While the renewables and fossil-fuel industries have been battling to win the argument over how the clean hydrogen required for the energy transition should be produced, a third option is now competing for the limelight — and offering a carbon-negative solution: hydrogen from waste.
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 a kilogram… [within] five years.”
By comparison, the cost of green hydrogen from wind or solar costs about $11-16 per kg today, according to Hydrogen Europe, although it adds that this cost could halve by 2023-25.
“We can supply renewable hydrogen, just like solar and wind-powered electrolysed hydrogen, but without using the vast space that solar panels require,” says Kindler. “Plus, our technology solves another issue, which is the waste crisis.”
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.
“We expect tipping fees of about $70 per tonne,” Kindler tells Recharge. “We see situations in California where municipalities have to pay well over $100 per tonne of their waste to have it processed.
“I saw a French company that had been fined because they were sending plastic waste from France all the way to Malaysia. If they want to get rid of this waste, they have to pay.”
Ways2H’s plants can also operate 24 hours a day, 365 days a year — unlike electrolysers powered purely by wind and solar — an efficiency that contributes to lower production costs.
‘Save wind and solar for electricity’
Kindler argues that the electricity sector needs to be decarbonised, requiring many gigawatts of wind and solar power, especially with the coming growth in demand from electric vehicles (EVs).
“Let’s use that power to charge EVs, rather than use the power to electrolyse water to produce hydrogen,” he says.
“In places that don’t have the capacity or capability to build more wind or solar, turning waste to hydrogen makes much more sense — everywhere that people live, waste is generated, but not everywhere that people live is great for wind or solar.”
Kindler believes that waste can one day provide a third of the world’s clean-hydrogen needs.
“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.
Furthermore, Kindler says, “our goal is to produce hydrogen from waste, then capture and store the carbon, which [makes the process] carbon-negative.”
Ways2H has been “approaching partners to have carbon sequestration, or at the very minimum, have carbon-use solutions on the sites where our systems are installed”, he adds.
How the technology works
Ways2H — a joint venture between US-based Clean Energy Enterprises, and Tokyo-based Japan Blue Energy Corporation (JBEC) — uses technology that has been developed over the past 20 years by JBEC.
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.
For every tonne of dry waste put into the system, roughly 40-50kg of hydrogen are produced — although this can vary between 30kg and 120kg depending on the contents of the waste stream. Any water, or moisture, in the feedstock contains hydrogen, which also contributes to the proportion of H2 produced.
Ways2H plants come in two flavours — a mobile solution capable of processing one tonne of waste per day, which fits inside three shipping containers, and scaleable stationary solutions that can process between eight and 50 tonnes of feedstock a day.
Ways2H has a mobile demonstration unit in Japan that can produce 50kg of hydrogen a day, and is in discussions to build three commercial pilot projects in California, Japan and South America.
The company is also in talks with California healthcare centres to develop projects that would convert medical waste — including all the personal protection equipment needed during the coronavirus pandemic — into hydrogen.
“Our plans are definitely to be a major player in hydrogen production,” says Kindler. “I'm not saying this will happen overnight. I'm not saying that I want to kill all the solar panels and wind turbines that are producing hydrogen through electrolysers. But I do think that a reasonable mix of [hydrogen from waste] would help the planet getting rid of at least a major fraction of the waste that is currently being produced. And this is what we want to do and we definitely aim at being a leader in this industry.”
More than 95% of the hydrogen produced today is derived from unabated fossil fuels (natural gas or coal), resulting in nine to 12 tonnes of CO2 emissions for every tonne of H2. This is known as grey hydrogen.
However, 'green hydrogen' can be produced with zero emissions by using renewable electricity to split water molecules into H2 and oxygen inside a machine called an electrolyser; a process known as electrolysis.
Or the CO2 emissions from natural-gas-based H2 production can be captured and stored, resulting in what is known as blue hydrogen. Strictly speaking, this would be classed as low-carbon hydrogen as not all the CO2 from the production process can be captured.