Alternating Current (AC) is currently used to power your home, office, or any other building every day. But why is Direct Current (DC), commonly found in most digital electronic devices, not used in these power grids?
Simply put, alternating current can change voltage levels using just one transformer, making long-distance transmission easier compared to direct current, which requires many complex electronic circuits for this conversion.
Alternating current can change voltage levels using just one transformer.
The charge in alternating current periodically reverses, causing the voltage levels to fluctuate. Therefore, alternating current needs to be stepped up when transmitted over long distances, but this does not affect the speed of the conversion process. This ease of conversion allows alternating current to be used in generators, motors, and power distribution systems. The necessity of only one transformer to change voltage levels is perhaps the greatest advantage alternating current has over direct current, as direct current can only generate a magnetic field, making it incompatible with transformers.
However, at the Three Gorges Dam in China, high-voltage direct current transmission lines transport electricity to the public with less energy loss compared to alternating current, indicating that the use of direct current in households is becoming increasingly common. Siemens Engineering has even installed a 65-mile (approximately 105 km) high-voltage direct current (HVDC) line stretching from the Pennsylvania/New Jersey power grid to Long Island. Such projects can significantly enhance the use of renewable energy, and while direct current grids can be challenging to monitor, high alternating voltages can be reduced to safer levels as they are transmitted from power stations.
Alternating current has established its presence in homes, with the fact that modern lighting systems operate more efficiently with alternating current. Incandescent bulbs can use either type of current, but fluorescent lights are optimized for alternating current. However, while alternating current is primarily used for large power grids, direct current powers LED lights and solar panels. This leads to the question: what if environmentally friendly lighting could become more desirable than it currently is? There are many methods for converting direct current to higher or lower voltages. This indicates that the world will adapt to these potential changes.
Despite concerns about the increasing use of direct current, including the installation of devices with different voltages or issues with leakage due to more components, its benefits are still quite evident. In addition to the widespread use of LED lights, direct current systems will narrow the energy supply and waste less energy. As more devices begin to use lower voltages, the demand for power conversion decreases. The greatest current benefit of direct current remains its application in low-voltage scenarios, especially for charging things like batteries and applications in aircraft. It also has advantages over AC-powered LEDs, which tend to flicker, meaning there is continuous fluctuation in light output from on to off.
However, the world continues to favor the simplest method of energy transmission. Alternating current creates efficiency and has been continuously validated over time. Currently, the number of devices operating on direct current is not sufficient to support its larger-scale use, and the economic and practical outcomes of a complete shift to direct current are unpredictable. While direct current is gradually becoming more efficient for long-distance energy supply, alternating current remains very easy and reliable to supply, allowing people to use electricity comfortably in their daily lives.
