The European Commission has intensively discussed the mandatory separation of natural gas transmission from production and services. However, economic theory is ambiguous on the price effects of vertical separation. In this paper, we empirically analyse the effect of ownership unbundling of...

In 2007, Germany changed network access regulation in the natural gas sector and introduced a so-called entry-exit system. The re-regulation’s spot market effects remain to be examined. <p> We use cointegration analysis and a state space model with time-varying coefficients to study the...</p>