A Case Study In Grid Resilience — Dominican Republic
Puerto Rico, as most of us know, was hit by two hurricanes in as many weeks. Irma and Maria made a mess of the island, and it will take months to get things back to normal. When the island does get its electric system back to normal, however, it will not be as things were. It will be new, and hopefully better.
A surprisingly large number of organizations are contributing to the efforts to get the island back on its feet. Some, including Tesla and sonnen, are making headlines with bold moves. CleanTechnica readers saw this in the story, “Tesla & Sonnen Working Overtime To Power Up Puerto Rico,” and I will soon have an update on a GoFundMe campaign first reported in the CleanTechnica article, “A Response To ‘A Call For Help For Puerto Rico.’”
I will give a spoiler on the second of these. Joseph Mangum, of Sunnyside Solar in Brattleboro, Vermont, has just left to Puerto Rico with 5 solar systems. They will be set up mostly in communities in the central, mountainous regions of the island, and some are scheduled to go into places that have no road access yet, because all bridges to them have been wiped out. They will go where Joseph feels they will do the most good. He will be there for three weeks, and has promised me that he will send emails whenever he has internet access, telling his story. I suspect it will be an epic trek into the mountains. I plan to pass that news on to readers when I can.
I will make up for the spoiler by holding out a teaser. The money that donors have given at the gofundme site has been used to put together systems at a cost lower than any I have seen before. I would say the cost is not merely incredible; it is almost unfathomable.
But getting back to the main story of this article, there were a lot of island nations slammed by these hurricanes. Some were hit worse than others, but one has a story that stands out among the rest. And the story of that nation is one worth knowing about. It is the story of how the Dominican Republic weathered Hurricane Irma. I would like to say, that poor little country did a good deal better than Florida did with the same storm. In fact, as far as hurricane preparedness goes, the Dominican Republic beat the United States hands down. (Perhaps they were not handicapped by climate deniers down there.)
Different media outlets covered the story of the Dominican Republic in very different ways. An article in Energy Storage News had a fair number of technical details, which is a very good thing for those who want to know about them. At the center of the story is a pair of AES lithium-ion batteries that did yeoman service maintaining the country’s power grid while the transmission lines were falling to the ground and power generators were having to go offline.
The other article, which appeared at the AES Energy Storage blog, was written by Praveen Kathpal, a vice president of AES Energy Storage. While the article mentions the help AES Energy Storage is providing in Puerto Rico, doing such things as helping clear roads and getting diesel fuel to a sewage authority, its central issue is the storage batteries in the Dominican Republic. AES installed them not all that long before the country was hit by Irma.
The two battery arrays were sited near Santo Domingo. They were intended to help maintain the AC power frequency. Each had a discharge capacity of 10 MW, but with only the ability to discharge at that rate for 30 minutes. While that might not sound like much, the battery systems were the equivalent of a much larger capacity of thermal plants, because they could respond to changes in demand instantly, instead of having to ramp up and down.
The most violent period of Irma’s onslaught lasted 10 hours. During that time, the batteries went through heavy use, both discharging and charging at rates far higher than normal. As the power grid was being battered, somewhere between 40% and 55% of the thermal plants were forced offline. Meanwhile, the transmission authority ordered the AES batteries to keep working. They did so under remote control from one of Dominicana’s thermal plant control rooms with an AES Energy Storage team monitoring them.
The bottom line on this story is that the Dominican Republic managed to keep its grid operational, and bring it back under very adverse conditions, partly due to the fact that resilience was already being built into the national grid when disaster struck.
There is nothing new about microgrids. They are very common on islands. Truth be told, nearly every ship at sea has a microgrid. In the old days, these systems were powered by diesel oil or coal, and they had the problems of those resources. One of the big problems with microgrids powered by fossil fuels is a lack of resilience. When renewable resources with battery backup are set up to power a microgrid, however, things are very different.
Praveen Kathpal made one statement in his post that I want to look at deeper, because it seems to be looking to a future I had not yet considered. He said, “[We] believe that the best and most cost-effective way to achieve resilience for entire communities is through the development of unbreakable grids, ones that are impervious to disruptions in the first place and ‘self-healing.’”
It all gives me hope.
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