In the present world, there is a noticeable surge in renewable energy investments to promote renewable energy production. This current scale of investment, promotion and increased regulation in renewable energy is unprecedented, motivated partly by climate policy objectives. Resultantly, in the past few years, a significant number of renewable energy disputes have been initiated under EU law and the Energy Charter Treaty (ECT) framework. Against this backdrop, this paper, primarily, highlights the tensions that have arisen between regulations seeking to promote renewable energy in achieving climate policy objectives and economic considerations regarding investor protection. Moreover, this paper looks at the international law disputes concerning renewable energy investments in the EU in the context of ECT. At a more abstract and academic level, this paper seeks to examine the interaction between private and public interests in an area where private investments are fully dependent on the details of the applicable regulatory framework.