Sector-by-Sector Blueprint: How to Phase Out Fossil Fuels
- Eric Anders
- Apr 24
- 32 min read
Introduction: Beyond Renewables—The Sector-by-Sector Imperative for Nuclear and Clean Fuels
In a recent public exchange with renowned environmental advocate Bill McKibben, captured in my blog post, "Dear Bill McKibben: Earthrise, Climate Truth, and the Nuclear Gap," we engaged in a respectful but critical debate about the limitations of a renewables-only strategy for combating climate change. McKibben, an influential voice in the environmental movement, maintains optimism about the potential of wind, solar, and battery storage to comprehensively decarbonize the global economy. While sharing the fundamental goal of rapid and deep decarbonization, I argued that this renewables-only vision, despite its popularity and moral appeal, is fundamentally at odds with the physical, technological, and geopolitical realities we face today.
This essay dives deeper into that argument by examining sector-by-sector the world's major energy-consuming activities—from heavy industry and transportation to agriculture and buildings—and evaluating whether renewables alone can realistically replace fossil fuels in each case. As we explore these sectors, it becomes increasingly evident that the intermittency and variability of renewable sources, their significant land and resource footprints, and their inherent limitations in providing continuous, high-density energy render them insufficient as standalone solutions.
At Earthrise Accord, we advocate that a comprehensive climate justice strategy must recognize and integrate the profound potential of nuclear power and hydrogen-based clean fuels. Nuclear energy uniquely offers a firm, reliable source of zero-carbon electricity and high-temperature heat, essential for many industrial processes and robust grid operation. Meanwhile, hydrogen and nuclear-powered direct air capture synthetic fuels (NucDACSF) offer practical pathways for decarbonizing difficult-to-electrify sectors such as aviation, shipping, and steelmaking.
In the following detailed sectoral analysis, we demonstrate that fully decarbonizing the global economy within the narrow timeline required by climate science cannot be achieved through renewables alone. Rather, a clear-eyed approach demands embracing nuclear energy, expanding clean hydrogen infrastructure, and scaling synthetic fuel technologies. Recognizing these truths is not a retreat from environmental goals but a bold step toward achieving true climate justice, sustainability, and energy security for generations to come.
Industry (Manufacturing, Steel, Cement, Chemicals)
Emissions Profile & Fossil Dependency: Industry is responsible for about 24% of global GHG emissions (2019) directly (Global Greenhouse Gas Overview | US EPA), primarily from burning coal, oil, and gas on-site for heat and power. Heavy industries like steel and cement are major contributors – the steel sector alone accounts for ~7–8% of CO₂ emissions and cement for ~7% (IEA report lays out strategy for zero emission steel and cement). Industrial processes often inherently produce CO₂ (e.g. cement releases CO₂ from limestone calcination), and the sector’s energy needs are immense and continuous. Today, most high-temperature heat in industry comes from fossil fuels (e.g. coal-fired blast furnaces for steel, natural gas kilns for cement, steam crackers in petrochemicals), making the sector deeply fossil-dependent.
Challenges & Limits of a Renewables-Only Approach: Many industrial processes require temperatures above 800°C and 24/7 operation. Intermittent renewables like solar and wind struggle to provide firm, high-grade heat on demand. Facilities cannot simply shut down when the sun sets – a blast furnace or cement kiln needs constant energy. Massive electric furnaces or heat pumps could replace some combustion, but relying on variable renewable electricity would require prohibitively large energy storage or excess capacity to guarantee reliability. Moreover, some processes need a chemical reducing agent (carbon in the form of coke in steelmaking, or gas as feedstock in chemicals). A purely renewables-electric route would need vast battery banks or hydrogen storage to buffer intermittency, with significant efficiency losses and material use (for example, storing enough energy to run a steel mill through a wind lull could entail enormous battery packs with their own ecological footprint in mining and disposal). In short, renewable energy alone often cannot easily deliver the continuous, high-density energy and chemical feedstocks that heavy industry demands.
Decarbonization Pathways: Multiple technological routes must be combined to fully remove fossil fuels from industry:
Electrification of Heat and Processes: Wherever possible, switch to electric furnaces, boilers, and mechanical heat pumps powered by clean electricity. For example, electric arc furnaces (EAFs) can recycle scrap steel using electricity instead of coal, and are already widely used. Advanced electro-thermal technologies (microwave, induction, plasma) can provide process heat for certain applications if powered by a carbon-free grid. This requires a massive expansion of clean electricity supply (with nuclear providing firm power to keep these processes running consistently).
Clean Hydrogen for High-Temperature Heat & Feedstock: Hydrogen can replace fossil fuels in many industrial roles. In steel production, green hydrogen (produced via electrolysis with low-carbon power) enables direct reduction of iron ore, avoiding coal-based blast furnaces. This technology, already demonstrated in Sweden’s HYBRIT project, produces steel with water vapor as the byproduct. Hydrogen (or hydrogen-derived fuels like ammonia) can also fuel high-temperature furnaces and kilns in cement, glass, and ceramics, providing combustion heat without CO₂. In the chemical industry, clean hydrogen can substitute for natural gas as a feedstock – for example, ammonia (for fertilizers) made from water electrolysis hydrogen instead of methane, and synthetic hydrocarbons (plastics, methanol) made by combining clean H₂ with captured CO₂, rather than refining petroleum. These shifts cut off the fossil carbon input to chemical processes.
Nuclear Heat and Power: Nuclear energy can directly supply heat and electricity for industry around the clock. High-temperature reactors (including advanced modular reactors) are being designed to deliver process heat >700°C, suitable for hydrogen production or industrial steam. Co-locating small modular reactors (SMRs) with industrial facilities could provide a steady heat supply and power for electrolysis, free of carbon. For instance, an SMR could provide the steam and electricity for a chemical plant or oil refinery retrofit, eliminating the need to burn fossil fuels on-site. Nuclear’s reliability is crucial – a typical nuclear plant runs >92% of the time at full power, a capacity factor unmatched by any other source (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy), which makes it uniquely capable of meeting continuous industrial energy demand. In a net-zero scenario, every zero-carbon power source is needed: the IEA estimates ~530 million tonnes of low-carbon hydrogen may be required annually by 2050, a scale “impossible to attain” without using all clean generation including nuclear (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy) (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy).
