Adapting solar energy to irrigated sugarcane production at Bundaberg, Queensland

The concept of renewable and Hybrid Energy systems (HESs) are highlighting opportunities for electrification of isolated or energy-deficient areas, and where grid-supplied electricity costs exceed these alternatives. The concept of utilising solar photovoltaic (PV) as an energy source for irrigation in sugarcane production has been promoted by grower representatives and governments as a solution to the energy trilemma, particularly the escalating cost of grid- supplied electricity. However, there is a deficit of independent, publicly available data on the true value proposition of solar in this context. The critical issue is whether such a system is capable of maintaining the peak irrigation requirement for the daytime energy demands of current sugarcane production; and whether solar powered systems could change irrigation management practice leading to increased farm productivity. Adoption of new technology is limited by knowledge around capability and viability, particularly where the technology is to be deployed to meet a specific crop demand, such as irrigated sugarcane production, and where significant capital investment will be required. A demonstration and evaluation trial of new energy technologies on-farm was installed at Bundaberg to overcome barriers to adoption, such as attaining proof-of-concept and to provide financiers with confidence to support the capital expenditure required. This paper outlines the design specifications and crop considerations associated with the adoption of HES across a range of irrigation methods utilised in the Australian sugar industry. The Bundaberg project also trialled ECODRIVE Variable Speed Drive (VSD) technology in combination with solar, providing an opportunity to test the benefits of lower pump motor energy demand with a hybrid or blended system that enables longer daytime operating hours to meet the motor energy requirement regardless of time-of-day or atmospheric conditions. Variable speed technology also provides ongoing cost reduction during night-time operation. The hypothesis posed is, can a solar system provide a stand-alone energy supply for sugarcane farming operations that have high seasonal demand for irrigation and, if not, what combinations of solar and grid or other energy are the most efficient. This project has demonstrated that when optimally designed, HESs prove to be more reliable and economical than single energy source systems for irrigation and can lead to productivity gains. Key words Sugarcane, Bundaberg, renewable, hybrid energy systems