When it comes to an all of the above energy menu, there is a place for solar energy, but it tends to be rather situational to say the least. But if you are going to go solar, there aren’t too many places in the United States more promising than Hawaii. They enjoy an average of 240 days per year of sunny or at least partly sunny weather. What’s not to like? With that in mind, the Aloha state embarked on an ambitious program of expanding their solar energy generation capability, which is now approaching 80% of the peak capacity on the island of Kauai. But things got a bit complicated.
That puts Kauai on the leading edge of solar power penetration, and KIUC has bruises to show for it. Power fluctuations from a first large plant installed in 2012 have already largely burned out the big batteries installed to keep solar from destabilizing the island’s grid.
Now KIUC is taking a second try with batteries and hoping energy storage technology has progressed sufficiently to keep the same problems from recurring. The new system, installed beside the solar farm nearing completion on Kauai’s northeast shore, is one of the first commercial installations of grid-scale lithium-ion batteries manufactured by the French battery giant SAFT…
The intermittent nature of renewable energy sources like solar power presents a range of challenges to utilities, depending on their grid’s size and design. Kauai’s difficulty is most acute when clouds drift over a solar plant. That can slash a plant’s power output by 70 to 80 percent in less than a minute. If the plant is providing a substantial share of the grid’s power, that rapid power loss can cause the frequency of the grid’s alternating current to drop well below 60 hertz, damaging customer equipment or even causing a blackout.
The Kauai installation had massive lead-acid battery arrays which were supposed to take over when solar output dropped. And they did… for a while. But as with any battery, repeated cycles of draining and charging shorten the lifespan considerably. Kauai gets a lot of sun, but they do get intermittent patches of clouds, and when those glide by the output of the solar array drops precipitously. In a relatively short time the batteries were shot and they had to increasingly rely on backup generators which run on – you guessed it – gasoline or diesel.
They are now retooling and it looks like there is some promise of more durability to be found using Lithium-ion batteries instead of the originals. This has been in expensive learning curve for Kauai, but it may result in a working model which can be used in other places which get a lot of sunshine like the desert southwest. If that’s the case… great. The grid can use all the energy we can manage to throw on it. But at this point, expecting renewables to shoulder the majority of the load in most areas is still a long, long way off.