Carbon Capture for Process Emissions: Certain industrial CO₂ sources are chemically inherent and will persist even with clean energy. The prime example is cement manufacturing – decarbonizing cement “poses one of the most difficult challenges” because ~50% of its CO₂ comes from the calcination reaction in making clinker (). Here, carbon capture is indispensable: capturing CO₂ from cement kiln exhaust (and potentially even directly from the clinker cooling process) can achieve deep emissions cuts () (). Captured CO₂ can be permanently stored underground (geological sequestration) or utilized (for example, combined with hydrogen to produce synthetic fuels or aggregates). Similarly, steel plants that still use blast furnaces could employ CCS on their furnace exhaust as an interim step. Nuclear power can assist by providing energy for carbon capture systems (which often require heat and power) and by enabling direct air capture for any residual emissions that are otherwise hard to eliminate.
Infrastructure & Policy Needs: Industrial decarbonization demands coordinated infrastructure build-out and strong policies. Key needs include: expanding clean electricity grids (with transmission to industrial sites) and establishing hydrogen production hubs with pipeline networks to supply factories. Investments in CO₂ transport and storage infrastructure (shared CO₂ pipelines and storage sites) are essential to scale up carbon capture in industries like cement. Governments should implement policies like carbon pricing or industrial carbon taxes (to make low-carbon processes cost-competitive), carbon border adjustment mechanisms (to prevent offshoring of emissions and incentivize cleaner production globally), and procurement rules that favor green steel, cement, and chemicals (creating market demand for low-carbon products). Funding for R&D and pilot projects is also critical – e.g. demonstration of SMRs for industrial heat, or large-scale hydrogen reduction steel mills. In summary, a mix of firm clean energy (nuclear), new fuel production (hydrogen), and carbon capture will enable industry to shed fossil fuels. Relying on renewables alone in this sector would leave critical gaps – continuous reactors and hydrogen systems are needed to ensure the smokestacks of heavy industry stop burning coal and gas for good.
Transportation (Road, Freight, Aviation, Shipping, Rail)
Emissions Profile & Fossil Dependency: The transport sector accounts for roughly 15% of global GHG emissions (Global Greenhouse Gas Overview | US EPA) and remains overwhelmingly dependent on petroleum. Indeed, “almost all (95%) of the world’s transportation energy comes from petroleum-based fuels” (gasoline, diesel, jet fuel, marine fuel) (Global Greenhouse Gas Overview | US EPA). Road vehicles (cars, trucks, buses) are the largest sub-sector, responsible for ~12% of global emissions (Sector by sector: where do global greenhouse gas emissions come from? - Our World in Data). Aviation contributes about 2%–3% (and rising) and shipping about 1.7% (Sector by sector: where do global greenhouse gas emissions come from? - Our World in Data). Rail and others make up the rest. This sector’s fossil fuel lock-in is evident in the ubiquitous internal combustion engine – billions of vehicles and engines designed for gasoline, diesel, or kerosene.
Challenges & Limits of a Renewables-Only Approach: While light-duty transportation can be electrified relatively easily, heavy and long-distance transport is much harder to electrify. Battery-electric vehicles face weight and range limitations that are especially problematic for heavy trucks, ships, and airplanes. For example, an analysis of long-haul trucking found that achieving 600+ km range with current batteries would add “thousands of kilos” of battery weight – potentially making the battery as heavy as the truck’s cargo payload, which is “not really feasible” (Challenge of batteries for heavy-duty EVs - E-Mobility Engineering). In aviation, batteries are far too heavy and energy-poor for anything beyond small short-range planes – today’s lithium batteries store only ~0.25% of the energy per kg that jet fuel contains, making electric flight impractical for large aircraft. As one assessment notes: “Batteries, while successful in powering smaller aircraft, remain too heavy and energy-limited for commercial jet aviation”, so fully hydrogen or synthetic fuel is the only long-term solution for flying (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). Shipping faces similar issues: an ocean freighter on a multi-week voyage cannot carry a battery the size of a cargo hold; the energy density of fuel is hard to beat for ships.
Even for modes that can be electrified, a renewables-only strategy has pitfalls. Converting all cars and trucks to electric will vastly increase demand on the power grid – if that grid is dominated by intermittent wind/solar, meeting peak charging loads (e.g. charging millions of vehicles overnight or during a wind lull) could be challenging without huge storage buffers. Likewise, producing clean fuels (like hydrogen or ammonia) for transport via renewables requires continuous large-scale electricity supply. Intermittency is a major concern: fueling and transportation needs are year-round and cannot wait on the weather. A synthetic fuels plant or hydrogen electrolyzer cannot economically sit idle half the time due to lack of sun – it needs either massive energy storage or a steady power input. In practice, trying to produce all transport fuels with only variable renewables would entail immense overbuilding of capacity (to cover downtime) and/or giga-scale battery or hydrogen storage to buffer fluctuations, with significant land and material requirements. The land-use impact is non-trivial: powering thousands of terawatt-hours of transport with only wind/solar would require vast swaths of land for turbines and panels, plus mining for battery materials for buffering. Biofuels – another renewable option – are limited by land as well: converting a significant share of global transport to biofuels would compete with food production and ecosystems. Thus, a purely renewables-based approach in transport risks being infeasible for the hardest segments (aviation, shipping, long-haul trucking) due to energy density and reliability constraints.
