Vehicles, heating, and industry decarbonization shares
Transport (cars, trucks, buses, aviation) accounts for roughly 27 percent of CO2 emissions from energy. Building heating (residential and commercial) adds another 20 percent. Industrial heat and process fuels (cement kilns, steel furnaces, chemical plants) comprise 30 percent. Together, these three sectors drive 77 percent of energy-related emissions. Decarbonizing each has different timelines and technical maturity: EV adoption can happen over 20 years with existing technology; building electrification (heat pumps, induction cookers) over 30-40 years; heavy industry requires breakthroughs in hydrogen, sustainable aviation fuels, and process redesign.
The chart maps what share of each sector's energy must come from electricity for different net-zero scenarios. Transport typically leads the race, reaching 80-100 percent electric by 2050. Heat follows more slowly due to building retrofit inertia. Industry lags furthest, with 30-50 percent still relying on hydrogen or biomass rather than direct electricity.
Limits of direct electrification and the hydrogen frontier
Direct-electric technologies work well for transport and low-temperature heat (up to 80-100 degrees Celsius with heat pumps). Above that, and for cement/steel/chemical production, the heat is too concentrated or too hot for electricity. Hydrogen (made by electrolysis using renewable power) or biomass-derived fuels become necessary. However, hydrogen is expensive, has a poor round-trip efficiency (~40-50 percent for electrolysis plus compression), and lacks infrastructure.
The pathway diagram reveals an uncomfortable constraint: a true net-zero grid cannot run on renewables plus batteries alone. It requires electrification where possible, hydrogen where not, and significant overproduction of renewable capacity to feed both electricity demand and hydrogen production. The cost and feasibility of this mix will determine whether net-zero targets are met or deferred.