Path to Decarbonization (Free version)

This is the e-book version of Path to Decarbonization booklet by The Energy Consortium, IIT Madras.







ccording to a recent McKinsey study (2022), India is the third-largest emitter of CO2

coming in at 2.9 GtCO2e (4.9 percent of global emissions) which amount to about 1.8 tons

CO2e per capita (versus the United States at 14.7 and China at 7.6). These emissions will

only increase as the country is going through a growth phase in multiple manufacturing

sectors of the Indian economy. And these sectors will be consuming power which will

only add to the emissions burden.

Collective action is critical to reducing these emissions while keeping the longer goal

to reach net-zero by 2070. Forums like this are key to getting India to reach that goal.

But the pathway is not easy. There are dauting factors to consider including accelerated

innovation in technologies, reducing transition costs, mobilizing capital, reskilling the

workforce, and re-thinking the land use issue, just to name a few.

The G20 summit that concluded recently focused on key climate issues such as

the agreement to pursue tripling renewable energy capacity globally by 2030 and the

acceptance and need to phase-down unabated coal power. Like any other country India

will need technology development through R&D, economic support from private and

public sectors to deploy technologies, and enabling policy as the three pillars that must

be shored up to realize the goals to decarbonize.

As the rich collection of articles in this magazine highlights, significant technology

advances are being made through applied R&D that are helping in the decarbonizing

process. The manufacturing sector that includes cement, aluminum, and steel

industries contributes significantly to greenhouse gas emissions. The articles highlight

new and innovative ways to reduce these emissions, including process optimization

through effective models that include use of power electronics, electrification of calcined

clay in cement manufacture, waste heat recovery, energy storage, and , innovative use

of hydrogen in steel manufacturing. The articles also cover issues related to minimizing

emissions in the building sector, and policy related changes and modeling to achieve net-

zero emissions. Also addressed are innovative uses of materials such as carbon black,

and assessment of critical raw materials and their impact on the circular economy.

All these technologies have the potential to decarbonize and transform many

sectors of the economy. In terms of technology, R&D forums like the 2023 IIT Energy

Summit have the potential to highlight the most recent advances being made in solar,

wind, geothermal and other renewable sources. For India to achieve its goal, Small

Modular Reactors for nuclear deployment that the US and other countries are pursuing

must be actively investigated. And in terms of both funding and policy, India needs to

commit in a similar manner to the US , where they passed the Infrastructure Law, as

well as the Inflation Reduction Act, which in turn is spurring an unprecedented push to

decarbonize the electricity sector by 2035 and the economy by 2050.

We hope that this summit will catalyze this community and the country to speed the

path to decarbonizing the industrial and power sectors and help India meet or beat its


Bhima Sastri* PhD,

Vikram Rao PhD,

Director, US Department of Energy,

Excutive Director,

Washington DC, USA

Research Triangle Energy Consortium

* The opinions expressed in this journal are my own and do not in any way reflect the

positions taken by the US Department of Energy.



ransition to a low carbon society requires action on energy

use in multiple domains such as transportation, industries,

commercial and residential energy systems. It is also imperative

to achieve these transitions in an equitable and sustainable

manner without creating additional challenges. India’s energy

sector is currently dependent on fossil fuels and our panchamrit

goals (COP27) envisage a rapid infusion of renewables and

other measures to reduce the carbon intensity of our economy.

The challenge is to manage the transition while maintaining

affordability, accessibility, and other externalities such as urban

air quality issues. There are also issues related to high prices of

oil and PV module imports, concentration of lithium resources,

stranded assets of coal power plants and losses of the distribution

companies. These are global challenges that have a local impact,

which require innovative, cost-effective solutions and contextual

technologies such as renewable integration with storage, hybrid

energy systems, use of analytics and artificial intelligence,

cyber-physical and connected systems, green hydrogen etc. For

management of legacy and base-load systems during transition,

technologies for mitigating carbon emission such as carbon

capture and storage, underground coal gasification, renewable

natural gas (RNG) need to be developed.  