Decarbonization Pathways: A combination of electrification, clean fuels (hydrogen, ammonia, synthetic fuels), and efficiency will eliminate fossil fuels from transport:
Electric Vehicles (EVs) for Road Transport: Electrifying road transport is a cornerstone. Battery-electric cars, SUVs, and buses have zero tailpipe emissions and can be charged by clean power. Many countries are already mandating a phase-out of new gasoline/diesel cars by the 2030s. For light vehicles and urban buses, EVs provide a direct replacement, with the bonus of higher efficiency (electric drivetrains can be ~3× more efficient than combustion engines). However, ensuring these EVs are truly zero-carbon means decarbonizing the electricity supply that charges them – which underscores the need for firm low-carbon power (nuclear, hydro, etc.) especially during peak demand. Infrastructure: Widespread EV adoption requires robust charging networks (fast chargers along highways, residential chargers, etc.) and grid upgrades to handle the load. Policies like EV purchase incentives, fuel economy/CO₂ standards, and investment in charging infrastructure are helping accelerate this transition.
Hydrogen Fuel Cells and Clean Combustion for Heavy-Duty Road Freight: For heavy trucks and long-haul freight where batteries may be impractical due to weight or range constraints, hydrogen offers a promising alternative to diesel. Fuel cell electric trucks can convert hydrogen to electricity on-board, emitting only water. Several companies are piloting hydrogen trucks, and fueling stations for hydrogen are being planned on major freight corridors. Alternatively, hydrogen or ammonia can be combusted in modified engines for trucks or heavy machinery. Clean hydrogen thus provides an energy-dense, refillable fuel for applications where charging a huge battery is unworkable. Infrastructure: This pathway needs a network of hydrogen production (ideally from electrolysis powered by nuclear/renewables, or from natural gas with CCS) and refueling stations for trucks. Government policies can support this by funding hydrogen hubs and setting fleet purchase mandates or incentives for fuel-cell trucks, as well as R&D in improving fuel cell durability and hydrogen storage.
Decarbonizing Aviation: Aviation is one of the toughest sectors to decarbonize and cannot be directly electrified with current technology. Here, synthetic fuels and hydrogen are key. In the near term, carbon-neutral synthetic jet fuels (also known as electrofuels or e-fuels) offer a drop-in solution. These fuels are made by combining clean hydrogen with CO₂ (captured from air or industrial sources) to produce liquid hydrocarbons that are chemically similar to kerosene. They can be used in today’s jet engines and infrastructure without modification. This is a crucial bridging strategy: “Synthetic fuels, produced by combining hydrogen and captured CO₂, can seamlessly replace conventional jet fuel without requiring costly changes to existing aircraft or fueling infrastructure,” allowing immediate emissions reductions (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). Several plants (e.g. in Norway and Germany) are beginning to produce synthetic jet fuel using renewable electricity; scaling them up is the next challenge. Nuclear-powered Direct Air Capture Synthetic Fuels (NDACSF): To meet aviation demand at scale, nuclear energy can play a pivotal role. A recent analysis highlights that shifting synthetic fuel production to a nuclear-powered model could greatly enhance scalability (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). In this concept, nuclear reactors provide the continuous electricity and heat to run direct air capture of CO₂ and to generate the massive hydrogen volumes needed, sidestepping the intermittency of renewables. In fact, “renewable energy alone is insufficient to power large-scale DAC-to-fuel systems due to intermittency and energy-density limitations,” whereas nuclear can run the process 24/7 (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). This ensures the CO₂ used for fuel is actively pulled from the air (achieving true carbon-neutral fuel). Over the longer term (post-2040), hydrogen-powered aviation may become viable – hydrogen fuel cell or combustion turbines in aircraft are being researched (prototype hydrogen passenger planes are expected in the 2030s). But hydrogen planes will require new aircraft designs and infrastructure (cryogenic hydrogen storage at airports, etc.), and widespread adoption may not occur until mid-century (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF) (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). Thus, for the next couple of decades, synthetic drop-in fuels are indispensable to cut aviation CO₂ (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF) while we also pursue efficiency improvements (better aerodynamics, air traffic management) and limit demand growth (e.g. via high-speed rail alternatives for short flights where applicable).
Decarbonizing Shipping: For maritime shipping, the leading solutions are ammonia and other hydrogen-derived fuels. Ammonia (NH₃) contains no carbon; it can be made from green hydrogen and used in modified ship engines or fuel cells, releasing only nitrogen and water. Major shipping firms are testing ammonia-fueled ships, and the International Maritime Organization is pushing for zero-emission vessels. Another approach is methanol made from green H₂ and captured CO₂ (already, some new container ships are being built to run on methanol). These fuels can replace heavy fuel oil in ships with relatively minor engine modifications. Wind-assisted propulsion (retrofits like rotor sails) can also augment fuel savings but won’t eliminate fossil use alone. Infrastructure: Ports worldwide will need to provide new fuels (ammonia, methanol, or hydrogen) – requiring bunkering infrastructure and safety protocols. Nuclear power can facilitate the production of these fuels by providing reliable energy for hydrogen production at ports or fuel plants. (In theory, nuclear reactors could even directly power ships – nuclear propulsion exists in naval vessels – but for civilian shipping the focus is on clean fuels rather than on-board reactors.) Policy measures such as global maritime fuel standards, port fuel switching incentives, and R&D support for ammonia engines will hasten the transition.
Rail and Other Transport: Rail is relatively easier to decarbonize – many rail networks are already electrified (especially passenger rail in Europe/Asia). Expanding electrification of rail lines allows trains to run on clean grid power (again underscoring the need for a clean, reliable grid). For rail lines where electrification is not economical (some freight lines), hydrogen locomotives or battery-electric trains can be used as alternatives to diesel. Meanwhile, ancillary transport like pipelines (used to move oil/gas) will diminish as fossil fuels are phased out, and any remaining pipeline energy use (pumping) can be electrified.
Infrastructure & Policy Needs: Transforming transport requires massive infrastructure changes and supportive policies. On infrastructure, a priority is building charging and refueling networks: electric charging stations for vehicles; hydrogen fueling stations for trucks and buses; port facilities for ammonia/hydrogen bunkering; and CO₂ transport links for synthetic fuel plants (to source CO₂ for recycling or send it to storage). Electrical grids must be reinforced to handle EV charging and possibly electrified highways or rail. Another infrastructural element is battery recycling facilities to handle end-of-life EV batteries sustainably, and hydrogen pipelines or storage caverns to distribute hydrogen efficiently.
