e-fertiliser
Agricultural nitrogen fertilizers such as Urea and Ammonia Nitrate are essential for global food production.
The Royal Society estimate that without them, half the world population would starve. But the production of ammonia, which is the basis for all of these fertilizers, is the most carbon emitting chemical process on the planet, consuming 20% of industrial natural gas output worldwide.
For farmers, the price of fertilizer varies widely because it is linked to the price of natural gas. This makes it very difficult for farmers to plan. Hydrogen Refinery breaks this link by producing the ammonia from mixed waste instead.
Hydrogen Refinery strategy is to align nitrogen fertilizer production with the United Nations’ (UN) Sustainable Development Goals.
According to the International Fertilizer Association (IFA), “The production of fertilizers is emission intensive. It is estimated that 1.3% of global carbon dioxide (CO2) emissions come from the production of mineral fertilizers. The production of ammonia, the starting point for all mineral nitrogen fertilizers, accounts for roughly 90% of the fertilizer industry’s total energy consumption and about 2% of the world’s total energy consumption. Its production is a carbon emissions and energy-intensive process, relying primarily on natural gas and coal as feed stocks.
Approximately half the food we eat today has been produced thanks to mineral fertilizers. At the same time, its use is associated with GHG emissions equivalent to an estimated 720 million tonnes of carbon dioxide (CO2)a year. To help guide a long-term sustainability strategy, IFA is working with partners and its members on decarbonization.“
Urea
The most widely used nitrogen fertilizer globally is Urea. This can be supplied in liquid form, but is normally a granular prill that contains 46% Nitrogen (N) by weight.
Urea is made by combining ammonia with carbon dioxide.
Some Urea blends included inhibitors to prevent nitrous oxides or carbon dioxide releasing to atmosphere after it has been applied to the soil.
Ammonia Nitrate
Some farmers and food producers prefer to use ammonia nitrate (AN) or calcium ammonia nitrate (CAN). Again this can be supplied in liquid form, but is normally a granular prill that contains 34.5% Nitrogen (N) by weight.
Although AN contains less nitrogen by weight, it does not release nitrogen or carbon dioxide to atmosphere. AN is made by combining ammonia with nitric acid.
Carbon footprint of Hydrogen Refinery Urea and AN production
Demand for both urea and AN continues to rise because a growing world population demands more and more food. At the same time the amount of land used for food production reduces every year. This puts farmers under pressure to produce more from less. So to increase yields fertilizer use is essential.
One day alternatives to urea and AN may exist, but these may take many years to develop, pass food safety trials, be accepted by farmers for widespread use and then scale to the 200+ million tonnes used every year. Until that day arrives, it is essential to reduce the carbon footprint of urea and AN production. Also, to make life easier for farmers to bring price stability to the market.
Hydrogen Refinery is also working with leading food retailers and supermarkets such as Tesco to help reduce their Scope 3 emissions in their supply chain.
Hydrogen Refinery carbon negative process
Hydrogen Refinery can provide both 46% N Urea and 34.5% AN in a carbon negative production process. This is because the feedstock used is waste.
Waste processing today is responsible for 4% of global emissions. Most waste is processed in 1 of 2 ways, either dumped in landfill or burned. Landfills create methane emissions, 28x more harmful than carbon dioxide (CO2). Burning waste in incinerators or energy-from-waste (EfW) plants creates on average 1 tonne of CO2 for every tonne of waste burned. With a growing global population, the human race is creating more waste. Despite efforts towards recycling, recycling rates remain low and more and more waste is being illegally dumped on land, in rivers and in the sea.
Hydrogen Refinery provides a third alternative to landfill or burning waste, by removing the waste from the environment with zero emissions. This is why the process to produce e-fuels or e-fertilizer is carbon negative, because we avoid the emissions from landfill or incineration and provide a step-up in the waste hierarchy.
Why is this much better for the future
As identified by the IFS, most of the emissions from fertilizer production are from the ammonia and hydrogen steps. Ammonia (NH3) is made using the Haber-Bosch (H-B) process where hydrogen (H) is combined with Nitrogen (N) from the air at high temperatures and pressures. Ammonia is essential for both urea and AN. The catalysts used in H-B are an expensive part of the process and are very sensitive to certain impurities including oxygen.
Over 95% of ammonia is made from hydrogen produced from steam methane reforming (SMR) where the methane (CH4) either originates as natural gas or as coal gas from coal gasification. Both these fossil fuel processes result in excess carbon dioxide (CO2) emissions. Some of the CO2 is absorbed in urea production. SMR provides heat to improve the efficiency of the H-B process.
Coal gasification is much more carbon emitting than using natural gas in SMR. Urea or AN produced from coal gasification has a carbon footprint of 4 tonnes of carbon dioxide (CO2e) per tonne while natural gas 1 tonne CO2e.
‘Green’ hydrogen from water electrolysis
Many attempts have been made to replace SMR for the hydrogen production with ‘green’ hydrogen from water electrolysis. Few of these projects have yet reached a final investment decision (FID) because the hydrogen produced is substantially more expensive. Water electrolysers use electricity to split water (H2O) into hydrogen and oxygen. About 900 litres of purified and de-ionised water is required to make 1 tonne of fertiliser (9,000 litres to make 1 tonne of hydrogen). The oxygen must be removed to parts-per-million (PPM) levels to prevent damage to the H-B catalysts. The overall process requires more energy because the additional CO2 required for urea production must be generated separately and so does the heat for H-B.
If renewable electricity is used the urea or AN produced can have a zero carbon footprint, but will be 2x to 6x the price. This is because vast quantities of electricity are required and additional energy storage. Since the H-B process must be continuous to maintain the expensive catalysts at high temperature and pressures, battery storage and hydrogen storage must be added to smooth out the intermittent nature of renewable electricity.
If grid electricity is used that is generated from a fossil fuel source, then the carbon footprint is the same as SMR from natural gas or about 1 tonne CO2e. Industrial grid electricity is on average $100 to $200 per MWh (Mega Watt Hour). As 50MWh is required to make 1 tonne of hydrogen, the cost of hydrogen is $5,000 to $10,000 per tonne ($5 to $10 per kg). This alone can add $500 to $1,000 to the cost of the urea or AN.
Hydrogen Refinery process
The Hydrogen Refinery plasma electrolysis system (PES) removes waste from the environment with zero emissions. If the waste was destined for incineration, then the carbon footprint of the urea or AN produced is negative (-ve) 10 tonnes CO2e. If the waste was destined for landfill, then because the resultant methane emissions would be 28x more harmful, the carbon footprint is negative (-ve) 280 tonnes CO2e.
Moreover PES produces the same CO2 and heat as SMR improving the efficiency of the overall process. However the costs of production are lower than coal gasification or natural gas, because there are no costs for the fossil fuels. Instead we replace these costs with a revenue stream for processing waste or gate fees.
Carbon soot for ‘green’ cement and green ‘carbon black’
In coal gasification, a coal ash or carbon soot is produced which is the base material for aggregate production in the cement industry. PES produces this same material but in a ‘green’ way because there are no emissions from the process.
Also, the carbon soot produced from PES can be used as precursor for ‘green’ carbon black to make vehicle tires.