Rotary kilns are major point sources of carbon dioxide (CO2), accounting for over 3 GtCO2/yr globally. We are currently investigating and developing new low-carbon solutions that can provide high-temperature heat for rotary kilns via renewable gas and/or electricity. A hybrid system - where both biomass and electricity acts as a heat source - opens up possibilities for large-scale balancing of grids dominated by variable renewables such as wind and solar. Globally, such low-carbon furnaces can potentially reduce more than 1 GtCO2/yr of carbon emissions.

1. Development of a
Low-Carbon Furnace
for Industrial-Scale
Grid Balancing
EUBCE 2019
Ilkka Hannula* and
Eemeli Tsupari
31/05/2019 VTT – beyond the obvious

2. 31.5.2019 VTT – beyond the obvious 2
INDUSTRIAL GHG
EMISSIONS
15 Gt
PER YEAR
+2.2%ANNUAL INCREASE

3. 31.5.2019 VTT – beyond the obvious 3
2.9 Gt
Iron &
steel
3.0 Gt
Cement
Finland’s total GHG emissions 0.05 Gt/yr
Germany’s total GHG emissions 0.9 Gt/yr

4. Rotary kilns are large point sources of CO2
Materials produced using rotary kilns
 Cement ~ 3 Gt/yr
 Lime ~ 0.5 Gt/yr
 Iron ore pellets ~ 0.03 Gt/yr
 Asphalt
 Refractories
 Metakaolin
 Titanium dioxide
 Alumina
 Vermiculite
 Spodumene
31/05/2019 VTT – beyond the obvious 4
Figure: General layout of a direct fired counter-current
rotary kiln used in cement manufacture (Wikimedia).

5. Energy is only part of the story
 Significant share of emissions
from rotary kilns released by
chemical reactions.
 Cannot be mitigated with low-
carbon energy.
 Fuel combustion still responsible
for over 1 Gt of CO2 from rotary
kilns globally.
31/05/2019 VTT – beyond the obvious 5
Global aviation emissions ~0.9 GtCO2/yr
Global maritime emissions ~0.9 GtCO2/yr

6. 6Photo courtesy of Finnsementti
FOSSIL REFERENCE
RENEWABLE REFERENCE
(used at several pulp mills) UNDER DEVELOPMENT
Electric
heat
Electric
heat
Photo: Juho Kauppinen /VTT

7. Techno-economic assessment of high
temperature industrial heat supply
 Case: Industrial furnace/kiln with 50 MW energy demand.
 Fossil reference:
• Hard coal (steam coal)
• Heavy fuel oil (HFO)
 Low-carbon alternatives:
• Biomass-derived fuel gas
• Electrical heating
31/05/2019 VTT – beyond the obvious 7Source: https://www.iea.org/statistics/kwes/prices/

8. Techno-economic assessment of high
temperature industrial heat supply
 Case: Industrial furnace/kiln with 50 MW energy demand.
 Fossil reference:
• Hard coal (steam coal)
• Heavy fuel oil (HFO)
 Low-carbon alternatives:
• Biomass-derived fuel gas
• Electrical heating
31/05/2019 VTT – beyond the obvious 8Source: https://www.iea.org/statistics/kwes/prices/
Median coal price 103 USD/tonne
(13 EUR/MWh)

9. Techno-economic assessment of high
temperature industrial heat supply
 Case: Industrial furnace/kiln with 50 MW energy demand.
 Fossil reference:
• Hard coal (steam coal)
• Heavy fuel oil (HFO)
 Low-carbon alternatives:
• Biomass-derived fuel gas
• Electrical heating
31/05/2019 VTT – beyond the obvious 9Source: https://www.iea.org/statistics/kwes/prices/

10. Techno-economic assessment of high
temperature industrial heat supply
 Case: Industrial furnace/kiln with 50 MW energy demand.
 Fossil reference:
• Hard coal (steam coal)
• Heavy fuel oil (HFO)
 Low-carbon alternatives:
• Biomass-derived fuel gas
• Electrical heating
31/05/2019 VTT – beyond the obvious 10Source: https://www.iea.org/statistics/kwes/prices/
Median HFO price 511 USD/tonne
(38 EUR/MWh)