Policy will play a critical role in accelerating adoption. Standards and mandates can drive change – e.g. zero-emission vehicle (ZEV) mandates for automakers, fuel economy standards that effectively require electrics, mandates for a certain percentage of airline fuel to be sustainable aviation fuel (as planned in the EU), or international agreements capping shipping emissions. Carbon pricing or fuel taxes that account for CO₂ could tilt economics in favor of electric and hydrogen fuels (for instance, making diesel more expensive relative to green ammonia for ships). Governments can also subsidize the early deployment of expensive technologies (like underwriting the cost difference for early synthetic fuel or hydrogen use). Investment in R&D remains important too – better batteries (with higher energy density), more efficient fuel cells, and lower-cost electrolyzers will all help. Crucially, decarbonizing transport also calls for sector coupling with power: a clean, nuclear- and renewable-based grid to charge EVs and produce hydrogen is the foundation. A holistic plan ensures that as millions of vehicles plug in or tons of hydrogen fuel are produced, the upstream energy is carbon-free and reliably available. In summary, a mix of electrification (for efficiency) and clean fuels (for energy-dense storage) will replace oil in transport. A strategy relying only on intermittent renewables would struggle to fuel a 24/7 global transport system – by integrating nuclear and hydrogen, we gain the firm energy and fuel needed to keep the world moving without carbon.
Buildings (Residential & Commercial)
Emissions Profile & Fossil Dependency: Buildings (residential homes and commercial buildings) directly emit about 6% of global GHGs (on-site combustion) (Global Greenhouse Gas Overview | US EPA), primarily from burning fuels for heating, cooking, and hot water. When including the electricity used in buildings (which is counted under the power sector), buildings account for ~16% of global emissions (Global Greenhouse Gas Overview | US EPA). Fossil fuels are common in building energy: natural gas or fuel oil furnaces for space heating, gas water heaters, propane stoves, kerosene heaters, etc. In colder countries, space and water heating can constitute a large share of energy use – and is often dominated by gas. For example, in the U.S. and EU, a majority of households use natural gas for heating. In developing regions, there’s a mix: some use gas or kerosene, while others still rely on traditional biomass (which has its own environmental and health issues). Overall, the building sector’s fossil dependency is evident in our boilers, furnaces, and cookstoves.
Challenges & Limits of a Renewables-Only Approach: On the surface, buildings are one of the easier sectors to decarbonize – technologies like electric heat pumps and induction stoves already exist to replace fossil appliances. However, a renewables-only strategy for buildings faces two main challenges: (1) Seasonal and peak demand timing, and (2) retrofit practicality. The highest heating demand often occurs during winter nights or cold spells when solar generation is minimal and heat demand spikes. Wind power is also uncertain – for instance, prolonged winter high-pressure systems can cause “dunkelflaute” conditions (dark, still weather) with low renewable output just when heating needs are extreme. If the grid were 100% wind/solar, meeting a multi-day winter cold snap with all-electric heating would require enormous energy storage or an oversupply of generation capacity to charge that storage in advance. Batteries sufficient to power entire cities’ heating for days would be massively expensive and resource-intensive to build (and still might run out in an extended lull). In contrast, firm generation (like nuclear or geothermal) can run steadily through a polar vortex or storm. In addition, without fossil gas as backup, there’s less flexibility if generation falls short – brownouts during a freeze could be life-threatening. Thus, relying only on variable renewables to electrify heating could compromise reliability or demand huge investments in grid storage and redundancy. (The Texas winter blackout of 2021, for example, illustrated how loss of generation during extreme cold can cripple heating; a diversified supply including resilient nuclear plants can help prevent such crises.)
The second challenge is that not all existing buildings can easily be converted in short order. Millions of buildings would need electrical upgrades to support high-power electric heating, and some old or poorly insulated buildings might struggle to keep warm with heat pumps alone in very cold weather without additional upgrades. A strategy that excludes any firm energy option might resort to retaining some fossil backup (undercutting climate goals) or oversizing everything in the electric system. Hence, while renewables are excellent for supplying low-cost electricity when available, excluding firm low-carbon power in a buildings scenario could lead to reliability problems and higher costs, especially in regions with harsh winters or limited land for renewables.
Decarbonization Pathways: The building sector can be decarbonized through electrification, efficiency, and clean fuels for the hardest cases:
Electric Heat Pumps for Heating and Cooling: Replacing fossil-fuel heaters with electric heat pumps is the linchpin solution for buildings. Heat pumps (which move heat instead of generating it) are extremely efficient – often 3-4 times more efficient than resistive electric heating – and can provide both heating and air conditioning. Modern cold-climate heat pumps can work even in sub-freezing temperatures, drastically cutting or eliminating the need for gas furnaces. Switching to heat pumps directly reduces emissions if the electricity is clean. As such, the building decarbonization playbook starts with aggressive deployment of heat pump systems for space heating, water heating, and even clothes drying. Infrastructure: This requires training contractors to install and service heat pumps at scale, and upgrading electrical panels in older homes if needed to handle the new load. Policymakers are implementing incentives and building codes to accelerate this; for instance, some jurisdictions ban gas hookups in new buildings, effectively mandating all-electric new construction.
Efficient Electric Appliances: Alongside heating, all other building services should be electrified with high-efficiency devices. Gas stoves can be replaced with electric induction cooktops (which heat faster and avoid indoor air pollution from burning gas). Gas water heaters can be replaced with heat pump water heaters or electric models. Fireplaces burning oil or wood can be replaced with electric heaters. In commercial buildings, gas-fired boilers for space heat or hot water should be replaced with large heat pumps or electric boilers. Efficiency upgrades such as LED lighting (already well underway), smart thermostats, better insulation, and efficient windows reduce the overall energy demand, making it easier for clean electricity to supply 100% of needs. Every bit of efficiency gained reduces the strain on the energy supply during peak times.
