91��Ƶ

Powering up the nation's second largest island with 100% renewable energy

Book editor's note: Kodiak Island is located 250 miles south of Anchorage and is the second-largest island in the United States. It is the first remote community in 91��Ƶ to be powered by almost 100% renewable energy year round. Kodiak Electric Association's recently retired president and CEO – Darron Scott – tells the story of how this microgrid uses innovative storage strategies to balance hydro and wind resources on 91��Ƶ's largest remote microgrid. This is an excerpt from a forthcoming book entitled “91��Ƶ’s Energy Innovators” to be published by the University of 91��Ƶ Press.  - Peter Asmus

By Darron Scott

I started my career in utility engineering with a large investor-owned utility in Texas. My newly married wife and I liked to go to the outback. For our honeymoon, we went backpacking out in the wilderness in central 91��Ƶ. Thank God we made it back out alive, as we survived some pretty rough conditions, but the experience in 91��Ƶ kind of worked on our heads. 

Soon thereafter, we decided we would try to move there. I started looking for work and in 2000 found a job at Kodiak Electric Association (KEA). They had just installed a diesel-powered combined cycle plant and it wasn't working too well. I had a lot of power generation experience with combustion technologies and therefore I met KEA’s immediate needs and was able to land the job. I’ve been here ever since.

Challenges facing an island microgrid

I really had no idea what I was getting into here at Kodiak Island. We're not connected to anybody else electrically. As a result, we have to resolve any issues with availability or stability all on our own. 

Between 25% and 30% of our customers are residents. The rest are commercial customers – such as grocery stores – or other large power institutional consumers like schools, hospitals and the Coast Guard, whose base here is their largest in the nation. Fish industry processing is our largest single customer load category, perhaps as much as 40% of our load during peak fishing season.

The seed of interest planted here regarding green energy wasn’t really about lowering pollution and responding to climate change. Instead, it was about cost volatility. Kodiak Island has been utilizing hydroelectric since 1984 when the Terror Lake Hydroelectric Project was constructed. But its output was not adequate to meet the growing electric power demand from the community. It generated maybe 41% of our electricity back in the year 2000. The remainder came from fossil fuels like diesel, whose prices fluctuate quite a bit. So we had no control of either the fossil fuel resources or the level of available hydro production. Our power cost was bouncing up and down and driving our large customers, who dominate our system, crazy. They didn't know what to budget for every year.  

We initially focused on the possibility of relying more on hydro because that's what we knew. But most of our island is a national wildlife refuge, which adds a whole different level of permitting barriers and rendered expansion difficult. Instead, we started our journey to 100% renewable energy with three of GE’s 1.5 MW turbines and then later added three more of the same turbines to create a 9 MW wind farm. The utility’s peak load for this microgrid is about 28 MW. We were able to meet virtually all of our customer loads from these two primary renewable energy generation sources. Depending upon the year, we were reaching 80% to 85% of our loads with hydro and the balance primarily from wind. The levels of rain and snow and the yearly deviations during the wind season were all factors since these percentages vary somewhat year-to-year.

Energy storage takes kodiak to the next level of sustainability

The original battery we installed was an advanced lead acid battery. The battery was rather low quality and was being exercised much more than originally anticipated, which was therefore impacting its longevity. The most innovative new components of the KEA system, however, was the addition of two 1-MW flywheel systems. Compared to batteries, flywheels are more of a power storage device. They can respond virtually instantaneously to inject power into the system. 

The need for integrating the flywheel arose when the City of Kodiak came to us to see if we could provide power for a large shipping crane they wanted to install. The previous one that had been operating on Kodiak Island ran on diesel fuel and was about half the size as the new one. Because it ran directly on diesel generators not interconnected with the island’s microgrid, we never had a good sense of what kind of load such a crane would impose on our system. 

We soon discovered that the load when it picked up a huge box filled with fish from a boat was often more than 2 MW! And then when the box is dropped, the crane is regenerative, so it injects about 1.5 megawatts back into the system. Well, our utility could handle doing that once or maybe twice in a day, but at this dock, you're loading and unloading a boat over a period of eight hours, multiple times a week. You could have as many as a thousand of those operations daily! That’s a lot of stress to put on a small isolated microgrid such as ours. 

Final steps toward a near 100% renewable energy system

Our renewable energy strategy continually evolved and tapped multiple types of storage which operate at different time scales: flywheel; battery; and hydro (which provides longer-term storage.) This became an efficient way to match fluctuating power system needs, especially when variable renewable penetration from our wind turbines is high. Along with the new lithium ion batteries - which represent 3 MW of energy storage peak output - we also did an upgrade to our hydro plant by diverting a couple of streams and we dug a new tunnel. With those improvements, we increased hydro energy production by 33%. As a result, we reach over 99% renewable energy penetration annually. 

What were our two most important lessons? The first is to forge partnerships with diverse stakeholders, including the environmental community. I think the second-biggest thing that we did that made us successful is we took an incremental journey on wind and then energy storage. We didn’t try to do everything all at once. I’m proud to say our transition to renewables has not impacted power quality.