The project, the largest new base load renewable energy project in Australia, is a joint venture between Delta Electricity, a major generator of power in New South Wales, and the NSW Sugar Milling Co- Operative.

The two facilities are located at Condong on the Tweed River and Broadwater on the Richmond River, both on the north coast of New South Wales. They are operating within sugar mills using bagasse and cane leaf, the by-products from the sugar harvesting and milling process, as fuel.

Each site has a cogeneration plant of 30 megawatts (MW) electrical generating capacity. Approximately 400 gigawatt hours (GWh) is expected from both plants each year. The electricity is contracted to Delta Electricity under a long term power purchase agreement. Delta will act as the agent to the joint venture for the sale of green rights.

Both the Condong and Broadwater mills were facing requirements for additional steam raising capacity for a variety of reasons, from the ageing of the existing plant to increased demand as a result of crop increases. The plants are now generating power for the two sugar mills and for 60,000 homes in the local areas. The power is available 24 hours a day, seven days a week, year round.

Delta Electricity CEO Jim Henness said “While coal still provides reliable base load power output, we recognise that diversifying the fuel sources for electricity generation is a positive response to the issues of climate change which is becoming more relevant to the community.”

The construction of the renewable energy plants is providing the NSW Sugar Milling Co-Operative members with another source of income.

NSW Sugar Milling Co-Operative CEO Chris Connors said the opening of the Condong and Broadwater plants was a watershed for the Co-Operative and its 600 members. “Our growers have faced the twin challenges of reducing greenhouse gas emissions and protecting their future with this project,” he said. “They identified an opportunity that has benefits for them and their communities beyond their lifetimes and responded. That’s quite significant.”

The technology

The cogeneration plants utilise conventional solid fuel power plant technology. The power cycle includes economisers, air hats and feedwater heating elements to improve cycle efficiency. The plants have been constructed to meet stringent noise emission requirements, with a range of treatments adopted, including silencers on fans and steam vents, enclosures around high noise sources and barriers at the plant’s perimeters to shield the adjacent communities.

One of the challenging aspects of the project was the fuel storage and handling system. The cogeneration plants require a surplus of bagasse fuel from the mill crushing season operations, which has to be stored for use in the non-crush season.

On the basis that the 60 MW of renewable energy will displace the equivalent amount of energy from a coal fired plant, the CO2 savings are around 400,000 tonnes each year. CO2 emitted from the biomass combustion is taken up by the sugar crop regrowth in the region.

The plants use wet scrubber technology to capture particulates. This technology also reduces other pollutants, particularly those with affinity for water. The Condong and Broadwater renewable energy plants are also going to provide environmental benefits to local areas. They will eliminate the burning of cane, reducing air pollution and the ‘black snow’, which has affected the whole district.

As an additional environmental benefit, treated effluent, which was previously discharged into the low flowing Rous River, is now recycled as water for the boiler and for plant cooling at the Condong cogeneration plant. Any treated water that is not required will then be returned to the Tweed River.

The capital cost of the project was in the order of $220 million. Construction contractors for the main power plant were Downer Energy Systems and Clyde Babcock Hitachi Australia.

Moving to low emission energy

Delta, formed in March 1996 as part of the New South Wales Government’s restructure of the electricity industry, now generates about twelve per cent of the power for the National Electricity Market. While most of its energy is generated for coal fired power stations at Wallerawang and Mt Piper near Lithgow, and Munmorah and Vales Point on the Central Coast, Delta has been investigating and trialling new options for power generation for a decade.

Coal-fired generators will be its core business for the foreseeable future, but Delta has been working to develop lower emission technologies for a new commercial environment. The company started with micro-hydro plants, the first at Chichester dam, near Dungog 250 km northwest of Sydney, and then embarked on the sugar cane project. Three gas-fuelled plants are currently in different stages of development. These plants will produce significantly lower levels of greenhouse gas emissions and use less water than coalfired power stations.

Together with the CSIRO, Delta has constructed a $5 million pilot-scale research facility at Munmorah Power Station on the Central Coast to capture up to 3,000 tonnes of CO2 each year. The project will investigate post combustion carbon capture processes under Australian conditions.

The joint venture partners in the sugar cane project have an option for a similar development at the NSW Sugar Milling Co- Operative plant at Harwood near Grafton. Mr Henness said the electricity generating industry should be the first to embrace the need for change in this area and to look for alternative ways to generate lower carbon emission base load power.

“That means being more creative and innovative in the way we meet the community’s demand for a reliable supply of electricity,” Mr Henness said.

“Of course, this is a challenge for us, but one that we are embracing. Our long term business success is dependent on our ability to adapt and develop more sustainable strategies,” Mr Henness said.