The years to come would see significant challenges as

the world transitions to newer ways of decarbonising energy

systems while ensuring adequate availability for societal needs.

Understanding transition pathways, availability of solutions and

the technology gaps is very critical to focus our attention on the

immediate needs as well as those of future. While these need

research along specific thrusts, typical applications require

interaction of multiple domains. The goal of the Energy

Consortium would be to integrate the various research

thrusts within its research hubs to benefit decarbonization

and industrial needs and we will continue to present

exciting developments from the world on the transitional

pathways from leading members of the industry and

academia. On this front, I am thrilled to see the launch of

the first edition of Path to Decarbonization by the Energy

Consortium containing glimpses of the opportunities to

reduce the carbon intensity of our infrastructure sector.

Happy reading!

Prof. Satyanarayanan Seshadri,

Head, Energy Consortium, IIT Madras

Assistant Professor, Dept. of Applied Mechanics,

IIT Madras

Editor’s Note


he Energy Consortium at IIT Madras was conceived with the

ambition of accelerating technology development and aiding

their translation, to effectively enable the global energy transition

towards low carbon sources. The aspiration was to become

the thriving ecosystem for experts from around the world to

collaborate with the demonstrated expertise in the energy domain

at IIT Madras, that had been already engaged in conducting

ground-breaking research and path defining inventions in energy

generation, storage, conversion, distribution and utilization.

Path to Decarbonization is a special issue with invited

contributions from consortium affiliated faculty, industry

founding members and knowledge partners. It showcases how our

researchers are pushing the envelope on the state-of-the-art and

devising strategies that will lead towards significant mitigation of

green-house gas emissions. And all this, while working in some of

the toughest sectors out there, those that have remained stubbornly

dauting and economically very challenging for energy transition

away from fossil fuels and more towards renewable sources of

energy. The deep technological approaches presented in all the

articles are very inspiring.

The eleven articles in this special issue have been compiled by 35

authors based in 5 countries and representing over 15 organizations.

The mixture of perspectives from academia, industry, government,

non-profits, and policy think tanks will be amply appreciated, and

it is the breadth offered by approaches - in research, technology,

innovation, product development, and policy – that will find a

positive resonance with our readers. The opening article on Net Zero

buildings sets the context starting with the modern lifestyle that has

so far in the developed world, and now more so in the developing

world, being essentially driving energy demands. We then have a set

of articles exploring how net zero can be incorporated by the hard

to abate manufacturing of Cement, Aluminium and Steel industries

and the Supply Chains therein. Following this we have articles

addressing Future Materials, Future Molecules and the Future that

is replete with Electrons and Photons – renewable energy – and

power electronics that is increasingly becoming pervasive.

It is a pleasure to release the Path to Decarbonization

at the Energy Summit 2023!

My deepest acknowledgements to all the authors

who have responded so beautifully for this call for

scientific articles on such an important topic, to the

design ideas from Srivatsan S that very aptly amplify

the essence, my co-editor, Prof Satyanarayanan

Seshadri for teaming up on this exciting initiative,

and a heartfelt thanks to the Energy Consortium

and IIT Madras for helping us realize this. I expect

this to only grow bigger at the 2024 energy summit

edition to be organized in Melbourne, Australia!

Nikhil Tambe, PhD

CEO – Energy Consortium, IIT Madras

Adjunct Professor, Dept. of Applied Mechanics,

IIT Madras

Academy Expert – India Energy Storage Alliance

Editor’s Note



Net Zero Buildings

Developing futuristic, vibrant,

net-zero infrastructure in cities

Cement Industry

Electrification of calcined clay: Path

to decarbonization of cement industry

Energy savings through

sustainability audits and process

optimization of cement plants

Supercritical Co2 power cycles

for waste heat recovery

Aluminum Industry

Aluminium industry net zero roadmap:

Challenges and opportunities

Green Steel

Green steel at scale needs synthetic

iron ore

Future Materials

The path toward zero

emission carbon materials

Future Molecules

Chemical energy carriers in energy

transition: Key role of molecules in

energy storage, transport and end-use

Supply Chains

Assessment of critical raw materials

and application of circular economy

for supply deficit minimisation in India

In search of the truth:

An analysis of recent hydrogen

supply chain evaluations

Renewable Energy

Feedforward control of grid-tied

inverters for harmonic elimination

using MSRF PLL

Copyright @IIT Madras.

