Technology readiness levels

Technology readiness levels are used by the US Department of Defense (DoD) and NASA to evaluate the maturity level of technologies that are to be integrated into technical systems (Mankins, 1995). The definition of technology readiness levels adopted in this thesis requires modification to the existing framework for two reasons: firstly, the traditional technology readiness level definition is from a technology developer’s point of view. Secondly, the standard technology readiness level framework is not specific enough for assessment of power generation technologies.

The new framework borrows elements from the traditional definition of technology readiness levels in the early stage, but incorporates key technology parameters in the later stages that are specific for the deployment of power generation technology. Therefore modified form of technology readiness levels contains non-technical parameters that are deemed to be required for successful technology deployment.

4.5.1.1 Methodology

Technology performance and cost are just two components to be considered when analysing investment in new technology. It is also valuable to estimate the developmental stage of the technology which influences the expected time to commercialisation. Both plants and sub processes can be graded on this scale. This enables a comparison of the various sub processes and plants.

The NASA definition of technology readiness levels is unsuitable for use as they are from a technology developer’s point of view. For the purposes of this report, the generators point of view is being considered. Therefore the definitions need to be modified to be applicable to the technologies under investigation (original definitions of technology readiness levels can be found in Appendix 4). A framework is established to identify and evaluate new technologies using a modified form of technology readiness levels.

New power generation technologies must go through four discrete stages before they are viable. The four main steps are research, advanced research and development, system demonstration and system deployment. The first two levels refer to the development and validation of processes at the sub system level. The key to third stage is to show that the sub-system can be integrated into the plant system. The final stage takes into account the requirements imposed by the wider generation system for the new plant to be successful, but only refers to the technology under investigation. It is important to note that in this

context, system, relates to the next level up in the hierarchy i.e. if the assessment is of a capture process, the system will be the plant.

TRL 1: Research

o Basic scientific principles observed and reported;

o Technology concept/application formulated;

o Analytical and experimental critical function or proof of concept validation.

TRL 2: Advanced R&D

o Component and process validation at lab, full plant integrated computer simulation;

o Component/process validation at pilot scale.

TRL 3: System Demonstration

o Operation demonstrated at pilot plant scale (hundreds of hours);

TRL 4: System Deployment

o Actual system integrated into full-scale plant and successfully deployed, operation at full scale for thousands of hours;

o Actual system market proven for economic, reliable, successful industrial operations.

The data used for the classification of plants against the technology readiness levels is given in the appendix and in previous Sections. Tables in Appendix 4 (Commercial activities for CCS demos) give details of PC, oxyfuel and IGCC plants that have a capture process, the capacity of the process and the location and company involved.

4.5.1.2 Results and discussion of technology readiness assessment

Applying the modified technology readiness levels to evaluate the current status of the standard plants with state of the art carbon capture gives the results shown in Table 4-3:

Table 4-23: Tables showing the technology readiness levels of various plant processes

PC TRL

Supercritical Boiler 4

Steam Cycle 4

Pollutant Controls 4

Carbon Capture 3

IGCC TRL

ASU 4

Gasifier 3-4

Syngas Clean 3-4

Water Gas Shift Reactor 3

Separation Process 3

H2Turbine 3¹⁴

HRSG 4

Oxyfuel TRL

ASU 4

Boiler 3-4

Steam Cycle 4

Pollutant 4

Carbon Capture 3

From the Table 4-23 it can be seen that PC plant with CCS appears to be the closest to commercialisation.

Interestingly, it is also the plant with the least sub-processes; one of the reasons for the first generation of IGCC being unreliable is the complexity of plant.

PC with CCS is closest to deployment, due to the advanced nature of its component processes. The main barrier for PC with carbon capture at present is to scale up the relevant technologies and test them i.e. a question of integration and optimisation.

