demonstrate that AC electricity was more dangerous than DC electricity, thereby hoping to incite fear into people who might've decided to champion AC electricity. To demonstrate this, Edison publicly electrocuted animals, and even recommended that AC electricity be used to power the new invention of the electric chair so that people would associate AC electricity with death.

The First Execution Using the Electric Chair

The End of the War of the Currents

Tesla and Westinghouse Succeed

Ultimately, Westinghouse won the contract to supply electricity to the 1893 World Fair in Chicago and would use Tesla’s invention of an AC motor to do it. The use of AC electricity at the World Fair created a snowball effect, and Westinghouse quickly secured other contracts, such as to construct the AC generators for a hydropower plant in Niagara Falls. When the plant demonstrated its ability to deliver electricity to Buffalo, New York (26 miles away), the War of the Currents was considered to be over.

Where is DC Electricity Now

From the late 1890s on, AC became the standard electricity distributed by power grids. This is still the case today, but an increasing number of high-voltage DC (HVDC) transmission lines are being built to transmit DC power. This is because DC electricity has many inherent benefits that were unable to be harnessed with the technology of the 19th century. After the development of mercury arc valves, however, it became more efficient to use DC electricity for transmission systems that are a minimum of 600km in length. It's also more cost effective to use HVDC transmission systems when cables travel underground or underwater because DC electricity has less capacitance losses due to it being entirely made up of active power. If you're not sure what this means, take a look at our previous blog article comparing high-voltage AC lines to high-voltage DC lines.

The world's first HVDC transmission link was built by ABB in the late 1950s, and there are many benefits to the transmission of DC electricity that inspired this. For one thing, DC electricity has inherently less capacitance losses than AC electricity. Benefits like this will lead to additional innovations being made on the technology involved in HVDC transmission lines, so they will be used more often once this technology is developed. Another motivating factor for the development of HVDC lines are data centers. The servers in data centers use DC electricity, and are large electricity users in general. In fact, according to an independent British report from 2016, data centers consume approximately 3% of the world’s electricity and account for 2% of total greenhouse gas emissions. Thus, proliferating the transmission system market with DC electricity, as opposed to AC, would effectively eliminate a significant percentage of electricity losses experienced by data centers. Reducing electrical losses in data centers, like the Lakeside Technology Center in Chicago, would play a significant role in reducing carbon emissions. Still not sure that data centers consume that much electricity? Consider this: the Lakeside Technology Center is the region's second-largest energy consumer behind O'Hare International Airport.


The Deciding Factor

So if DC electricity has so many benefits, why did AC electricity win the War of the Currents? Essentially, the infrastructure necessary to transmit DC electricity was too inefficient and expensive for it to be chosen. To explain this further, AC electricity is compatible with transformers, while DC electricity is not, so the technology that would replace transformers in DC transmission systems was just too expensive. Additionally, DC electricity needed repeater stations every few kilometers in order to be transmitted over longer distances. As you can see, at the time, it made sense for AC electricity to be chosen over DC. But now DC electricity can actually be more cheap and efficient to transmit than AC electricity. Additionally, even if you can't rely on power lines transmitting and distributing DC electricity, you can still distribute DC electricity throughout your building via the use of a local DC distribution system. The Argentum DC distribution system, for example, simply connects to your electric panel, makes one highly efficient conversion from AC to DC power, and distributes DC power to building systems and devices. About 80% of a building's systems and devices (including LED lights, HVAC systems, digital devices and more) run off of DC electricity, so providing them directly with the DC electricity they need, reduces both energy losses and bills.

If you'd like to learn more about Argentum's DC distribution system you can contact us here.

Or, if you like to learn more about the scientific reason why AC electricity was chosen over DC electricity, you can check out our article on the topic here.

blog author image

Erin Kelly

Erin is the Creative Director at Argentum Electronics. She has a New Media degree from the University of Toronto and 5 years of experience in the communications field. From 2017 - 2019 she worked with a manufacturing company on their YouTube content and strategy, and has done digital content creation for dozens of clients through her own business called Story Unlocked. Erin has built two computers, and loves technology, especially when it makes the world a better place.

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