District Heating and Thermal Networks: In dense urban areas or cold regions, upgrading individual buildings can be supplemented by district heating systems. These systems distribute hot water or steam from a central plant to many buildings. Decarbonizing district heat can be done by using nuclear reactors, large geothermal installations, or central heat pumps. For example, small modular reactors could be dedicated to co-generating electricity and heat for cities – the reactor’s waste heat can feed a hot water loop to buildings, replacing gas boilers in each building. Alternatively, surplus renewable electricity in summer could charge large thermal storage (like heating a huge water tank or underground thermal energy storage) that is then used in winter – essentially shifting energy across seasons. District heating powered by clean sources is a way to efficiently decarbonize buildings at scale, especially where legacy steam systems exist (e.g. parts of Europe).
Clean Fuels for Legacy Uses: A small subset of building energy use might be hard to electrify or change, such as certain industrial heating in commercial buildings, heritage buildings that cannot be easily retrofitted, or backup generators. For these, clean fuels like renewable gas or hydrogen can play a role. Biogas (from waste) or synthetic methane could be injected into existing gas grids in limited amounts to supply buildings that remain on gas, albeit this is a niche solution due to limited biogas potential. Another option being explored is blending hydrogen into natural gas networks (e.g. adding 10-20% hydrogen) to lower the carbon content of fuel used in homes – though ultimately a full switch to hydrogen for home heating is less efficient than using that hydrogen to run a heat pump electrically. Generally, the goal is to minimize reliance on combustion in buildings, but clean drop-in fuels can provide transitional solutions or cater to the few end uses that are impractical to convert.
Infrastructure & Policy Needs: Decarbonizing buildings necessitates a mix of market incentives, building codes, and planning for peak electricity supply. On the infrastructure side, nations will need to produce and distribute a lot more electricity in winter – implying investments not only in generation (nuclear plants, renewables, etc.) but also in grid infrastructure (transmission and distribution upgrades to handle electrified heating loads). Strengthening grid reliability is crucial if heating is fully electric; this could include adding energy storage, demand response systems (where thermostats can temporarily reduce heating to shave peak loads), and maintaining some reserve generation that can kick in during extreme peaks (which could be clean hydrogen turbines or long-duration storage systems). Building-level upgrades (like insulation retrofits) are infrastructure of a sort too – large-scale programs to insulate and weatherize homes will reduce the needed energy and improve comfort.
Policymakers are increasingly pushing measures such as strict building energy codes (requiring new buildings to be ultra-efficient and all-electric or solar-equipped), appliance standards (phasing out sales of inefficient gas heaters or requiring heat pump HVAC in new constructions), and financial incentives for retrofits (rebates for heat pump installations, tax credits for insulation or efficient appliances). Some cities have enacted ordinances disallowing new gas connections, effectively forcing new buildings to be fossil-free. Ensuring affordability and access is important for climate justice – low-income households may need subsidies to replace old heaters or to pay slightly higher electric bills during the transition, so robust support programs are needed. Finally, coordination with the power sector is vital: regulators and utilities should plan for the new load from building electrification by investing in nuclear and other firm generation to provide clean heating power on the coldest nights. In summary, buildings can be freed from fossil fuels mainly through electrification and efficiency – but it requires building a resilient clean energy system behind the scenes. A renewables-only plan would face the tallest order on the coldest days; including steady nuclear energy in the mix ensures that even in mid-winter, clean heat stays on.
Agriculture & Food (On-Farm Energy and Fertilizers)
Emissions Profile & Fossil Dependency: Agriculture, forestry and land-use (AFOLU) contribute about 22% of global GHG emissions (Global Greenhouse Gas Overview | US EPA), but most of that is from deforestation and livestock (methane) rather than direct fossil fuel use. The direct energy-related emissions in agriculture – mainly from farm machinery and irrigation, and from production of agrochemicals – are a smaller slice (approximately 1.7% of global emissions are from farm machinery and fishing vessels fuel use (Sector by sector: where do global greenhouse gas emissions come from? - Our World in Data)). Fossil fuels are entrenched in agriculture in two key ways: (1) Farm equipment fuel – tractors, harvesters, and fishing boats overwhelmingly run on diesel fuel; (2) Fertilizer production – the manufacture of nitrogen fertilizers (ammonia, urea) uses large quantities of natural gas both as feedstock (source of hydrogen) and energy, emitting CO₂. For instance, the Haber-Bosch process for ammonia fertilizer consumes about 3–5% of global natural gas production, making fertilizer a significant hidden source of CO₂. Additionally, food processing and distribution use energy, but those fall under industry/transport sectors. Here we focus on on-farm energy and fertilizer, as they represent fossil dependencies that must be addressed for a truly fossil-free economy.
Challenges & Limits of a Renewables-Only Approach: The agriculture sector’s fossil fuel use might appear easier to replace (being relatively small), but it has unique challenges. Farm operations are often remote and seasonal, requiring power-dense solutions. Battery-electric tractors and combines are being developed, but heavy-duty farm equipment working long hours in the field face similar battery limitations as trucks: weight and runtime. Refueling a diesel tractor takes minutes, but recharging a massive electric combine could take hours without extremely high-power chargers or battery swaps. Relying only on solar power in a rural farm, for example, might not reliably meet harvest-time energy needs (which often occur on a tight schedule when crops are ready). Intermittent renewables might not align with the timing of agricultural operations – e.g. running an electric irrigation pump during a drought when there’s no sun at night would demand storage. For fertilizer production, a renewables-only approach means running huge electrolyzer plants and Haber-Bosch reactors on variable power. Ammonia synthesis runs best as a continuous process; stopping and starting with the whims of wind would be inefficient and could drive up costs significantly (or require building costly hydrogen buffer storage). In short, while renewable electricity can and will play a major role (solar panels on farms, wind in rural areas), depending solely on intermittent sources to power tractors and fertilizer plants could impair the reliability of food production. Farmers need fuel when they need it – a cloudy week shouldn’t stop the planting season. Without firm energy, one would need oversized renewable capacity and large energy storage dedicated to farm operations, which could be uneconomical for the agriculture sector to shoulder alone.
