Economywide electrification also involves transitioning how people cook and heat their homes.
Today, 38% of Americans use a gas stove, and buildings that use gas or oil for heating and other purposes account for 13% of U.S. greenhouse gas emissions.
Carbon dioxide cannot be captured from gas stoves or from most furnaces burning fossil fuels; replacing these over time will translate to emissions reductions. Heat pumps can use electricity to heat and cool homes, while electric stoves and burners can be installed in kitchens. The IRA includes tax credits and rebates to drive improvements in home energy efficiency. Manufacturing standards for home heating and cooking, similar to the manufacturing standards for air conditioning, are another way that policymakers could encourage this transition.
Building more electricity transmission capacity, including long-distance transmission from areas where wind and solar energy are abundant to areas where they are not, will be a critical component of broader electrification efforts.
That is challenging in the United States, because the country has regional grids and a complex and fragmented permitting process that impedes rapid change. Recent federal legislation includes grants to facilitate and accelerate the siting and permitting of interstate transmission projects and to accelerate environmental review processes.
Building the necessary infrastructure will likely also require new regulatory structures to expand and increase the automation of electricity transmission and distribution.
Wind and solar power are already being deployed at a record pace in the United States. The NAS report found that to be on track for net zero by the middle of the century, the current pace will need to roughly double by the end of the 2020s.
Over the course of the 2030s, that pace would need to double again. This rate of increase is not unprecedented. For example, the increased use of natural gas and decreased use of coal occurred even more rapidly when hydraulic fracturing techniques became widely used after 2007.
Of course, the wind does not always blow and the sun does not always shine, so other technologies are needed to supply energy during the doldrums. The National Academies offer several possibilities that can provide some of this backup: batteries, hydroelectric power, and nuclear power. The United States is also endowed with plentiful supplies of natural gas that could generate backup power for renewable forms of energy. A natural gas electricity plant, which is essentially a set of jet engines tied to electric generators, can be throttled up when renewable energy sources are not available. As more wind, solar, and transmission capacity is installed, the use of backup power can decline.
Natural gas produces about half the carbon dioxide of a coal-fired electricity plant, but achieving net zero will require that these emissions be controlled as well. One option would be to capture the carbon dioxide emitted by electricity generation and reinject, or sequester, it into the reservoirs from which the gas was extracted.
Carbon capture and sequestration (CCS) projects at multiple scales are now operating around the world, but this technology will have to be scaled up dramatically. The U.S. EPA’s proposed rule that sets limits on the emissions from fossil fuel-fired power plants is based on technologies such as CCS.[See U.S. EPA, Greenhouse Gas Standards, supra note 22. The use and expansion of CCS technology is controversial because most stored carbon dioxide is used for enhanced oil recovery. The nation would also need a national transportation and storage network to ensure that carbon dioxide can be captured not just from power plants, but from scattered and small-scale sources across the country, and moved to geologic reservoirs where it can be kept out of the atmosphere. Further, for a transportation and storage network to be available when it is needed in the 2030s and 2040s, construction of this network would need to start in the 2020s.
If these solutions to the climate change problem are now available, why not institute them in less than 30 years and avoid potentially disastrous climate tipping points? As the NAS report points out, a faster transition is possible, but 30 years is about the lifetime of existing major assets in the energy system.
Retiring all those assets over the next decade would be costly, whereas replacing them as they wear out with cheaper, non-emitting alternatives would save money in the long run. Thus, a 30-year transition from 2020 to 2050 balances both the longevity of the capital stock and our current knowledge of the climate system.
The energy revolution of the past decade is unlike any that has occurred in the past century. Thoughtful policies and technological advances have steadily brought down the cost of wind and solar energy. As a result, electricity can now be generated without putting greenhouse gases into the atmosphere, at less cost than in the past.
IV. Provide Energy Sources for Technologies That Cannot Be Electrified
Some sectors of the economy, like aviation, shipping, cement making, steel production, and some manufacturing activities, will be difficult or impossible to electrify by 2050. For instance, a commercial airplane flying long distances could not operate on existing batteries, because it would be too heavy. Similarly, electric kilns used to make cement would be very expensive to operate on stored wind and solar energy when the sun is not shining and the wind is not blowing.
Greater energy efficiency is one of the most effective near-term opportunities to reduce emissions from these sectors. Governments have instituted many policies in the past designed to improve the efficiency of energy use, and building on these efforts could yield quick returns.
