Charter for the gradual introduction of direct current (DC) in the building industry and sustainable cities
Curbing greenhouse gas emissions will necessarily mean curbing our energy consumption, beginning with the construction and transport industries, since these two sectors alone account for respectively 30% and 29% of world energy consumption (source: IEA) (45% and 33% of energy consumption in France, according to ADEME).
Given that tomorrow’s world will be increasingly electric, we would do well to re-examine the benefits to be gained by having direct current as well as alternating current (AC) in certain use cases, to help shrink our carbon footprint. A growing proportion of energy sources will be renewable (41% of the world’s energy production sources, according to the REmap 2030 scenario) and a large part of that energy will be produced natively as direct current. Moreover, the bulk of the electrical energy produced and/or stored locally in a building is in direct current and the majority of the site’s consumption points run on direct current, beginning with the electric vehicles, LED lighting and all devices using electronic components.
It seems less and less logical, therefore, to transform locally produced and/or stored energy, which is natively in direct current, into alternating current, and then convert it back into DC at the point of connection to the terminating load, using static power converters.
Eliminating this double conversion at each electrical device by introducing a paradigm change will pave the way for miniaturised system solutions (high-frequency converters) or hybrid AC/DC solutions. This will effectively reduce the spatial footprint and cost of the devices and their maintenance, while at the same time increasing their durability. On the scale of a building, there are two distinct types of electrical architecture:
- For low-current applications: The DC network would simplify electricity distribution by delivering power and data in the same cable. This would in turn simplify certain practices, such as electricity metering at the point of consumption (which would enable electricity to be billed by the amount used), or the connection and control of electrical equipment. This would also lead to a reduction in buildings’ electricity consumption, since it would eliminate energy-consuming conversion devices. This would in turn reduce the number of devices to be maintained, the amount of end-of-life waste and the CO2 emitted to produce and transport the devices.
- For high-current applications: Medium-voltage direct current is well-known and well-regulated in the fields of rail transport and « renewable energies ». The same usage conditions can be transposed to the construction industry for devices that are natively in direct current, such as electric motors (ventilation equipment, pumps, lifts, etc.) and electric vehicles.
On the strength of this observation, I would like to encourage all of the stakeholders to make a determined commitment to collectively supporting and promoting this universally applicable project. This is the purpose of the following 10-point charter.