Hydrogen transport and generation powder Si+ was revealed last week, causing quite a stir with its promise of making renewable energy incredibly cheap, convenient and safe to transport – in stark contrast to the expense, inefficiencies and difficulties involved in transporting hydrogen as a gas, a cryogenic liquid or embedded in ammonia.

Much of the world seems to be coalescing around green hydrogen as a clean way to store, transport and export renewable energy, but as we outlined in another piece last week about a hydrogen storage powder developed by scientists at Australia's Deakin University, the high costs involved in compressing and containing the gas, cryogenically cooling and storing the liquid, or converting it to ammonia could place a heavy thumb on the cost scales. The green energy transition can't happen if the costs are so high that economies can't bear their weight.

Enter the solid-state hydrogen powders. Whether it's Deakin's ball-milled boron nitride or EPRO Advance technology (EAT)'s porous silicon, these powders can effectively transport green energy using cheaper and much more conventional means. Fill a truck or a shipping container with either, send it on a regular cargo boat, and somebody at the other end can use it to release hydrogen, ready to go.

Deakin's solution requires heat for the hydrogen release, EAT's Si+ product requires water and sodium hydroxide. Both offer a zero-emissions pathway, and leave the user with by-products that are either recyclable or potentially useful. And both claim to be radically cheaper than pure hydrogen, particularly when transport and storage costs are factored in.

EAT's Si+ powder is claimed to offer a higher density of energy storage per weight than the Deakin powder, and once combined with alkaline water to produce its hydrogen, it leaves nothing behind but silica, which can be sold off to make concrete. So it's of particular interest.

Naturally, you had questions. We did too, so to follow up from our original piece, we contacted EAT Executive Director and CEO Albert Lau over email. We put the following questions to him, and present Lau's answers below, in an edited format.