Burning “Liquid Sunlight” Instead of Fossil Fuels Is Getting Closer to Reality
by David Roberts (Vox) … However, some uses of energy are not easy to electrify in the short term, maybe even in the long term. They rely on energy-dense liquid fuels. So if we’re ever going to get to net zero emissions, we badly need zero-carbon liquid fuelsthat can substitute directly for fossil fuels in those areas that can’t be electrified.
So what kind of energy services need liquid fuels? Let’s focus on the US.
First and mostly, there’s transportation. About 26 percent of US emissions come from transportation (90 percent of which is powered by fossil fuels).
Some of that can be electrified; around 60 percent of transportation emissions come from light-duty vehicles, which are already on the road to being electrified. Most of the rest, though, come from medium- and heavy-duty trucks and airplanes, which are difficult to electrify without serious advances in the energy density of batteries.
Then there’s industry (another 21 percent of US emissions). Lots of high-heat industrial processes, like making steel and coke, require fossil fuel combustion. And industry uses lots of fossil fuels as feedstocks for chemical processes that make things like plastics. In both cases, there are no ready-to-hand substitutes for liquid fossil fuels.
There are many varieties of solar fuels being researched and tested right now. If you want the nitty gritty, see this 2015 report from MIT; this PNAS piece gets into detail about the latest research breakthroughs. I’ll just run through a high-level summary.
The research falls into two basic buckets: The first produces hydrogen; the second uses hydrogen to produce hydrocarbon fuels. READ MORE