What really matters to reduce the energy demand of household electronics? Global sensitivity analysis of circular economy strategies for the United Kingdom

Limiting the global temperatures to +1.5 degrees C from pre-industrial levels requires achieving net-zero greenhouse gas emissions by 2050. This should be achieved across all sectors, and for electrical and electronic equipment (EEE) the promotion of repair, lifetime extension and other Circular Economy (CE) strategies are often proposed as the main areas for intervention. However, few studies have quantified and compared the effectiveness of different CE strategies at reducing emissions at a national level and into the future. To fill this gap, an extended dynamic stock model was combined with a device energy consumption model to anticipate the embodied, operational, and repair energy requirements arising from the stocks and flows of seven devices up to 2050 in the United Kingdom (UK). To understand the relative influence of all model inputs on device energy demand in 2050, a variancebased sensitivity analysis was performed using the Sobol method. The results show that device size is the most significant variable for six out of the seven devices. Whereas substantial increases in device lifetime and repair rates were shown not to be significant in reducing energy demand. A reduction of 30% of energy demand by 2050 is possible for almost all EEE devices, except laptops and TVs. However, delivering these savings requires significant changes to consumption behaviours such as decreasing device size by about 40% or decreasing ownership rates by approximately two thirds through shared ownership. This analysis prioritises the most impactful strategies to reduce the total energy demand of EEE in the UK.