A Luxembourg-based technology company says it will soon be able to produce carbon-negative green hydrogen from non-recyclable waste at a cost of zero or below, with income from associated revenue streams offsetting the expense of H2 production.

Boson Energy has developed a plasma-assisted gasification process that uses extremely high temperatures to break down waste into hydrogen, carbon dioxide and a molten slurry that solidifies into a blue/grey glassy rock (pictured above).

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The process will essentially create several revenue streams, Boson CEO Jan Grimbrandt tells Recharge. The hydrogen, “green CO2” and rock would be sold for profit, while the company would also receive a “gate fee” from local authorities and recycling companies for treating the waste, and carbon credits for avoiding landfill methane emissions.

Despite being a greenhouse gas, carbon dioxide is an important product used by various industries, including carbonated drinks, food processing, food packaging and greenhouses, and is typically derived from fossil fuels. It could also be used to help cure cement and other construction materials, which would “fix” the CO2, preventing its release into the atmosphere.

The inert glassy rock can be used as industrial aggregate in cement, concrete and road-building.

The income from these revenue streams would essentially be enough to offset the cost of hydrogen production, thereby enabling the zero-carbon gas to be manufactured at zero or even sub-zero costs.

“If we do our business development right... we can actually bring the cost of hydrogen to zero or even past zero and go negative because we have other revenue streams,” says Grimbrandt.

According to Boson, the process will produce about 100kg of carbon-negative hydrogen for every tonne of waste — and require six times less renewable electricity per tonne than green H2 derived from water electrolysis.

And with about two billion tonnes of non-recyclable waste being dumped or incinerated globally each year, the potential market is enormous.

“You have 100 million tonnes of waste in Europe going to landfill [every year] and 100 million tonnes going to incineration. So you have 20 million tonnes of hydrogen potential in that waste,” Grimbrandt explains.

To put that volume into context, the European Commission has set a target of producing ten million tonnes of green hydrogen, largely from 40GW of electrolysers by 2030, and importing the same amount by the same date.

Boson says that even if the carbon dioxide it produces is released into the atmosphere after use, its process would still be “carbon-negative” due to the avoidance of emissions of landfill methane — which is 86 times more powerful a greenhouse gas than CO2 over a 20-year period.

The company believes that it would make more sense from an energy-security perspective for Europe to produce hydrogen locally from waste or biomass, rather than trying to import it from other parts of world — as Germany, the Netherlands and even the European Commission is planning.

Plus, Boson points out that H2 from waste and biomass can be produced at full capacity around the clock, rather than whenever the wind is blowing or the sun is shining.

How does the process work?

The system Boson has designed — based on 25 years of development — is remarkably simple. Roughly shredded waste enters a vertical “reactor” that is heated from the bottom by electric-powered plasma torches capable of producing temperatures of up to 7,000°C.

The temperature at the top of the reactor is far lower than at the bottom, so the waste goes through ever-increasing heat zones as it travels to the bottom, with each temperature zone performing its own important functions.

Screenshot from Boson Energy animation showing the plasma torches in the reactor's bottom chamber. Photo: Boson Energy

In the uppermost zone, the waste is dried and heated. It then moves down to a hotter zone where pyrolysis (decomposition by heat in the absence of oxygen) takes place. Biodegradable matter becomes pyrolytic gas, a mixture of hydrogen, carbon monoxide and light hydrocarbons (mostly methane).

In the next zone, the remaining matter — carbon and inorganic materials — is gasified by steam, and all the gases released in all these steps combine into syngas, a mixture of hydrogen and carbon monoxide (CO).

The gas leaving the reactor then goes through steam reforming and water gas shift processes, which convert the remaining hydrocarbons and CO into additional H2 and CO2. A final step separates the syngas into H2 and CO2. Left behind is a small amount of “rest gas”, consisting of nitrogen, some CO2 and a small fraction of hydrocarbons, which is used as an energy source for steam production.

The leftover material — mainly inorganic ash and slag — then falls to the bottom vitrification chamber, where it is heated by the plasma torches to 1,500-2,000°C into a molten state. This lava-like liquid is then extracted and allowed to cool into an inert glass-like material that Boson is calling “IMBY rock”.

Project pipeline

A commercial-size proof-of-concept plant has already been built and operated in Israel, which was validated and assessed by the national environmental authority and the engineering services firms SNC Lavalin, Juniper and WSP.

Boson is now developing ten commercial projects across Europe — in Spain, Germany, Sweden, Norway, Poland, the Netherlands and Luxembourg — which are included in the European Clean Hydrogen Alliance’s (ECH2A) pipeline of 750+ projects that meet European Commission criteria.

“Each of the projects have different time schedules,” says Grimbrandt. “One project is already permitted, we hope we will get permitting in place of two more projects this year.”

Boson’s first commercial-size demonstration plant for hydrogen from wood waste is already in construction and on track to be up and running by end of 2022.

The company expects to start up its first commercial plant for non-recyclable waste in 2023 — a project that already has waste supply and H2 offtake lined up.

“We have a project with one of the biggest recycling companies in Scandinavia that we are developing where they take in about two million tonnes of waste per year,” says Boson’s chief communications officer Heike Zatterstrom. “And they have almost a million tons of recycling refuse that they are currently sending for incineration. So they have to pay to get rid of a million tonnes of recycling refuse. But that million tonnes of waste is basically 100,000 tonnes of hydrogen that they are paying to get rid of.”

