Material Insights · Understanding the Material World

Recuperators and regenerators: Economics and contracts

One of industry's quickest paybacks, and its hidden risk

One of industry's quickest paybacks, and its hidden risk What this tab covers Economics and commercial structures: levelised cost of the recovered energy against the fuel it avoids, host-site risk, and service models such as heat-as-a-service.

Combustion-air preheating is one of the cheapest industrial efficiency measures, with paybacks of one to two years at high furnace temperatures. The asset is welded to one furnace, so its value depends on that furnace staying in service.

Levelised cost of heat or avoided cost

Favourable

DOE's worked example: a 2.9 MW (10 MMBtu/h) furnace at 870 C running 8,000 hours, gas at USD 9 per MMBtu (about USD 31 per MWh, calculated), receives 425 C air and cuts fuel by 22%. That saves USD 158,400 a year for a system costing USD 200,000 to 250,000, a payback of 15 to 19 months. This works out at roughly USD 39 to 48 of capital per MWh of gas saved each year (calculated). A Cadmus review of four utility-funded exhaust-air projects (exchangers, thermal oxidisers and a grain dryer, not furnace preheaters) found a lifetime cost of about USD 16 per tonne of CO2 and an average payback of about 2.2 years (calculated from the paper's project table).26

Simple payback, DOE example 15 to 19 months2 Annual saving, DOE example USD 158,4002 Capital per MWh of gas saved per year about USD 39 to 48 (calculated)2 Exhaust-air projects, lifetime cost about USD 15.80 per t CO26

Host factory credit risk

Mixed

The equipment has no resale value away from its furnace. If the host closes the line or switches to electric melting, the recuperator is stranded, though short paybacks limit the loss. Hosts are mostly steel, aluminium, glass and ceramics firms; steel and aluminium are among the sectors now paying the EU Carbon Border Adjustment Mechanism (CBAM), which raises the value of fuel savings for exporters to Europe but also squeezes weaker producers.8

CBAM sectors relevant to hosts iron and steel, aluminium (glass not covered)8

Heat-as-a-service and ESCO models

Mixed

Because a recuperator cannot be separated from the furnace, it is rarely sold as a service; hosts usually buy it from the furnace or burner supplier, or fold it into a rebuild. Shared-savings contracts are possible but would need metering of fuel per tonne of product. The nearest real model is Skyven Technologies' energy-as-a-service deal with California Dairies, where Skyven installs and maintains heat recovery and solar heat, savings are shared over 10 years, and Kyotherm provides third-party finance. This was boiler-side recovery, not furnace preheat.7

Skyven and California Dairies contract term 10 years, shared savings7

Sources

  1. Preheated Combustion Air, Process Heating Tip Sheet #1 (DOE/GO-102007-2482) US DOE Industrial Technologies Program, 2007
  2. Not Just Hot Air: Low-Cost Decarbonization through Heat Recovery (Zahlan and Talan, Cadmus), ACEEE Summer Study on Energy Efficiency in Industry ACEEE, 2021
  3. Skyven Technologies: Decarbonizing Industrial Process Heat through Public-Private Partnerships (implementation model) US DOE Better Buildings Solution Center, 2024
  4. CBAM definitive regime European Commission, DG Taxation and Customs Union, 2026