Spatially explicit assessment of renewable energy resources is critical for large scale landscape planning and design to maintain energy supply so that economic development and social advancement can be sustained. Renewable energy planning at the national level is pivotal to a nation’s socio-economic sustainability in the context of the oil crisis, anthropogenic climate change and the social and economic impacts of globalisation resulting in the international dispersal of energy supply and ownership. Using a case study from Australia, we investigate the annual spatial heterogeneity of solar energy potential across the country towards identifying the strengths and appropriate uses of spatial modelling for regional decision making in energy planning. The case study explores solar radiation distribution in Australia and its potential to supply energy at national, utility and household levels. This study demonstrates the usefulness for integrating these models in the design and planning process for carbon-neutral energy supply. It is also clear that the adoption of spatial modelling systems for solar supply also requires modelling of the political and social opportunities and limitations inherent in the solar landscape. This research advocates a holistic approach enabled by spatial planning through geodesign principles. We conclude with recommendations and guidance for future renewable energy planning as a useful practice for carbon emission reduction to climate change mitigation.