Decarbonizing the grid with a large share of renewables comes with reliability challenges Decarbonizing the US power supply with solar and wind generation entails the challenge of an intermittent supply that cannot reliably match power demand, especially the multiday variability of this demand.¹¹ The higher share of electrified energy demand implied by decarbonization will make reliability in the grid even more important, as electricity will be needed for residential heating and critical industrial processes.
There are several options for securing a reliable and dispatchable power supply in a decarbonized grid to address multiday variability (Exhibit 2). While various long-duration energy storage (LDES) solutions may be economic in some geographies to provide electricity during multiday periods of low renewable generation, natural gas is consistently the most reliable and cost competitive—even after accounting for carbon costs. Natural gas generation is known as a “dispatchable” energy source, meaning that the facilities for natural gas generation can be switched on or off depending on need—demonstrating its suitability as a security supply for the grid.
Exhibit 1 The share of renewables in the grid has a direct bearing on US decarbonization goals. US power generation mix, thousand terawatt-hours decarbonization goals. Gas Wind and solar
Hydro and nuclear
Other¹
7.5
0.8 6.9
0.2
0.9
0.2
1.9 0.8 5.8
0.2
1.1 5.1
4.6
0.1
4.3
0.9 4.3
1.7 0.6 1.0 0.9 4.3
1.7 0.6 1.0 0.9 4.3
0.4
3.8
0.4
1.2 1.1
5.8
1.6 1.2 1.1
2022 2030 2040 1.7 0.6 1.0 2.9
2.2
2.2
1.8
1.6
0.6
2022 2030 2040
2022 2030 2040
Scenario Current trajectory (CT)
Further acceleration (FA)
Achieved commitments (AC)
Description • Decline in cost of renewables continues and existing enacted targets are met, but no new policies are put into law
• Presupposes that most ambitious publicly discussed ambitions are met • In the US, this includes net-zero power by 2035 on a path to a net- zero economy by 2050 • Largely ignores supply chain issues and other constraints
• Driven by increased commitments, though financial and technological restraints remain
Slower
Faster
Speed of energy transition
1 Includes coal and dispatchable renewables like hydrogen and bioenergy.
McKinsey & Company
11 “Toward a more orderly US energy transition: Six key action areas,” McKinsey, January 12, 2023.
Accelerating the journey to net zero
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