Dive Brief:

• While approximately 50,000 American citizens remain without power in Puerto Rico, the Army Corps of Engineers is preparing to wind down its work and transfer the system's operation back to the island's utility, officials told an House Energy and Commerce subcommittee on Wednesday.
• The Corps mission will expire May 18, though officials made clear that the decision is made by the Federal Emergency Management Agency. Hurricane Maria devestated Puerto Rico more than six months ago, forcing a system-wide rebuild of the island's grid.
• The island's Power Restoration Coordinator Carlos Torres said he is preparing to wrap up his duties, stressing in filed testimony that "long-term management of the island’s energy grid ultimately must be borne by [the Puerto Rico Electric Power Authority]."

Dive Insight:

New analysis from Rhodium Group pegs the Puerto Rico blackout as the second largest in history — and in a class of its own within the United States. But as restoration efforts wind down, many questions remain as to the grid's future and the work which has been completed.  

There are several ways to look at Puerto Rico's power restoration efforts, and the tension between those points of view was on display at yesterday's Subcommittee on Oversight and Investigations hearing.

On the one hand, the Army Corps of Engineers has directed an effort that has now restored power to 96% of the island's residents following a devastating storm. The system was poorly maintained to begin with, and the rebuilds are a significant improvement, officials say.

On the other hand, as the federal mission winds down, there are approximately 50,000 residents still in the dark, more than six months after Hurricane Maria destroyed the island's electric grid. And officials concede that the island's power grid they have restored is not the more resilient grid that is really needed.

According to Rhodium, Maria has caused 3.4 billion lost customer-hours, making it three times larger than the next-biggest domestic blackout. Worldwide, only a 2013 typhoon that hit the Phillipines caused a greater disruption than Maria did in Puerto Rico and the Virgin Islands. Five years ago Typhoon Haiyan disrupted 6.1 billion customer hours, Rhodium said.

Lawmakers repeatedly pressed agency representatives whether the mission in Puerto Rico was truly complete, and if they would simply leave on May 18.  Officials told the lawmakers they will halt work on May 18, but the exit will be orderly with a transition team left behind.

Lawmakers were clearly interested in how the system is being rebuilt, repeatedly calling for microgrids, renewables and distributed resources. Puerto Rico's grid was just about 2% renewable before the storm, thought it has a goal of 12%.

The Army Corps of Engineers installed 10 microgrids, including one on Vieques that was commissioned on Tuesday. There are four still running, though, as some were uninstalled as power was restored. Lawmakers questioned whether more distributed resources and microgrids could be installed permanently, and whether the effort was hamstrung by laws or policies.

Bruce Walker, assistant secretary of the Office of Electricity Delivery and Energy Reliability at the U.S. Department of Energy, said "there are a number of significant improvements we can make" to the Stafford Act, which sets of standards for disaster relief. Among possible issues is whether the law allows for the grid to be improved or merely replaced to its previous condition, and whether Puerto Rico's power company will need to pay 10% of the restoration costs — money the bankrupt utility does not have.

One barrier to a more distributed rebuild, said Walker, is that PREPA did not maintain a strong model of their system and so it is difficult to know where to site resources. "You just can't build a grid overnight. You just can't," said Walker. "PREPA does not have a good model of their system. We are building it for them."

The completed work will help inform where distributed resources and renewable energy should be sited — models Walker said that PREPA would typically have already completed.

Walker said DOE is working with the Federal Emergency Management Agency "developing a model that incorporates critical infrastructure ... the template exists, the critical infrastructure is in it, and we've divided up the component pieces for load flow algorithms."

However, just dropping in microgrids "is not very feasible on the fly," he said.

Charles Alexander Jr., director of contingency operations and homeland security at the Corps, stressed that while the work done may have been somewhat limited in scope it still represents a major improvement.

"While it is not the long-term resilient grid we know we all need, the grid we are going to restore today will be in much better condition than the grid that was there last year," Alexander told the subcommittee. "We are doing it to code. New transmission lines, new poles ... while nothing has been done to underground or harden substations, the work we have done is not all for naught."

The mission is now at the so-called "final mile," and it is the hardest one. Alexander said the remaining repairs are in rough terrain and much of it requires work done from helicopters.

The cost to rebuild Puerto Rico's more distributed and renewable grid will cost an estimated $17.6 billion, according to an assessment completed by Navigant Consulting and the Puerto Rico Energy Resiliency Working
Group.

Eugene Shlatz,  a director in Navigant’s global energy practice, told lawmakers that "the magnitude of devastation, while unprecedented, now provides an opportunity to rebuild and transform the system to one that is hardened, smarter, more efficient, cleaner, and less dependent on fossil fuel imports."

The largest chunk of that cost would go towards overhead distribution lines, to the tune of $5.27 billion. Overhead transmission lines are next, at $4.3 billion. Generation is estimated to cost $3.1 billion, and distributed resources $1.45 billion.

Among Navigant's recommendations was to shift oil-fired fossil generation to "mostly dual-fuel units, with primary fuel as natural gas."

Torres, the island's Power Restoration Coordinator, said he has notified Governor Ricardo Rosselló of plans to "wrap up my duties ... in the coming week."

He said the grid has been rebuilt to PREPA's specifications—from a hardening perspective that might mean composite or concrete poles. But if they were not available, "in order to expedite restoration we used wood" Torres said.

It is unclear what lies ahead for PREPA. The utility remains mired in debt and is being managed with federal oversight. The utility has been considering privatization; and in February, PREPA's governing board adopted a plan to transform the power company into what it calls a "reliable, sustainable, customer-focused" utility.

Shlatz told lawmakers "a rebuild project of this magnitude requires the consideration of several technical and non-technical factors necessary for the success of the project including," and in total could be a decade-long process. Among the many issues that will need to be addressed includes compliance with the Stafford Act, which generally would require the use of U.S.-sourced material; a supply chain that incorporates competitive bidding; and strong project and cash-flow management.

Shlatz warned lawmakers in his testimony that developing Puerto Rico's new electric grid will be an arduous task that "requires a coordinated effort to undertake projects and initiatives that, collectively, are expected to take 10 years or more to complete."