All rights reserved.

This special issue may not be reproduced in its entirety without permission.





Nikhil Tambe

Srivatsan S



Francis J




J Sathya



















Ashwin Mahalingam,

Dept. of Civil Engineering, IIT Madras,

Chennai, India

Net Zero Buildings


Nearly half a billion people

live in India’s cities and towns

today. Over the next 25 years,

this number will increase

substantially. Conservative

estimates suggest that another

300 million people will move

into urbanized areas by 2047.

Many of our cities are already

bursting at their seams and are

facing considerable challenges in

delivering basic urban services.

Not everyone has access to safe

drinking water, and even fewer

are connected to wastewater

networks (nearly 60% of urban

sewage is untreated). Large

urban agglomerations generate

considerable amounts of solid

waste that municipalities

struggle to collect and safely

manage. Travel times are starting

to increase in several cities due

to traffic congestion on the roads

and the lack of reliable mass-

transit options.

The development of our

existing cities has also happened in

a haphazard manner. In contrast

to planned development where

infrastructure services precede

the development of residences,

commercial and industrial

facilities; low land costs have

led to development outpacing

the delivery of infrastructure in

the periphery of cities leading

to the phenomenon of urban

sprawl in many Indian cities.

Such development has several

environmental and social

consequences and has resulted

in the loss of agricultural land,

open green spaces and water

bodies. Furthermore, several of

our cities are characterized by the

rise of informal settlements and

encroachment of water bodies,

especially among low-income

residents. All of this decreases the

resilience of cities to withstand

shocks and stresses and leads to

cities becoming prone to disasters

such as flooding and places

an ever-increasing burden on

municipalities to deliver water,

transport and other services. How

do we fix our cities? How will we

simultaneously cater to a massive

increase in the population of cities

over the next 25 years? These are

key questions to ponder.

One of the challenges that

India’s urban settlements have

faced stems from a fragmentation

in the governance framework

for urban management. While

cities such as Paris and London

have elected Mayors who are

vested with powers to coordinate

services across the city, our

municipal governments are

not vested with sufficient

responsibilities or resources

– both human and financial.

Decision making is in the hands

of multiple authorities. Take

for instance the management of

water resources in the city of

Chennai. Various responsibilities

pertaining to water sources,

distribution and management

are divided between multiple

agencies such as the Public

Works Department, the Chennai

Metrowater Sewerage and

Sanitation Board, The Chennai

Metropolitan Development

Authority, the Greater Chennai

Corporation, and the Chennai

River Restoration Trust to name

a few. This scenario persists in

other sectors and in other cities

as well. Policies for each of

these agencies are often made

independently, coordinating

these policies is extremely

challenging and the result is

often policy incoherence leading

to haphazard growth.

Further, our planning

processes are often outdated

and assume predictable growth

in cities. Masterplans are often

reduced to zoning plans which

do not take into consideration

the nature of cities as dynamic,

complex systems. We lack a

scientific understanding of

critical parameters of our cities

– trends in land-use and density

changes, the hydrology of cities

and so on. In some cases, the data

for scientifically understanding

the state and evolution of cities is

not available, while in other cases

the data is dispersed and hard

to aggregate. As a result, while

several cities across the world

have used Urban Simulation

models and other sophisticated

methods to understand and

plan for urban growth, these

techniques are at a very nascent

stage of adoption in India.

