The Transition to Low-Carbon Energy

The Public Ledger

Environment & Energy

Published: July 28, 2026 - 10:56

Last Updated: Never

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The transition away from fossil fuels is no longer primarily a question of whether cleaner technologies exist. The harder question is whether they can be deployed at sufficient scale while keeping energy affordable, reliable and secure.

For most of modern history, economic growth has been closely tied to fossil fuels. Coal powered industrialization. Oil transformed transportation. Natural gas became a major source of electricity and heating. Together, fossil fuels still provide the overwhelming majority of the world's energy.

Changing that system is therefore not comparable to replacing one consumer product with another. It is an attempt to rebuild the infrastructure underlying modern civilization.

The transition to low-carbon energy involves power stations, transmission lines, pipelines, mines, factories, vehicles, buildings, heating systems, industrial processes and millions of individual decisions. It also involves enormous amounts of capital and, in many countries, political choices about land use, energy prices and industrial policy.

There is substantial evidence that the transition is technically possible. The Intergovernmental Panel on Climate Change has concluded that electricity systems dominated by renewable sources are increasingly viable, while the International Energy Agency reports that renewables are expanding faster than any other major energy source in its scenarios.¹

But technical possibility is not the same thing as easy implementation.

A low-carbon energy system must answer several questions simultaneously:

• Can it provide enough energy?

• Can it provide that energy when people need it?

• Can it be built quickly enough?

• Can its materials and supply chains support expansion?

• And can consumers afford it?

Those questions make the energy transition less a contest between individual technologies and more a problem of designing an entire system.

The transition has already begun

The transformation of the electricity sector is not merely hypothetical.

The IEA's Electricity 2025 report projects that renewables and nuclear power together will meet all of the growth in global electricity demand through 2027, with renewables accounting for approximately 95 percent of that additional demand. It also projects that renewables will provide more than one-third of global electricity generation in 2025, overtaking coal.²

The change is being driven particularly strongly by solar power.

Solar photovoltaic technology has become dramatically cheaper over the past decade, while wind generation has also experienced major cost reductions. The IPCC reported that between 2015 and 2020, the cost of electricity from solar photovoltaic systems fell by 56 percent and wind by 45 percent, while battery prices fell by 64 percent.³

These trends have changed the economics of energy investment.

But electricity is only part of the problem.

A society can replace coal-fired electricity with wind and solar and still have a large fossil-fuel dependence in transportation, heating, aviation, shipping, agriculture and industrial processes.

The transition therefore increasingly depends on electrification.

Electric vehicles can replace internal-combustion engines. Heat pumps can replace many fossil-fuel heating systems. Industrial processes can increasingly use electricity directly, while hydrogen and synthetic fuels may have roles in sectors where direct electrification is difficult.

The result is a paradox: decarbonization requires reducing fossil-fuel consumption while simultaneously increasing the importance of electricity. That means the world does not simply need cleaner electricity. It needs much more electricity.

The electricity system is the foundation

The shift towards electricity changes the central challenge of the energy transition.

A fossil-fuel power plant can store its energy source on site and increase output when demand rises. Wind and solar generators operate according to weather conditions. A nuclear plant can operate for long periods at high output, while hydroelectric facilities can offer substantial flexibility where geography permits.

The challenge is therefore not simply generating enough electricity over the course of a year. It is generating and delivering enough electricity at the right time.

A wind farm producing large quantities of electricity during a period of low demand does not solve a shortage several days later when wind conditions are poor. This is why energy storage, transmission, flexible generation and demand management are so important.

A 2023 review in Nature Energy found that storage can play several different roles in deeply decarbonised electricity systems, including shifting electricity across time and reducing the need for other forms of generation and infrastructure.⁴

But batteries are not a magic solution.

Short-duration batteries are well suited to shifting electricity across hours, such as storing solar energy during the afternoon and using it in the evening. They become more complicated when the problem is a prolonged period of low wind and sunlight.

A system designed around substantial renewable generation may therefore require several forms of flexibility: batteries, pumped hydroelectric storage, transmission between regions, flexible demand, dispatchable low-carbon generation, hydrogen and potentially other technologies.

The IPCC's assessment is consistent with this. It identifies storage, transmission, smart grids, demand-side management, hydrogen and other technologies as part of the portfolio required to accommodate large renewable shares.¹

The grid may be the overlooked bottleneck

Generating clean electricity is only half the job. The electricity must also reach the people using it.

Transmission infrastructure has historically received less public attention than wind turbines, solar panels and nuclear reactors, but it may become one of the most important constraints on the transition.

