It’s undeniable that the energy resources we currently depend on cannot sustain the long-term ambitions of humanity. Fortunately, renewable energy continues to thrive. Over the course of a decade, the cost of solar power has dropped up to 90%, and the cost of wind energy from turbines have dropped up to 60%. Across the world, renewable energy is already cost-competitive or better, with wide-scale projects ranging from Costa Rica to notoriously oil-happy Texas.
At the same time, even today’s cutting-edge methods have limits. Mining of rare-earth metals needed for electric cars comes with negative environmental consequences, and solar and wind farms need to expand the ability to store surplus energy to smooth spikes in demand when those resources are not active. Thanks to dramatic drops in the price of wind and solar, however, there is renewed interested in using hydrogen as that energy store.
Hydrogen is an ideal fuel to burn (or generate electricity from using a fuel cell), since its byproduct is just water (O2 + 2H2 = 2H2O). Not all hydrogen is created equally, so the three shades to consider for the future of sustainable hydrogen are Gray, Blue, and Green.
Also known as “brown” hydrogen, this type is the most common, and also the least environmentally-friendly or sustainable. Hydrogen made here is a byproduct of natural gas, or even coal. While the hydrogen produced still burns clean, the process by which it is made isn’t that much of a step in the sustainable direction.
“Blue” hydrogen improves on gray procedures by implementing carbon capture and storage of greenhouse gases emitted in the process. The generation at this point can be up to carbon-neutral, which is much better for overall environmental impact, albeit still imperfect.
“Green” hydrogen is the ideal expansion point for the hydrogen industry. This type of generation uses excess electricity generated by renewable resources to create hydrogen (e.g. excess solar energy can be used for electrolysis of water). As a result, the entire process has minimal environmental impact and is sustainable for longer-term energy needs. Most importantly, green hydrogen generation allows for smoothing of renewable energy supply to meet peaks in demand during off-peak generation for renewable resources (if it’s nighttime and there’s no wind, but you have hydrogen reserves, you can now burn hydrogen to generate clean electricity).
I’m very curious to see how improvements to hydrogen fuel plays out. Over the past decade alone, dramatic decreases in the cost of wind and solar increasingly make them not just viable options for energy, but the obvious choice from a cost perspective. Right now, hydrogen is still expensive, with an estimated cost of $6/kg via electrolysis. Further improvements in hydrogen over as short a time period as the next 10 years, coupled with continued improvements in wind and solar options to produce “green” hydrogen, can complete a trifecta of options that will power our healthier, sustainable future.