In 2007, the company I work for was the first to propose 48V-DC as the voltage of choice in a local DC system, when we introduced DC-ready LED lighting. Schneider of France and General Electric (GE) followed suit in 2013 and 2014.

DC will be the on-site electricity distribution of choice. More and more technology-driven companies are recognizing this, and as a result, there is now agreement that 48 V-DC is the voltage of choice, for now, for local battery systems and DC distribution.

However, this is still based on lead-acid technology being the cheapest in 12-volt increments and the low-voltage directive. With LiFePO battery systems that have 3 volts per cell and with no odd voltage cost penalty, actual local system voltages can go from 48 volts (24 lead-acid based cells) to 66 volts LiFePO based on) and the power DC equipment will have to tolerate input voltages of 40 to 75 V-DC.

More and more devices in the home and workplace are native DC devices that will benefit from direct DC power. Such devices include most of the essential elements of modern home and office life, such as solid-state LED lighting, solid-state cooling, heating and air conditioning, computers, telephones and networks, access control, entertainment systems. , water treatment and pumps. Even the heaviest production machinery can be converted to DC devices at a reasonable cost.

A DC infrastructure with a battery storage system lends itself to direct power from an alternative energy source, such as solar or wind. Generating and using the energy yourself has a significant impact on the effectiveness of alternatively generated energy. For example, when it is generated by feeding the network and taking energy from the network, it has a minimum loss of the entire process of 30%.

Losses in alternating current (AC) systems (other than heating) typically range from 15-30%, this is typical for a laptop or PC power supply, a microwave oven power supply, or a LED lighting power supply. If those devices can be equipped with a DC-to-DC power supply with efficiencies ranging from 90-95%, additional savings will result.

The effect of NOT powering the grid and using DC to DC power supplies is that close to all the locally generated power can be used rather than wasting half in a system that uses the grid rather than battery storage.

Multiple factors from recent technological advancements make DC more viable now than in the past:

• When Edison made batteries until a few years ago, the technology was not very durable and represented the highest cost in a local DC system. The batteries lost their capacity quickly, were heavy and difficult to maintain, lasting around 1 to 3 years depending on the depth of the cycles. New battery technologies are now commercially available at reasonable prices that promise a useful life of 10 years and 85% of their original capacity at the end of their useful life with daily cycles.
• Solar panel prices are at an all-time low.
• Semiconductor power device technology has become so good that system losses for charging or discharging batteries are in the range of 1% to 2% for systems with a load of more than 5 kW.
• Most of the devices are internal DC devices.
• The lighting will be completely moved to LED, which is a DC-driven semiconductor technology.

In 2007, I have been accurately predicting that LED technology will replace each and every light and now it is clear that it will.

DC Systems will enter the home and office space in the future because it is the most efficient way to use alternatively generated local power in the most efficient way and in doing so provides a robust backup and disaster strategy.

Another advantage of DC systems that use the network as a backup is that they can significantly reduce demand on the network. For companies that pay for both demand and energy used, this can also result in a significant reduction in their energy bill.