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Do we have the technology to go carbon neutral today?

We still need new breakthroughs to decarbonize many parts of our modern economy, especially if we don’t want to drive up the price of energy and goods. But we can make real progress with today’s technology, and invest in good ideas for the next generation of low-carbon solutions.

 

What would our world look like if we became completely carbon neutral? Could we still enjoy today’s electricity, transportation, heat and manufacturing if we put no more greenhouse gases into the atmosphere than we take back out? “Unfortunately, these are not solved problems,” says Desiree Plata, MIT Professor of Civil and Environmental Engineering. “While we do have the technology to make a lot of systems nearly carbon neutral, none of these systems can run the same way they do today and the cost to implement [some of today’s solutions] is prohibitively high.”

First, the good news. We’ve gotten pretty good at making low-carbon electricity. Today, solar panels and wind turbines can make electricity at a similar price to coal or natural gas. And we can also use that clean electricity to drive (like with electric cars) and to heat our homes and water (like with electric furnaces and hot water heaters): things that today mostly run on oil or gas.

However, says Plata, it’s not so simple to switch out the old, fossil fuel technologies for the new, low-carbon ones. Solar and wind power aren’t always there when we need them, the way coal and gas are. “For example,” Plata says, “solar energy is best captured and stored during the middle of the day, but is least accessible at night when the demand increases. One of the only technologies to meet that rapidly accelerating demand is fossil-derived carbon.” In other words, we still need fossil fuels to fill the gap when we don’t have enough sun or wind. To get more of our electricity from wind and solar, we first have to change the way we use and distribute electricity, or come up with better ways to store energy that can work on a large scale and at low cost.

Then there are areas where today’s carbon neutral technologies can’t match the performance of fossil fuels. “Transportation would have to change drastically, as carbon neutral energy cannot provide as much power for large vessels as fossil fuels,” says Plata. “Think about air travel. Solar planes have to be very lightweight. So, passenger jets have to be shrunken down from the traditional form to much smaller units. Instead of an Air Bus, you need an Air Car.” Heavy trucks and rail transport have similar limitations.

Finally, there are areas where our technology isn’t ready to support a switch to cleaner energy sources at all. The steel and concrete manufacturing sectors in particular don’t yet have options to stop using fossil fuels to generate the high amount of heat they need. So, the next best method is to capture and store the carbon dioxide these facilities emit when they burn fossil fuels. Some factories around the world, making everything from fertilizer to steel to gas, have been adding carbon capture technologies in recent years, effectively keeping their carbon emissions out of the atmosphere. And some coal- and gas-fired power plants have started to follow suit.

“This has grown appreciably in the last decade,” says Plata. However, “there is a significant cost to implement these technologies, measured in millions of dollars to stand up the needed infrastructure. This is not currently economical for most plants, and it only becomes economical if you put a price on the carbon to incentivize its trapping.” That’s one example of a political solution that could work alongside technological ones: if companies had to pay for the greenhouse gases they emit, they would have an incentive to become carbon neutral even with today’s technologies.

Just because we don’t have all the technology we need to overcome the climate crisis today doesn’t mean there’s nothing to be done. We are far from using today’s technologies to their full potential. Wind and solar power, carbon capture, and electrified heat and transportation all have lots of room to grow. And for those sectors where we still need new options, scientists and engineers are working on innovative approaches to energy storage, manufacturing, new transportation fuels, automated and low carbon air travel, and everything in between. “It’s a great time to be a technologist,” says Plata. “There are so many ways young scientists, engineers, and policy architects can contribute to solve these important problems.”

 

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