Electric Glass Furnaces

Joule heating · hybrid · melting

Glass conducts electricity once molten, so electrodes can heat the melt directly. All-electric works up to a few hundred tons a day; large float lines are still gas-fired.

Bar chart of melting capacity per furnace in tons per day: all-electric furnaces typically up to about 200 to 300; Ardagh's NextGen hybrid furnace about 350; a typical gas-fired float glass line 600 to 800; a large float line about 1,200. Below: all-electric furnaces heat the glass itself by Joule heating; hybrid furnaces use about 80% electricity plus burners; fossil furnaces use regenerative gas firing. MELTING CAPACITY PER FURNACE, TONS PER DAY All-electric, typical max ~200-300 t/d Ardagh NextGen (hybrid) ~350 t/d Typical float line (gas) ~600-800 t/d Large float line (gas) ~1,200 t/d HOW THE MELT IS HEATED All-electric Joule heat in the glass Hybrid ~80% electric + burners Fossil Regenerative gas firing
Melt temperature
1,300-1,550 °C
Hybrid electric share
~80%
Largest hybrid
Ardagh NextGen
Companies tracked
9, 1 Chinese
Hub
Industry

Finding

Electric melting is proven for container, fiberglass and specialty glass, and hybrid furnaces now push it to container-glass scale, but float glass remains the hard case

Molten glass is an ionic conductor. Molybdenum electrodes through the furnace floor or walls pass current through the melt, which heats from within under a cold top of unmelted batch; heat escapes less, and thermal efficiency reaches 80-90%, against roughly 40-50% for a regenerative gas furnace. Electric melting has long been standard for small specialty and fiberglass tanks, with life limited by refractory wear.

Scale-up is the current story. Ardagh Glass Packaging started its NextGen hybrid furnace at Obernkirchen, Germany at the end of 2023: about 350 t/day of container glass, heated about 80% by electricity, cutting CO2 by up to 60%. Verallia built a large all-electric container-glass furnace at Cognac, France. Fiberglass makers such as Owens Corning and Saint-Gobain run electric melters, and Libbey and others have moved tableware furnaces toward electric melting. Furnace design comes from Horn Glass and Sorg (Germany), Fives (France), Toledo Engineering (US) and China Triumph International Engineering (CTIEC).

Float glass is the hard case: lines run 600-1,200 t/day without stopping for 15-20 years, and electrodes only boost gas firing. China makes more than half the world's flat glass, including most solar cover glass, on gas-fired lines, and its molybdenum producers, led by CMOC, supply much of the electrode metal. Electric furnaces also need tens of megawatts of steady grid supply and cannot easily ramp, which is why hybrid designs that can shift between electricity and gas are spreading first. For ceramics, electric kilns fire stoneware and porcelain to about 1,300 °C; reduction firing still needs gas.

Furnace types

Glass melting options compared

Glass furnace heating methods
TypeHeatingTypical sizeWhere used
All-electric (cold-top)Joule heating through molybdenum electrodesUp to ~200-300 t/dayFiberglass, specialty, tableware, smaller container lines
Hybrid~80% electric plus oxy-fuel or air-gas burners~350 t/day (Ardagh NextGen)Container glass
Electric boostElectrodes add 5-20% of heat to a gas furnaceAny sizeFloat and container lines
Regenerative or oxy-fuel gasBurners over the meltUp to ~1,200 t/dayFloat glass, large container lines

Constraints

What limits deployment

Electric glass melting constraints
ConstraintDetail
SizeAll-electric limited to a few hundred tons a day per furnace
Furnace lifeRefractory wear can shorten campaigns against gas furnaces
Glass qualityRedox and bubble control differ under electric heating
PowerTens of MW of steady supply; limited ability to ramp
CostElectricity costs several times more than gas per unit of heat in the US

Vendors

Furnace builders, electrode and refractory makers

All-electric melters come from a few German, French, British and US builders; molybdenum electrodes and fused-cast refractories set how long an electric furnace lasts. Active companies first, then pilots, research groups and companies that exited.

Furnace builders
CompanyProductsHQTechnologyStatus
China Triumph International Engineering (CTIEC)Float and specialty glass lines, furnace engineeringChinaGas, oxy-fuel and electric boostingactive: CNBM group
ElectroglassAll-electric glass meltersUKCold-top electric meltingactive
FivesElectric and hybrid glass furnaces (Prium)FranceAll-electric and hybridactive
Horn Glass IndustriesAll-electric, hybrid and gas glass furnacesGermanyElectric boosting, all-electric meltersactive
Nikolaus SorgAll-electric and hybrid melters, electric boostingGermanyAll-electric VSM meltersactive
Toledo Engineering (TECO)Glass furnace design, electric melters and boostingUSAll-electric and boosted furnacesactive
Electrodes and refractories
CompanyProductsHQTechnologyStatus
PlanseeMolybdenum glass-melting electrodesAustriaMolybdenum electrodesactive
RHI MagnesitaGlass furnace refractoriesAustriaFused-cast and bonded refractoriesactive
Saint-Gobain SEFPROFused-cast AZS refractories for electric and gas meltersFranceFused-cast AZSactive

Sources

Sources and scope

Scope
Electric Glass Furnaces
Sources
Ardagh Glass Packaging, Verallia announcements; furnace maker data; glass industry energy benchmarks
Updated
October 2026