This blog post explores how a super grid connecting national power grids could play a role in expanding renewable energy and ensuring stable power supply.
Oil reserves are finite, and their profitability is steadily declining over time. Nuclear power, once touted as a next-generation energy source, is losing trust in its safety and economic viability due to successive accidents and waste disposal issues. In this context, the need to transition from the current fossil fuel and nuclear-based energy system to one based on renewable and clean energy is growing increasingly urgent. However, the transition to a renewable energy-based system is extremely challenging. First, renewable energy sources themselves lag behind fossil fuels, the existing primary energy source, in several aspects. They offer low supply stability, are difficult to store, and present various challenges. Countries like China, Mongolia, and Russia, with vast territories and abundant clean energy resources, are in a somewhat better position. However, countries like South Korea, with limited land area and scarce clean energy resources, face an even more unfavorable outlook. In this context, the ‘super grid’—a continent-scale, cross-border power network—is gaining attention as a potential key to the energy system transition. So, what exactly is a super grid, and what role can it play in advancing toward a new energy system?
A super grid refers to a continent-wide power network created by connecting smart grids between nations. Here, a smart grid is a next-generation power network designed to supplement the efficiency of existing grids. By integrating information and communication technology, it enables real-time information exchange between power suppliers and consumers, facilitating more resilient power supply and consumption. Electricity, among energy resources, is particularly difficult to store, and its economic viability drops sharply when stored. Therefore, production and consumption must always occur simultaneously. Current power grids generate over 10% more electricity than expected consumption to prepare for emergencies, but most of this surplus power goes unused and is wasted. This represents significant energy waste. By enabling two-way communication between consumption and production sites through smart grids, real-time demand can be assessed, allowing electricity to be produced only as needed, thereby saving energy. Examples of super grids include the ‘Nordic-EU SuperGrid’, the ‘Sud EU-Magherb SuperGrid’ (connecting Southern Europe with North Africa and the Middle East), and the ‘Grand Inga Project’ (Southern African Grid).
Ultra-high voltage direct current (HVDC) transmission technology played a significant role in enabling the construction of power grids between countries separated by distances of thousands of kilometers. In fact, since the commercialization of electrical energy, alternating current (AC) power sources have been preferred over direct current (DC) sources for power transmission. In the AC power we use, reactive power is generated due to the phase difference between current and voltage, leading to power loss. Furthermore, the nature of AC causes transmission efficiency to drop due to increased reactance from electromagnetic induction and the skin effect. In contrast, direct current (DC) power sources do not change the direction of current flow, making them free from issues like reactive power, electromagnetic induction, and skin effect. They also require fewer transmission lines, resulting in higher transmission efficiency. However, the critical drawback of DC is the difficulty in transforming voltage. While AC voltage can be easily adjusted using simple transformers, DC requires complex technology and equipment for transformation. To minimize losses during transmission, voltage must be increased, which is why AC was preferred over DC. However, AC’s lower transmission efficiency meant its economic viability significantly diminished over longer distances, becoming a major obstacle to the development of super grids, which fundamentally rely on long-distance transmission. HVDC technology solved this problem. Simply put, HVDC is a technology that transforms power into AC for voltage conversion and back into DC for transmission, leveraging the advantages of both AC and DC. This greatly improved the economics of long-distance transmission. Consequently, as long-distance transmission became feasible, the super grid—a continent-scale, cross-border power network—is no longer a utopian concept but has become a viable model.
So, why is this super grid, connecting national power grids, essential for the energy system transition? The primary reason is that it overcomes the low storability of renewable energy compared to fossil fuels. Both fossil fuels and renewable energy tend to be geographically concentrated. South Korea, for instance, lacks abundant renewable energy resources. It has insufficient vast plains suitable for solar power generation, and while it has strong winds for wind power, the wind direction is inconsistent. In contrast, Mongolia boasts an annual wind power generation capacity of 1,110 TWh and solar power generation capacity of 1,500 TWh. This is an enormous amount, far exceeding South Korea’s total electricity production of 526 TWh in 2016. While fossil fuels can be transported to where they are needed for power generation, renewable energy has a major weakness: electricity must be consumed at the same time it is produced. Energy must be supplied immediately when demand arises. However, in renewable energy-based systems, the current power grid may face supply and demand issues due to the distance between production and consumption sites. Yet, if a super grid is successfully established, it can resolve these problems. This is because a continental-scale, cross-border power grid connects energy production and consumption sites into a single network, enabling the smooth supply of electricity to areas with energy demand.
South Korea is currently pursuing the ‘Northeast Asia Super Grid’ project alongside Mongolia, Russia, China, and Japan. As mentioned earlier, South Korea lacks abundant renewable energy resources and has relatively high electricity demand compared to other countries. Therefore, the importance of a super grid is particularly emphasized for the successful establishment of a renewable energy-based system. However, the ‘Northeast Asia Super Grid’ currently faces several obstacles. The first problem is the significant lack of basic infrastructure required to build the super grid. Even in South Korea alone, many argue that smart grids are premature due to high initial investment costs. For the super grid to be successfully established, smart grids spanning thousands of kilometers across the five countries must be formed. This includes regions like Mongolia and eastern Russia where development is virtually nonexistent, making the initial investment costs even more burdensome. The second problem is that for the ‘Northeast Asia Super Grid’ to operate successfully, the interests of the five countries must align well. Northeast Asia remains entangled in complex interests, and if tensions arise between nations during super grid operation, disruptions in power supply could occur due to energy conflicts. However, there is also a perspective that such disadvantages could actually be mitigated through the super grid. According to the current blueprint, the super grid does not pass through North Korea. However, future routing through North Korea could potentially ease tensions on the Korean Peninsula. Furthermore, sharing energy systems among the five nations could open avenues for diverse economic cooperation.
Thus, the ‘Northeast Asia Super Grid’ still faces numerous challenges. South Korea ranks ninth globally in energy consumption. However, it is also an energy-poor nation, producing 86.5% of its total energy from fossil fuels and nuclear power, while importing 96% of these energy resources from abroad. Given this reality, for South Korea—which lacks even abundant clean energy resources—to successfully transition its energy system, the ‘Northeast Asia Super Grid’ project is anticipated to be essential, despite the aforementioned challenges.
