Microgrids : a sustainable energy solution?

About 17% of the world's population lives without electricity. Microgrids are a possible solution for accessing electrical energy for people living in isolated rural areas or island territories, in which the deployment of the network proves to be too expensive and unprofitable. However, this is not the only area of application for microgrids: they would also be an alternative to conventional centralized electrical networks which are increasingly criticized by public opinion. Finally, they would encourage the production and consumption of renewable energy locally.

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Grids, what is it?

Microgrids, or microgrids, are small electrical networks designed to provide a reliable and independent supply of electricity to a small number of consumers.

They consist of local energy production facilities (e.g. diesel generators, solar panels, mini-wind turbines, etc.), as well as consumption, storage, monitoring and demand management systems.

Finally, they may concern different types of places and territories (e.g. buildings, industrial areas, villages, etc.).

The challenges of microgrids

Microgrids are favoured by isolated territories

In the case of island territories or remote rural areas, the microgrid system may be of interest to ensure a reliable energy supply and/or reduce the energy bill of the territory concerned. Microgrids integrate equipment for the production and local storage of energy, limiting the risk of network failure.

In French Polynesia, ENGIE's local subsidiary, EDT (Electricité de Tahiti), has deployed a nationwide hybrid energy solution, including solar panels, batteries and diesel generators, to supply up to 70% of the island's energy needs with green energy and reduce the cost of supply for local residents.

Microgrids: an opportunity for all territories?

In addition to isolated areas, microgrids could well prove to be a sustainable energy solution for other territories due to their many advantages:

  • Techniques: microgrids allow optimal management of energy flows between production (especially renewable), storage and consumption facilities at the local level. In addition, potentially interconnected with the public distribution network, they offer a complementary service to maintain the stability of the electrical voltage,
  • Economical: Depending on its size, a microgrid can adjust to the energy demand. And thanks to the proximity between production and energy consumption, they also make it possible to reduce network investments,
  • Environmental: microgrids are intended to integrate decentralized energy production sources, including renewable energies (RES). Since RE is inherently intermittent, 100% RE microgrids must also be able to modulate energy consumption according to available storage capacity and production forecasts, hence the advantage of combining weather stations.

By replicating the challenges of deploying Smart Grids on a small scale,

microgrids can also be used as low-cost tests before the full-scale implementation of these smart power grids, which may take several years.

Microgrids: a major economic challenge

Microgrids are interesting for large industrial and commercial complexes because of the energy self-sufficiency they can provide, i.e. the islanding capacity: the ability to operate without being connected to the grid over a given period. Microgrids are an optimization model for the power grid, and allow customers to reduce their energy bills in the short term (depending on the payback period), ensure their security of energy supply in the event of a national grid failure by isolating themselves, and promote the ecological nature of the installation.

The implementation of microgrids: context and challenges

A global context favourable to the development of microgrids

The agreement reached at COP21 in 2015 marked a political will on the part of the signatory countries to better control their energy consumption and to replace fossil energy sources with renewable energies.

In this context, two factors argue for the development of microgrids:

  • The growing interest of individuals and companies in small-scale green energy production: in addition to saving on their electricity bills, financial mechanisms are being implemented to frame the economics of making energy produced on the national grid available,
  • The rapid and constant improvement of energy production and storage technologies (e.g. the average cost of photovoltaic electricity has decreased by 80% since 2008).

These two factors would therefore make it possible to envisage a future generalisation of microgrids, favouring the production of RE. However, the technical and economic challenges regarding the deployment of microgrids are still numerous.

Challenges raised by microgrids

The first challenges raised by microgrids are of a technical nature:

  • It is necessary to ensure the stability of the network in all circumstances: islanding is a concept which, although controlled, requires robust and specific equipment to maintain the level of voltage, power and energy quality to meet demand,
  • The electrical safety of the deployed microgrid must be ensured: in the event of an electrical incident, the protections must isolate the critical part of the microgrid in order to guarantee the safety of people and property, and to facilitate maintenance operations. This implies that the electrical architecture of the network has been judiciously designed during the design phase,
  • Energy production and storage technologies must be improved: in general, the microgrids in the pipeline do not yet allow total autonomy from the national electricity grid. In addition, a microgrid based only on RE is still an expensive solution.

The second are socio-economic in nature:

  • The role of network managers must be rethought: they will only be called upon in the event of a local failure, and will therefore only play an insurance role,
  • We must prepare for the arrival of new players and new competition: microgrids naturally lower the cost of entry into the electricity grid sector, which was previously protected by heavy investment. Many companies could seize this opportunity, involving an increase in the privatisation of electricity infrastructure,
  • A new pricing and regulation model must be invented: because microgrids pave the way for self-consumption, they challenge the traditional model of pricing and use of electricity networks.

External sources

www.engie.com

www.smartgrids-cre.fr

http://fichiers.cre.fr

www.navigantresearch.com

www.ey.com

Tactis - Directeur associé - Benjamin Fradelle- Aménagement numérique des territoires

Benjamin Fradelle

Associate Director

Since 2002, Benjamin Fradelle has been developing expertise in digital spatial planning, both in terms of defining the strategy of local authorities and in the technical and economic approaches associated with public initiative networks.

Contact Benjamin Fradelle

Hello, do you have a question about microgrids ? Need to remove doubts in view of a future project? Send an email to Benjamin Fradelle, Tactis Associate Director.



Tactis - Directeur associé - Benjamin Fradelle- Aménagement numérique des territoires

Benjamin Fradelle

Associate Director Tactis

Since 2002, Benjamin Fradelle has been developing expertise in digital spatial planning, both in terms of defining the strategy of local authorities and in the technical and economic approaches associated with public initiative networks.

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