To further reduce emissions, several technological pathways are possible. One option relies on the use of hydrogen as a fuel, which produces only water vapor as a byproduct when it is combined with oxygen to produce heat.
For example, long-haul trucks could use either advanced batteries, which are now under development, or hydrogen as a fuel. Moreover, to produce hydrogen, the element must be first isolated from its parent molecule. In commercial hydrogen production, methane is commonly used for this purpose. Hydrogen is separated from methane by a technique called steam-methane reformation, but this process also produces some carbon dioxide. It is alternatively possible to split hydrogen from water molecules using electricity, but that electricity could come from either renewable or non-renewable sources. Thus, hydrogen has the potential to be a source of low- or no-emissions fuel, but it is not inherently so. The use of hydrogen as a fuel remains expensive today compared with other alternatives, but greater use might likely bring down the price of hydrogen energy, as has been the case with solar and wind power. Research and development (R&D) will need to be expanded during the 2020s to ensure that the costs of these technologies come down enough so that they are cost-competitive for decarbonization in the 2030s and 2040s.
According to another NAS report on negative emissions technologies, natural gas with carbon capture and sequestration is another possible source of energy in sectors that are hard to electrify.
Before the hydraulic fracturing and horizontal drilling revolution of the 21st century, supplies of gas were uncertain in the United States, but new sources made available by these technologies have eased concerns about supply. A major remaining concern is that uncombusted methane, the major component of natural gas, will leak as “fugitive emissions” into the atmosphere during its drilling, extraction, and transportation and exacerbate global warming. This is especially concerning since methane is more than 25 times as potent as carbon dioxide in its warming potential over a 100-year period.
If fugitive methane emissions can be controlled along with the carbon from burning natural gas and from burning off excess methane from wells, natural gas with carbon capture and sequestration potentially could provide the United States with a non-emitting source of energy for more than a century. The IRA provides tax credits and R&D funding both for carbon capture and for direct air capture, in which carbon dioxide is removed directly from the atmosphere and sequestered underground. Though carbon capture and sequestration remains expensive and would need to be deployed on a very large scale, solving these problems and applying carbon capture to gas-fired power generation could provide significant employment and economic benefits across a range of economic sectors.
Critical research and development efforts are still needed to determine exactly how non-emitting technologies can help decarbonize the energy system. For example, small modular nuclear reactors could make significant contributions to energy supplies, but issues of cost, safety, spent fuel disposal, and nuclear proliferation remain to be resolved. Hydrogen as a fuel and an energy storage system remains expensive, but it could play a large role later in the transition to net zero. Both are supported through funding provided in the IRA.
V. Reduce Other Greenhouse Gases in Addition to Carbon Dioxide
As described in the What Is Causing Climate Change? module, gases other than carbon dioxide also cause greenhouse warming.
Especially problematic is the powerful greenhouse gas methane, which results from agriculture (particularly the raising of livestock), leaks from the natural gas systems mentioned above, decomposition of wastes in landfills, and coal mining. Nitrous oxide, which results from agriculture as well as from the combustion of fossil fuels, also accelerates greenhouse warming. Another contributor to warming is fluorinated gases, such as hydrofluorocarbons used in refrigeration and air conditioning, that are released into the atmosphere when equipment leaks or is discarded.
The greatest impact on these non-carbon dioxide greenhouse gases would come from changes in the energy system.
In natural gas and oil systems, inspection and maintenance of energy plants could significantly mitigate the release of these gases. Controlling uncombusted natural gas emissions from wellheads and pipelines can prevent excess release of greenhouse gases. In coal mining, methane in the air could be extracted and burned for power with subsequent carbon capture or be otherwise sequestered from the atmosphere.
To reach net zero, the use of current refrigerants and other fluorinated gases will need to be reduced, which may require a variety of approaches. Companies may have to employ recovery and recycling methods as well as production techniques that do not involve fluorinated gases. Governments may limit the production of fluorinated gas emissions in sectors such as electronics manufacturing and aluminum and magnesium production. Recently, engineers have developed a high-temperature incinerator for the safe destruction of fluorinated gases.
Despite such advances, the NAS decarbonization report concluded that the most feasible option to meet the nation’s climate goals would be to reduce the use of fluorinated gases in all sectors as quickly and as reasonably as possible.
