“…A number of the papers identified, while acknowledging the existence of barriers, mainly explore the differences between the effectiveness and efficiency of particular implemented policies (proposed solutions). For example, a number of papers [113][114][115][116] examine Feed-in-Tariffs, carbon tax, trading schemes, green certificates [117], energy performance contracts [118], and renewable standards. Indeed, two papers examine implemented policies to propose an optimal mix of policy solutions to enable the scaling up of renewable technology deployment [119,120], while one proposes a real options analysis tool for investors to use based on the different types of uncertainty they are faced with [47].…”