The IGCC process requires many more sub processes than the other plants. Therefore, questions arise over reliability and integration of these components. The IGCC process also requires the H2 turbine to be developed (Eurelectric, 2008b), However, if pre-combustion capture for natural gas fired plants is to come to fruition, the H2 turbine must also be developed for a CCS CCGT plant. The oxyfuel plant is above the IGCC plant in terms of process readiness. The oxyfuel process is being demonstrated at scale-30MW plant at Schwarze Pumpe and significant understanding of the oxyfuel combustion process exists from oxyfuel plants in other industrial processes. In general, advances in shared technologies e.g. more efficient CO2 compression will benefit all competing technologies.

Error! Reference source not found. shows the current status of current and future potential capture technologies split by plant type on the y axis and TRL on the x axis. The first thing to note is the wide range of TRL’s covered for all three plant technologies. The second point to note is that alternative capture processes for PC are higher up the TRL scale than for other plants e.g. aqueous ammonia and sterically hindered amines are both in TRL 3 or 4 while for IGCC plant there appears to be no alternative capture technologies in TRL 3. The reason for this could be the relatively small number of operational

14 Source: (EURELECTRIC (2008b) Letter to Mr Chris Davies MEP Union of the Electricity Industry.Eurelectric, 2008)

IGCC plants compared to PC plants and also the ease of integrating a test capture process into the technology i.e. it is fairly simple to create a slipstream off the exhaust of a PC plant, but more complex (and uneconomical) to install the necessary equipment on an IGCC plant.

It is also useful to determine when these technologies might become commercially viable options for carbon capture. The US DOE and EPRI have produced documents estimating the time to commercialisation (system deployment) of new technologies. However, it appears that this data is subjective. For example; it is the opinion of Eurelectric that it will take until 2020 for CCS to overcome additional technical hurdles (Eurelectric, 2008b). Much of this will be due to process integration issues.

Figure 4-24: Graphical representation showing readiness of novel capture technologies (2008 as base year) Table 4-24: Expected time to commercialisation for various capture processes (Figueroa et al., 2008).

PC Oxyfuel IGCC Time to

PC

Figure 4-25: Possible position of novel CCS technologies in 5 years (with 2008 as base year) Figure 4-25 shows the possible future position of capture technologies in 5 years based on the expected rate of development. The graph shows the various capture technologies rated according to the TRL scale and is based on the information in the academic reports in the literature survey and company information.

As can be seen, there should be a number of PC capture technologies to choose from, sterically hindered amines, MEA, amino acid salts, potassium carbonate and chilled ammonia. This is because a number of proposed demonstration PC plants are using different processes i.e. the Meri Pori plant in Finland will use amino acid salts, the Pleasant Prairie plant in the USA uses chilled ammonia(see Appendix 4 for further details). Meanwhile most oxyfuel projects and IGCC projects are projected to use current technology. As a result, progress in IGCC and oxyfuel technology is expected to take place over a longer timescale.

It is unlikely that all potential capture technologies will reach maturity. Experience has shown that when multiple technologies compete for adoption, not all prospective technologies will reach full maturity (Wainwright and Clark, 1992). Figure 4-26 shows the result visually: the so called technology development funnel illustrates that the number of alternative technologies available to fulfil an objective decrease with increasing technology maturity levels.

Technology Readiness level

Technology

2

1 3 4

Technology Readiness level

Technology

2

1 3 4

This is consistent with the refinement and evaluation that goes on as part of the development process.

This is likely to be the case with the alternative capture processes, with a significant number of alternative technologies being lost along the way. At present it is difficult to state which technologies will drop out, but it appears that the technologies to be adopted will include sterically hindered amines, MEA, aqueous ammonia and amino acid salts for PC plant, while for IGCC plant, selexol is the only clear capture process that will be adopted in the near term. This judgement is based on the proposed capture process for demonstration plants worldwide and the characterisitics of the capture processes that were presented in the appendix.

Finally, it is important to note that there is a difference between technology readiness levels and system readiness levels. The next Section looks at the assessing the whole CCS system.