The years immediately following German reunification were defined by transformation on almost every front, and nowhere was this more evident than in the country’s power sector. The challenge, for anyone seeking to document the structural changes, lies in teasing out the interplay of old and new: East and West, public and private, legacy and integration. ISIC 3510—electric power generation, transmission, and distribution—serves as the official framework for tracking firms, but its usefulness, as usual, depends on how carefully the data is filtered and interpreted.
The first step is to compile a comprehensive list of companies coded under ISIC 3510 for both the former West and East Germany as of 1992. Prior to reunification, the two power systems were run under very different logics—centralized state enterprises in the East, more decentralized but still heavily regulated firms in the West. The registry after 1990 shows a proliferation of new entities, some the result of breakups or privatization, others formed to drive integration or modernization projects.
Correlating these firm-level changes with the physical integration of the grid is where things become especially intricate. Immediately after reunification, there was a national drive to connect the two grids—requiring new high-voltage lines, upgraded substations, and investment in control systems. Project documentation from the era, held by the Federal Ministry for Economic Affairs and Energy or the transmission system operators themselves, often details which firms led which integration projects. Analysts can map these projects onto the firm roster, flagging those most actively involved in the cross-border buildout.
The next step is to track changes in firm output—primarily measured in megawatt-hours generated, though ancillary services also matter. Annual reports, regulatory filings, and, in some cases, international agency data provide figures for total generation by company and sometimes by fuel type. By comparing pre- and post-integration output, it’s possible to see which firms expanded, consolidated, or, in a few cases, declined as a result of grid integration and shifting market dynamics.
Grid integration did not impact all companies equally. Many East German generators, facing stricter environmental standards and new market pressures, saw output shrink or plants mothballed. Some were absorbed by Western firms through privatization, others reinvented themselves or focused on modernization. Western utilities, on the other hand, often grew—expanding their service areas and increasing output to supply a larger, unified market. Documentation is crucial: every assumption about corporate continuity, every step of data linkage, and any interpolation for missing figures should be carefully logged.
A further dimension involves the chronology and geography of integration projects. Some regions experienced faster connection and modernization, resulting in earlier output changes; others lagged behind. Overlaying project completion dates and locations onto company output figures provides a more granular map of how the sector evolved.
Not all data aligns neatly. Corporate boundaries shifted, plant ownership transferred, and reporting standards changed over the transition period. Even so, by layering ISIC 3510 firm records, project documentation, and output data, it’s possible to reconstruct the broad contours of Germany’s post-reunification power sector. The trends are uneven, sometimes ambiguous, but unmistakable in their direction: a sector adapting to integration, modernization, and the evolving demands of a unified national economy.