11. Fossil-fired vs Biomass-fired
31/05/2019 VTT – beyond the obvious 11
Cost assumptions
- Gasification plant: 23 M€
- WACC: 6 %
- Economic life: 20 years
- O&M 4%/yr of investment
- Availability: 8000 h/yr
- Calculated in €2018
EU ETS 25 €/tCO2
Biomass-fired
more competitive
Fossil-fired
more competitive

12. Coal103USD/t*
Fossil-fired vs Biomass-fired
31/05/2019 VTT – beyond the obvious 12
Cost assumptions
- Gasification plant: 23 M€
- WACC: 6 %
- Economic life: 20 years
- O&M 4%/yr of investment
- Availability: 8000 h/yr
- Calculated in €2018
EU ETS 25 €/tCO2
Biomass-fired
more competitive
Fossil-fired
more competitive
HFO511USD/t*
*Median price for industry based on:
https://www.iea.org/statistics/kwes/prices/

13. 31/05/2019 VTT – beyond the obvious 13
Fossil-fired vs Electrically heated
EU ETS 25 €/tCO2
Electrically heated
more competitive
Fossil-fired
more competitive
Cost of electrically heated
kiln assumed same as
fossil-fired kiln

14. 31/05/2019 VTT – beyond the obvious 14
Fossil-fired vs Electrically heated
EU ETS 25 €/tCO2
Electrically heated
more competitive
Fossil-fired
more competitive
Cost of electrically heated
kiln assumed same as
fossil-fired kiln

15. 31/05/2019 VTT – beyond the obvious 15
Fossil-fired vs Electrically heated
EU ETS 25 €/tCO2
Electrically heated
more competitive
Fossil-fired
more competitive
Cost of electrically heated
kiln assumed same as
fossil-fired kiln
Coal103USD/t
HFO511USD/t
*Median price for industry based on:
https://www.iea.org/statistics/kwes/prices/

16. Electricity price time series for Finland in 2018
31/05/2019 VTT – beyond the obvious 16

17. Hybrid furnace (biomass + electricity)
 Hybrid furnace with two heating options:
• Biomass-derived fuel gas (100 – 50% of total heat requirement)
• Electricity (0 – 50 % of total heat requirement)
 Possible benefits:
• Hedges against price volatility
• Large-scale load for grid balancing
• Frequency Containment Reserve (FCR)
• Improves kiln temperature control*
• Increases CO2 concentration  decreases CO2 capture costs*
• Enables use of bioenergy despite regionally limited biomass resources?
* not taken into account in economic assessments
31.5.2019 VTT – beyond the obvious 17

18. Utilisation of electric assistance
2015 realised electricity prices, biomass 15 €/MWh
31.5.2019 VTT – beyond the obvious 18
 Electric assistance 130 h/a

19. Utilisation of electric assistance
2015 realised electricity prices, biomass 25 €/MWh
31.5.2019 VTT – beyond the obvious 19
 Electric assistance 1203 h/a

20. Utilisation of electric assistance
2015 realised electricity prices, biomass 25 €/MWh, operation in FCR-N market
31.5.2019 VTT – beyond the obvious 20
 Electric assistance 5227 h/a
FCR-N (2015) price: 16.21 €/MW,h

21. Summary
 Paris Agreement targets cannot be met without reductions in industrial emissions.
 Industrial emissions generally hard to reduce, but some solutions are available.
 Rotary kilns a major source of CO2 emissions globally
• ~1/3 from fossil fuel use
• ~ 2/3 from chemical reactions
 Biomass-based solutions already commercially available and competitive.
 Electricity-based solutions under development for regions where
• biomass not available, but
• continuous access to low-cost low-carbon electricity (hydro, old nuclear).
 Hybrid furnace possibly attractive for (future) regions where electricity grid dominated by
wind and solar.
31.5.2019 VTT – beyond the obvious 21