Puerto Rico’s first cooperatively managed microgrid to use Rivian donated batteries

Commissioned by Casa Pueblo in partnership with the Honnold Foundation, the community-owned microgrid in Adjuntas, Puerto Rico will have nearly 700 solar modules installed on seven rooftops in the town’s center, backed by 1 mW of battery storage in two locations. This decentralized, hurricane proof, energy accessible battery storage solution installation is expected to be able to serve the entire community for up to 10 days of off-grid functionality. The microgrid is owned and managed by a local nonprofit entity, the Community Solar Energy Association of Adjuntas (ACESA), and will provide clean, reliable power to 14 of Adjuntas small businesses, and set a precedent for energy access throughout Puerto Rico and the Caribbean.

Adjuntas is historically one of the hardest-hit communities in Puerto Rico during natural disasters, and this 187 kW microgrid will ensure that the power stays on. The solar power will be stored in a custom built battery storage system (BESS) manufactured by ELM and purpose built for the microgrid, totaling 1.107 MWh. The BESS system includes batteries, inverters, controls, and other equipment, and was contracted and then donated by Rivian. The batteries are expected to provide more than 10 days of off-grid storage for the current size of the system. Meanwhile, the construction will allow for the full PV count to double, while still providing at least 5 days of off-grid storage.

After Hurricane Maria hit the island in 2017, the town of Adjuntas was without power for nearly a year. The building that houses Casa Pueblo, a community organization focused on the sustainable development of the region, was the only building in town with power—thanks to its solar installation. Other areas of the town were powered by diesel generators to provide refrigeration, internet access, a phone charging station, and more. Due to the need for more reliable power, business leaders alongside a few community stakeholders formed the nonprofit, ACESA, which owns and operates the microgrid. Energy is sold back to the grid via a power purchase agreement, but approximately 50% of those savings (the final rate to be determined) will be reinvested back into both microgrid maintenance and future community projects.

The community-owned microgrid can serve as an open sourced model for all of Puerto Rico. Additionally, with funds saved from the power purchase agreement, the intent is to bring other homes onto the current microgrid. Ultimately, provided there’s additional philanthropic support, more homes could be plugged into the Adjuntas microgrid.

One of the partners is the Honnold Foundation, founded ten years ago by the rock climber Alex Honnold. The Foundation’s mission is to partner with marginalized communities to expand equitable solar energy access. In the past three years, the Honnold Foundation has helped 48 Partners in over 20 different countries and territories use solar energy to build equity, increase climate resilience, and support communities’ right to self-determination.

The foundation doubled its grantmaking this year to fund $2 million in solar energy projects. In November of 2022, the foundation announced that venture capitalist Peter Levine was providing a multimillion dollar gift over the next three years to launch the Levine Impact Lab in partnership with the Honnold Foundation. The lab intends to offer long-term support to organizations and individual leaders who otherwise might lack access to the best-in-class resources typically reserved for VC-funded startups.

“The repercussions of climate change are felt in every corner of the world with rising temperatures, increased frequencies of natural disasters, food and water insecurity, and economic disruption,” said Honnold. “Meanwhile, communities on the frontlines of the climate crisis are receiving the least amount of support, despite the best efforts of grassroots organizations and community leaders.”