Geographically isolated Santa Barbara is connected to the world by a thin thread. Nearly all its electricity comes via a single pair of power lines coming in through remote, wildfire-prone terrain. If that pair is cut by fire or earthquake or preventatively shut off during high winds—or if the power grid is crippled by a natural disaster—Santa Barbara could go dark.

Santa Barbara-based Direct Relief can never afford to lose power.

Its 155,000-square-foot pharmaceutical warehouse, the largest in the U.S. run by a charity, stores insulin and other drugs that need a constantly cold temperature, between 36- and 41-degrees Fahrenheit. Power is essential to maintaining that refrigeration. Such temperature-sensitive medications can spoil within hours if Direct Relief loses power. If temperatures rise even nominally, “cold chain” medicine can lose its efficacy and must be destroyed, according to law.

Worse, Direct Relief would be unable to respond to the very natural disaster that brought it offline. The group’s warehouse—2/3 the size of a Manhattan city block— is a crucial depository for emergency medicine and medical supplies needed after earthquakes, wildfires, hurricanes and other natural disasters. During the raging wildfires of 2017, Direct Relief was California’s largest source of breathing masks that protected people from the choking smoke. The organization is also responding to the deadly Camp and Woolsey Fires burning across California.

To ensure Direct Relief never loses power, Direct Relief engaged Tesla to build a microgrid that keeps the organization running and its cold-chain medicine protected even if it loses grid power for many months. The microgrid system sustainably maximizes resiliency by combining three power sources: solar panels to provide the bulk of its electricity needs; battery storage to keep the power going when the sun isn’t shining; and Direct Relief’s diesel generators as a backup. The system is run by Tesla’s smart software that is able to seamlessly switch between power sources as conditions change and send excess solar power back into the grid for others to use.

Tesla designed the microgrid system after deploying similar systems in Puerto Rico, which experienced the longest-ever blackout in U.S. history after Hurricane Maria in 2017. Health facilities lost power for weeks or months, and more than 80 percent of the island’s vaccines and other medicines that require refrigeration were destroyed as a result of power loss, according to the CDC. Tesla and Direct Relief worked together on the island in the hurricane’s aftermath to identify key health facilities, restore power, and deliver aid to residents.

Recognizing that power is a prerequisite for health, Direct Relief and Tesla continue to equip dozens of local health facilities in Puerto Rico with reliable energy sources including solar power and battery storage. The solar and battery systems are integrated with existing generators and the grid, giving each health center a smart microgrid system that can pull power from the most efficient source and prevent going dark.

Diesel generators work well for short-term power outages, but they’re unreliable and costly as a long-term solution. Some Puerto Rican clinics that had generators eventually lost power when generators broke down or fuel supplies ran out. Those that continued relying on generators during the months it took to restore electricity faced tens of thousands of dollars a month in fuel costs and unreliable results.

The organizations also deployed several mobile power units to areas of Florida and Georgia hit by the recent Hurricanes Michael and Florence.