Forskere bringer mere pålidelig elektricitet til Puerto Ricanske mikronet

Da orkanen Maria ramte Puerto Rico i 2017, knækkede vinden træer og ødelagde huse, mens kraftig regn forvandlede gader til floder. Men efter stormen passerede, fortsatte den menneskelige vejafgift med at vokse, da beboerne kæmpede uden elektricitet i flere måneder. Fem år senere forbliver strømafbrydelser lange og hyppige.

For at levere mere overkommelig, pålidelig og bæredygtig elektricitet til undertjente samfund som disse, samarbejder forskere fra Department of Energy's Oak Ridge National Laboratory med lokale organisationer, nonprofitorganisationer og universiteter for at opbygge modstandskraft i uafhængige mikronet drevet af vedvarende energi. ORNL udvikler en teknologi, der vil styre grupper af små mikronet som en klynge, hvilket øger deres pålidelighed, selv når de er beskadiget.

Mikronet er små netværk, der generelt har deres egen energiforsyning fra nærliggende vedvarende kilder som vind og sol. Hvis der tilføjes batterilager, kan mikronet isoleres og fungere uafhængigt i "ø-tilstand", når det bredere forsyningsnetværk svigter.

ORNL-ingeniørerne Ben Ollis og Max Ferrari leder et team, der skal udvikle en mikrogrid-orkestrator, der skal installeres i den Puerto Ricanske by Adjuntas. Et community microgrid-projekt er allerede ved at blive installeret der gennem et partnerskab mellem den lokale nonprofitorganisation Casa Pueblo og Honnold Foundation.

Honnold, som finansierer solenergiprojekter for at reducere global energifattigdom, investerer 1,7 millioner dollars for at skabe to mikronet med sol- og batterilagring, sagde Honnold-projektkoordinator Cynthia Arellano. Solpanelerne blev installeret sidste år og vil blive tilsluttet den resterende infrastruktur, der tilføjes i år.

Det er her, ORNL træder ind:Oprettelse af et nyt orkestratorværktøj til at styre en klynge af mikronet, så de direkte understøtter og kommunikerer med hinanden, hvilket gør dem mere modstandsdygtige under lange strømafbrydelser. Hvis f.eks. et mikronet mister en del af sin solcelleproduktion, kan det tilstødende mikronet eksportere strøm til sin nabo, hvilket minimerer virkningen af ​​skaden.

"Jeg kender ikke til en microgrid controller nogen steder, der kan kommunikere og koordinere med en anden controller," sagde Ollis. "Vi er ved at designe en arkitektur for multi-microgrid-kontroller, så et hvilket som helst antal mikrogrids kan fungere uafhængigt, men dele information med en orkestrator, der vil forudsige, hvornår skift, routing og tilslutning skal ske."

Ferrari sagde, at indledende simuleringer indikerer, at mikronettene kunne holde hinanden kørende i mindst en uge. Men med ideelle forhold kan de potentielt blive ved med at fungere på ubestemt tid.

Det er ikke kun et spørgsmål om bekvemmelighed. "Mange mennesker døde efter orkanen, og mange af dødsfaldene var relateret til strømsvigt," siger Arturo Massol-Deyá, administrerende direktør for Casa Pueblo, som fremmer retfærdig og bæredygtig udvikling omkring Adjuntas. Denne mangeårige samfundsorganisation installerede et solcellepanel i sin bygning i 1999. Efter orkanen Maria var Casa Pueblo i stand til at dele den elektricitet, den genererede, med beboere, der stolede på medicinsk udstyr i hjemmet såsom åndedrætsværn.

"We noticed how many people got sick who were pre-diabetic, or had high blood pressure, or were exposed to unhealthy living conditions and food—preventable conditions," said Massol-Deyá. "Energy security being interrupted is about quality of life, and there were long-term consequences in the community." Grassroots support for solar power built steadily as a result.

Community-wide benefits

The Adjuntas microgrids include solar installations on the roofs of 13 businesses, whose owners agree to provide critical services like medicine, refrigeration and cell phone charging to residents during major power outages. In return, the businesses save money on electricity and avoid the use of expensive diesel generators during natural disasters, Ferrari said.

"ORNL deploying this kind of controller system is going to be a really powerful tool for the community," Arellano said. It's unusual for so many businesses and owners to be linked by a microgrid, she added, and the infrastructure will support adding even more.

On a recent trip to Adjuntas, ORNL researchers met with local business owners to better understand their electricity use patterns. For example, when Ferrari visited the bakery, he learned what times refrigerators must run for the dough to rise properly. He and Ollis sought to identify the most critical electricity loads so they can design a system that focuses scarce power where it's most needed.

"Hopefully it will help not only to manage the microgrids, but also to protect the critical components like the energy storage unit," said Massol-Deyá, who is also a professor at University of Puerto Rico Mayaguez, or UPRM.

The income produced by the community-owned microgrids will fund their maintenance and expansion, as well as installation of independent solar systems for the most disadvantaged Adjuntas residents, he said.

A sense of urgency

Fabio Andrade is a UPRM engineering professor and a visiting scientist at ORNL collaborating on the Adjuntas project. His students model strategies, tools and algorithms for sharing solar power among microgrid users. UPRM colleague Gerson Beauchamp guides students through analyzing the solar equipment and predicting how much energy it will produce. At current electricity prices, the businesses can collectively expect to save as much as $78,000 a year by buying solar energy from the microgrids, Beauchamp said.

Ferrari is incorporating information from UPRM colleagues into his simulations, which are being tested live with actual microgrid hardware at DOE's Grid Research Integration and Deployment Center, or GRID-C, at ORNL. The next step is running the configuration in the facility's brand-new networked testbed for microgrids. In another year, the orchestrator will be deployed in Adjuntas.

While the ORNL-derived technology could be a literal lifesaver in Puerto Rico, it also holds broader potential for enabling microgrids to play a key role in the global grid of the future. Intelligent microgrids that incorporate renewable energy are poised to advance grid flexibility and resiliency while supporting vital decarbonization efforts.

"The orchestrator includes a framework of algorithms that can be expanded and deployed to many microgrids at any site," Ollis said. "They could provide more reliable electricity to many rural communities at the grid edge. I want to see a future where we have hundreds of microgrids working together to protect critical infrastructure at local, regional and national levels." + Udforsk yderligere

Technology enhances solar option during outages