Continuous Current

Context

With the rise of semiconductor technology, continuous current (also referred to as DC or Direct Current) has become widely established. This is especially true in low-voltage applications and for most electronic circuits.

Because conversion from alternating current (AC) to DC generates significant losses, the basis for the predominance of alternating current is being altered. We have become comfortable with DC technologies through the explosive growth of low consumption appliances such as cell phones, portable devices, and electronic gadgets. These usually require only a few watts that can be provided by batteries. But even as the widespread use of these devices rapidly grows, the grid still provides us with 110/220 V AC electricity that is unsuitable for our new needs. Meanwhile, the ongoing development of decentralized electric power production, through renewable sources system integrated into buildings (predominantly DC native sources like photovoltaic panels) continues. This alone, should encourage reconsideration of the structure and organization of the energy network.

AC predominates when it comes to electricity transport but there exist a number of high to very-high-voltage DC transmission lines throughout the world. Recently, the British company Moixa Energy called for the debate to be re-opened stating that small consumer loads can be driven by local renewable DC sources.

Applications

All systems powered by batteries, including vehicles, cell phones, and cameras and systems requiring an AC adapter like printers, fax, and notebooks, could be easily retrofitted to DC with a simple modification. Thanks to CFL and LEDs, lighting should also be included.. In all, there are only a very few appliances that would still require AC current. These involve direct heating, freezing, and some industrial processes.

A recent study demonstrated that a typical office building partially supplied by photovoltaic arrays consumes 15 per cent more electricity due to conversion losses. Direct use of DC production on the other hand consumes 15 per cent less electricity for an overall savings.

Gains are not easily quantifiable. But getting rid of transportation and conversion loses, utilizing local DC generation as alternative to centralized production, and pushing users/manufacturers to use very-low consumption appliances, are just a few of the advantages of DC. Perhaps the time has finally come for Edison’s revenge over Tesla.