Avec les microgrids, repenser l’énergie à l’ère de la résilience

Microgrids: rethinking energy in the era of resilience

What can be done in the face of climate change and the global rarefaction of resources? Today, numerous scientists, observers and citizens agree that “the current approaches to achieving a sustainable management of natural resources are disappointing.”

Welcome to the era of resilience

This report on the failure of traditional sustainable development is that of the advocates of a new paradigm: the American scientists and professors Brian Walker and David Salt, authors of the book Resilience thinking: Sustaining ecosystems and people in a changing world, who claim there is a need to turn the tables. They believe that it is essential that we step away from our “business as usual” behaviour, which is too reliant on the search for efficiency and optimised performance. Like many others, Walker and Salt speak out in favour of the idea of resilience.

Resilience is defined as the ”ability of a system, a community or a society to come through disturbances while at the same time preserving its main functions”: any complex system – a town, a network – must be able to adapt to an unforeseen turn of events, notably climatic. Thinking about the system on this scale ensures that organisations and infrastructures have the ability to integrate major changes, and even to provoke them when necessary. But this is not just a question of survival: “resilient thinking” also allows parameters that were once undervalued to be brought into the thought processes, and hence obtain hitherto unknown benefits.

Energy, too, has reached the era of resilience

In recent years, major natural disasters, and the need to get organised to fight the risk of terrorism, have brought about the notion of resilience, in particular among urban thinkers and designers: in London, to prepare for the terrorist threat during the Olympic Games, in Paris to find a response to the possibility of a centennial flooding of the Seine, and above all in Haiti, Fukushima and the United States, rebuilding after the hurricanes Katrina or Sandy. All these cases put the idea of resilience at the heart of the responses, in radical opposition to “the 20th century technicist ideology, which held that the risks could be reduced”. Here, the idea by design is to (re)build authentically resilient ecosystems.

The question of energy resilience is a key part of this movement. The challenge lies in transforming the energy chain on the scale of urban areas, which represent as much as 75% of world demand. This means no less than ensuring the sustainability of the “basic” commodity – energy – for citizens and industries, in a word, guaranteeing energy security in this era of disasters. 

“Without major investments in more resilient (energy) infrastructure, millions of people will suffer from ongoing, serious losses of services in vulnerable countries, disrupting lives and livelihoods,” the World Bank noted in 2017, qualifying energy resilience as an urgency.

What’s more, this discussion about energy networks becomes linked with another, which is no less crucial and which, paradoxically, appears as a huge challenge: the need to fight against climate warming while, at the same time, demand for energy continues to grow. This demand, heightened particularly by the electrification of mobility industries and the growth in demand linked to domestic electricity uses, will rise by 30% by the year 2040! The responses to this problem are well known: the energy efficiency ideal (temperance of the demand and balancing it with the offer; increased yield of heating and electricity networks, but also the development of renewable energies and their integration in the network.

Can microgrids be levers in the transition to resilience?

But these responses also represent huge technological challenges in themselves, since they invite us to rethink energy networks as dynamic systems that can be managed “intelligently”. It is therefore not by chance that microgrids, these small, decentralised electricity networks, as the French Energy Regulation Commission (CRE) puts it, will “overturn the energy sector in the future”. Microgrids, which allow for the local management of electricity production and demand, offer the advantage of being able to isolate themselves automatically from the bigger network they are part of, thereby guaranteeing the maintenance of the local network even when the “macro-network” breaks down. They have become ”the technology of resilience”.

California is one of the pioneers in this technology, and has planned a huge investment in the field. The frequency of fires in the Golden State, which experienced the most devastating episode ever at the end of 2018, encouraged the Californians to turn to microgrids. The state faces the prospect of having to cut the power of electricity lines increasingly frequently when the weather is hot and dry, and in this case continuing to provide power to the areas susceptible to fire via autonomous systems, such as solar panels working on batteries. In the short term, microgrids would seem to be inevitable.

Beyond the single objective of resilience

Certain equipment has already proved its worth on an ad hoc basis.

In New York in 2012, during the hurricane Sandy, the Washington Square medical campus of New York University withstood a blackout. How? By using distributed storage and power generation technologies: the campus was equipped (by Veolia) with a local energy network, powered by a 13 MW heat and electricity cogeneration system. This textbook case has contributed to making microgrids the pillars of future strategies in energy resilience.

What will the global situation be in ten or twenty years’ time? In Puerto Rico, following the hurricane Maria, microgrids are already proving to be the solution for the future. During the disaster, the collapse of an already fragile electricity network had complicated water supplies and the telephone network. Microgrids stood out in reconstruction strategies, and major investments were planned to set up decentralised networks, which can be put into operation in the case of a blackout and/or enable local electricity supply to be restored swiftly. Closer to home, in France, microgrids are already being used to make rural or isolated areas autonomous. Moreover, as the microgrids are solar-powered, this enables the creation of carbon-free energy networks, in which energy is stored in lithium-ion batteries, or, once transformed, as hydrogen. In the case of peaks in demand or a lack of sun, this hydrogen can be instantly re-injected into the network in the form of electricity, using fuel cells. The development of microgrids is also keenly awaited by industrial sites, which could opt for cooperative micro-networks, as a pilot project has done in Belgium, fuelled by a mix of photovoltaic panels, hydraulic turbines and storage units. According to the CRE, by 2020 depending on the sector, between 20% and 60% of the cost of electricity could be saved by comparison with today’s rates. The savings will come from a better adjustment between production and consumption afforded by microgrids’ intelligent energy management. Other factors, often corollaries of this large-scale optimisation, can explain these savings: a reduction in the peaks of power necessary, the assurance of greater resilience and greater network stability (in terms of frequency and voltage), or again the possibility of improving market regulation and price arbitration.


The CRE notes that in 2030 and even more so in 2050, the thesis whereby the development of microgrids will “ensure local supply at neighbourhood level” seems to be the most probable. In Australia, an exercise looking ahead to 2040 forecasts the growth of local energy marketplaces around blockchain platforms where solar energy is traded peer to peer thanks to microgrids. Beyond facilitating new resilience targets, microgrids also stand out as a leading technology in the flexible and dynamic use of renewable energies in the future. /p>


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