We Still Have No Idea How to Eliminate More than a Quarter of Energy Emissions
by James Temple (MIT Technology Review) Air travel, shipping, and manufacturing are huge sources of carbon that we lack good options for addressing. — … But a new paper in Science offers a stark reminder that there are still huge parts of the global energy system where we simply don’t have affordable ways of halting greenhouse-gas emissions.
Air travel, long-distance transportation and shipping, steel and cement manufacturing, and remaining parts of the power sector account for 27 percent of global emissions from the energy and industrial sectors. And the authors say we need much more research, innovation, and strategic coordination to clean up these sources.
But batteries and fuel cells are still too heavy and expensive for long-distance hauling and shipping, as well as the vast majority of air travel. For these, the authors conclude, liquid fuels are likely to remain the preferred energy source, given the amount of energy that can be packed into a given weight and volume.
The researchers survey a range of solutions, including hydrogen or ammonia fuels, advanced biofuels, synthetic fuels, and solar fuels produced using what are known as artificial leaves (see “The race to invent the artificial leaf”). But none of these can be generated anywhere near as inexpensively as a standard gallon of gasoline or diesel.