Building green energy facilities may generate substantial carbon emissions, but speedy construction could negate most of these negative effects, a new study has found.

The construction of wind turbines, solar panels and other infrastructure comes with a price: consumption of the same fossil fuels that they are replacing, the study authors wrote.

But a rapid scale-up of these technologies could help emissions dramatically decrease, according to the research, published on Monday in the Proceedings of the National Academy of Sciences.

With more renewable energy powering the grid early on, fewer fossil fuels would be powering the clean energy changeover, the scientists found.

“The message is that it is going to take energy to rebuild the global energy system, and we need to account for that,” lead author Corey Lesk, who conducted the research as a Ph.D. student at the Columbia Climate School, said in a statement.

“Any way you do it, it’s not negligible,” Lesk continued. “But the more you can initially bring on renewables, the more you can power the transition with renewables.”

Lesk and his colleagues drew their conclusions by calculating the potential emissions generated by energy use in mining, manufacturing, transporting and building solar farms, wind turbines and the more limited infrastructure required for geothermal and other power sources.

Previous studies have projected that the cost of such new infrastructure would amount to about $3.5 trillion annually until 2050 to reach net-zero emissions, or about $14 trillion total for the U.S., the researchers noted.

But Monday’s study, they explained, is the first to forecast this cost in greenhouse gasses.

If the current slow pace of renewable infrastructure production persists — leading to about 2.7 degrees Celsius (4.9 degrees Fahrenheit) of warming by 2100 — these activities would generate 185 billion tons of carbon dioxide within the same time frame, according to the study.

This amount would be equivalent to about five or six years of current global emissions, the authors explained.

But countries could cut those emissions in half, to 95 billion tons, if they built the same infrastructure quickly enough to limit warming to 2 degrees Celsius (3.6 degrees Fahrenheit), the scientists found.

World leaders agreed to stay below that 2 degrees Celsius mark at the 2015 United Nations climate change conference in Paris.

Even better results could occur if countries produced the infrastructure fast enough to keep warming under 1.5 degrees Celsius (2.7 degrees Fahrenheit) — a more ambitious goal that Paris delegates had said they hoped to achieve.

With such a build-out, the cost of the renewable energy transition would be only 20 billion tons by 2100, or just about six months of current global emissions, according to the study.

While emphasizing that such efforts would provide significant benefits to the planet, the authors acknowledged that their emissions estimates are probably quite low.

They accounted neither for the materials necessary to build new electricity transmission lines or batteries for storage, nor for the cost of replacing combustion-powered vehicles with electric ones.

The authors also said they focused only on carbon dioxide emissions — which today cause about 60 percent of warming — and not on those from other greenhouse gasses, such as methane and nitrous oxide.  

Other impacts of the transition to clean energy could also be substantial, but remain difficult to quantify, the scientists stressed. Many necessary commodities could come from previously untouched places, while solar and wind farms would consume large parcels of land, they added.

“We’re laying out the bottom bound,” Lesk said.

“The upper bound could be much higher,” he added, noting, however, that “the result is encouraging.”