Decarbonization (or decarbonisation) is reducing the amount of carbon dioxide (CO2) released into the atmosphere as a component of greenhouse gas (GHG) emissions. Decarbonization efforts focus on replacing fossil fuels with low-carbon or no-carbon energy sources for the transportation, electricity generation, industry, agriculture, commercial (buildings and cooling/heating), and residential sectors.
Why is Decarbonization Critical?
The intent of decarbonization is to reduce the impact of human activity on our planet’s climate in order to slow global warming. The 2015 Paris Agreement set the goal of limiting global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre-industrial levels, by mid-century. In order to do this, countries, cities, regions, companies and individuals all need to work ambitiously toward achieving carbon neutrality by 2050. The health of the planet depends on government policy, technology innovation, and widespread public support working together to create a pro-climate culture, lower the cost of no-carbon energy, and accelerate decarbonization efforts to meet climate goals.
Why Is the Transport Sector Critical to Decarbonization?
Because transport, at 37%, is globally the largest CO2 emissions contributor compared to other end-use sectors, it offers significant opportunities for reducing CO2 in the atmosphere — as well as significant challenges. Even with the temporary drop in mobility in 2020 due to the COVID-19 pandemic, emissions from transportation are still rising globally. Policies in place today are not enough to meet GHG reduction needed in transportation.
Projections show that to meet climate goals, we need to reduce emissions by about 40% by 2030 and 80% by 2050. Given the growth in transportation and demand for passenger cars, the per-vehicle decarbonization targets will need to be even larger. Deep decarbonization should also address reducing CO2 emissions in the manufacture, transport, and disposal of road vehicles and their components.
What is the Role of Electric Vehicles in Decarbonizing Transportation?
Replacing internal combustion engine (ICE) vehicles with battery electric vehicles (BEVs) — called electrification — is the only way to substantially reduce CO2 emissions in the transportation sector. One study found that, by far, battery electric vehicles have the lowest lifecycle GHG emissions compared to all other technologies. The assessment, based on an average medium-sized passenger vehicle, found:
- ICE vehicles fueled by a fossil/bio-fuel mix emit 245-253 g CO2/km
- BEVs fueled on today’s average grid electricity are 105-124 g CO2/km
- BEVs fueled by a fully renewable grid go down to 41 g CO2/km
While there is ongoing research into e-fuels — sustainable zero-emission alternatives to fossil fuels — they won’t be price competitive with fossil fuels before 2050 at the earliest, the study says.
Electrification of light-duty road vehicles — cars, SUVs, and small trucks — will address more than half of the sector’s CO2 emissions. Municipal and school buses are also good candidates for electrification, followed by vans and medium- or heavy-duty trucks used for deliveries and freight transportation. The transportation sector also includes aircraft and ships, which have limited potential for electrification but are the focus of efforts to develop low-carbon fuels. Rail, which comprises only 2% of transportation emissions, is also a candidate for low-carbon or no-carbon fuels.
The number of electric cars sold doubled in 2021 to 6.6 million, driven primarily by government policies. The auto industry is increasing the number and variety of EV models available and working to bring prices down to parity with comparable ICE vehicles. However, much work remains to be done to build the EV charging infrastructure required to address the very real charge anxiety that drivers experience today. That, and providing a predictable and reliable charging experience for EV drivers with smart EV charging management, are crucial to increasing consumer confidence in electrification.
Renewable Grid Energy is Essential to Transport Decarbonization
The degree of CO2 emission reduction in transport depends on the source of the electricity powering EVs. In a renewable grid, electricity comes from green sources — solar, wind, and hydropower. Globally, renewable energy made up 29 percent of electricity generation in 2020 and is steadily growing. However, it varies widely depending on location. Norway is the world’s leader in renewable energy use, with 45% of generation from hydropower.
Electrification of transport and greening of the grid must advance hand-in-hand to reach decarbonization and Paris Agreement global warming mitigation goals by mid-century. Electric vehicles themselves can also be part of the solution for greening the grid by serving as “batteries on wheels.” Vehicle-to-grid (V2G) technology and smart energy management enable EVs to charge at times when demand for electricity is low, and help balance the grid by transferring electricity back when demand is high.