Microgrid Power System Created for Children’s Home in Puerto Rico

 

 CHALLENGE

Located on a rural mountain top in Puerto Rico, Hogar Albergue para Niños Jesús de Nazaret serves as a home and school for neglected children up to 11 years of age. Before 2017, the staff and children there had routinely experienced power outages following storms. After Hurricane Maria in 2017, however, the facility was without power for months. The children’s home needed a power solution that accounted for the site’s frequent lengthy outages and offered long-term reliability. Engineers Without Borders responded to make reliable power a reality.

SOLUTION

Engineers without Borders worked with its student chapter at the University of Wisconsin – Madison and turned to Affiliated Engineers, Inc. (AEI) of Madison, Wisc., for solutions. Together, they designed a microgrid power system that could be supplied by the normal utility source, or operate independently using an on-site generator, photovoltaic panels, and storage batteries. To make the system work, it would need inverters to convert stored energy from batteries to AC when back-up power was needed during utility outages. To connect to back-up power, the system would also need one transfer switch to transfer building load between the utility and emergency power sources, and another transfer switch to select between stored power in batteries or the facility’s diesel generator. The facility would normally operate on utility and solar power. While doing so, solar cells would charge lithium-ion storage batteries to capacity.

During utility outages, the primary transfer switch transfers load to the solar/battery system, and the secondary transfer switch remains connected to the solar/ battery system. If they become depleted,the secondary transfer switch starts the engine and transfers load to the emergency generator. When utility power is restored, the transfer switches return all of the power devices to their normal operating state.

To complete the project, the team specified the following equipment to supply backup power to the 120/240V 24.6 kW ac power distribution system:

• 96 Hanwha Q+ 340-watt photovoltaic panels
• Four Blue Ion 2.0 50 Vdc lithium-ion storage batteries, rated 16 kWh each
• Two 6.8 kW and two 5.5 kW Context XW+ Inverters from Schneider Electric
• Two 200 Amp SERIES 300 Open Transition Automatic Transfer Switches (ATS), donated by ASCO Power Technologies

OUTCOME

The project team began work in 2018, and the microgrid equipment was installed and ready for start-up in the Autumn of 2020. Installation, start-up, and commissioning services were provided by an independent electrical contractor. The system began service without significant technical problems or delays.

“Implementing this project remotely with an all-volunteer team was both challenging and extremely rewarding, says Alberto G. Cordero, PE – EWB Mentor and Electrical Engineer at AEI. “Not only was an innovative design implemented between the inverters and two-ATS combination, but the collaborative spirit of all the professionals and students was inspiring and an example to follow. The Hogar’s staff and children report nothing but many thanks and appreciation and are delighted to have been selected for this project.”

Today, the shelter’s power system provides reliable back-up power whenever needed. With this solution, the facility can run for up to 12 hours on stored energy from a renewable source and can run on a diesel generator for extended outages. The facility is now more resilient to extreme weather events, including the seasonal hurricanes that affect its region.

Since commissioning, the children and staff at Hogar Albergue para Niños Jesús de Nazaret have learned the benefits of having reliable, economical, and eco-friendly power. ASCO Power Technologies is privileged to have been part of a solution that keeps children thriving and learning.

TEAM

• Client: Hogar Albergue para Niños Jesús de Nazaret, Mayagüez, PR
• Design and Project Management: Engineers without Borders – University of Wisconsin – Madison
• Project Oversight: Affiliated Engineers of Madison, Wisconsin
• Local Engineering: AZ Engineering; Angel Zayas, PE; Carolina, PR
• Contractor: Renewable Solutions Engineering; Ernesto Rivera, PE; Mayagüez, PR
• Batteries: Blue Planet Energy, Honolulu, Hawaii
• Inverters: Schneider Electric, Grenoble, France
• Transfer Switches: ASCO Power Technologies, Inc., Florham Park, N.J.