00:00 Earned $1,200 selling electricity: What is the secret?
02:04 A "refrigerator" that charges when cheap and discharges when expensive
04:23 Silicon Valley of the desert: Electricity as urban competitiveness
06:26 Why is this missing in Korea, a "battery powerhouse"?
1. Earned $1,200 selling electricity: What is the secret?
A home in Texas, United States. A billing screen sent by the power company reads, "You're getting paid for your solar!" With $123 this month and $1,200 so far, this household does not merely buy and use electricity; it earns money by selling it. The secret lies in a box—a unit about the size of a travel suitcase that has transformed this home. But doesn't this seem unusual? South Korea is a global battery powerhouse. So why don't our homes have something like this? To find the answer, we visited Texas. This is the homeowner, Craig Kincaid. A year and a half ago, he installed 50 solar panels on his roof and placed four Energy Storage System (ESS) battery units in his shed to store electricity. The total investment was around 50 million won, and the results were clear. His monthly electric bill, which used to run between $400 and $500 (over 600,000 won), has dropped to just $20 to $30 (about 30,000 to 40,000 won). Here is why he invested that considerable sum.
[Craig Kincaid / ESS-installed homeowner: I wanted to secure emergency backup power for my wife and daughter at home, in case the air conditioning cuts out during the summer or heating goes down in the winter.]
Texas experiences everything from tornadoes and hurricanes to winter freezes, making blackouts frequent. Yet this home stays lit even when the entire neighborhood goes dark. That was the case on the day of the last World Cup final.
[Craig Kincaid / ESS-installed homeowner: The entire neighborhood lost power on the day of the World Cup final. We had a lot of guests over, and thanks to the battery, our house was able to watch the whole game together until the end.]
This was possible because the electricity generated by the rooftop during the day was stored in these batteries. Everything is managed right from a smartphone. In real time, the app displays how much electricity the rooftop panels are generating, how full the batteries are, and whether power is being bought or sold at any given moment. On sunny days, surplus electricity is sold back to the power company. Under the rate plan Kincaid subscribed to, the utility credits the sold electricity at the same retail rate it charges and deducts it from the bill. That is how he earned the $1,200 mentioned earlier.
2. A "refrigerator" that charges when cheap and discharges when expensive
This raises a question: Is it profitable to install only batteries without solar panels? The CEO of a residential battery company in Texas uses batteries at his own home without solar panels, charging them when electricity is cheap and using that power when rates are high. It works essentially like a refrigerator where you buy groceries when cheap, store them, and consume them when prices soar. The price difference in electricity becomes profit. Moreover, the cost of this "refrigerator" itself has dropped sharply. The secret lies in a change of battery materials. In the past, expensive metals such as nickel and cobalt were used. Today, the mainstream technology is LFP (lithium iron phosphate) batteries. Iron and phosphate are abundant and inexpensive materials. Although their energy density is somewhat lower, that is hardly a drawback for storage units installed at homes or next to power plants. Instead, they are cheap and carry a relatively lower fire risk. South Korean battery makers are also transitioning toward LFP, and a Korean company supplies the battery firm used by Kincaid. However, there is a twist in this market.
[Brian Pascoe / CEO of Signature Solar: In the past, many states allowed you to sell back excess electricity, but policy changes mean fewer places can do that now. That is why demand for batteries is exploding. Instead of selling it, you store it and use it yourself.]
Solar power peaks during the day, whereas electricity consumption peaks in the evening. If excess power cannot be sold, it must be discarded, so people choose to store and consume it. Whether you make money by selling it or save money by storing it, you come out ahead either way. And this profitable model is not limited to private homes. Here in the Arizona desert:
[This is a massive power complex 22 times the size of Yeouido. Eight out of ten new power facilities built in the United States are these solar and battery installations.]
One of the largest hybrid power complexes in the United States is currently under construction. The batteries deployed here are also manufactured by a South Korean company at its U.S. facility. This complex operates on the exact same principle as the home in Texas: storing power during the day and discharging it when demand peaks. Only the scale is different.
[Electricity generated in the desert right now is stored in these batteries and sold as far as California in the evening.]
