Micro-grids powered by photovoltaic panel arrays

Pro­fes­sor Manuela Sechi­lar­iu has been Direc­tor of the UTC Avenues research unit since 2016. Since the lab­o­ra­to­ry was set up in 2006, micro­grids, in par­tic­u­lar those pow­ered by pho­to­volta­ic pan­els, have been one of its major areas of research.

“What­ev­er the nature of renew­able ener­gies (RE), they require mul­ti­source sys­tems, whether they be autonomous or con­nect­ed to the grid. In oth­er words, an elec­tri­cal micro­grid. For our part, we are work­ing on micro­grids pow­ered by renew­able ener­gies, in par­tic­u­lar pho­to­voltaics arrays (PV), equipped with on site stor­age, loads and con­nect­ed to the nation­al grid”, explains Manuela Sechilariu.

At an ear­ly stage, the team began to con­sid­er how to opti­mise these tech­nolo­gies, or how to achieve min­i­mum ener­gy costs while at the same time max­imis­ing the use of renew­able ener­gy sources. Two areas of appli­ca­tion were iden­ti­fied: build­ing sup­plies and recharg­ing of elec­tric vehi­cles (EVs).

What about the build­ings? “We opt­ed to use PV ener­gy sources, asso­ci­at­ed with a micro-grid inte­grat­ed into the build­ing and aimed at ener­gy effi­cien­cy. To max­imise the ben­e­fits of ener­gy from PV, we pro­posed DC pow­er sup­ply net­works for build­ings, and we opti­mised the ener­gy cost and sta­bil­i­sa­tion of this micro-grid, either autonomous or with a con­nec­tion to the pub­lic grid”, says Manuela Sechilariu.

What choic­es were made for EVs? “We had to adapt our con­cepts. In this par­tic­u­lar case, there is the ques­tion of the utilis­er, giv­en that the EV involves inter­mit­tent and ran­dom arrivals and depar­tures depend­ing on the driver’s needs. In a build­ing, on the oth­er hand, it’s the client who defines the cri­te­ria for load shed­ding, oper­a­tion or min­imis­ing the use of a cer­tain num­ber of ener­gy loads,” she explains.

These are use­ful tech­nolo­gies in the face of the cli­mate emer­gency, but they nonethe­less require an in-depth analy­sis of their own car­bon foot­print. “We have cre­at­ed a set of method­olo­gies and tools — some of which are sim­pli­fied and can be used by eco­nom­ic play­ers — for siz­ing these micro­grids, whether they are inte­grat­ed into build­ings or EV charg­ing sta­tions. Siz­ing that meets envi­ron­men­tal, eco­nom­ic and tech­ni­cal con­straints. Thanks to these tools, we can analyse the life cycle of the var­i­ous com­po­nents, both PV and micro­grids, from their cre­ation to their final destruc­tion or recy­cling. This analy­sis enables us to cal­cu­late the car­bon impact of these tech­nolo­gies over thir­ty years, as well as their over­all cost”, she points out.

These tech­nolo­gies cer­tain­ly pro­duce clean ener­gy, but they require oper­at­ing and util­i­sa­tion oper­a­tional con­di­tions that encour­age a form of sobri­ety on the part of the user. “In a build­ing equipped with a micro­grid pow­ered by PV, for exam­ple, ener­gy is of course pro­duced, but the user who should be made aware of the need for a form of sobri­ety in con­sump­tion. As for EV own­ers, they should adopt habits for charg­ing their vehi­cles that enable them to min­imise the cost of ener­gy and max­imise the use of PV. For exam­ple, rather than quick­ly charg­ing their EVs once a week, which means draw­ing on the nation­al grid, dri­vers could charge a lit­tle every day using renew­able ener­gy. The lat­ter would also be less cost­ly for them”, says Manuela Sechilariu. 

Anoth­er area for research? “As part of a sci­en­tif­ic pro­gramme launched by the Inter­na­tion­al Ener­gy Agency, we are going to study a spe­cif­ic field of appli­ca­tion: the impact of the elec­tri­fi­ca­tion of pub­lic road trans­port. In par­tic­u­lar, we need to study the impact on the net­work of bat­tery­pow­ered elec­tric bus­es and eval­u­ate the most effi­cient solu­tions that incor­po­rate renew­able ener­gy sources,” she concludes.

Le magazine

Avril 2024 - N°62

Faire face aux enjeux environnementaux

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