Hawaii's Energy Future

Renewable

Energy Sources

Biomass

Biomass history in Hawaii

The future of biomass

Garbage-to-energy

Biomass gasification

Landfill gas

The term "biomass" includes diverse fuels derived from timber, agriculture and food processing wastes or from fuel crops that are specifically grown or reserved for electricity generation. Biomass fuel can also include sewage sludge and animal manure.

Direct Combustion power plants burn biomass directly in boilers; they supply steam to power turbines like those used in fossil fuel plants. With biomass gasification, biomass is converted into a gas that can then fuel steam generators, combustion turbines, combined cycle technologies or fuel cells. The primary benefit of biomass gasification compared to direct combustion is that gases can be used in a variety of power plant configurations.

Given the continuing stream of waste and the ability of plants to regenerate, these biofuels are considered to be renewable. Further, burning crop residues or garbage to generate electricity may offer environmental benefits in the form of preserving precious landfill space. Growing plants, particularly timber, for biomass fuel can be beneficial in reducing greenhouse gases if the plantations are done in an environmentally appropriate way.

In terms of capacity, biomass power plants represent the second largest source of renewable energy in the nation.

Biomass history in Hawaii

Hawaiian Electric, Maui Electric and Hawaii Electric Light Company (as well as the utility on Kauai) traditionally purchased biomass power from local sugar mills, helping to extend the viability of this agricultural commodity in Hawaii. The same was true on Kauai. Historically, as much as a half to a quarter of electricity needs on some islands were generated by the burning of bagasse.

The Hawaiian Commercial and Sugar (HC&S) plantation on Maui, the last remaining sugar plantation in the islands, continues to burn bagasse, or sugar cane waste, to produce electricity for its operations, with up to 12 MW sold to Maui Electric Company. However, sugar operations may be coming to an end and HC&S has announced plans to expand its renewable energy business.

The U.S. Department of Energy, though the University of Hawaii, and the U.S. Department of Agriculture and Navy will receive $4 million annually over several years to help HC&S determine whether it is feasible within the next ten years to convert the more than 130-year-old company into an "energy farm," or a high-tech producer of renewable fuels.

The decision could result in HC&S growing sweet sorghum or tropical grasses or perhaps green sugar cane, which does not require the unpopular practice of cane burning to harvest the crop.

How Biomass Works – U.S.Department of Energy

The future of biomass

On Hawaii Island, Hu Honua Bioenergy LLC (http://huhonua.com) has bought the coal-burning power plant and the buildings that were once run by the Hilo Coast Processing Company sugar operation. The company is in discussions with several wood scrap sources, including two companies that plan to harvest eucalyptus trees on former Hamakua Sugar property, for fuel to supplement coal in the plant.

Garbage-to-energy

Trash can be burned to make steam to turn a turbine. On Oahu, the City’s HPOWER Garbage-to-Energy Plant is capable of providing 46 megawatts of electricity to the Hawaiian Electric grid. HPOWER, formally the Honolulu Program of Waste Energy Recovery, has the primary function to reduce the volume of municipal solid waste (MSW). The plant is presently capable of consuming 2,160 tons of garbage per day, reducing the volume of refuse that goes to the landfill by 90%. HPOWER processes the garbage burning it at 1,800 degrees Fahrenheit and turning it into inert ash. The boiler produces steam that drives a turbine generator. The electricity generated by this waste-to-energy plant is distributed to customers by HECO.

In December 2009, the City & County of Honolulu broke ground on construction of a third boiler at the HPOWER plant at Campbell Industrial Park. Construction could be completed by late 2011 or early 2012 adding capacity to burn 900 tons a day. With the third boiler, HPOWER is estimated to be able to supply six percent of Oahu's electricity, up from the current 4.5 percent.

Biomass gasification

On Oahu, Honua Power Company has negotiated a contract with Hawaiian Electric to sell electricity to the utility. The contract has been submitted for consideration to the Public Utilities Commission with input from the Consumer Advocate. The plant could be in service about within about two years of the pending approval of the contract.

Honua is proposing a biomass gasification power plant. To be located on about 2.5 leased acres at Campbell Industrial Park on Hanua Street in the vicinity of the Kalaeloa Partners, HPOWER and Hawaiian Electric CIP Generating Station. It will produce about 7 megawatts of electricity.

The facility will generate a high-quality biofuel synthesis gas (also called syngas) from biomass materials such as construction and demolition debris, green waste, agricultural biomass crops, and waste, scrap tires, and otherwise non-recyclable paper and plastics.

The biofuel syngas will be used to fire proprietary boilers and generate steam for steam turbine generator to produce electricity. Power is renewable and considered “as available” since the contract does not stipulate a certain amount of power delivered at a certain time. The contract is for 20 years.

How waste to energy works – Covanta Energy, U.S. Environmental Protection Agency

Landfill gas

Landfill gas is another way to create electricity from trash. Compressed solid waste creates methane gas which can be trapped, piped to a small plant and burned to turn a turbine or internal combustion engine and create electricity. The technology is well established and has been used in the past at the Kapaa Landfill in Kailua.

Developers are exploring landfill gas for the Waimanalo Gulch Landfill in Kapolei and Kapaa Landfill in Kailua (on Oahu), at Waena in Central Maui and at Puuanahulu in West Hawaii on the Big Island.

U.S. EPA Landfill Gas brochure

Energy Information Administration Landfill Gas Statistics