Water Journal : Water Journal November 2011
technical features 76 NOVEMBER 2011 water greenhouse emissions at recycled water plants for energy production; • Identifying less energy- and greenhouse-intensive alternatives during investments in capital infrastructure, such as the installation of more efficient pumping regimes and transfer systems, and alternative processes; • Optimising our water resource supplies, including maximising the use of low- energy locally sourced resources, such as recycled water, groundwater and stormwater, and influencing water consumption patterns to minimise long-term carbon impact; • Investigating increased renewable energy generation. • Assessing the expected impact the introduction of a carbon tax will have on Western Water's services. Western Water has implemented a number of key projects to mitigate our carbon footprint. A number of these are outlined here. Melton Biogas Cogeneration Plant As part of measures to achieve our target, a biogas co-generation plant was installed at the Melton RWP. This plant utilises biogas, a by-product generated during the production of recycled water, to produce heat and energy. The biogas co-generation plant has been operational since August 2010. To date, the plant has generated approximately 600 MWh of electricity, which is equivalent to offsetting 738 tonnes of carbon dioxide. With significant growth planned for the Melton region, biogas available for electricity production at the cogeneration plant will also increase with time. The implementation of this project has the potential to offset carbon dioxide emissions by 1,800 tonnes per year. The biogas co-generation plant produced enough energy to provide the energy needs for the Class A Recycled Water Plant at Melton, which supplies 'fit-for-purpose' recycled water to residential customers in Eynesbury and the growth area of Toolern. It is expected that the operation of the Class A recycled water plant will achieve carbon neutrality through heat and electricity produced by the cogeneration plant and the purchase of a minor amount of offsets. The verification process is currently underway to assess the plant's carbon neutrality against the National Carbon Offset Standards. As part of this verification process, Western Water led the Victorian water industry project to develop a Carbon Neutral Guide for the water industry using the biogas co-generation plant as a case study. This project has attracted the interest of Low Carbon Australia, which oversees Carbon Neutral Claims. Melton EcoDepot The Melton EcoDepot is an ambitious project that aims to deliver Western Water its first carbon-neutral depot. Works at the depot commenced with the implementation of a range of energy- and water-efficient measures identified through a recent audit, such as: the de-lamping of lights; switching off appliances when not in use; installing motion sensors; and cleaning of light diffusers and the installation of a split system heating unit. The roof of the depot was also applied with a heat-reflecting paint to reduce heat stress among staff in summer and reduce summer cooling needs. Staff at the Melton depot have also installed a 22,000 rainwater tank for vehicle and equipment cleaning and a biodiesel filling station has been installed. In June, a 2 kilowatt solar array was placed on the depot roof to produce renewable energy to power around 22% of the depot's energy needs. The sustainability initiatives at the depot have helped to significantly reduce the site's energy consumption by 44% at this time. The installation demonstrates an environmentally sensitive approach to depot operations. Partnering with the Water Industry on Climate Change Initiatives Western Water partnered with the water industry through the Water Services Association of Australia (WSAA) to develop a Cost of Carbon Abatement Tool. The tool provides Western Water with a methodology for assessing the cost effectiveness of a range of options to reduce greenhouse gas emissions. Through this partnership, Western Water was also involved in developing a Victorian water industry energy and carbon price forecast, which will be used to inform purchasing decisions and plan for the future, as well as a calculator to assist energy and greenhouse reporting requirements for the water industry. In partnership with Victoria University, Western Water is undertaking research into the use of algae as biofuels. When harvested, this algae could be utilised in our digester to generate additional biogas, which could then create heat and electrical energy through the biogas co-generation plant. There are current knowledge gaps prior to commercialisation of this process. This research is aiming to close these gaps and is looking to identify growth rates of the selected algae species, ideal growth conditions and discover the most efficient technique for harvesting the algae. Energy Saver Incentive Scheme Western Water has also continued its involvement in the Victorian Energy Saver Incentive Scheme, which is a State Government initiative to reduce greenhouse gas emissions with the creation and sale (to date) of 94 Victorian Energy Efficiency Certificates (which is equivalent to savings of 94 tonnes of greenhouse gas emissions) from our WaterTight residential customer assistance program. Adaptation to a Variable Climate Western Water recognises the potential threat that climate variability and population growth poses, and a multi- faceted response to sustainable and integrated water cycle management has been developed. We have already had some experience of what that will be like, with high population growth, drought and record flooding rainfall all experienced over the past few years. To date, Western Water has focused on improving our climate resilience by ensuring we have access to alternative portfolio sources of water to supplement the water available from our own reservoirs. This has involved considerable investment in upgrading water supply, sewerage and recycled water systems and assets. Such work has included: • Building pipelines from Melbourne to provide greater water security and improving interconnections to the Melbourne system, including desalinated water. The desalination plant will provide further water security, with greater access to a climate- independent supply of drinking water for a growing population. • Increasing storage and supply capacity of recycled water facilities. In 2009--10, Western Water recycled 85% of its water. This led to the replacement of over 1,500 million litres of drinking water with recycled water where it was fit for the purpose, and a 50% reduction in drinking water supplies to areas where Class A recycled water is provided via dual pipe. • Integrated water cycle management and third-pipe recycled water supply in large-scale residential developments to provide drinking water alternatives.
Water Journal December 2011
Water Journal September 2011