Decarbonization Pathways: Key strategies to eliminate fossil fuels in agriculture include electrification of equipment where feasible, clean fuel alternatives for heavy machinery, and green production of fertilizers:
Electric and Hydrogen-Powered Farm Equipment: Lighter farm equipment (such as small tractors for orchards or vineyard equipment) can be electrified with batteries, especially as battery energy densities improve. Companies are beginning to offer electric tractors for smaller-scale farming which can be charged on-site (potentially from farm solar panels). For heavy-duty tractors, combine harvesters, and long-range fishing vessels, hydrogen or ammonia fuels offer a solution. Hydrogen fuel cell tractors or ammonia-fueled engines could replace diesel, providing high power without direct emissions. Ammonia in particular is being researched as a carbon-free fuel that could be used in modified diesel engines – it could allow farmers to refuel quickly similarly to diesel. Another option is biodiesel or renewable diesel (made from waste oils or non-food crops) as a drop-in fuel for existing farm equipment, though feedstock availability is limited. In some cases, biogas from farm waste can be used to run generators or equipment on-site (closing loops by using manure to produce biogas, for instance). Overall, a mix of electric-drive for efficiency and hydrogen-based fuels for energy density will likely emerge for farm machinery. This again hinges on having ample clean electricity or hydrogen fuel deliverable to rural areas.
Green Fertilizers (Clean Hydrogen for Ammonia): Decarbonizing fertilizer production is crucial to phasing out fossil fuels in agriculture. The current process uses natural gas (CH₄) to produce hydrogen (via steam reforming) which is combined with nitrogen to make ammonia, emitting CO₂. The sustainable alternative is green hydrogen via electrolysis (using renewable or nuclear power) or potentially pink hydrogen (hydrogen produced with nuclear energy) to feed the ammonia synthesis. Several companies are now building or planning electrolysis-based ammonia plants – sometimes called power-to-ammonia. If powered by nuclear or renewable electricity, these plants can create ammonia with zero CO₂ emissions. This ammonia can then be used directly as fertilizer or upgraded to urea or other products with captured CO₂, all without fossil gas. Additionally, innovations in fertilizer application (like precision agriculture, using only the needed amount of fertilizer at the right time) and alternatives like nitrogen-fixing cover crops can reduce overall fertilizer demand, easing the transition. In the longer term, green ammonia might also double as a fuel (as mentioned, for tractors or generators), creating synergies between fertilizer supply and fuel supply on farms.
On-Farm Renewable Energy and Nuclear Integration: Farms often have land or roof space for solar panels or wind turbines, which can provide some of their electricity needs (for barns, cooling, charging equipment). Integrating more renewables on-site can reduce farmers’ fuel bills and emissions. However, for larger energy needs, community-scale energy projects or even small modular reactors in agricultural regions could provide a steady supply. For example, small advanced reactors could be deployed in rural cooperatives to produce electricity and hydrogen, which is then distributed to farms in the region for both power and fertilizer production. This kind of localized energy approach could ensure that even rural communities have access to reliable, clean energy to run farm operations year-round, mitigating the risk of being at the end of an unreliable grid or fuel supply chain.
Infrastructure & Policy Needs: Transitioning agriculture off fossil fuels will require supportive infrastructure and policies that recognize farmers’ needs. On infrastructure: establishing rural hydrogen supply chains (or ammonia distribution networks) will be important if hydrogen/ammonia tractors are to be adopted – this could mean building hydrogen electrolysis hubs in farming regions, with tankers or pipelines delivering fuel to local cooperatives or fueling stations for farm vehicles. For electric equipment, ensuring that farms have access to three-phase power and sufficient grid capacity to charge machinery is important (many remote farms currently have limited electrical service). Supporting the build-out of charging/fueling depots in agricultural areas (perhaps integrated with grain silos or co-ops) could provide a convenient way for farmers to refuel with clean energy. Another aspect is expanding training and extension services to help farmers use new tech (electric tractors, precision ag) and maintaining these advanced machines.
Policymakers can assist by providing subsidies or low-interest loans for farmers to purchase electric or hydrogen-powered equipment – farm equipment is a capital-intensive investment, and many farms operate on thin margins, so financial help is key to spur adoption. Governments could also implement incentives for green fertilizer production and use: for instance, tax credits or feed-in tariffs for green ammonia, procurement of green fertilizer for government-supported agriculture, or even regulation to phase out the most carbon-intensive fertilizer production methods. Research and development funding specifically for agricultural decarbonization (like developing a viable ammonia engine for tractors, or small-scale modular electrolysis units for farms) will address technical gaps. Importantly, because agriculture is a sector that directly affects food prices and rural livelihoods, climate justice considerations are paramount – policies should ensure that decarbonization does not drive up food costs for the poor or put undue burden on small farmers. This could involve measures such as income support or crop price support if needed during the transition, and prioritizing solutions that are cost-effective and accessible (for example, making green fertilizer price-competitive with conventional fertilizer via carbon pricing or incentives). In essence, agriculture’s fossil fuel phase-out will hinge on empowering the farming community with clean alternatives that are reliable and affordable, underpinned by investment in both local renewables and dependable clean energy (including possibly nuclear-assisted hubs for fertilizer and fuel production).