Recognizing this, the United States ratified the Kigali Amendment to the Montreal Protocol, which aims to phase down hydrofluorocarbons 85% by 2036. Replacements of these compounds could also be made opportunistically. For instance, when a refrigerator or air conditioner needs to be replaced, the new device might use coolants that are more climate-friendly.
The greatest challenges are associated with the agricultural sector. Demand for food is growing, which puts pressure on increasing the use of land and other inputs to agriculture. However, known techniques applied to livestock and croplands could substantially reduce emissions. Promising examples include better management of manure, cropland strategies such as no-till practices.
As prices increase, changes in diets could cut emissions even as the demand for food rises.
VI. Employ Natural Climate Solutions and Negative Emissions Technologies to Compensate for the Remaining Emissions
Even after the economy is electrified and emissions of other greenhouse gases are minimized, U.S. households and businesses will still be releasing some carbon dioxide and other greenhouse gases into the atmosphere. To reach net zero, the United States would need to remove the equivalent amount of these greenhouse gases from the atmosphere and sequester them.
Several negative-emissions technologies can contribute to this job.
Practices that increase the amount of carbon stored in living plants or sediments in tidal marshlands, seagrass beds, and other tidal or saltwater wetlands—collectively known as coastal blue carbon—are relatively low cost, though their capacity to store carbon is limited.
Crops, which take up carbon dioxide as they grow, can be used to produce electricity, liquid fuels, or heat, with the carbon dioxide produced in these processes being captured and sequestered underground. However, agricultural land is also used to supply food for people and for livestock, and using land to solve the climate problem might create a food supply problem, especially as demand for food increases.
The most promising ways for the United States to sequester carbon dioxide over the next few decades are to manage forests to retain more carbon, plant more forests, and adjust agricultural practices to enhance carbon storage in the soil.
Plants eat carbon dioxide for a living. They use water, nutrients, and sunlight to turn carbon dioxide in the atmosphere into living tissue.
For example, the forests east of the Mississippi River in the United States have been gaining weight for decades as former cropland has reverted to forests and as existing forests have grown. These and other forests in the United States could store more carbon if trees were cut down more selectively and science-based forest management practices were applied. Similarly, agricultural practices can rebuild the carbon content of soils that have been degraded, which improves agricultural productivity while removing carbon dioxide from the atmosphere. If all but the essential emissions of greenhouse gases were eliminated by 2050, the growth of plants in the United States should be enough to compensate for remaining emissions, allowing the United States to reach net zero.
This approach would have many benefits in addition to mitigating climate change. It would improve forests, croplands, grazing lands, and wetlands that support human health and well-being. It would improve habitats for other organisms, increase soil fertility and water-holding capacity, and decrease air and water pollution.
In some places, the co-benefits of enabling ecosystems to flourish could be even more valuable than the benefits from climate mitigation.
Current federal legislation relies mostly on incentives and subsidies to reduce the buildup of greenhouse gases in the atmosphere, and a more diverse portfolio of policies, including regulatory changes, the use of carbon markets, and payments for co-benefits, would likely be needed to reach net zero. The barriers to change, including institutional, technological, political, and cultural factors, are substantial, but means exist to address them. For example, storing carbon in plants will require monitoring and verification, which will require adequate governance structures. Also, the availability of land is finite, and competing uses of land for food production, conservation, and carbon goals will have to be resolved.
Despite the benefits that natural climate solutions could provide, many of the most effective opportunities will not be available indefinitely. For instance, slowing emissions by preventing tropical deforestation requires an intact forest as a starting point. Waiting until too little forest remains to regenerate new forests reduces the possibility of using this technique as part of the climate solution.
Despite the challenges, rapid change is entirely possible. For example, the United States has a large amount of rainfed pastureland and cropland some of which could be converted to forestland if people were to eat less meat. While the demand for meat remains strong today, projections for the growth of U.S. demand have recently been dropping,
and the development of the alternative (plant-based or synthetic) meats industry could provide an opportunity to free up land for storing carbon.
As with direct capture of carbon from the atmosphere, negative emissions technologies and natural climate solutions all need concerted research efforts to overcome the constraints that currently limit deployment. This research will need to address not just gaps in scientific and technical understanding, but also the steps that are needed to bring negative emissions technologies to scale, including cost reductions, deployment, and monitoring and verification.
VII. The Social Dimensions
Achieving net zero by 2050 will inevitably change the lives of some people.
