Using P-DfMA to decarbonise coal-fired power stations

[edit] Introduction

Repurposing Coal is a current (late 2021) initiative led by Terra Praxis, a non-profit organisation focused on action for climate and prosperity, exploring the idea of converting coal-fired power stations to use advanced heat sources (such as Generation IV Advanced Modular reactors) to generate emissions-free, uninterrupted energy. Terra Praxis are working with Bryden Wood who are developing a Platform Approach to Design for Manufacture and Assembly (P-DfMA) approach to enable the transition at the scale necessary, in the time required. Other project partners include specialists from MIT, University at Buffalo, Microsoft and KPMG.

[edit] Context

The world is a long way from meeting the Paris Agreement goals of limiting global temperature increase to 1.5C by 2050. Current projections, even including significant expansion of renewables generation, show that fossil fuels will still make up the majority of world energy use by mid-century.

The Intergovernmental Panel on Climate Change (IPCC) says that in order to meet the limit of a 1.5C rise in global temperatures, human-generated carbon dioxide emissions must be halved by 2030 and reach net zero by 2050. To prevent the worst-case scenarios, electricity and heat production must be decarbonised.

[edit] The problem with coal

As of late 2021, more than 2,000 gigawatts (GW) of coal-fired capacity is operating. It adds c.15 billion tons of CO emissions per year. This amounts to almost half of all carbon emissions.

But most coal plants are young assets: more than half are less than 14 years old. Existing coal-fired power plants retain significant value in terms of established markets, grid connections, access to cooling water and experienced personnel necessary for the generation and distribution of power. As such, it is unlikely that countries (and companies) will simply shut down coal plants.

The purpose of the Repurposing Coal initiative is to demonstrate coal plants can also act as flexible generators, complementing renewables in support of delivering reliable, affordable and resilient electricity grids.

Installing advanced heat sources to replace the coal-fired boilers at existing coal plants will enable the continued use of existing infrastructure for emissions-free electricity generation.

[edit] A platform (P-DfMA) approach

A traditional approach to design, procure and build nuclear plants at the scale required to achieve the necessary level of carbon emission reductions faces these challenges:

• It would be too costly to be attractive to utilities companies and plant owners.
• It would be too risky because of the typical levels of cost uncertainty in nuclear projects.
• It would take too long and be too disruptive to do the required refurbishments.
• It would be too risky because of the typical levels of programme uncertainty in these types of projects.
• It would be impossible to review and approve the design to ensure the required quality for these types of highly regulated buildings.
• It would be impossible to get the required supply chain capacity for the required design, manufacture, and construction capabilities..

Repurposing Coal proposes a fundamental rethink with regards to the future of coal and how nuclear facilities are conceived, designed, procured and delivered. Instead of approaching the task as thousands of individual refurbishments, the initiative is based on a unified approach where the design is simplified and standardised in such a way that a much wider range of designers, manufacturers and contractors can participate, and the design knowledge is embedded in building systems and design tools so that everyone involved can benefit from the learning on all the other projects.

To achieve this, Repurposing Coal aims to:

• Reduce, rationalise, standardise and optimise the building and engineering systems that are needed for a refurbished plant, in order to
• Reduce, rationalise, standardise and optimise the design, approval, manufacture, assembly and operation processes, in order to
• Reduce, rationalise, standardise and optimise the interactions between the required different supply chain organisations, to realise the processes described above at the scale that is required.

Terra Praxis's business model is to use technology to connect people, organisations and resources in an interactive ecosystem in which value can be created and exchanged. To realise this ecosystem, Bryden Wood is involved in developing a technological infrastructure to provide tools and services that will facilitate the interaction of customers and suppliers to realise the required refurbishments.

Bryden Wood are also designing an engineering platform solution: a construction system that can deliver the required variety of solutions for differing requirements in different situations, but that is rationalised, standardised and optimised appropriately to enable the required simplification of all processes that make it possible for the supply chain to collaboratively deliver this built solution.

[edit] Simplification and standardisation: systems

Existing coal plants vary widely. There are very different site layouts and different levels of site conditions. Seismic conditions in particular are important, having a major impact on the design of the safety systems and therefore increasing design complexity. Existing power stations also vary in capacity, and nuclear reactor technologies also vary.

The strategy for achieving the required level of standardisation is to isolate variability:

• Six standardised seismic isolation solutions to deal with most seismic conditions.
• A standardised, customisable heat transfer system that will allow the new nuclear systems to 'plug in' to the existing coal plant infrastructure.
• A standardised cross-section design that encloses the various types of reactor technologies, while being able to expand to deal with variety in capacity.
• The non-safety related systems for different reactors have strong similarities and can be standardised across different reactor technologies.

A key driver for cost and duration of projects is the complexity of design, construction and approval process for safety related systems. Traditionally, custom-designed nuclear grade facilities enclose a mixture of safety-critical, safety-supporting and other systems. The approach here is to separate out these systems and then standardise and optimise them as much as possible.

[edit] Simplification and standardisation: process

A standardised, mass-customisable design solution would make it possible to use algorithmic design for key design tasks:

• Assessing coal plant viability for refurbishment using automatic tools
• Producing initial concepts using algorithmic design tools
• Producing detailed design outputs for manufacturing automatically

The review and approval process would be greatly simplified. Safety related and non-safety related systems are separated and simplified. The amount of information to be reviewed is significantly reduced. Standardised solutions mean that detail is available early and can be pre-approved.

The variation of the design and interfaces are standardised and controlled: only the differences need to be reviewed. Rich data representation can provide regulatory reviewers with relevant information in the appropriate format at each stage of the process. Data-rich models can generate automatic reports to demonstrate design compliance.

[edit] Enabling simplified interactions

The platform (P-DfMA) solution described above, and the simplification of processes, enable simpler and standardised interactions between customers and producers, and between the producers that make up the supply chain to deliver these buildings. This would allow Repurposing Coal to achieve the scale and speed of refurbishments that are required.

Significant amounts of the design are simpler and can be done much more quickly by a wide range of designers. The components that make up the built solution can be mass produced by existing manufacturing supply chains. Significant parts of the assembly process can be done by non-nuclear construction supply chain, much more quickly, and decoupled from the nuclear parts of the building.

This would all mean that coal plant fleet owners will have access to a relatively cost-effective, lower-risk and quick solution for replacing coal. A wide range of reactor manufacturers will have access to a significantly increased and different range of clients. Interesting investment opportunities will become available, in companies that develop and deliver the constituent parts of the overall solution. This will become an attractive proposition for communities, to keep jobs, attract other investment and create a better local environment.

[edit] Impact on carbon emissions

This approach is designed to be rolled out world-wide and to attract customers and supply chain partners to realise coal plant refurbishments in other critical locations. Fourth generation nuclear reactors will likely be available by 2027, by which time Bryden Wood aim for the platform to be sufficiently developed to realise carbon savings at significant scale by the end of this decade. Alongside deployment of renewables, the refurbishment of 2TWe of coal globally would make it possible to achieve ambitious decarbonisation targets.

This article is adapted from an article on Bryden Wood's website.

--Bryden Wood 13:30, 09 Nov 2021 (BST)

[edit] Related articles on Designing Buildings

• Coal.
• Platform approach to construction.
• Power generation.
• Renewable energy.