The Limits of a Renewables-Only Strategy and the Need for an Integrated Solution
Across all sectors examined – industry, transport, buildings, and agriculture – a common theme emerges: there is no single silver bullet, and certainly not an intermittent one. A strategy relying solely on wind and solar, while scaling up energy storage, efficiency, and demand response, can make big strides in decarbonizing electricity. However, as the foregoing analysis shows, many end-uses have requirements that intermittent renewables alone struggle to meet: continuous high-temperature heat, high energy-density portable fuels, or round-the-clock power during peak demand. The inadequacy of a renewables-only approach is especially pronounced in the so-called hard-to-abate sectors – heavy industries (steel, cement, chemicals) and long-distance transport (aviation, shipping, long-haul trucking) (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy). These sectors need solutions like hydrogen, synthetic fuels, and carbon capture, which in turn need firm, abundant clean energy inputs. As experts have observed, hydrogen will be crucial for heavy industry and transport, but producing hydrogen at the required scale with only variable renewables is extremely challenging (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy). For instance, if steel mills, fertilizer plants, and airlines all depend on green hydrogen, society must generate enormous quantities of reliable carbon-free electricity to supply electrolyzers – far beyond what a wind/solar-only grid could stably deliver without massive overbuilding. In contrast, nuclear energy provides a high-capacity, zero-carbon backbone that can run electrolysis, direct air capture, and industrial facilities at full tilt, complementing renewables. Nuclear reactors operate at over 90% capacity factor (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy) and can produce heat as well as electricity, making them well-suited to plug the gaps left by renewables (which have lower capacity factors and no heat output).
A purely renewable strategy also often implies a heavy materials and land footprint due to the need for large-scale energy storage and redundant generation. To cover seasonal lulls, one might need fields of batteries and hydrogen storage tanks, and to cover land constraints, sometimes biologically rich areas get targeted for solar/wind farms. A holistic approach that includes nuclear power, clean hydrogen, and synthetic fuels can ease these burdens – by providing concentrated energy with a tiny land footprint (nuclear plants) and by allowing energy to be stored in chemical form (hydrogen, ammonia, synthetic hydrocarbons) that are more energy-dense and versatile than batteries. In other words, incorporating firm nuclear and power-to-fuel pathways reduces the extreme scaling of storage and land use that a 100% renewables system would require. One analysis found nuclear to be 50 times more land-efficient than wind on a per-unit energy basis (How does the land use of different electricity sources compare?), illustrating the land conservation benefit of a mixed strategy.
Recommended Holistic Strategy: To achieve deep decarbonization and climate justice, we must deploy “all of the above” in clean technologies, matching each to the application where it fits best. This means: rapidly scaling up renewables and nuclear for power generation, electrifying everything we reasonably can (especially in buildings and light transport), but also building a robust infrastructure for hydrogen and synthetic fuels to tackle the rest. Concretely, a holistic strategy would include:
Decarbonized Power Grid as the Foundation: Prioritize cleaning the electricity sector (which, as noted, is the single largest source of emissions (Global Greenhouse Gas Overview | US EPA)). Expand renewable capacity (solar, wind, etc.) wherever feasible and cost-effective, but in tandem, expand nuclear power to supply the firm, 24/7 carbon-free electricity that renewables cannot always provide. A mix of variable and firm low-carbon generation will ensure the grid stays stable. This firm nuclear power undergirds many other solutions – charging EVs at night, running heat pumps on frigid evenings, producing hydrogen fuel continuously, and providing process heat. Policies here include streamlined licensing for new reactors (especially modular designs), maintaining existing nuclear plants, investments in grid upgrades and storage for renewables, and integrating regional grids to share resources. The end goal is an electricity system capable of meeting vastly increased demand (due to electrification) with near-zero emissions and high reliability.
Electrification & Efficiency in End-Use Sectors: Wherever direct electrification is practical, it should be pursued aggressively – this means electric vehicles replacing combustion cars, heat pumps replacing furnaces, electric machinery replacing diesel engines, and so forth. This not only cuts emissions but often improves efficiency and local air quality. Enhanced efficiency (better insulation, efficient motors, recycling of materials) reduces overall energy demand, easing the scale of the challenge. Governments should enforce and tighten efficiency standards and incentivize electric end-use technologies to accelerate this shift.
Clean Hydrogen as an Energy Carrier and Industrial Feedstock: Hydrogen is a versatile energy carrier that connects the power sector to various end uses. The strategy calls for a massive scale-up of clean hydrogen production – via water electrolysis using surplus renewable and dedicated nuclear power, and possibly via gas with CCS as a bridging source. This hydrogen will feed into steel plants, chemical factories, trucks, ships, and perhaps power plants (as a replacement for natural gas). Setting up “hydrogen hubs” – clusters where production, storage, and use of hydrogen are co-located – can jump-start local hydrogen economies. Policies like subsidies for electrolyzers (as seen in the EU and US Hydrogen Earthshot initiatives), targets for hydrogen use in industry (e.g. quotas for green steel), and certification of green hydrogen will support this. It’s important to ensure the hydrogen is produced with very low emissions; hence emphasis on nuclear (often dubbed “pink hydrogen” when made with nuclear energy) and renewables-powered electrolysis. Notably, nuclear can provide both electricity and high-temperature steam to future high-efficiency electrolyzers (like solid oxide or thermochemical processes), potentially producing hydrogen more efficiently than electrolysis with low-temperature renewables (Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen - Energy Insight from OurEnergyPolicy).
Synthetic Fuels and Carbon Capture for Hard-To-Electrify Applications: For sectors like aviation, long-haul shipping, and certain industrial processes, synthetic carbon-neutral fuels offer a lifeline. The strategy should invest in power-to-fuels facilities that use captured CO₂ and clean H₂ to make diesel, jet fuel, methanol, and other fuels. This goes hand-in-hand with deploying direct air capture technology to obtain CO₂ from the atmosphere, closing the carbon loop. Nuclear-powered DAC and fuel synthesis (NDACSF) is a game-changing concept that could provide these fuels at scale without being bottlenecked by weather (From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF). Early steps would involve scaling up demonstrations of DAC, incentivizing airlines to use a blend of e-fuels, and perhaps requiring a steadily increasing share of shipping fuel to be zero-carbon (pushing the market for ammonia/methanol). Carbon capture isn’t only for making fuels – it should also be used to neutralize remaining fossil uses during the transition (for example, capturing emissions from a few remaining gas plants or from cement factories until alternatives fully take over). Governments should fund CO₂ transport and storage infrastructure and create credit systems for captured carbon (such as credits for atmospheric CO₂ removal, which reward DAC).
