Israeli Research Into Solar/Hydrogen

Whenever anyone has criticized the proposed hydrogen-fueled vehicles as being energy-inefficient, I've always thought that they are missing the point. To me, the value of hydrogen is as a medium between electrical generators and cars, allowing any form of electricity to become fungible and portable in the way that petroleum is today. Until batteries get much more powerful than they are now, hydrogen seems the best potential way to transport energy from central generators to the end-user. Personally, I've been hoping that hydrogen could be refined from solar power, allowing for a "green economy."

Apparently, I'm not the only one:

The production of nonpolluting hydrogen fuel could be facilitated by innovative solar technology successfully tested on a large scale at the Weizmann Institute of Science in Rehovot. Scientists say it also promises to expedite the storage and transportation of hydrogen....[N]early all hydrogen used today is produced by expensive processes that require combustion of polluting fossil fuels. In addition, it is very difficult and expensive to store and transport the gas. The new solar technology tackles these problems by creating an easily storable intermediate energy source form from metal ore, such as zinc oxide.

With the help of concentrated sunlight, the ore is heated in a solar reactor to about 1,200 C in the presence of wood charcoal. The process splits the ore, releasing oxygen and creating gaseous zinc, which is then condensed to a powder. Zinc powder can later be mixed with water to produce hydrogen for fuel, and zinc oxide, which is recycled back to zinc in the solar plant. In recent experiments, the 300-kilowatt installation produced 45 kilograms of zinc powder from zinc oxide in one hour, exceeding projected goals.

The process generates no pollution, and the resultant zinc can be easily stored and transported and converted to hydrogen on demand. The zinc can also be used directly, for example, in zinc-air batteries, which serve as efficient converters of chemical to electrical energy. Thus, the method offers a way of storing solar energy in chemical form and releasing it as needed.

The project is actually a collaboration between a number of countries (full details here), but the science was originally developed and the facility was eventually built in Israel. Israel is extremely interested in solar technology, for obvious reasons, and has developed a lot of expertise on the subject.

How effective is the process? According to the Society of Manufacturing Engineers,

The first trials of the solar power-plant have used thirty-percent of available solar energy and produced forty-five kilos of zinc an hour, exceeding projected goals. During further tests this summer a higher efficiency is expected. Industrial size plants, for which this is a prototype, can reach efficiency levels of fifty- to sixty-percent.

This is amazing. Modern photovoltaic cells average about 16% efficiency, and the best dish-sterling systems (not yet on the market) get about 26%. Solar power towers can get around 60%, but that is before any transaction costs for converting the electricity into a portable form. And in any event, solar power towers are incredibly expensive to set up, though cheap to run.

I haven't found any data on how much the new process actually costs, so it's tough to tell whether and how quickly this could help hydrogen replace gasoline. But I continue to be optimistic. I predicted a year or two ago that we would replace fossil fuels within thirty years, and I'm sticking by that prediction. After all, we've got Israelis working on the problem...