Grimbrandt points out that the ten ECH2A projects alone would produce 60,000 tonnes of carbon-negative hydrogen per year.

“And if you put that volume in an electrolyser context, it’s basically 1GW of wind-powered electrolysers,” he explains.

Boson’s vision is to work in partnership with local waste management companies and municipalities to jointly build, own and operate small-scale, pollution-free waste-to-hydrogen plants, with each standard facility only having a spatial footprint of 40 by 60 metres and producing 3,500 tonnes of clean H2 every year.

The waste would therefore become a profitable asset, rather than a cost to the taxpayer, as well as reducing each local authority’s greenhouse gas emissions by avoiding landfill methane.

“We call ourselves the in-my-backyard (IMBY – hence the name of the rock) company... we believe in small-scale distributed solutions... part of the concept is to basically allow people and communities to take care of — and benefit from — their own waste, to avoid the Nimby issues that come with all large-scale infrastructure where you have to take care of other people’s problems,” says Zatterstrom.

Boson has calculated that it would take 60,000 of its distributed plants to convert all the world’s annual two billion tonnes of unrecycled waste to hydrogen. And that if all that H2 was used to power electric vehicles — either via onboard fuel cells or off-grid hydrogen-powered EV charging points — it would reduce global energy-related CO2 emissions by 20%.

Boson is now working with partner companies that will supply equipment and systems, including Siemens Energy, Montreal-based PyroGenesis, Vienna-headquartered RHI Magnesita, Norwegian green technology company Haldor-Topsoe and US conglomerate Honeywell.

Why is waste-to-hydrogen better than incineration?

According to European waste-to-energy trade association, ESWET, incinerators that produce “low-emission” power, heat and industrial steam supply 2.4% of the EU’s energy demand every year.

ESWET says that burning waste prevents methane landfill emissions and that the 39TWh of electricity and 90TWh of heat that European incinerators produce annually saves up to 50 million tonnes of CO2 that would otherwise be emitted by fossil fuels.

But while those points are valid, incinerators also emit greenhouse gases — including carbon dioxide and NOx emissions, as well as other pollutants that are harmful to human health.

A 2016 scientific paper, Toxic Pollutants from Plastic Waste – A Review, published in the journal Procedia Environmental Studies, pointed out that about 12% of municipal solid waste consists of plastics, which when burned release “toxic gases like dioxins, furans, mercury and polychlorinated biphenyls into the atmosphere… the toxic substances thus released are posing a threat to vegetation, human and animal health and [the] environment as a whole… polystyrene is harmful to [the] central nervous system… the hazardous brominated compounds act as carcinogens and mutagens”.

It adds: “Dioxins settle on the crops and in our waterways where they eventually enter into our food and hence the body system. These dioxins are the lethal persistent organic pollutants and its worst component, 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD), commonly known as Agent Orange, is a toxic compound which causes cancer and neurological damage, disrupts reproductive thyroid and respiratory systems.

“Thus, burning of plastic wastes increases the risk of heart disease, aggravates respiratory ailments such as asthma and emphysema and cause rashes, nausea or headaches, and damages the nervous system.”

So from a human health perspective, incineration isn’t great. Nor is it ideal from an economic perspective, according to Boson.

Zatterstrom points out that not only do waste management businesses have to pay for incineration companies to take away their non-recyclable waste, their sustainability footprints are also “loaded with the CO2 emissions from that waste, and also the ash. And a million tonnes of waste is 250,000 tonnes of ash.”

When incinerated, waste produces fly ash, which is present in flue gases, and bottom ash, which accumulates at the bottom of the incinerator. The latter can be added to tarmac, but the former is a hazardous materials has to be treated and disposed of in mines or quarries at extra cost.

“The other big thing that is coming up against incineration now is the curtailing — the fact that incineration, just like coal and gas, is expected to give way to renewables in the grid,” explains Zatterstrom. “And if you have a coal plant or a gas plant, you can do that. If the grid operator says, ‘okay guys, this weekend, I don't need you, so no coal power this weekend’, then the plant will say, ‘okay’, and they can just leave the coal sitting in the yard.

“But the incinerator cannot do that. They cannot tell people, ‘okay, this weekend we don't need waste’, because the waste is produced all the time, and needs to be processed, and they need to keep temperatures in the ovens up for, for environmental compliance reasons, etc, for compliance. So they have to continue to run, but are not able to supply the power. And they are already now at a pretty low profitability. They are making €15-20 per tonne of waste treated today. And already now in a few European markets, they are expected to not produce power for 1,000 hours a year. And they have no idea where this will go. They think it could go to 2,000, to 30,00 hours of not producing power, but you still have to run.

“Shifting over from incineration to [Boson’s] process will bring you from €20 per tonne to €200 per tonne in profit.”

Zatterstrom points out that if we don’t use non-recyclable waste for power or hydrogen production, it will be left to rot in landfills, producing methane that is 84 times more powerful a greenhouse gas than CO2 over a 20-year period. Other potential energy sources don’t have that problem.

“Natural gas, we can choose whether we use it or not. Electricity, we can choose whether we use it or not. The wind and the sun are not gonna kill us if we don't make energy from them. But the waste will actually kill us.”