For example, communities that today are tightly tied to fossil-fuel production will face job and revenue losses, just as the ongoing decline in the coal sector has been hollowing out some communities across the nation. Many other communities will thrive, as new jobs and new industries result from the development and implementation of non-emitting technologies. The social dimensions of the energy transition will necessitate as much attention as the technological dimensions.
In the past, changes to energy systems have caused suffering in the communities that house these systems, and many communities have suffered historically and continue to suffer today because of the pollution and other negative consequences of energy systems (see Climate Justice module). These communities may be resistant to mitigation measures, or demand recompense for past harms as energy systems change. Poor and historically marginalized groups have suffered disproportionate harm from fossil pollution while receiving disproportionately low benefits from fossil energy. High energy prices contribute to poverty, and many people who lack adequate capital cannot take advantage of opportunities like tax credits for electric cars or weatherization programs for homes.
The IRA authorizes more than $60 billion for community investments and energy justice, including block grants to states, local governments, and tribes. For example, it provides funding for community-led projects in places that have experienced negative impacts of pollution and climate change. Reducing and eliminating the injustice built into the energy system would in general help create a more just and equitable society.
Governments at all levels have many policy options to address inequities. Communities and workers that have been harmed in the past or are at risk from future changes could be included to a much greater extent in the development of solutions.
Comprehensive education and training programs could provide the workforce needed for the transition to clean energy. Regional centers could allow state and local leaders to access resources and knowledge related to climate change adaptation, establishing a baseline of shared information that quantifies and helps to address inequities. A new federal office at the level of the White House could establish targets and advance federal programs aimed at a just and equitable transition. A national organization drawing on resources from both the public and private sectors could provide funding specifically to address the social impacts of the transition to net zero.
The transition to net zero provides an opportunity to build an energy system without the social injustices such as disproportionate impacts of emissions that characterize the current system and to allow communities and individuals to share equitably in future benefits. Public support for the transition may depend in part on how well U.S. policies ensure a fair distribution of costs and benefits.
The upside of the transition to net zero is substantial.
A variety of studies have concluded that the transition to net zero will create millions of new jobs.
Deep decarbonization could accelerate U.S. innovation, revitalize U.S. manufacturing, and increase employment, mostly in the form of blue-collar jobs. New educational and training opportunities could give displaced workers the skills they need to prosper in the renewable and green energy industries. Workers displaced by the transition could be employed in local projects or new businesses in their communities funded by community block grants, though wages may need to be increased to match those paid in the fossil fuel industry. People who do not have access to such opportunities may need direct assistance in such areas as housing mobility and lost income.
A diverse policy portfolio may help to ensure that communities have equal access to these benefits and are not disproportionately exposed to the risks of new energy systems.
Workers and communities will want access to accurate information about how the transition to net zero could affect them, and governments at all levels will need to respond to the prospect of job losses. Transition planning will benefit from ensuring that economic and health disparities are not exacerbated. Strategies will be needed to help local, state, and tribal governments replace revenue lost from the closing of plants, mines, and other industrial facilities. If the technological and social transitions to net zero take place hand-in-hand, and if equity is built into the DNA of any decisions that are made, then the costs, benefits, risks, opportunities, and burdens of decarbonization can be distributed more fairly.
VIII. Leading the World
Unless other nations join the United States in achieving net-zero greenhouse gas emissions by 2050, the levels of greenhouse gases in the atmosphere will continue to increase. However, there are good reasons to believe that the rest of the world can achieve net zero in approximately the same time scale, depending in part on the actions the United States takes in the next few years.
As part of the Paris Agreement, many nations have committed to a rapid transition to net zero.
Britain, France, and Germany have said that they will achieve that goal by 2050. China has pledged to reach net zero by 2060. Others have said that they will achieve net-zero emissions well before the middle of the century.
Net zero can create a dilemma for countries that are struggling to raise substantial portions of their populations out of poverty. Despite the rapid price decreases for wind and solar energy, many countries still have incentives to burn fossil fuels using existing technologies.
Issues of fairness also come into play (see Box 3).
The United States built massive infrastructure, such as its interstate highway system, using carbon dioxide emissions. It may be seen as unfair to other countries to say that they cannot build similar infrastructure that would improve the quality of life for their citizens. It may also be seen as inequitable that other people should sacrifice so that people in the United States do not face a worsening climate.
