Exploring the effects of mineral depletion on renewable energy technologies net energy returns

Abstract

The energy transition poses a set of new challenges related to mineral scarcity and depletion. The process of mineral depletion is characterised by increasing energy consumption per tonne of valuable minerals mined (i.e. energy intensity of mining), due to the decline in the quality of mined deposits. As renewable energy technologies are heavily reliant on a range of minerals, some of them scarce, the net energy returns (i.e., the share of energy available to provide energy services) of renewable energy technologies may be significantly affected by this decline. This may in turn jeopardise the ability of renewable energy technologies to provide sufficient net energy, and hence, support decent living standards. The aim of this article is therefore to explore, using net energy analysis techniques combined with Life Cycle Analysis data, the effects of mineral depletion on the net energy returns of four renewable energy technologies: solar photovoltaic, concentrated solar power, onshore wind, and offshore wind.The results indicate that the effects of mineral depletion on the net energy returns of renewable energy technologies will be marginal. Indeed, even for very high increases in the energy intensities of mining, the share of net energy returns decreases by less than 3 percentage points by 2060 for each technology analysed — 2.3% for wind offshore, 1.6% for solar photovoltaic and concentrated solar power, and 1.1% for wind onshore. These results are validated with a Monte Carlo simulation conducted on the energy intensities of mining. In addition, the article discusses that technological factors, such as improvements in metallurgical energy efficiencies and material intensities of manufacturing have the potential to somewhat offset the effects of mineral depletion. Hence, although constraints related to mineral scarcity and depletion may be critical for the energy transition, concerns regarding the impacts of these issues on the net energy returns of renewable energy appear to be unfounded.