Renewable resources are not distributed according to population or existing infrastructure. Areas with excellent wind resources may be far from major cities. Large solar installations may be built in regions with abundant sunlight but limited local demand.

This creates a geographic problem.

The more widely electricity can move, the more geographically diverse the system's generation can become. When one region is experiencing weak wind, another may be producing heavily. When clouds reduce solar output in one area, electricity can potentially be imported from elsewhere.

Research published in Nature Energy has found that expanding long-distance electricity transmission could increase renewable deployment while reducing the need for some other generation and storage investments. One global modelling study found that greater intercontinental renewable electricity trade could reduce cumulative power-sector carbon dioxide emissions by as much as 9.8 percent under the scenarios examined.⁵

This is not necessarily an argument for building a single global supergrid. It is an illustration of a broader principle: a low-carbon energy system can become more reliable when resources and demand are connected across larger areas.

Building that infrastructure, however, requires money, planning, land and political agreement.

Transmission lines can take years to permit and construct. Local opposition can delay projects. Governments must coordinate across jurisdictions. Existing grids must be upgraded while continuing to operate.

The energy transition is therefore partly an infrastructure transition.

Nuclear power complicates the picture

Any serious discussion of low-carbon energy must address nuclear power.

Nuclear reactors have a major advantage: they can produce large quantities of electricity without direct carbon emissions and without depending on the weather. The IPCC identifies nuclear power alongside renewable energy, hydroelectricity, carbon capture and storage, and other technologies as potential components of low-carbon electricity systems.³

Yet nuclear power has its own problems.

Large reactors can take many years to build and can experience substantial cost overruns. Financing large projects is difficult because most of the capital must be committed long before electricity sales begin.

This creates an important distinction between technological capability and economic practicality.

A reactor can be capable of producing reliable low-carbon electricity while still being an expensive way to add new generating capacity in a particular market.

Research into advanced nuclear technologies also demonstrates how dependent the economics are on construction costs, financing and the characteristics of the surrounding grid. One 2024 study of advanced nuclear deployment in a decarbonised US Eastern Interconnection found that the economic value of advanced reactors depends heavily on their capital costs and on what other technologies are available to the system.⁶

This does not mean nuclear power has no role.

It means that the debate should move beyond nuclear versus renewables.

A country with an existing nuclear fleet may reasonably choose to preserve it while rapidly expanding renewable generation. Another country may decide that new nuclear construction is too expensive or slow. A country with abundant hydroelectric resources may have little need for either large amounts of nuclear generation or enormous quantities of batteries.

There may be no single optimal energy mix.

The economics are more complicated than the price of electricity

One of the most common arguments in the energy debate is that a particular technology is “cheapest.” That statement can be misleading. The cost of generating a kilowatt-hour is only one component of the cost of an electricity system.

A solar panel produces electricity when the sun is shining. A nuclear plant can produce it continuously. A battery stores electricity but does not generate it. A transmission line may spend much of its time underutilized but become extremely valuable during periods of high demand.

Comparing the cost of individual technologies without considering these differences can therefore produce misleading conclusions.

The relevant question is not simply: “How cheaply can this power plant produce electricity?” It is:

• How cheaply can an entire electricity system provide reliable electricity while meeting its environmental objectives?

• That is a much harder calculation.

• It is also why the cost of the transition cannot be reduced to the price of solar panels or wind turbines.

A country may need to pay for new generation, transmission, storage, distribution infrastructure, electric vehicles, charging networks and building renovations simultaneously.

The benefits can also be distributed unevenly.

A household with a suitable roof may be able to install solar panels and batteries. A renter cannot necessarily make the same investment. A wealthy household may be able to purchase an electric vehicle years before a lower-income household can afford one.

Recent research in Nature Energy examining more than 500,000 US households found that solar-and-battery systems could reduce electricity costs for many households and provide valuable backup power, but also found significant disparities in access and viability.⁷

The transition therefore raises an issue that is sometimes missing from purely technological discussions:

Who pays, and who benefits?

The minerals beneath the transition

Low-carbon technologies do not eliminate resource requirements. They change them.

Solar panels require materials including silicon, aluminium and copper. Wind turbines require large quantities of steel and other materials, while some designs use rare earth elements. Batteries require minerals such as lithium, nickel, cobalt and graphite.

The IEA has identified critical minerals as one of the major vulnerabilities of the energy transition. Its Global Critical Minerals Outlook examines growing demand, geographic concentration, supply-chain bottlenecks and geopolitical risks surrounding materials needed for clean-energy technologies.⁸

This presents a genuine contradiction. A transition intended partly to reduce environmental damage can require an enormous increase in mining.

