In 2007, the company I work for was the first company to propose 48 V-DC as the voltage of choice in a local DC-System, when we introduced LED lighting that was DC ready. Schneider of France and General Electric (GE) were following suit in 2013 and 2014.
DC will be the on-site electricity dispensing of choice. More and more technology pushed companies are recognizing this and as a consequence there is now agreement that 48 V-DC is the voltage of choice, for now, for local battery systems and DC dispensing.
However, this is nevertheless based on rule acid technology being cheapest in increments of 12 Volt and the low voltage directive. With LiFePO battery systems having 3 Volt per cell and no cost penalty for strange voltages the real local system voltages may move from 48 Volt (24 cell rule acid based) to 66 Volt systems (22 cell LiFePO based) and strength DC equipment will have to tolerate 40 to 75 V-DC input voltages.
More and more devices in the home and the place of work are native DC devices that will assistance from direct DC feeds. Such devices include most of the modern life essentials for home and office like substantial state LED lighting, substantial state refrigeration, heating and air-conditioning, computers, phones and networking, access control, entertainment systems, water treatment and pumps. already heavier production machinery can be converted to DC devices at a reasonable cost.
A DC infrastructure with a Battery Storage system lends itself to direct satisfy from an different energy source such as solar or wind. Generating and using the energy yourself has a meaningful impact on the effectiveness of alternatively generated energy. For example when generating feeding the grid and taking strength back from the grid has a minimum loss of the complete course of action of 30%.
Losses in alternating current (AC) systems (other than heating) are typically between 15 to 30%, this is typical for a Laptop or PC strength supply, a Microwave Oven strength supply or an LED Lighting strength supply. If those devices can be equipped with a DC to DC strength supply with efficiencies ranging from 90 to 95% additional savings will be achieved.
The effect of NOT feeding the grid and using DC to DC strength supplies is that close to all of the locally generated energy can be used instead of throwing half of it away in a system that uses the grid instead of battery storage.
Multiple factors of recent technology advances make DC more viable now than in the past:
- When Edison was making batteries up until a few years ago the technology was not very lasting and represented the highest cost in a local DC system. Batteries lost their capacity quickly, were heavy and difficult to continue, lasting around 1 to 3 years depending on the thoroughness of the cycles.
There are now new battery technologies commercially obtainable at reasonable prices promising a 10 year lifetime and 85% of their original capacity at end of life with daily cycles.
- Solar Panel prices are at a historical low.
- Semiconductor strength Device Technology has become so good that system losses for charging or discharging batteries are in the 1% to 2% range for systems above 5 kW load.
- Most devices are internally DC devices.
- Lighting will move completely to LED which is a DC pushed semiconductor technology.
In 2007 I have been precisely predicting that LED technology will replace any and all lighting and it is now clear that it will.
DC Systems will be entering the home and office space in the future because they are the most efficient way to use local alternatively generated energy the most efficient way and by doing so provide a strong disaster and backup strategy.
Another advantage of DC systems using the grid as a backup is that they can considerably reduce the need on the grid. For companies that pay for the need in addition as for the energy used, this may also consequence in a meaningful reduction of their energy bill.