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.

Today, I call:

On manufacturers to incorporate the « direct current » aspect into their R&D programmes, so that we can have low-voltage devices that can be directly interconnected in direct current, along with the corresponding secure electricity distribution infrastructures with voltages up to 48 volts.
On HVAC engineering industrialists to expand the development of devices that are directly powered by a DC network.
On building industry stakeholders to include in all of their projects from now on (new or renovation) the infrastructure necessary to supply devices directly with direct current.
On public and private project owners in charge of developing property complexes (data centres, campuses, shopping centres, hotel complexes and eco-districts), which are potentially major producers of renewable and stored energy, to examine the possibility of installing DC electrical systems catering for self-supply, to boost energy efficiency (among other reasons).
On developers to build direct-current Smartgrid demonstrators combining the production of local renewable energies from various sources, and energy storage.
On local authorities to build concrete projects demonstrating the benefits to be gained by combining local renewable-energy production and/or storage with the supply of DC electricity to public facilities such as: street lighting, building lighting, video surveillance, urban mobility, urban billboard advertising, street furniture, charging stations.

On the public authorities to encourage this change by simplifying the standards and by bringing in incentives, particular in connection with energy renovation. This should concern both local and/or distributed energy production and storage, along with electricity distribution in the region and in buildings. It should also include the promotion of microgrids or nanogrids around local energy communities.
For the introduction of a set of standards for rating buildings and regions that meet the challenges of direct current distribution and its gradual incorporation, involving all of the parties in the value chain.
For the public authorities to bring in an awareness-raising plan for all of the stakeholders
On all of the stakeholders responsible for new electrification projects, whether urban or rural, to include the direct current aspect from now on, in particular in islanded microgrids operating independently of the distribution electricity grid.

Founder of Fonds MAJ

Mail :
Twitter : @EM_Francois1

Saint-Didier au Mont d’Or, January 7, 2020

Industrialist, manufacturer, HVAC engineering industrialists, building industry stakeholders, local authorities, public authorities, citizens… if you want to support the gradual introduction of direct current (DC) in the building industry and sustainable cities, we invite you to sign this charter.