Energy return on energy and carbon emissions investments for New Zealand wind energy farms

Abstract

This paper analyses the Energy Return on Energy Invested (EROI) and Energy Return on Carbon Emissions (EROC) of current wind farms in New Zealand. The weighted average EROI for a New Zealand wind energy farm over a 20 year life span is 35, with some sites above 50, while others are as low as 6.5. These values are higher than many other electricity generation methods reported in the literature with hydropower being the main exception. The average EROC value for NZ wind energy farms is 0.477 GJ/kg CO2-e, which is 56 times the EROC of a combined cycle natural gas power station. The substantial range of EROI values are driven by two factors: (1) average wind speeds for a given site and (2) the blade diameter of the turbine, where larger is better. Future work will include an economic analysis of the wind farms.