While support is growing for the need to decarbonize the global economy, many believe it will be very challenging to get there. And a growing number agree we’ll need all the tools available to us if we’re going to have a shot by mid-century, in time to avoid the worst impacts of climate change. Included in a sweeping DOE announcement last week of carbon capture studies was some good news about our prospects for decarbonizing fuel production.
Currently, about 80% of the energy delivered to consumers globally is in the form of hydrocarbon molecules (e.g., gasoline and diesel for transportation, natural gas for heating, etc.) while only about 20% is in the form of electricity. If we are to fully decarbonize, in addition to eliminating the emissions associated with electricity generation, we need to figure out what to do about the 80% of final energy we get by just “burning things we’ve found” (as Jon Stewart would say).
Hydrogen, and ammonia, which is hydrogen bonded with nitrogen from the air, could play a key role. Hydrogen carries more energy by weight than any other molecule, and because it contains no carbon, it emits no CO2 when burned. Analysts differ on the ultimate prospects for deploying hydrogen in the energy system, but if we replaced half of current global car and truck fuel with hydrogen, we would need about 150 million tonnes of the stuff annually. Today, we get about 53 million tonnes annually by reforming natural gas and 1.4 million tonnes annually using electricity to split water in electrolyzers.
Unfortunately, today’s natural gas reforming processes release large quantities of CO2 into the atmosphere. But, this hydrogen can be “decarbonized” when the CO2 produced during the reforming process is captured before it is released and sequestered geologically. Two highly successful projects in North America already do just that: a project by Air Products in Port Arthur, TX, and a project by Shell in Alberta, each of which captures and sequesters about a million tonnes of CO2 a year.
DOE’s announcement last week is potentially even more significant. Industrial gas major Linde will join forces with DOE to study the application of carbon capture to a large natural gas reformer already under construction in Louisiana. The reformer will produce around 150 thousand tonnes of hydrogen annually and if built the additional equipment being studied would capture at least 90% of the CO2 produced.
In equivalent terms, this is approximately the same amount of decarbonized hydrogen as would be produced by an 800 megawatt electrolyzer running around the clock, or 2000 megawatts or more of solar- or wind-powered electrolysis. Linde’s Louisiana project thus joins the ranks of other world-scale proposals such as the NEOM ammonia project in Saudi Arabia (4000 megawatts, powered by solar) and the NortH2 hydrogen project in Europe (3000 – 4000 megawatts, powered by wind).
Decarbonization is a big lift, and we will need all the clean energy sources we can get. Hydrogen produced by reforming natural gas with carbon capture, also known as “blue” hydrogen, can help provide large volumes of hydrogen on rapid timescales and at acceptable costs, complementing low-carbon electricity and electrolysis in a green transition. Of course, as CATF has noted elsewhere, the natural gas supply also needs to be cleaned up. The DOE announcement is good news of an important step in the right direction for decarbonization.