We review candidate long duration energy storage technologies that are commercially mature or under commercialization. We then compare their modularity, long-term energy storage capability and average capital cost with varied durations. Additional metrics of comparison are developed including land-use footprint and equivalent efficiency based on idle losses to account for emerging long-duration storage applications and use cases. The technology landscape may allow for a diverse range of storage applications based on land availability and duration need, which may be location dependent. These insights are valuable to guide the development of long-duration energy storage projects and inspire potential use cases for different long-duration energy storage technologies. This analysis also lays the foundation for future relevant modeling and decision-making studies that implement emerging long-duration energy storage. • Review commercially emerging long-duration energy storage technologies (LDES). • Compare equivalent efficiency including idle losses for long duration storage. • Compare land footprint that is critical to market entry and project deployment. • Compare capital cost-duration curve.