Integrating Sectors and Storing Surplus Energy: A holistic approach blurs the lines between sectors – excess renewable electricity on a windy day might be converted to hydrogen (power-to-gas) and stored for later use in a factory or peaking power plant; a nuclear plant at night might make heat for district heating or for industrial uses. This kind of sector coupling increases overall system resilience and efficiency. Utilizing energy storage in various forms is also part of the strategy: batteries will balance short-term fluctuations, hydrogen or ammonia will store seasonal energy, and pumped hydro or thermal storage will have niche roles depending on geography. By having multiple forms of storage and energy carriers, the system can handle variability without leaning exclusively on one solution like mega-batteries.
Global Equity and Climate Justice: Finally, a holistic strategy emphasizes that how we deploy these solutions matters for justice. Ensuring developing countries have access to advanced decarbonization technologies is crucial – for instance, making financing available for nuclear plants or electrolyzers in countries heavily reliant on coal, or funding grid expansions in energy-poor regions so they can electrify cleanly. Climate justice also means remediating the harms of fossil fuels in disadvantaged communities: replacing diesel generators and kerosene lamps in poorer areas with clean alternatives (solar plus storage or micro-nuclear reactors for remote areas) to improve health and resilience. The concept of “energy reparations” has even been proposed, where wealthy nations and fossil fuel companies fund clean energy infrastructure (like nuclear and hydrogen projects) in the countries most affected by climate change (A Manifesto for Nuclear-Driven Energy Reparations). Prioritizing nuclear and hydrogen in these regions can deliver reliable power and industrial growth without the carbon baggage, aligning climate action with development goals. Robust international collaboration (through climate finance, technology transfer, and fair supply chains for critical minerals) is part of the broad strategy so that no region is left behind in the transition from fossil fuels.
In summary, achieving climate stability in line with justice requires deploying the full toolkit of solutions across all sectors. A renewables-only strategy, while well-intentioned, would leave significant emission sources unaddressed or unreliable. By complementing renewables with firm nuclear power, scaling up clean hydrogen and synthetic fuels, and employing carbon capture where needed, we can create a sector-by-sector blueprint for phasing out fossil fuels that is both technically robust and equitable. This integrated approach ensures that whether it’s a factory running through the night, a cargo ship crossing the ocean, or a family heating their home in a blizzard, the energy supporting it is clean, secure, and just. Such a comprehensive strategy is essential to achieve deep decarbonization by mid-century and to uphold climate justice for all communities. As multiple analyses have concluded, we need “many solutions to decarbonize the economy” – focusing on just one (be it electricity or transport or any single technology) is insufficient (Sector by sector: where do global greenhouse gas emissions come from? - Our World in Data). Instead, embracing a diverse portfolio of nuclear, renewables, efficiency, hydrogen, and synthetic fuels will drive each sector to zero emissions.
This multi-pronged blueprint is how we finally end the age of fossil fuels, sector by sector, and usher in a clean energy era that leaves no one – and no sector – behind.
Conclusion: Embracing Reality for a Truly Sustainable Future
Our sector-by-sector analysis underscores a crucial reality: the renewables-only approach, despite its noble aspirations, falls short of addressing the comprehensive energy demands of a fully decarbonized global economy. Each sector we examined—from heavy industry and transportation to agriculture and buildings—faces unique challenges that renewables alone cannot fully overcome. Intermittency, land use constraints, storage limitations, and the sheer scale of energy demand highlight the impracticality of a purely renewable energy system.
Instead, our findings reinforce the urgent necessity of integrating firm, dependable, and scalable clean energy solutions, particularly nuclear power and hydrogen-based fuels. Nuclear energy's capability to deliver consistent, high-density power and heat makes it uniquely suited to meet industrial demands and support grid stability. Simultaneously, hydrogen and nuclear-powered direct air capture synthetic fuels (NucDACSF) provide versatile, carbon-neutral solutions crucial for sectors where electrification is either impractical or impossible, such as aviation, maritime shipping, and heavy industry.
Ultimately, the path to true climate justice and a sustainable future demands realism, openness to innovation, and the courage to embrace all viable technologies. By integrating nuclear energy and clean hydrogen into our energy strategies, we ensure a robust, equitable transition that addresses not only environmental sustainability but also energy security and global equity. The urgency of the climate crisis leaves no room for ideological rigidity; rather, it calls for bold, inclusive strategies rooted firmly in scientific and technological reality.
Sources
Intergovernmental Panel on Climate Change (IPCC). (2023). AR6 Synthesis Report: Climate Change 2023. Retrieved from https://www.ipcc.ch/report/sixth-assessment-report-cycle/.
International Energy Agency (IEA). (2023). World Energy Outlook 2023. Retrieved from https://www.iea.org/reports/world-energy-outlook-2023.
U.S. Environmental Protection Agency (EPA). (2023). Global Greenhouse Gas Emissions Data. Retrieved from https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data.
Jenkins, J. D., Luke, M., & Thernstrom, S. (2021). Net-Zero Needs a Clean Hydrogen Catalyst: The Case for Nuclear Hydrogen. OurEnergyPolicy. Retrieved from https://www.ourenergypolicy.org/resources/net-zero-needs-a-clean-hydrogen-catalyst-the-case-for-nuclear-hydrogen/.
Anders, E. W. (2024). From Fossil Fuels to Future Fuels: How Norway Can Bridge Aviation's Hydrogen Gap with NDACSF. Earthrise Accord. Retrieved from https://www.earthriseaccord.org/post/from-fossil-fuels-to-future-fuels-how-norway-can-bridge-aviation-s-hydrogen-gap-with-ndacsf.
These resources collectively provide a rigorous, data-driven foundation for the sector-specific decarbonization pathways and substantiate the argument against a renewables-only strategy, underscoring the necessity of nuclear energy, clean hydrogen, and synthetic fuels for a successful and equitable transition to net-zero emissions.
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