We lack a scientific

understanding of critical

parameters of our cities

– trends in land-use

and density changes, the

hydrology of cities and so on.

In some cases, the data for

scientifically understanding the

state and evolution of cities

is not available, while in other

cases the data is dispersed

and hard to aggregate


How do we then approach

this problem? First we have to

rethink our urbanization strategy.

Currently India is in the process

of expanding the boundaries

of many of its cities and is

creating mega-cities. Alternate

options to explore are whether

we can create and strengthen

smaller agglomerations. Can

we make Tier 2 and Tier 3 cities

more attractive destinations

for urban expansion? Can we

develop satellite towns and cities

or industrial townships that

can decrease the requirements

for travel? Should we consider

building new towns altogether and

if so where would we situate them

in relation to existing cities? How

would we motivate investment in

physical and social infrastructure

in these towns in order to entice

communities to form?

Second, we need to think

through how we would design

these cities. What spatial and

technological choices would

we make? For instance, would

we increase urban density by

building vertically in our cities.

If so, how would we deal with

associated challenges such as

the quantum of solid and liquid

waste that would be generated,

the need for parking and so on?

Can we consider decentralizing

these functions through smaller

scale infrastructure such as

decentralized water supply and

treatment plants. Can innovative

technologies be developed in this

area? Can a new-urbanism style

philosophy be applied to urban

design to ensure mixed-use

development leading to reduced

transportation requirements and

congestion. These and a number

of similar issues need to be

thought through.

Third, we will need to relook

at the business and economic

models that underly the growth

of cities. Land economics often

dictates urbanization and low

land prices at the periphery

lead to urban sprawl. Can

mechanisms such as transferable

development rights (TDRs) lead

to more even urban development?

For long governments have been

the primary providers of urban

services. What role can Public

Private Partnerships (PPPs) play

in providing urban services?

PPPs have been extensively used

for developing infrastructure

such as national highways but

their role in developing cities

remains nascent. What PPP

models are likely to work best

for urban infrastructure? What

India ranks #2 in the world on urbanization & 

within coming decade will have 590 million people 

staying in urban areas (over half of its population)

Autonomous vehicles more likely in countries like India

Can help traffic decongestion but 

significantly under served

Resource Starved: Only 138 police 

for 100k population makes India 5th

lowest amongst 71 countries [1]

Resource Starved: No data on how 

many ambulances run on Indian roads. 

Complex large scale operations 

demand automation & technology

Biggest challenge is lack of drivers 

as many are lost to urbanization. 

Driver salary constitutes 2nd largest 

cash outflow for a farmer [2]

Transportation Segments Facing Challenges


[1] “India's ratio of 138 police personnel per lakh of

population fifth lowest among 71 countries”, 13 Jul 2018

[2] Based on previous self study conducted by Nikhil

Tambe on this subject. Icons obtained from open source

Ministry of Transportation, Govt. of India has a pivotal role to play!

Source: Nikhil Tambe



other innovative business models

can entrepreneurs come up with

to decongest cities.

To make the cities of

tomorrow function better, we

need to promote policy coherence

(policymakers), develop a better

scientific understanding of how

cities work (academics from the

technological and social sciences)

and develop new technologies

and business models for how to

deliver better services in cities

(entrepreneurs). We therefore

need policymakers, academics

and entrepreneurs to join hands

to build more vibrant cities.

One specific area that

needs attention in this regard

is the way in which we design

and build facilities going

forward to minimize our

environmental footprint. The

process of constructing and

operating buildings is one of

the chief drivers of greenhouse

gas emissions and requires a

systematic re-think in the urban

context. It is to this that we now

turn to in the rest of this article.



hile estimates vary, there is no doubt that India will have to augment its built environment

stock – housing, infrastructure and so on - considerably over the next few decades. Just looking

at urban areas, the Mckinsey Global Institute predicted a USD 1.2 Trillion spend by 2030 and

suggested that we need to build ‘a new Chicago every year’1. What would happen if we undertook

this development in a ‘Business as Usual’ fashion? For one, our projects would be heavily delayed

and over budget. A joint study by the Project Management Institute and KPMG pointed out that 89%

of construction projects across sectors do not meet their scheduled completion date, often exceeding

expected durations by 79%. 69% of projects exceed their budgets by a factor of 2.5x on average2!

