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The Federal Government’s renewable energy target requires wholesale purchasers of electricity to contribute towards the generation of renewable energy.
A target of 9,500 GWh in 2010 will be phased in through a series of interim targets over the period 2001-2010. The interim targets are set out below as it occurs in Section 40 of the Renewable Energy (Electricity)Act 2000 (Cth)
At this stage there are no provisions in the Renewable Energy Act for liabilities on or after 2021.
Renewable Energy Certificates (RECs) are created on the basis of accredited renewable energy generation from the operation of eligible renewable energy generation assets using eligible fuels. RECs remain valid until they are surrendered to the regulator. Thus RECs can be stored for a number of years.
The bagasse, cane trash and wood waste fuels used by Sunshine Electricity are categorised as eligible fuels under the Renewables Electricity Act.
Contributing to a sustainable environment
Carbon dioxide (CO2) emissions are regarded as the major contributor to the ‘greenhouse effect’ or global warming. Global warming is the increased retention of solar heat by the earth’s atmosphere. There is an increasing consensus amongst the scientific community that higher levels of CO2 and other gases in the atmosphere has resulted in increasing temperatures on earth. These higher temperatures are leading to increased glacial melting and the thermal expansion of the oceans and consequent rising sea levels.
As a result, the greenhouse effect and CO2 emissions have become a major concern to our community.
Carbon neutrality
The sugar industry has operated in a greenhouse neutral mode - that is, CO2 emissions from the harvesting and refining of cane and the burning of bagasse are balanced by reabsorption and photosynthesis required for growing sugar cane.
The sugar cane converts CO2 by using solar energy to power photosynthesis. This process creates the fibre and pith structure of the sugar cane and its leaf mass. Simple sugars are converted and stored as sucrose, which is the commercial form of sugar produced by the sugar milling process.
The other inputs to the growing sugar cane are water and sufficient levels of nitrogen, phosphorus and potassium.
Historically, once the sugar cane was ready to harvest, the cane crop was set on fire to burn away dead leaf and tops, which comprise approximately 25% by weight of the whole crop. This disposed of a significant mass of material which was an impediment to economic harvesting and milling of the crop and, until now, unusable to the industry.
Pre-harvest burning of sugar is a cumbersome and potentially dangerous activity. It must be conducted under low wind conditions, usually at night. The resulting cloud of ash and cinders can be carried to an altitude of 2000 metres and the fallout distributed over 8 kilometres down-wind.
The two co-generation facilities will provide an opportunity to use the cane leaves and tops as fuel. This will also reduce air pollution and fallout, which affects the whole district surrounding a sugar cane farm.
The carbon dioxide cycle
Using a sugar can crop tonnage of 1,150,000 tonnes, all inputs and outputs have been analysed for the Condong and Broadwater milling and co-generation operations - see graphics below. Note that all inputs and outputs are expressed in thousands of tonnes (or kilotonnes) equivalents of CO2 which is calculated from the intrinsic carbon content of the input or output.
Fuel sources
Both co-generation facilities will use bagasse (rthe esidue of sugar cane after milling) and trash (cane leaves and tops normally burnt in the field pre and post harvest). Timber woodwaste will be used in the event that supplementary fuel is required.
The timber resource providing supplementary woodwaste must comply with the Consent Conditions and must have been sourced from Office of the Renewable Energy Regulator (ORER) accredited supply, either:
• Plantation forests managed under the Plantations Code of Practice; or
• Biomass by-products of sustainably managed plantations; or
• Other ORER accredited supply.
The timber resource must also comply with the NSW “Protection of the Environment Operations (General) Regulation 1998”, Chapter 3B - Burning of bio-material in electricity generating works. |
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