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The state of Hawaii will soon embark on the most ambitious plan in the U.S. to deploy renewable energy.

The state legislature in early May passed and sent to Gov. David Ige House Bill 623 that sets a renewable portfolio standard (RPS) of 100 percent of net electricity sales by 2045. The bill will test the abilities of utility planners as they are challenged with delivering reliable power to customers while integrating the highest percentage of variable generation onto a utility grid.

Along the 30-year pathway of achieving this goal, some would suggest that the island grid system will become a giant laboratory for renewable energy, testing the limits of what is reasonably and practically achievable for distributed generation, according to Kevin Kerschen, East Region Director for Renewable Energy at Black & Veatch.

The interim RPS goals contained in the legislation are 30 percent by 2020, 40 percent by 2030 and 70 percent by 2040. Hawaiian Electric Industries (HEI), the parent of the three principal operating utilities, achieved a consolidated renewable energy portfolio standard of 21.3 percent for 2014, the company said in its latest Renewable Portfolio Standard Status Report. The utility’s own goal is 65 percent renewable energy by 2030.

HEI supplies power to 95 percent of the state’s population through Hawaiian Electric Co. Inc., Hawaii Electric Light Co. Inc., and Maui Electric Co. Ltd. The electricity supply on Oahu is primarily reliant on a fleet of utility-operated, oil-fired steam generating plants that were installed more than 50 years ago and were designed to operate as baseload plants operating at full and constant load, Kerschen said. The utility also purchases power from independent power producers that operate additional baseload and intermediate load plants.

On Oahu, firm capacity generators provide about 1700 megawatts (MW), whereas the variable generators – primarily wind and solar – provide about 350 MW. The variability of the renewable energy resources puts operational strain on the firm capacity generators that must operate in a flexible manner – which they were not designed for – to balance supply with demand, Kerschen noted.

Renewable Energy Beyond Solar

Achieving the final RPS goal is a long-term proposition that will be 30 years in the making. Meeting the standard will require a balance of all renewable energy generation options – well beyond the behind-the-meter rooftop solar installations under the net energy metering program, which has already made substantial inroads, Kerschen said.

Other operational renewable energy technologies on Oahu include wind energy and utility-scale solar PV installed under the Feed-in-Tariff (FIT) program, and the prior renewable energy solicitation conducted by the utility about four years ago.

For HEI utilities, renewable energy facilities operate primarily on the three main islands. “There is approximately 100 MW of wind energy on the north shore of Oahu, the most populous island, where rooftop solar has grown to over 200 MW of generation – which is significant on a 1,200 MW grid,” Kerschen said.

Maui has a significant amount of wind energy – some supported by energy storage – along with hydropower, rooftop solar and FIT solar. The big island of Hawaii has geothermal, hydro, wind, rooftop solar and FIT solar, he noted.

“As the renewable energy sector develops, additional rooftop and utility-scale (5 MW or greater) solar will help increase the energy diversity of the grid, but it will also put added strain on the utilities’ ability to operate reliably,” he said. Because of this, utilities could turn to biodiesel power generation, he said.

“Today’s RPS plan, even without the goal of 100 percent renewable energy, represents an opportunityfor biodiesel generation.” A utility-owned 50-megawatt biofuel reciprocating engine project is in development, he added. It will be dispatachable and with biofuel as its source, it would be deemed renewable.

A recently issued utility request for proposals was seeking up to 200 MW of energy storage on Oahu, not limited to batteries, Kerschen said. The program is advancing to install several large energy storage facilities that will provide ride-through capability in the event of the loss of a large generator, and frequency and voltage support to the grid.

Unique Nature of Island Power

What are the implications of such a deep reliance on renewable energy? Island utilities have complications that mainland utilities typically do not face. During periods of system disturbances, an island electric company does not have the ability to wheel in power from another system, Kerschen noted. Usually, an island grid is relatively small and the loss of a large generating unit can have a significant impact on the stability of the system.

He said discussions have been going on for years about the feasibility of laying a costly undersea cable tying together the power of wind-rich Maui with demand-rich Oahu, but there are no firm plans as of yet.

To help wean the power system off imported oil, Kerschen said, imports of liquefied natural gas (LNG) are also under consideration to replace the current use of fuel oil. The plan would initially deliver LNG to the islands in ISO containers, but the eventual delivery would be by bulk shipment to a receiving terminal at a port on Oahu. It is a long-term prospect that would require regulatory and environmental approvals. While the development timeline is uncertain, it is probable that the earliest that LNG could be delivered would be 2019 or later, he said.

In the midst of the transformation of Hawaii’s utility sector, NextEra Energy Inc. has proposed a merger with Hawaiian Electric Industries – a $4.3 billion deal, including debt. NextEra is the parent of the regulated utility Florida Power & Light Co. and, with its non-regulated operations, has operations in 27 states and Canada and a major presence in solar and wind generation. The merger could give Hawaii’s electric sector access to lower-cost capital, Kerschen said.

The takeaway for the state’s ambitious goal is that “a significant amount of advanced planning will be required so that flexible and resilient generation and transmission and distribution systems are in place to accommodate the ever-increasing variable generation required to meet the RPS,” he said. In spite of all efforts to properly plan for this transformation, “there will be a lot of learning as you go,” he said.

Hawaii has been charting new ground on deploying renewable energy technology at a faster pace than most other utility systems. “The state is on a path toward tremendous reshaping of the utility system over the next 10 years – on top of significant changes that have happened in the last five,” Kerschen said.

Story by Samuel Glasser, Black & Veatch 

Published originally on Black & Veatch Solutions 

Solar rooftop photo courtesy of Shutterstock