(371v) Technology Value and Techno-Economic Criteria of Unicorn Technology for Carbon Capture and Sequestration for Electricity System Decarbonisation

Technology value and techno-economic criteria of unicorn
technology for carbon capture and sequestration for electricity system
decarbonisation

Yoga W. Pratama^1,2, Niall Mac Dowell^1,2*

¹Centre
for Environmental Policy, Imperial College London, London, UK

²Centre
for Process Systems Engineering, Imperial College London, London, UK

*Corresponding author's
e-mail address: niall@imperial.ac.uk

Keywords:

carbon capture and sequestration, electricity system
decarbonisation, unicorn technology

ABSTRACT

It has been recognised that carbon
capture and sequestration (CCS) is a key technology in energy systems
decarbonisation. Yet, despite the readiness of incumbent technology, e.g. conventional
CCGT with post-combustion CCS (CCGT-CCS), the technology is constantly perceived
as a “pre-commercial technology” [3]. Consequently, instead of focusing on the
deployment of the technology, many proposed projects were frequently delayed the
current “action” is waiting for the appearance of a so-called “unicorn”, i.e.
a very efficient and cheap technology capable of providing low-carbon and
low-cost electricity and ancillary services [4].

While the appearance of such
technology is highly uncertain and rare, deep decarbonisation of the energy
system to mitigate climate change has to be met. In the present study, we use the
UK’s electricity system as a case study where the system is expected to reduce
its carbon intensity to less than 10 g/kWh by 2050. A range of next-generation
CCS technologies [5] that can be a potential “unicorn” is evaluated. Those
technologies include: 1) natural gas-based technologies with CCS (IRCC pre-combustion
CCS, Allam cycle with post-combustion CCS, and CCGT-MCFC[1]
CCS), and 2) coal- and biomass-based technologies with CCS (supercritical post-combustion
CCS, oxy with pre-combustion CCS, and IGCC with post-combustion CCS). Their
competitiveness is compared with the incumbent technology, i.e. CCGT -CCS using
the electricity systems optimisation framework considering endogenous
technology cost learning (ESOXEL [6]). We subsequently evaluate a range of
technology costs and efficiencies to find the range of features a unicorn
technology should have in order to make an appreciable difference to the
structure and cost of the electricity system within which it is operating.
Finally, the value[2]
of unicorn technology to the system is also evaluated.

Fig 1 shows the optimal energy
output and capacity expansion in the UK’s electricity system considering a
range of next-generation technologies for CCS. The results show that whilst the
next generation technology remains inferior in term of efficiency and
technology cost compared to the incumbent technology, all CCS plants deployed
in the system are CCGT-CCS, replacing unabated CCGT to provide low-carbon and ancillary
services for the system. To achieve zero carbon in 2050, conventional biomass energy
with Post-Combustion CCS (BECCS) is selected to offset residual emissions from CCGT-CCS
and embodied emissions from imported electricity. Although the technology cost
per gross capacity of the conventional-, oxy-, and IGCC- BECCS are comparable, the
drawback of the more advanced technologies (i.e. oxy- and IGCC- BECCS) are
having a higher capacity penalty for their own-use utility. Even though those
technologies are more efficient than the conventional one, the primary role of
BECCS in the system is to provide negative emissions rather than generating
electricity. Therefore, conventional BECCS, which is slightly less efficient, allows
better use of its capacity in delivering more negative emissions, by burning
more biomass and storing more CO₂, rather than generating
electricity.

Fig. 1. Optimal energy
output and capacity expansion in the UK’s electricity system.

All next-generation
CCS technologies are included in the model but not selected.

The results on the evaluation of
the techno-economic features of the unicorn technology need to have can be seen
in Fig 2. The results indicate that only a “unicorn” which costs less than £
1500/kW will be deployed in the system. Technology with this cost, however, has
to have an efficiency of around 64%, which is equal to the maximum theoretical
efficiency of oxy-combustion CCS.  Unicorns with lower efficiency, e.g. around
55%, will be preferable to the incumbent technology, i.e. CCGT-PostCCS,
only if the cost is as low as the cost of unabated CCGT. The anticipated costs
and efficiencies of next-generation technologies, however, are inferior
compared to the current anticipated cost and efficiency of CCGT-PostCCS.

Fig 2. The share of
unicorn technology in total CCS capacity in 2050

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