Superstorm Sandy slammed into the eastern United States three years ago this month, causing dozens of deaths and $70 billion in damages in 24 states. Millions of people were left stranded without power, some for several weeks. For vulnerable populations whose lives depend on electricity to power essential services, medical equipment, elevators, water pumps and more, the power outage was no mere inconvenience.

It doesn't have to be this way. New research shows that the emerging-technology combination of solar panels and battery storage systems, known as "solar+storage," could power critical public facilities and protect vulnerable populations such as low-income seniors, families and disabled people during prolonged power outages while providing an economic return to building owners.

A new study from the nonprofit Clean Energy Group, "Resilience for Free," examined solar+storage systems and affordable housing developments in New York City, Chicago and Washington, D.C. In each case, it found that solar+storage can power critical loads, protect residents from harm and pay for itself over time. These systems can also continue to generate revenue for building owners by providing valuable grid services such as power frequency regulation and helping to balance supply and demand.

Solar+storage systems provide essential power to critical facilities and services when grid outages occur. And they generate electric power and economic benefits every day, as opposed to diesel-powered and other emergency backup generators that sit idle most of the time and are prone to failure when finally called upon. In the three cities analyzed in the report, the cost to install solar+storage systems ranged from $130,000 to as much as $900,000.This upfront cost to the developer or owner is paid back quickly in savings-in D.C., a solar+storage project can pay for itself in as little as three and a half years-and can generate hundreds of thousands of dollars in revenue over time.

Given this new understanding of how solar+storage can serve public needs, policymakers should develop smart, targeted incentives to improve the economics of solar+storage systems in states such as New York that lack effective market structures to support them in low-income communities. Governments can help to grow resilient power markets in their states and drive the adoption of solar+storage systems in the affordable housing sector now, not years from now.

The looming specter of climate change is forcing state governments across the country to reevaluate their preparedness in the face of natural disasters like Sandy. Much of the attention given to weather emergencies happens after the fact-how many homes were destroyed, how much aid the government provides, for instance-but not enough emphasis is placed on finding ways to prevent that damage in the first place. Policymakers should act proactively to protect residents, particularly those at the lowest income levels, from the next storm.

With enough public support for these programs, it will be possible to drive private market participation in solar+storage in low-income areas. Targeted incentive programs would inspire companies such as Tesla and SolarCity, which are at the forefront of the solar+storage movement for private, commercial customers, to bring the technology's social promise to vulnerable populations that stand to benefit most from resilient power.

The bottom line is that resilient-power technologies can save lives in low-income communities, and they are economically viable now. To bend the trend of solar+storage to serve public needs, policymakers must act first to create conditions that will encourage housing developers, energy companies and residents to come together to implement these changes. And with the next Sandy just around the corner, there's no time to waste.