What do you do with 5,000 tonnes of Macadamia Nut shells? Create electricity of course! Australia’s largest energy retailer, AGL, is helping to create biomass fuel from macadamia nut shells, as part of its effort to invest in sustainable energy sources.

One of Australia’s first waste-to-energy (biomass) renewable cogeneration projects can be found at Suncoast Gold Macadamias in Gympie, Southeast Queensland.  ‘Cogeneration’ is generation of both electricity and useful heat that can be used onsite. In this case it is employed via a heat exchanger to dry the macadamia nuts and to reduce the kernels water content.

What is Biomass?

Biomass is all matter that can be used as fuel for industrial production.  It can also include biodegradable wastes that can be burnt as fuel.

How is Biomass energy created?

Biomass can be thought of as storage of solar energy in chemical form. It can be combusted to generate heat and then subsequently converted into other forms of energy.

How do you create energy from Macadamias?

Creating energy from a waste product like the macadamia nut shells involves the following process:

* Nut shells are burnt in a fire boiler, which creates steam

* Some of the steam is used to dry the macadamia nuts

* The majority of the steam is used to drive a turbine to generate clean, renewable electricity

* Suncoast Gold Macadamias consumes up to 1,400 megawatt hours per annum for all their electricity needs – about 20% of the energy produced

* The remaining 80% of the electricity is sent to the national power grid as GreenPower

What does this mean for the environment?

The macadamia plant produces enough energy from the macadamia nut shells to power the company’s entire manufacturing and processing activity, as well as about 1250 Queensland homes.

This innovative waste-to-energy project cuts Australia’s greenhouse gas emissions by around 7,500 tonnes per annum - equivalent to taking about 1800 cars off the road each year.  It has also solved the problem of what to do with the 5,000 tonnes of macadamia shells, enough to fill three Olympic-sized swimming pools, that Suncoast Gold Macadamias processes each year.

Suncoast Gold, which exports Australia’s largest native agricultural crop to more than 20 countries including Japan, Europe and the US, has had its efficiency significantly boosted by the provision of electricity, heat and steam.  It has also enhanced its green credentials in the European and Asian markets where consumers are extremely environmentally aware.

By 2010, more than 150 growers throughout Queensland and northern New South Wales are expected to supply Suncoast Gold with about 10,000 tonnes of macadamia nuts each year, doubling the Gympie facility’s output.

AGL’s Asset Manager Neil Cooke says the innovative plant has achieved several firsts.  It’s the first of its kind in the world,” he said. “It also has the largest macadamia shell silo (400 tonne capacity, 18 metres high and 10 metres in diameter) in the world and the boiler is showing that it is possible to achieve consistent performance from a renewable energy plant operated on shells.”

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Written by Giselle Pethard