Linear demand formulations for price competition in horizontally differentiated products are sometimes used to compare situations where additional varieties become available, e. g. due to market entry of new firms. We derive a consistent demand system to analyze such situations

The seasonal demand for natural gas requires supply flexibility. This "swing" is now largely provided in northwestern Europe by indigenous production. Declining reserves will increase the dependency on imports from far-off sources, which are less flexible. Hence, flexibility must be provided by...