Opportunities in Otaki for Improved Energy Efficiency in Retail Lighting and Its Offsetting through Renewable Resources

In 2010 the town of Otaki decided to go "Off the Grid", obtaining all its electricity supply from renewable resources. To support this goal, this thesis documents and quantifies the electricity demand for the Otaki retail stores along State Highway 1. It was found the majority of the load in these 33 stores was for lighting. To minimise the renewable electricity generation capital requirements, the load was optimised by exploring energy efficiency opportunities. Energy audits to AS/NZS 3598:2000 Energy Audit Level 2 were undertaken in 23 of the stores. These created a consistent set of data on the lighting load and energy consumption. Potential energy savings opportunities were then identified to reduce the lighting load by 26% through lamp replacement and removal. When combined with improved lighting management, these could reduce annual electricity consumption by 34% to 248,321 kWh. An investigation of available renewable resources (Photovoltaic (PV), wind and hydroelectric) found that PV generation was the most suitable for this urban setting. PV generation using 53 by 4 kW panels, at a capital cost of $1.3 million, which would generate 250,425 kWh per year. This would meet the annual electricity demand, but there would be a summer surplus and winter deficit. The absence of net metering provision makes this option uneconomic, although the creation of an Otaki mini-grid may be a viable alternative.