This is Part 3 of a four-part series on renewable energy.

If you’ve followed this column for the last few weeks, you’re familiar with how addressing climate change requires a rapid transition to 100 percent renewable energy.

But by now you’re also familiar with the dark side of renewable energy and the even darker side of going off-grid. Given all this darkness, how can we shine some light on the path to a clean and equitable energy future?

The Port Allen electrical facility at the Kauai Island Utility Cooperative includes diesel, steam turbine and combustion turbine generators.

The Port Allen electrical facility at the Kauai Island Utility Cooperative includes diesel, steam turbine and combustion turbine generators.

Kauai Island Utility Cooperative

Before we can get there, here are some of the unique challenges facing Hawaii:

• Each of our electrical grids acts in isolation. Colorado, Texas, Iowa, South Dakota, Kansas and Oregon all get a lot of credit for incredible amounts of wind energy, even though, as journalist David Roberts explains here, that’s not really the case—because while individual locations have lots of wind or solar, “very few whole grid systems have achieved double-digit penetration.” Utilities in all of those high renewable states buy and sell from a larger regional grid, which in turn part of an even larger grid. But here in Hawaii, each of our islands is its own isolated whole grid. So each has to maintain a stable electrical system without buying or selling power from anywhere else.

• Other isolated grids, such as in Costa Rica and Iceland, already have reached 100 percent renewable, but they do so largely with hydroelectricity and geothermal. Hydroelectricity can only provide a fraction of our total energy needs (max potential for 20 percent on Kauai, and likely even less on the other islands). And while the Big Island and Maui do have the potential for large scale geothermal, only building a controversial interisland cable would make it a statewide answer. Whereas hydro and geothermal can provide consistent power all day long, wind and solar depend completely on the weather. That variability has led many utilities to look at 50 percent to 60 percent as the total solar and wind penetration possible at any given time.

• In Hawaii, our peak electricity usage occurs in the evening, after the sun has set. Most of the developed world experiences peak demand in the middle of the day. This is important because as utilities ramp up to cover their peak, they use increasingly less efficient forms of generation. When peaks occur in the middle of the day, solar can minimize the need for extra generation capacity, saving up to 40 percent in energy costs. But with an evening peak, we can’t realize those cost savings, because solar panels don’t generate any power at night.

• Here on Kauai, we’re even further handicapped by our lack of wind potential. Utility-scale turbines (which provide power on Maui and Oahu) are off the table because of economies of scale, a lack of regular high winds and our high number of endangered birds.

Cooperative Advantages

Despite all of this, the Kauai Island Utility Cooperative reached 80 percent solar penetration during the day last week and is on track for 50 percent renewable by 2019. The utility expects to reach 100 percent renewable well in advance of the 2045 goal established by Gov. David Ige.

As they blaze through this uncharted territory, how are they doing it?

Most importantly, they are a member-owned cooperative, meaning every customer on Kauai owns a small share of the utility. All profit gets returned to customers in the form of an annual dividend check; and each member has a voice in the direction of the company through its elected board of representatives. This freedom has allowed them to experiment much more than a for-profit utility ever could.

“The good thing about being a cooperative,” said Power Supply Manager Brad Rockwell, “is that we don’t have shareholders driving us to increase revenue and profit each quarter.”

And, because of our island’s small size, KIUC’s generation profile is different from that of Oahu and most of the mainland. There, maximizing power production means using a steam turbine. So large boilers and nuclear power provide the majority of the power for larger grids. But because we’re smaller, Kauai runs primarily off of internal combustion generators.

As the following two slides show, this flexible generation capacity is a critical component of KIUC’s success. The first picture shows what the energy load on Kauai was before solar power.

This chart shows the typical mix of sources for electrical power in Kauai before the rapid growth in solar power usage.

This chart shows the typical mix of sources for electrical power in Kauai before the rapid growth in solar power usage.

Kauai Island Utility Cooperative

And the second shows a day with high solar penetration. This drastic energy profile is just a future hypothetical for mainland utilities. But it’s a daily reality for KIUC.

This chart shows the sources of electrical power on a recent sunny day on Kauai.

This chart shows the sources of electrical power on a recent sunny day on Kauai.

Kauai Island Utility Cooperative

And it’s incompatible with steam turbines. While a boiler takes nine hours to warm up, a diesel or naphtha generator can be online in just a few minutes. And, unlike a boiler, it provides an adjustable source of electricity. So KIUC’s reliance on smaller generators allows them the flexibility to cover this wildly fluctuating demand.

But the daily demand curve does present KIUC with some problems.

In case of sudden cloud cover over the solar arrays, the utility needs to be able to provide instantaneous power to cover that dip. So even on Kauai’s sunniest days, KIUC still needs to run a generator. While it provides just a few megawatts to the grid, the generator has the flexibility to instantly ramp up and down to balance out the variable power coming in from the solar arrays.

Add in our seven hydro stations, biomass plant, and our incredible amount of solar (none of which are flexible sources of power)—and Kauai is sometimes producing too much electricity in the middle of the day.

Who Pays For Solar?

And because too much power on a grid is as much of a problem as too little, somebody’s solar array has to be curtailed.

So, in the future, every cloudless day may present KIUC with a choice: curtail their own solar power or curtail the power generated by the 10 percent of homes with oversized rooftop solar systems.

If you’ve invested in a big rooftop solar system, then you don’t want KIUC to tell you that they’ll no longer pay you for your electricity on sunny days. Yet, if you’re a member of the co-op whose monthly bill has helped finance two large utility scale solar plants, then you don’t want to be told that your electric bill is going into the pockets of customers with oversized PV systems even when that power isn’t needed.

While there is no easy answer to that dilemma, the problem can be minimized by shifting our demand curve.

Which is why KIUC is exploring time of use rates. Their current pilot program reduces daytime rates by 25 percent. As Utility Dive reported: KIUC “wants to shift load to the daytime hours when solar production is at is peak in an effort to avoid curtailing production and shift load away from the dirtier oil-fired plants that run at night.”

Finding A Fair Rate

Even if KIUC can solve the curtailment problem fairly, there is another problematic inequity with rooftop solar: As mandated by the Public Utilities Commission, the rate that KIUC pays customers for their excess solar is based on the avoided cost of fuel. The idea was that every kilowatt-hour of solar power being fed back from a customer saves one kilowatt-hour’s worth of fuel. And when oil was the cheapest way to generate power, paying customers for their solar based on the avoided cost of fuel made sense.

But now, rooftop solar doesn’t compete with oil as the low cost provider of electricity; it competes with utility-scale solar.

And while KIUC filed a request in 2008 with the PUC to start basing their payback rate on the current price of solar (the amortized cost of the solar array over its lifespan) instead of fuel, the commission still hasn’t made a decision.

I could focus an entire weekly column just on efforts to find the fairest rate structure, and we still wouldn’t come to a perfect answer. Yet these are the problems that KUIC and utilities across the country are being forced to grapple with.

How our little island navigates the renewable revolution may set the tone for the rest of the world to follow. And with Kauai’s unique cooperative structure, we all have an opportunity be part of the solution.

Next week: the pathway to 100 percent renewable

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