Biofuel - a fishy business?

UniSea's Dutch Harbor, Alaska seafood processing facility
credit: Steigers Corporation

Like residents of other remote northern and island communities with no power grid, Alaskans depend on large generators for electricity production. The diesel required to run the generators is transported over long distances and is expensive. Faced with recent price rises, the Alaskan Energy Authority (AEA) is now expanding a successful programme to replace diesel with a locally available biofuel - fish oil. The oil, a by-product from seafood processing, is already being used to run some generators in the region, and has potential for many other coastal communities. Converting the oil into biodiesel could broaden its potential still further.

Waste not...

Besides being economically viable, recovering fish oil from seafood waste for use in heating and electricity generation also provides important advantages over petroleum-based fuels including biodegradability and non-toxicity. In addition, burning fish oil fuel adds less smoke, volatile hydrocarbons, and carbon monoxide to the air. Fish oil is separated from processing waste by first heating the waste and then separating liquids from solids. The solid fish wastes are dried and converted into bone meal and fish meal, to be used in livestock and aquaculture feed. The water and oil which make up the liquid component are separated and the oil is filtered and purified to remove any remaining water and sediment. The oil is then stored for use in electrical generators and furnaces.

Generators at the seafood processing facility, which routinely operate on 50 to 70 per cent fish oil to diesel blends.
credit: Steigers Corporation

Utilising fish waste has the added advantage of reducing the environmental impact of seafood processing. Twenty-one million gallons of fish oil are produced annually by Alaska's shore-based and floating fish processing plants - mostly located on and around the Unalaska and Akutan Islands - and yet two-thirds (13 million gallons) are currently discarded. Fish waste, if not processed immediately, degrades rapidly and quickly loses its value, for example as an animal feed. Dumped into the sea in high concentrations, the waste can also disrupt marine ecosystems.

Following the fleet

Currently about eight million gallons of fish oil are extracted from the state's processing plants. However, only one million gallons is blended for use in power production and heating; most of the rest is used as boiler fuel for drying the fish and bone meal, with a small amount sold for livestock feed supplements and other uses. But in some remote communities, such as Ketchikan in southeast Alaska, public utilities and private fish processors have begun efforts to recover the oil and process it into fuel. The AEA and its partners are also developing small, portable fish oil recovery facilities. These can move between communities in different regions, following the seasonal movements of the commercial fishing fleets, and thereby maximising their year-round use. Each community using the facility would need to create storage for the recovered fish oil. According to John Steigers, AEA project manager, there are dozens of communities that could adopt the system, which will be funded mainly by the Environmental Protection Agency of the US federal government and the state government of Alaska, with support from community partners and processors.

The system could also provide a solution to a growing fuel use dilemma. This stems from the fact that even though many Alaskan generators can use up to 100 per cent fish oil, an increasing number of newer models cannot tolerate fish oil in any significant concentration. Biodiesel, which can be made from natural oils including fish oil, can be used in any engine. The AEA is also, therefore, developing portable biodiesel production units to be used alongside the fish oil recovery system in order to convert the fish oil to biodiesel. Portable oil extraction and biodiesel conversion technology has the potential to be used elsewhere around the globe and interest has been expressed by several organisations including the World Bank. John Steigers points out however, that Alaska is probably the only place in the world where fish oil is worth less than imported diesel, and is therefore more economically valuable as a fuel than as a product in its own right.

By Treena Hein