Which Green Technology to Subsidize? Evidence from Electric Vehicles in South Korea
This paper argues that in South Korea's passenger vehicle market, subsidizing intermediate hybrid electric vehicles (HEVs) is currently more effective at reducing total greenhouse gas emissions than subsidizing the cleanest battery electric vehicles (BEVs), because HEVs induce greater substitution away from high-emission conventional cars until electricity generation becomes sufficiently decarbonized.
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine you are trying to clean up a messy room, but you only have a limited amount of cleaning spray. You have two types of mess: a thick, sticky goo (representing old, polluting cars) and a light, dusty powder (representing newer, cleaner cars). Your goal is to use your spray to get rid of as much mess as possible. In the world of climate science, this is the challenge of reducing greenhouse gas emissions. Governments have been pouring money into subsidizing the "cleanest" technology—battery electric vehicles (BEVs)—hoping they will replace the "dirtiest" ones, gas-powered cars. But there's a twist: sometimes, the cleanest tool isn't the most effective one for the job if it doesn't convince enough people to stop using the dirty tool. This paper dives into that puzzle, asking a simple but tricky question: Is it better to give money to the ultra-clean cars, or to the "middle-ground" cars that are cleaner than gas but not quite as clean as electric?
The authors of this study, focusing on the car market in South Korea, decided to test this idea with a mathematical model. They built a simulation that acts like a giant, digital traffic jam, tracking how millions of different drivers make choices based on price, how far they drive, and what kind of car they prefer. They looked at three main players: the old gas cars (ICEVs), the hybrid cars (HEVs) that mix gas and electricity, and the fully electric cars (BEVs). The researchers wanted to see what would happen to the total amount of pollution if the government took the money currently spent on electric car subsidies and gave it to hybrid car subsidies instead.
Here is the surprising result: The paper suggests that shifting the subsidies from electric cars to hybrid cars could actually reduce total greenhouse gas emissions by an additional 47%.
Why would a "less clean" car win? Think of it like this: Fully electric cars are the "gold medal" of cleanliness, but they are expensive and require a specific infrastructure (charging stations) that not everyone trusts yet. Because of this, when the government gives a big subsidy to electric cars, many people who buy them are already driving relatively efficient gas cars. They are just upgrading from a "silver" car to a "gold" car. The government is paying for a small improvement.
Hybrid cars, on the other hand, are the "silver medal." They are cheaper and feel more like the gas cars people are used to. When the government subsidizes hybrids, they act like a powerful magnet, pulling a huge number of people away from the "bronze" gas cars and the even dirtier used cars. Even though a hybrid car isn't as clean as an electric one, the sheer number of people switching away from the dirty gas cars makes a bigger dent in the total pollution. The study found that electric car subsidies mostly cause people to switch between different types of electric cars or from efficient gas cars, whereas hybrid subsidies cause a massive switch from the most polluting vehicles.
The researchers also ran a "what-if" scenario to see when electric cars would finally become the better choice for subsidies. They found that for electric car subsidies to beat hybrid subsidies, the electricity used to charge them would need to become about 45% cleaner than it is in South Korea right now. Currently, South Korea's electricity mix is similar to the United States and Germany, but it still relies heavily on fossil fuels. The study suggests that until the power grid gets much greener, or until consumers become much more willing to switch to electric cars, subsidizing the "middle-ground" hybrid technology is the smarter move for the planet.
In short, the paper argues that in the race to clean up the air, the "best" technology isn't always the one you should fund. Sometimes, the most effective strategy is to support the technology that gets the most people to stop using the dirtiest option, even if that technology isn't the absolute cleanest one available. The authors suggest that for South Korea, and potentially other countries with similar electricity grids, subsidizing hybrids is currently the more powerful tool for fighting climate change.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.