It's elemental, my dear Watson:
Hydrogen as power storage offers important advantages:
1) It can be “transmitted” via electricity from an AZ solar farm or OK wind field to electrolyzers a thousand miles away. No pipelines or fuel trucks needed!
2) At its new home, it can be stored in tanks built out to any size and number. That's unlimited energy storage.
3) At those locations it can be produced whenever there's extra power on the grid: After midnight when the city sleeps; During the day when solar or wind are over-producing.
4) Some of those locations will be thousands of gas stations, extracting H from water to fuel the next day's vehicles.
One key to truly unlocking all this will be “solid state” H storage, using hydride, nanopore or another system. We don't have that...yet. A few $billion spent wisely now on research to develop low pressure, high-density H storage will solve most energy-related climate change problems. It will make H storage simple, safe and efficient, to back up the grid and in vehicles and aircraft.
It’s my view that much of our transportation will eventually use hydrogen, because it’s the lightest of all possible fuels. By a lot! That’s because the hydrogen atom, the original element, is the only one with no neutron (just a lone proton). All other atoms are much heavier with respect to the number of electrons available to make electricity. It’s elemental, my dear Watson! There are other reasons why hydrogen may be the ultimate fuel, but weight is the key. Why is that?
Weight is an important factor in vehicles, aircraft and rockets; most anything that moves, especially if it flies. Less weight means more distance without refueling, and for long-haul trucks it also means more payload -- they must deal with highway load limits. It’s why there’s so much aluminum and plastic in modern cars, replacing cheaper steel to improve gas mileage.
Note that producing hydrogen from electricity, then generating electricity later from that stored hydrogen, is less energy-efficient than simply charging a battery. But, lower weight in an H-powered vehicle or aircraft returns some of that loss during use, and it becomes crucial when batteries are just too heavy to fly a plane very far. We've never worried about the overall efficiency of gasoline as a transportation fuel -- after figuring in the cost to find the crude, frack it loose and bring it up, transport it to a refinery, rework the molecules to make unleaded gasoline, truck it to a gas station and burn it in a piston engine, gasoline's efficiency is much lower than hydrogen's. Even ignoring everything but the piston engine, hydrogen is converted to vehicle motion roughly twice as efficiently as gasoline. We accept that because it's been the only way to move a vehicle until now. That same logic applies to hydrogen as a vehicle fuel, especially where batteries are just too heavy to function.
In addition, hydrogen produced using excess solar/wind electricity allows that power to be stored for later use. There are other ways to store huge quantities of power, for example by pumping water up to a pond on a hill then running it back through a generator, but making and storing hydrogen also works on the flatlands, and the amount that can be stored is limited only by the number of tanks installed or added later. Batteries are backup power champs too, but storing enough power to run NYC or LA for long periods would require impossibly large batteries, at least for the foreseeable future. Hydrogen’s ability to store excess power becomes a serious benefit as we move in a big way to renewable but intermittent electricity. Solar power is already being wasted on some sunny days in California, and we’ve just begun that transition.
Battery weight in a Tesla Model S is 1200 lbs – the Tesla can drive up to 400 miles before a recharge. That battery weight is compensated by excellent engineering and the use of light materials in the body and chassis. But there are still 1200 pounds of batteries being pulled up the hills. Battery weight in a Ford Lightning pickup is a literal ton, with the vehicle frame reinforced to hand the excess weight, and that's all that can be squeezed into the truck with a range, under ideal conditions, of about 300 miles.
The weight of the hydrogen in a Hyundai Nexo fuel cell SUV is 14 (yes, fourteen) pounds, powering the same 400 miles as the Tesla. Add in the storage tank and fuel cell, and the H system running a Nexo weighs about 10% of a Tesla’s battery.
As we’ve discussed elsewhere on this site, we must find a way to store hydrogen without the hassles of extreme compression or super-low temperature. I think the breakthrough will happen, since it’s so important to both transportation and renewable energy storage.
Watch this space for updates...
We’ll also need lots of battery-electric cars to get rapidly from carbon to clean, but I think that hydrogen wins the transportation contest in the long run, especially for larger vehicles, aircraft, ships and probably locomotives. That's a lot.
Our motto: “No Neutrons!”