Waste-to-Hydrogen
California start-up Ways2H can take municipal solid waste (MSW) — the rubbish thrown away by homes and businesses — as well as plastics and hazardous medical waste, and convert them into hydrogen — at a far cheaper cost than green H2 produced from renewables via electrolysis...
“[The cost] is very much dependent on what kind of feedstock we have, but typically we are now comfortable at $5 per kilogram,” chief executive Jean-Louis Kindler tells Recharge. “And we can go down to about half that, let’s say 3 dollar a kilogram… [within] five years.”...
Part of the reason why the cost of Ways 2H’s hydrogen is relatively low is that the raw materials are cost-negative — municipalities pay companies so-called “tipping fees” to take away their waste...
“There is a [US] Department of Energy report that mentions the existence of potentially more than a billion tonnes of biomass [waste] available [annually]. If you extract all the hydrogen out of this, you would literally have enough hydrogen to produce the equivalent of what is actually consumed in the US every year as gasoline in motor vehicles,” he explains...
Another reason to convert MSW, which contains more than 50% biomass, into hydrogen is that landfill waste is a major source of methane — a greenhouse gas that is 84 times more harmful to the climate than CO2 over a 20-year period. Utilising this waste biomass means this methane would not be released into the atmosphere...
The waste feedstock — from which inert materials such as metal and glass have been removed — is first processed to reduce the waste to particles of between 0.5 and 3cm. This is then fed by a screw conveyor into a gasification vessel, where it is mixed with ceramic beads that have been heated to around 1,000°C.
At these temperatures, most of the organic waste and plastics are converted into a mixture of methane, hydrogen, carbon monoxide and CO2. Solid carbon and minerals remain as char, which is removed together with other inert materials, such as metal and glass that may have remained in the mix before preparation.
The gas mixture then enters the reforming vessel, where steam is added, which breaks down the methane into hydrogen, carbon monoxide and dioxide, to improve the ratio of hydrogen to more than 50% of the volume.
Contaminants that may appear, such as chlorine and sulphur are removed in the process. The resultant syngas is cleaned and a separator recovers pure hydrogen, while the carbon gases are either released into the air or captured..
The char that was recovered from the gasification vessel is burned in a separate vessel to provide the 1,000°C heat, which is used to heat the ceramic beads.