That does not make the transition pointless. It means that the environmental cost of extraction must be included in the analysis.

Mining can disrupt ecosystems, consume water and create pollution. Refining can be energy-intensive. Supply chains can also become concentrated in a small number of countries, creating strategic vulnerabilities. Recycling may reduce some of these pressures.

The IEA argues that recycling can create a secondary source of critical minerals, reduce reliance on new mines and improve supply security, although it also emphasizes that recycling cannot eliminate the need for new mining and refining capacity as demand grows.⁹

The energy transition is therefore not a movement from a resource-intensive energy system to a resource-free one. It is a movement towards a different resource system.

What about natural gas?

Natural gas occupies an uncomfortable position in the transition.

It produces substantially fewer carbon dioxide emissions at the point of combustion than coal, and gas-fired generators can often adjust their output more easily than some other forms of generation. This can make gas useful in electricity systems with large quantities of variable renewable generation.

But natural gas remains a fossil fuel.

Its climate impact is therefore not eliminated, and methane leakage during production and transportation complicates comparisons between gas and other energy sources. The IPCC notes that methane from fossil-fuel production is a significant component of global greenhouse-gas emissions.¹

The question is therefore whether gas should be considered a permanent part of a low-carbon system, a temporary bridge, or a declining source reserved for situations in which other resources cannot meet demand. There is no universal answer.

Countries with abundant hydroelectricity may have little need for gas as a balancing resource. Countries without substantial storage or transmission may rely on it for longer. Carbon capture could theoretically extend the useful life of fossil-fuel infrastructure, although the economics and practical deployment of carbon capture remain uncertain.

This is one reason why energy policy cannot simply copy a single country's strategy.

Canada presents an unusually interesting case

Canada demonstrates why national circumstances matter.

The country already has a relatively low-carbon electricity system compared with many industrialized economies, largely because of hydroelectricity and nuclear generation. But electricity demand is expected to rise significantly as transportation, buildings and industry become more electrified.

The Canada Energy Regulator's Canada’s Energy Future 2026 scenarios illustrate the scale of that change. Under its Net-Zero scenario, end-use electricity demand rises 84 percent between 2023 and 2050, with electricity becoming Canada's largest end-use energy source by 2050.¹⁰

That is a crucial distinction. Canada does not simply need to make its electricity cleaner. It needs substantially more of it.

The federal government has consequently set a goal of doubling Canada's electricity supply by 2050 and has established Clean Electricity Regulations that begin imposing emissions limits on covered fossil-fuel electricity generation in 2035.¹²

Whether these policies succeed will depend partly on whether the country can expand generation and transmission quickly enough to meet growing demand.

The federal government itself recognizes that reliability must remain central. Its modelling and policy framework identify new generation, storage and transmission as important components of a reliable electricity system.¹³

Canada therefore faces a problem that is simultaneously environmental, economic and infrastructural.

The country has a relatively strong starting position, but electrification could make its electricity system substantially larger and more important to the economy.

The strongest argument against the transition

There is a serious argument against the way the energy transition is sometimes presented. It is possible to underestimate how difficult it is to replace an energy system built over more than a century.

Governments can announce targets faster than they can build power stations. Wind and solar capacity can be installed faster than transmission infrastructure. Batteries can be deployed quickly, but their ability to address long-duration shortages is more limited. Nuclear can provide reliable low-carbon generation, but new projects can take many years and require enormous upfront investment.

The IPCC itself does not describe the transition as effortless. It states that economic, regulatory, social and operational challenges increase as renewable shares rise, and that supplying the entire energy system with renewable energy is more difficult than decarbonizing electricity alone.³

There is also a risk of focusing too heavily on electricity while neglecting the harder sectors.

A car can be electrified relatively easily compared with an intercontinental aircraft. A home can use a heat pump, but some industrial processes require extremely high temperatures or chemical feedstocks. Shipping and aviation may require alternative fuels rather than direct electrification.

The transition could therefore take longer and cost more than optimistic projections suggest. This argument deserves to be taken seriously.

But it does not establish that continuing to rely heavily on fossil fuels is a better long-term strategy. It establishes that the transition must be designed around physical and economic constraints rather than political slogans.

The case for a broader energy portfolio

The strongest evidence points towards a system in which technologies complement one another.

Solar and wind can provide large amounts of low-cost electricity where resources are favourable. Hydro can provide both generation and flexibility. Nuclear can provide firm low-carbon generation. Batteries can shift electricity across hours. Transmission can move power between regions. Demand response can alter when electricity is consumed. Hydrogen and other fuels may address sectors that are difficult to electrify directly.

