Melt tank and glass melting plant

A melt tank for the production of a glass melt from at least one solid starting material, the melt tank comprising:

• an inlet opening for a supply of the at least one solid starting material, an outlet opening for an outflow of a molten glass, the melt tank configured in such a way that the glass melt flows in a direction of flow from the inlet opening to the outlet opening during the melt process;
• a floor that limits the melt tank at a bottom;
• at least two side walls that adjoin the floor and that laterally limit the melt tank;
• and,
• a roof that is connected to the side walls and that limits the melt tank at a top,
• wherein the melt tank includes a melting segment and a refining segment, the glass melt first passing through the melting segment and subsequently through the refining segment when flowing in the direction of flow, wherein an atmosphere above the glass melt in the melting segment is in communication with an atmosphere above the glass melt in the refining segment,
• the glass melt having a first bath depth B1 in the melting segment and having a second bath depth B2 in the refining segment, a threshold running transverse to the direction of flow being situated in the floor of the melt tank in a transition area of the melt tank between the melting segment and the refining segment, a third bath depth B5 over the threshold being smaller than the first bath depth B1 and smaller than the second bath depth B2, wherein the threshold forms a highest raised part in the floor of the melting tank with a smallest bath depth,
• the melt tank being configured such that for the melting of the at least one starting material of the glass melt:
• an electrically produced, first heat energy portion (Qelec) is supplied via a multiplicity of electrodes that extend into the glass melt, and
• a second heat energy portion (Qfossil), produced by a combustion of fossil fuel, is supplied in at least one burner situated in a side wall, in the roof, or both, above the glass melt,
• a total supplied heat energy being made up of the first heat energy portion and the second heat energy portion,
• wherein the melt tank is configured in such a way that the first heat energy portion comprises at least 30% of the total supplied heat energy,
• wherein a first row of electrodes is situated in the floor of the melt tank on the threshold, in the glass melt flow, the first row of electrodes including a multiplicity of electrodes and the first row of electrodes running transverse to the direction of flow, and
• wherein a section of the roof is configured such that a lower surface of the section is distanced from the glass melt surface, wherein the section comprises the melting segment to a beginning of the threshold.