Nothing comes for free. The global energy system still depends on fossil fuels, and renewable sources will also generate emissions during construction. Wind turbines, solar panels, and other new infrastructure require energy, some of which comes from fossil fuels.
The key is speed. Quick deployment can curb this unintended consequence significantly. Research published in the Proceedings of the National Academy of Sciences suggests that rapid implementation of renewables will cut overall emissions, because a larger share of energy needs is met by clean sources from the outset. For the first time, the study measures the ecological transition in greenhouse gases rather than dollars.
The message from the researchers is clear: energy is required to rebuild the world’s energy system, and this must be acknowledged. The lead author, a doctoral student at the Lamont-Doherty Earth Observatory, stated that no matter how the transition is pursued, it cannot be ignored. The sooner renewable sources are included, the longer they can drive the shift.
The team estimated the emissions tied to the energy used in mining, manufacturing, transporting, and constructing large solar and wind farms, along with the infrastructure for geothermal and other sources.
Previous analyses quoted the cost of new energy infrastructure in dollars, with figures around $3.5 trillion annually by 2050 to reach net zero, or nearly $14 trillion for the United States in the same period. The new study offers the first assessment in terms of greenhouse gas cost.
At the current pace of renewable infrastructure growth, the predicted warming could reach about 2.7 degrees Celsius by century’s end. The study projects that these activities could emit about 185 billion tons of carbon dioxide by 2100, comparable to five to six years of current global emissions and placing a heavier burden on the atmosphere.
Halve the effect
If the world accelerates build-out so that warming is kept near 2 degrees—the target of current international agreements—emissions from the transition could be halved to roughly 95,000 million tons. Pursuing an ambitious path toward 1.5 degrees would reduce the 2100 emissions to about 20 billion tonnes, roughly six months’ worth of today’s total.
The researchers caution that their estimates are likely conservative. They do not account for materials and construction costs for transmission lines or the batteries needed for storage, both of which require substantial energy and resources.
They also do not quantify the substitution of gasoline and diesel vehicles with electric options or the full extent of making existing buildings more energy efficient. The study focuses on carbon dioxide and does not cover other greenhouse gases such as methane and nitrous oxide.
Other effects of the renewable transition are harder to quantify but important. The shift will demand large quantities of base metals like copper and iron, plus nickel and rarer elements such as lithium, cobalt, yttrium, and neodymium that were less common in prior energy systems.
Extraction of raw materials
Raw materials may need to be sourced from previously undisturbed areas with fragile ecosystems, including deep-sea regions, tropical forests, and rapidly melting landscapes like Greenland. Solar panels and wind turbines will occupy substantial land areas, potentially affecting local ecosystems and communities. The researchers note that the lower bound is clear, while the upper bound may be higher, yet the outlook remains encouraging.
In the coming years, recent price declines for renewable technologies could enable 80–90% deployment of what is needed, especially if subsidies for fossil fuels are redirected toward renewables.
If a more aggressive plan is pursued, the perceived problem could diminish. Delays in investment over the next 5–10 years would be detrimental. The study also examined emissions from adaptation to sea level rise, finding that constructing levees and relocating communities could add about 1 billion tons of CO2 by 2100 under certain scenarios.
These adaptation costs are only part of the broader equation. The authors emphasize that decarbonization can be expedited, and emissions from the transition can be substantially lowered when rapid deployment of renewables is paired with strategic political action to accelerate implementation.