Three steps that will help Puerto Rico’s grid survive the next hurricane

Power Lines destroyed in Puerto Rico due to hurricane maria
Credit: US Department of Energy

On September 6, 2017, Hurricane Irma hit Puerto Rico and left a million people without power. Two weeks later, on September 20, Hurricane Maria finished off the job and destroyed nearly 100% of the island’s grid.

In early October, the governor, Ricardo Rosselló, optimistically predicted that 95% of the power would be restored by mid-December. But, as of Dec 29, 2017, the island’s utility only reports 70%.

Puerto Rico’s ongoing power disaster has pushed the sleepy topic of grid resiliency into the international spotlight. Experts across the spectrum are offering advice as FEMA, the Army Corp of Engineers and PREPA (Puerto Rico Electric Power Authority) race to stitch the island’s grid back together.

There is wide agreement that years of underinvestment and poor maintenance by the island’s recently bankrupt utility contributed to this disaster. There is far less agreement, however, on how to rebuild the grid so that it can better withstand future hurricanes.


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Expert opinions

AES, the global power utility that operates several power plants on the island, has said that mini-grids are a big part of the answer. Leaders from the New York Power Authority, who learned countless lessons from Superstorm Sandy, have collaborated with Puerto Rico’s leaders and various trade groups to take a comprehensive view of reliability. Their mid-Dec report, called Build Back Better, recommends a long list of improvements largely focused on making components of the grid more resilient to flooding and hurricane winds.

Even Elon Musk offered an opinion. In a Twitter exchange with the island’s governor, Musk offered Tesla’s solar panels and batteries as a quick fix to some of the most critical areas.

Musk wasn’t just making a suggestion. He proved it. In just 19 days, Telsa’s team built a complete solar + battery system that fully restored the power to the San Juan Children’s Hospital.

After looking through all the expert recommendations, their advice can be consolidated into three simple steps…

Step 1: Get power restored

In all the dialogs between experts, politicians, and pundits, the most obvious and most important step is often taken for granted. The first step to a more resilient grid is to restore power to the million or so people that still have no grid at all.

FEMA’s job is to restore power as quickly as possible. Even if there was time to design a newer, more reliable grid, the Stafford Disaster Relief and Emergency Assistance Act only allows FEMA to rebuild infrastructure to its initial design – upgrades and improvements are outside its charter.

So, whether we like it or not, much of Puerto Rico’s grid will be rebuilt around a design that is decades old. If we want a better, more resilient grid, we’ll have to look at upgrading the current grid after it is working again.

Step 2: Harden the infrastructure

Florida has proven you can make a grid more resilient. Based on massive, multi-week outages from Hurricane Wilma in 2005, the state invested US$3 billion to “harden” its grid. When Irma hit the state with winds of up to 145 miles per hour and 6 million people lost power, Florida utilities were able to restore 99% of the power within 10 days.

New York’s hurricane lessons were even more recent. Superstorm Sandy hit the state in 2012 and, at the time, was the second most costly weather event in East Coast history. New York, which is home to more Puerto Ricans than any other state, not only shared its experiences, it also rolled up its sleeves. Con Edison, the state’s largest utility, sent 220 trucks and 350 utility personnel to Puerto Rico to help rebuild the grid and restore power.

Rebuilding Puerto Rico's power grid
Credit: Mark Dye, Con Edison

Hardening the grid means many things, including:

  • Installing wind resistant power poles made of cement or special steel.
  • Putting “break-away” connectors on power poles so that when one power pole goes down, it won’t act like dominoes and pull all the other poles with it.
  • Building walls around substations to prevent flood surges from shorting out systems.
  • Burying power lines underground to avoid hurricane winds. Unfortunately, this doesn’t always help. Most of San Juan’s power lines were underground and much of them were shorted out by flood waters.

Step 3: Begin upgrading the grid with more local energy

AES calls for mini-grids. Elon Musk pitches microgrids. Build Back Better makes the case for distributed generation. These are all variations on the same theme – local energy.

Puerto Rico is a tragedy of outdated grid design. Just look at the map below.

Puerto Rico's outdated power grid design
Click to see full resolution. Source: Freeing Energy, Wikipedia, other.

Nearly all the population lives in the northeast part of the island yet two-thirds of its power generation takes place in the south. Long distance power lines, known as transmission lines, are required to cross dozens of miles of treacherous mountain terrain so southern power plants can light northern cities. These transmission lines are sitting ducks in strong winds and were the primary victims of this year’s hurricanes. Making matters worse, many of them are so remote they can only be repaired by helicopter.

While it will take years to roll out, local energy is the best way to keep Puerto Rico’s lights on when the next hurricane arrives:

Use microgrids to make sure the most important buildings remain powered. The US Department of Energy has identified 200 locations that could benefit from microgrids. These include hospitals, police stations, water treatment plants, and emergency shelters.

Build power plants closer to the population centers. In fact, as they were repairing the transmission lines, the first Army Corps of Engineers also installed 50 MW of new power generation just outside of San Juan.

New 50 MW generators being installed at the Palo Seco plant in northeast Puerto Rico. Credit: US Army Corps of Engineers

Use solar to reduce the dependence on fuel oil power plants. PREPA spends US$2 billion a year on diesel and fuel oil to provide 70% of the island’s power. Expensive and dirty fossil fuel power is one of the reasons Puerto Ricans electricity rate is nearly twice that of the US average. It also undermines resiliency because most of these plants can only keep a few weeks fuel supply on hand. Even though several of the island’s 127 MW of solar farms were destroyed during the hurricanes, the ones designed for high winds survived. In fact, thanks to forethought and solid design, San Juan’s VA Hospital rooftop solar array continued to operate even during 180 miles per hour winds.

The world is watching

Tragically, Puerto Rico has become an involuntary laboratory for the future of the grid. The silver lining is that the island’s crisis is forcing a long overdue conversation about the ways we build and operate all the grids that power our country and the world.

As experts investigate and analyze, one idea is rising above the rest: centralized grids are simply too fragile to withstand the increasing frequency and intensity of major weather events. Fortunately, local energy solutions like microgrids, mini-grids and other distributed resources are not only more resilient, they are increasingly less expensive, too.

Credit: Mark Dye, Con Edison



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