With rising energy prices and an imperative to reduce carbon dioxide emissions, growers are seeking lower energy solutions for greenhouse production. This project, which ran from 2010 to 2013, sought to advance energy efficiency for growers, including evaluating lower energy heating technology for greenhouses.

Before energy and environmental emissions can be reduced, growers need to understand where their energy is being used. The research team developed a self-assessment energy efficiency audit pack that allows growers to identify and estimate the energy use efficiency of their greenhouse production facility.

The energy audit pack provides a three-step process for identifying all energy-using equipment and systems onsite, calculating what they cost to run over a year, and includes information on the options for lower cost methods that may be used to improve energy efficiency.

The audit method was developed from data obtained from eight greenhouse facilities that represent different crops, geographical locations, and the level of technology used.

During development of the audit tool, the researchers found that users benefited from the process in ways other than simply estimating energy use. In using the tool, growers came to think about energy use differently, and began separating out the operating costs of specific equipment as well as taking a whole-of-farm approach to best energy saving strategies.

The second part of the project, a cost-benefit analysis of three alternative heating technologies for greenhouses, showed that significant energy and cost savings can be achieved.

Following greenhouse trials, researchers calculated that a hydronic heating system linked to a geothermal heat pump and heat exchange loop was the most cost-effective option, followed by natural gas, then LPG and finally, direct heating with electricity.

While solar alone was found not viable at this time, solar options could work as a supplemental heating source.

This project has been funded by Hort Innovation, using the research and development levies listed below and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

• Vegetable Fund