The purpose of this Thesis is to provide an overview of the world of international arbitration regarding investment protection in energy disputes under the ECT and BITs. Significant reverberations of globalisation can be seen in all sectors with no exception in the field of law. Rapid dispute settlement of many disputes is produced independently of national jurisdiction, specifically in the energy sector, as a result of international investors’ and investments’ mechanisms. International investment law and arbitration are one of the fastest-developing areas of public international law. International investment law has become increasingly prominent in the international legal order and the catalyst was the explosion of Bilateral Investment Treaties between States and a sharp increase in international investment disputes. In the past decades, there has been an impressive rise in the number of bilateral investment treaties and other agreements with investment-related provisions, followed by a drastic rise in the number of disputes between private investors and sovereign states. This Thesis will highlight decisions under the ECT jurisdiction, but it is not desirable and possible to discuss all issues raised in the field of international investment arbitration. This Thesis’ conclusion is that, since future investment disputes between companies and Host States are inevitable, there are some developing tendencies, that deal with the consideration of the Host States to reclaim part of their regulatory sovereignty.