This is not all. Earlier, projects were benchmarked primarily on time and cost performance.

This should (and often is) no longer (be) the case. Projects are meant to create social, economic and/

or environmental value. Delays or overruns that result in value creation must be acceptable in the

context of India’s growth. Emphasis therefore needs to be paid to factors such as quality, resilience,

sustainability, and safety. Sadly, the scorecard appears grim here as well. The quality of construction is

often so poor that maintenance costs exceed the capability of users – particularly low-income residents

– to pay. It is also very well known that buildings and the built environment contribute significantly to

global carbon emissions, both in terms of the energy they consume during operation, and the energy

required to produce raw materials that are used in construction. In a simulation-based study at IIT-

Madras, we estimated that if the population of the city of Chennai alone grows at a rate of 3%, carbon

emissions due to the building stock that will need to be built and operated to account for this population

may account for 230 Million tons of CO2 by 2042, if conventional techniques are used! This does not

include the consequent augmentation of infrastructure, and Chennai is merely one out of several

cities in India that are likely to experience rapid growth over the next 2 decades. The environmental

consequences of unfettered building could be disastrous!3

All of this indicates that we need to radically change the way infrastructure and housing projects are

conceptualized, built and used. Luckily, it is not all doom and gloom. Several solutions are available.

First, we can choose our construction materials more carefully. Different materials have different

levels of embodied energy and there are alternative materials available that provide the same structural

performance, with lower levels of embodied energy. Take for instance regular cement-based concrete

versus, fly-ash based substitutes. Furthermore, there exists considerable scope to reuse construction

materials, particularly construction and demolition waste as aggregates.

Second, we should rethink our existing construction processes. To combat time and cost overruns, a

number of ‘Rapid Construction Technologies’ have been developed and proven in India. Several of them

have been endorsed by the BMTPC4 and guidelines for construction as well as schedules of rates are

available. Many of these rely on principles of prefabrication and assembling at site which reduces project

duration and improves the quality of construction.



Third, our project management systems are archaic, and often non-existent. While digital

technologies have made significant advances in many fields, the adoption of such technologies in the

construction industry is still in its nascent stages. Tools such as Building Information Modeling (BIM) or

Digital Twins that are becoming commonplace internationally, and which allow us to ‘Virtually Design

and Construct’ need to be adopted to ensure that we monitor projects in a more professional fashion.

Complementary project management paradigms such as Lean construction can also be adopted to ensure

time, cost, safety and quality compliance.

Fourth, buildings need to be designed both actively and passively to reduce their energy loads during

operation and more renewable forms of energy need to be deployed to meet these operational needs.

While all these technologies and systems exist, why are they not being adopted? The construction

industry is a notoriously slow adopter of innovation worldwide due to its deeply fragmented nature where

large numbers of highly specialized firms need to come together to execute a project. Several attempts

at vertical integration at the level of the firm have met with failure, primarily due to the cyclical nature

of demand in this industry. Since innovation propagates slowly, supply chains are often underdeveloped

leading to a cost disadvantage in comparison with conventional methods. Take for example the Glass Fibre

Reinforced Gypsum (GFRG) panel technology championed by IIT-Madras. Low demand led to high supply

side costs as manufacturers faced little competition and were also not achieving economies of scale as

their factories were not manufacturing these panels at full capacity. Workers did not see value in skilling

themselves on this technology, leading to a shortage of labour and high manpower costs, all of which

negated the advantages of high quality, prefabricated materials. Given that our procurement systems work

on a ‘lowest cost’ basis, this technology has not proven to be competitive and has remained in pilot stage!

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