This paper focuses on how to promote regional cooperation in electricity. We begin by discussing the theory of international trade cooperation in electricity, with a view to discussing what preconditions might be important in facilitating wide area trading across national borders. We then develop lessons based on the comparison of four case studies. These include three regional developing country power pools - the Southern African Power pool (SAPP), West African Power pool (WAPP) and the Central American Power Market (MER). We contrast these with Northern Europe's Nord Pool. These cases highlight both the potential and difficulty of having cross-jurisdictional power pools. In the light of the theory and evidence we present, we draw key lessons in the areas of: preconditions for trading; necessary institutional arrangements; practicalities of timetabling; reasons to be hopeful about future prospects. (C) 2015 Elsevier Ltd. All rights reserved.