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Why is the Transition to DC Buildings necessary

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Why is the Transition to DC Buildings necessary

According to the International Energy Agency (IEA), the construction and building sector is responsible for about 40% of global energy consumption and 36% of CO2 emissions1. As if that were not enough, the sector is expected to grow rapidly in the coming decades, mainly due to phenomena such as increasing urbanisation and population growth.

These data lead to reflect on the importance of decarbonising and making the building sector increasingly sustainable, so as to achieve the Net Zero goal by 2050 and limit global warming to 1.5°C, as established by the Paris Agreement.

 

1. International Energy Agency, Buildings
 

One of the main strategies to achieve this goal is undoubtedly to increase the use of renewable energy sources within homes and buildings. However, most renewable energy sources produce direct current (DC) electricity, while the majority of buildings are designed to run on alternating current (AC) electricity, which has been the standard since the late 19th century. This means that DC electricity generated by renewables has to be converted into AC electricity before it can be used by buildings, and this conversion process results in losses in energy, efficiency and quality. On top of that, there is also an increase in costs and a great complexity of the whole system.

But let's go step by step. What is meant by direct current and alternating current, and what is the difference between the two?

 

Difference between direct current and alternating current

Direct current, commonly abbreviated as DC and introduced by Thomas Edison towards the end of the nineteenth century, indicates a flow of electrical energy that, through a conductor, always circulates in one direction only and with a constant amplitude over time. Alternating current (or AC), introduced around the same time by Nikola Tesla — giving rise to what has gone down in history as the War of the Currents — is instead a flow of energy that reverses its direction and amplitude over time, assuming a sinusoidal and oscillatory trend.

The distinction between the two types relates in particular to their field of application:

  • Direct current — which tends to be low voltage — is used especially in equipment powered by batteries (one example would be the electrical system of the car);
  • Alternating current, on the other hand, is used in the production and transport of high-voltage electricity (such as in the electrical systems of buildings).
 

Why switch to direct current in buildings?

Nowadays, more than 70% of devices found in buildings require direct current to operate. As mentioned, the conversion from alternating current to direct current causes major inefficiencies in terms of energy waste. As a result, eliminating — or limiting as much as possible — the conversion process has positive environmental consequences, as the losses due to conversion are eliminated or reduced.

In addition to greater efficiency, switching to direct current leads to higher quality and reliability, as DC electricity is more stable and less subject to fluctuations and interference than AC electricity, and greater safety, since DC electricity has constant and lower voltage and current levels than AC electricity, and can therefore prevent fire and short circuit risks.

Finally, DC electricity ensures greater sustainability and levels of intelligence, as it can enable the integration of smart devices and systems such as sensors, controllers, and monitors that can improve the performance of buildings and reduce environmental impact. In addition, DC facilitates the integration of renewable sources and energy storage, making buildings greener, more resilient and autonomous.

 

The challenges of using direct current in buildings

The transition to DC-powered buildings is a complex and multidimensional issue, involving several technical, economic and social aspects. DC is an innovative and promising technology that can revolutionise the way buildings are powered, connected, and operated. In addition, the use of DC contributes to the improvement of the efficiency, sustainability and safety of buildings, as well as the quality of life and wellbeing of people. However, it also requires a paradigm shift and change in mindset regarding AC, which has been the dominant standard for over a century. This paradigm shift brings with it a number of challenges, first and foremost the potential resistance from stakeholders in the construction industry, who may have concerns or worries about the safety and affordability of this new technology. It is therefore necessary to undertake a process of informing stakeholders and raising their awareness about the benefits of direct current.

At the moment, there is also a lack of common and harmonised rules and standards for the design, installation and operation of DC systems in buildings that can ensure interoperability, compatibility and compliance between the different components and equipment.

Overcoming these barriers requires a strong commitment and close collaboration between all the players involved, who can share a common vision and strategy for the deployment and implementation of DC in buildings.

 

Change takes time

The above-mentioned barriers and challenges will inevitably slow down the transition to DC-powered buildings, but this transition is undeniably happening. Just think of the increase in solar panels on the roofs of buildings (which, as mentioned, produce direct current electricity), or the increasing spread of electric vehicles, which will require the presence of charging stations in homes and offices (we are talking about DC in this case as well).

All these factors are driving towards the adoption of direct current as a new paradigm for powering buildings, a transition that will bring with it technical and logistical challenges and a change in mentality, but also important — and necessary — benefits for the environment and society.