After three long introductory posts (part I, part II, and part III) — we can finally answer the question that began this series: How do we get to 100 percent renewable energy?



But wait, why invest in expensive measures right now when plasma gasification, carbon capture, or ocean energy technology is right around the corner?

Because we don’t have the time to wait for new technology to develop.

Kauai Island Utility Cooperative

The first solar cells were made in 1954. “The beginning of a new era” announced a front page New York Times article, “the realization of one of mankind’s most cherished dreams — the harnessing of the almost limitless energy of the sun for the uses of civilization.”

Yet 62 years later, solar power provides 0.65 percent of our country’s electricity.

The first nuclear power plants were built in the 1950s, and by 1986 The Economist magazine proclaimed that nuclear power was as “safe as a chocolate factory.” Less than a month later, reactor No. 4 melted down at the Chernobyl plant in Ukraine, forcing the resettlement of over 300,000 people. It’s now been 20 years since a new nuclear power plant has come online in the United States.

It’s not that power from the sun or atomic energy are bad ideas — they are beyond brilliant — it’s that technology takes a long time to reach commercial viability. And, because fossil fuels are cheap and easy to burn, it’s hard to compete against them. While we continue to hail every new tidal generator or hydrogen fuel cell as the technology that will save us, the reality of climate change is forcing us to cut carbon emissions now, not in some distant hypothetical future.

So, what’s Kauai’s realistic path to 100 percent renewable?

Our Water, Sun And Biomass Options

Water has been providing power in Hawaii since 1888. The Nuuanu hydroelectric plant commissioned by King David Kalakaua made Iolani Palace the second royal residence in the world to have electric lighting. And, as John Wehrheim of Pacific Hydro explained to me, the basic principles of generating electricity from flowing water are the same now as they were at the turn of the century. Which is why sugar-era hydroelectric facilities, including the 128-year-old plant in Nuuanu, are still supplying energy on most of the Hawaiian Islands.

If the Kauai Island Utility Cooperative develops the three hydroelectric plants currently under consideration on the west side of Kauai, then our combined hydro output (including our existing 15 megawatts) will cover about 20 percent of our island’s energy needs.

While solar power can produce the bulk of our power during the day, it generates nothing after the sun sets. So even if we maximize our potential, solar can only provide 25 percent of our total annual energy needs.

Our island’s biomass facility currently supplies 12 percent of Kauai’s electricity. It’s a state-of-the-art carbon neutral boiler that burns albizia and eucalyptus 24 hours a day.

As I wrote last week, boilers can’t be turned off and don’t provide a variable amount of energy. And so a grid that relies heavily on solar electricity isn’t compatible with generating too much power from boilers. While our biomass plant is a great consistent source of renewable energy for our island, it won’t be cost effective to build another one, because we’d be wasting massive amounts of power during the daytime.

Maximizing solar, hydroelectricity and biomass gets us to 60 percent. Which is just about where KIUC’s current approved projects take us by 2019.

Better Batteries

It’s the next half that’s the hard part. This is where the paradigm begins to change: The rate structure inequities have to be solved; we have to reduce our nighttime peak through demand response; and the utility model has to shift from producing electricity to balancing grid resources.

Most importantly, we need to begin storing solar energy from the daytime to use at night.

Solar City and Tesla are building the world’s first utility-scale solar array with battery storage which will, for short stretches, provide up to 13 megawatts (20 percent of our peak) of electricity by next winter. The batteries allow for a continuously adjustable source of electricity. If it’s used in the middle of a sunny afternoon, it will provide the flexible generation necessary to shut down KIUC’s last remaining daytime generator, and Kauai could be running at 100 percent renewable for a few hours each day. If it’s used in the evening, it will minimize the need for extra nighttime generation.

But it isn’t a silver bullet.

To make the product financially viable, it needs to qualify for federal tax rebates. And to qualify for rebates the batteries can only store energy produced by the solar plant. Which means that it doesn’t solve the curtailment issues, affecting homes with their own solar panels, that I discussed last week.

If we were to use battery storage to get us to 100 percent renewable, then Kauai, to provide adequate coverage round the clock, would need 12 more of these plants, each twice as large as the Solar City one, requiring a total of 1,200 acres of flat land.

The Risks

When I asked Brad Rockwell, KIUC’s power supply manager, what is stopping KIUC or Solar City from simply building those 12 plants, he answered succinctly, “performance and price risk. Nobody knows for sure that this solar and storage plant will work as expected, and nobody knows for sure how quickly, and how far, prices for this technology will drop.”

When the plan was first negotiated, it provided power for less than the price of fuel. But oil prices have since collapsed; and so now KIUC is locked into a 20-year contract at a rate about 15 percent higher than the price of fossil-fuel powered electricity. While nobody expects oil prices to stay this low, the wildly fluctuating price of petroleum is putting pressure on future renewable energy projects.

Until this current project is shown to be financially viable and the batteries durable enough to handle the fluctuating load, neither Solar City nor KIUC is ready to commit to the type of expansion necessary to get us to 100 percent.

Another storage option is pumped hydro. As KIUC’s website explains: “the system proposed for Kauai’s west side will use an upper storage pond connected by a five-mile-long buried steel pipeline to a lower pond. During the day, inexpensive solar power would be used to push the water uphill to the storage pond. At night, when demand for electricity is at its peak, the water would be released, flowing downhill through the pipe to turn a turbine and generate electricity.”

The project, under consideration by KIUC, is forecast to cost between $55 million and $65 million and would provide about 13 percent of Kauai’s electricity.

While it has the same federal tax rebate limitations as battery storage (can only pump water using its own solar array), it has the benefit of a stable technology. Whereas batteries need constant maintenance and must be replaced after a few years, hydroelectric turbines can last for a century with minimal maintenance.

The Economics Of Fossil Fuels

But, just like battery storage, the price competition with oil presents the biggest barrier.

Every time oil prices rise, fossil fuel companies dig a little deeper for harder-to-reach oil, car manufacturers invest in more fuel-efficient cars and utilities invest in more renewable energy. That slight increase in supply, matched with a slight decrease in demand, causes the oil pendulum to swing the other way — and prices plummet. This well observed market reaction is called a super-cycle.

As economist Paul Brewbaker described in his testimony to the Legislature on the 2016 economic outlook for Hawaii, the world is currently in the midst of its sixth petroleum price super-cycle.

And every time oil prices drop, renewable energy investment becomes less attractive.

Which brings us full circle to my original column on cap and trade. In order for renewable energy to compete in the marketplace, we need to put a cap on carbon emissions. Such a cap, by imposing additional costs on using fossil fuels to generate electricity, would make renewable energy more attractive.

Pumped hydro and battery storage will likely fill in the missing link in Kauai’s road to 100 percent renewable energy. But before we get there, our politicians need to work together to price carbon emissions accurately; our utilities need to continue to navigate the technological and inherent inequities of renewable energy; and we all need to begin reducing our power consumption and transitioning our use to daytime hours.