21
3. The vision
Figure 6: Global final energy demand and direct CO
2
intensity of cement
production in the roadmap vision (2DS)
Notes: Waste includes biogenic and non-biogenic waste sources. Petroleum coke is reported within oil.
0.00
0.15
0.30
0.45
0.60
0
2
4
6
8
10
12
14
2014 2020 2025 2030 2035 2040 2045 2050
Fi
n
a
l
e
n
e
rg
y
d
e
m
a
n
d
(E
J)
Low-variability case
Electricity
Waste
Biomass
Natural gas
Oil
Coal
Direct CO intensity - 2DS
2
Direct CO intensity - RTS
2
0.00
0.15
0.30
0.45
0.60
0
2
4
6
8
10
12
14
2014 2020 2025 2030 2035 2040 2045 2050
D
ir
e
ct
C
O
in
te
n
si
ty
(t
C
O
/t
ce
m
e
n
t)
2
2
High-variability case
Total CO
2
emissions from cement making can be
decreased by reducing the clinker to cement ratio.
14
Process CO
2
emissions released from raw materials
during the production of clinker can therefore
be decreased by integrating alternative cement
constituents that reduce the clinker to cement ratio,
which drops by 5% globally by 2050 in the roadmap
vision. This enables a reduction of the process CO
2
intensity of cement of 30% by 2050 from current
levels, with 364 million tonnes of carbon dioxide
(MtCO
2
) of carbon emissions savings. This is
equivalent to 16% of current global direct CO
2
emissions from cement making.
The reduction of the clinker to cement ratio also
enables CO
2
emissions savings related to the
avoided thermal energy consumption that results
from a lower clinker demand for the same amount
of cement produced. Cement constituents that
can be used instead of clinker include gypsum,
natural volcanic materials, limestone and industrial
by-products such as GGBFS (generated in the iron
and steel industry) and fly ash (produced in coal-
fired thermal plants), as well as others derived from
widely available resources such as calcined clay.
14. Clinker is the main constituent of most types of cement. The
share of clinker in cement on a mass basis is defined as the
clinker to cement ratio.
KEY MESSAGE: A reduction in the direct CO
2
intensity of cement of 32-38% is supported by a global
reduction of the share of fossil fuels in cement kilns of 24-27% by 2050 in the roadmap vision.
The calcination process of raw clay would incur
additional thermal energy needs. These are
estimated to increase the thermal energy intensity
of clinker by 11% globally in the roadmap vision
by 2050 compared to the average thermal
energy intensity of clinker in that same year. The
reduction of the clinker content in cement is highly
dependent on the local availability of cement
constituents instead of clinker, as well as on the
required properties for the final cement product,
which are dictated by local standards and technical
requirements of the end-use applications.
The roadmap vision assumes that the integration of
carbon capture technologies in cement production
reaches commercial scale by 2030. Captured CO
2
emissions represent 25% of the total emitted CO
2
in the sector globally in 2050, or 552 MtCO
2
/yr as
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