3. Silicon Valley of the desert: Electricity as urban competitiveness
Yet power plants are not the only places that require batteries. Just a two-hour drive away is Phoenix. In this city, emerging as the Silicon Valley of the desert, TSMC semiconductor fabs, a Korean company's battery plant, and AI data centers are converging. Here is what the official in charge of business attraction for the City of Phoenix had to say.
[Ryan Touhill / Director of Phoenix Community and Economic Development: To continue expanding our manufacturing base with global companies building next-generation semiconductor chips, having the power capacity to support that is absolutely essential.]
Where does that electricity come from? In this region, the answer is in the sky. The sun shines brightly for more than 300 days a year.
[Christine Mackay / President of Greater Phoenix Economic Council (GPEC): Arizona's battery and energy industry is experiencing explosive growth. In Arizona, where the sun shines 340 days a year, you can store that energy and use it when needed. This growth is not a temporary boom; it will continue to expand.]
Electricity has become the core competitiveness of cities. Powering a single large data center requires as much electricity as an entire mid-sized city. The prompts you send to ChatGPT are processed in places like this. However, while building a power plant takes five to ten years, a data center can be erected in just one to two years. Electricity supply inevitably struggles to keep pace with demand. Batteries are stepping in to bridge that gap.
[Tristan Doherty / Product Strategy Manager, ENGIE Storage: Data centers are the new heavy industry of the modern era. They place immense demand on the local grid. ESS is the way to reliably connect this demand to the power grid.]
As a result, the market has exploded. ESS battery capacity supplied in the first half of this year surged 71% compared to the first half of last year.
4. Why is this missing in Korea, a "battery powerhouse"?
Returning to the initial question: Why doesn't South Korea, a country renowned for making batteries, have this in our own homes? In searching for the answer, an interesting fact emerges. South Korea does have a massive "electricity warehouse": pumped-storage hydroelectric power, where water is pumped up to a mountain reservoir and released downward to generate electricity. This serves as the country's primary energy storage system. However, this warehouse operates differently from the home in Texas. Water is pumped up when power is in surplus and released when needed to balance supply and demand. It is not structured so that operators can freely store and sell based on real-time electricity prices. In short, it is not a lack of storage technology, but rather an underdeveloped market that fails to fairly compensate flexibility. Korea also wastes electricity. In spring and autumn, generation frequently outstrips demand, repeatedly forcing solar plants to curtail output or shut down entirely. While the U.S. stores surplus electricity to save money,
Korea is unable to properly store and utilize its excess power. Why is this the case? Experts point to the following.
[Lee Si-young / Professor of Electronic and Electrical Engineering at Hongik University: In South Korea, collective housing like apartments is overwhelmingly common, whereas the U.S. has many single-family homes, making North America more accommodating for installing and operating batteries. In Korea, while residential electricity rates fluctuate slightly, the price difference across time slots is not very large, which I think creates another key difference.]
The core issue is the tariff structure. In Korea, residential electricity rates remain virtually flat throughout the day. There is no distinction between cheap hours to buy and expensive hours to discharge. Consequently, there is no financial incentive to store power. To encourage investment, operators need to earn returns commensurate with their contribution, but such a market does not yet exist. The government has begun taking steps.
[Lee Si-young / Professor of Electronic and Electrical Engineering at Hongik University: There must be compensation for the ability to flexibly adjust output, but transaction systems and market frameworks for flexible resources remain very underdeveloped in Korea. Although the power exchange utilizes such assets, it lacks proper market services and compensation mechanisms. When ESS operators consider deploying facilities voluntarily in Korea, they inevitably feel they will not receive adequate market compensation.]
As a first step, long-term contracts are being used to guarantee returns to bring in batteries, and pilot programs for electricity trading have begun in Jeju. Looking back at that screen in Texas: "You're getting paid for your solar!" Korea already makes the batteries. What remains is building the market so that very sentence can appear on our own electricity bills.
Reported by Jang Seon-i | Story by Shin Hee-sook | Camera by Bae Moon-san | Video by Kim Hye-ju | Design by Lee Jung-joo | Produced by SBS Digital News
※
Copying, redistribution, and unauthorized use in AI training are strictly prohibited.