The precise combination will vary.

The IPCC's assessment reflects this reality: it identifies multiple possible configurations involving variable renewables, hydroelectricity, nuclear, carbon capture, energy storage, transmission, demand management and carbon removal.¹ That diversity is a strength.

It means the energy transition does not depend on a single technology becoming perfect. It also means that political debates framed as solar versus nuclear, batteries versus gas, or renewables versus fossil fuels often obscure the actual engineering problem. Modern energy systems are networks.

The most useful question is therefore not which technology wins, but which combination can provide reliable energy at acceptable cost with sufficiently low emissions.

A transition measured in decades

The energy transition will not be completed by a single election, technological breakthrough or international agreement.

Energy infrastructure lasts for decades. A power plant built today may still be operating in 2050. A transmission corridor can shape a region's electricity system for generations. A mine developed to supply battery materials can influence industrial supply chains for decades.

That makes investment decisions unusually consequential.

The world is already moving towards a more electrified energy system. The IEA's 2025 outlook describes an emerging “Age of Electricity” in which electricity becomes increasingly central to mobility, heating, industry, data centres and other forms of economic activity.¹⁴

The challenge is making that electricity system sufficiently clean without making it unreliable or unaffordable. There is no evidence that one technology can accomplish that alone. Nor is there good evidence that the transition will be effortless. But neither is there evidence that the physical challenge is insurmountable.

The technologies needed for substantial decarbonization already exist. The more difficult task is deploying them at scale, connecting them to functioning grids, developing the necessary mineral supply chains, maintaining reliability, and distributing the costs and benefits fairly.

That is why the transition to low-carbon energy should not be understood as a race towards a single ideal energy source. It is an exercise in systems engineering at a global scale.

The countries that manage it successfully will not necessarily be those that choose the most fashionable technology. They will be those that understand the limitations of every technology, invest in infrastructure before it becomes a bottleneck, maintain reliable electricity while the system changes, and adapt their energy mix to their own geography and economy.

The future energy system will probably not be entirely solar, entirely wind, entirely nuclear, or entirely anything else. It will be a system built from many technologies working together.

The question is no longer whether the world can imagine a low-carbon energy system.

It is whether it can build one that works.

Bibliography

¹ Intergovernmental Panel on Climate Change (IPCC). (2022). Climate Change 2022: Mitigation of Climate Change — Chapter 6: Energy Systems. IPCC Sixth Assessment Report, Working Group III.

² International Energy Agency (IEA). (2025). Electricity 2025: Analysis and Forecast to 2027. Paris: IEA.

³ Intergovernmental Panel on Climate Change (IPCC). (2022). Climate Change 2022: Mitigation of Climate Change — Chapter 6: Energy Systems. IPCC Sixth Assessment Report, Working Group III.

⁴ Levin, T., Bistline, J., Sioshansi, R., et al. (2023). “Energy storage solutions to decarbonize electricity through enhanced capacity expansion modelling.” Nature Energy, 8, 1199–1208.

⁵ Guo, F., van Ruijven, B. J., Zakeri, B., et al. (2022). “Implications of intercontinental renewable electricity trade for energy systems and emissions.” Nature Energy.

⁶ Cano Renteria, E., Schwartz, J. A. & Jenkins, J. D. (2024). “Evaluating Advanced Nuclear Fission Technologies for Future Decarbonized Power Grids.” Working paper/preprint.

⁷ Howland, M. F., et al. (2026). “Climate change reshapes resource adequacy risks and optimal renewable energy siting in wind and solar energy systems.” Nature Energy.

⁸ International Energy Agency (IEA). (2024). Global Critical Minerals Outlook 2024. Paris: IEA.

⁹ International Energy Agency (IEA). (2024). Recycling of Critical Minerals. Paris: IEA.

¹⁰ Canada Energy Regulator (CER). (2026). Canada’s Energy Future 2026: Energy Supply and Demand Projections to 2050. Government of Canada.

¹¹ Canada Energy Regulator (CER). (2026). Canada’s Energy Future 2026 — Net-Zero Scenario Fact Sheet. Government of Canada.

¹² Environment and Climate Change Canada. (2024). Clean Electricity Regulations. Government of Canada.

¹³ Environment and Climate Change Canada. (2024). Clean Electricity Regulations: Maintaining Reliability. Government of Canada.

¹⁴ International Energy Agency (IEA). (2025). World Energy Outlook 2025. Paris: IEA.