Here is a quote from The Global CCS Institute “CCS is a proven and well understood technology”.
The Global CCS also points out that the current fleet of CCS plants have capacity to capture and store 40 million tonnes of CO2 annually.
Furthermore there are three large scale CCS plants associated with hydrogen production.
One is the Quest plant in Alberta, Canada, that captures and stores CO2 from a reforming plant.
Against this background, I read with interest Energy Voice’s coverage of Equinor’s plans for CCS associated with a hydrogen plant at Saltend on Humberside.
Saltend is described as a demonstration project. But what is there to demonstrate; the Global CCS group stress that CCS is well proven?
I could ask the same of the Acorn project.
Another aspect of the Saltend project is to blend 30% hydrogen with natural gas in a nearby power plant. Here it is quoted that this “will significantly reduce the emissions associated with power and steam production”.
To my shame I initially thought that blending 30% hydrogen with natural gas would result in a CO2 reduction of 30%.
However, if consideration is given to the heating values of both gases that is not in the case. 1 cubic metre of natural gas will provide 35.8 million Joules of energy (1000 Joules/s = 1 kW of power/heat).
Hydrogen, being a much lighter gas, has a heating value of 10.8 million Joules per cubic metre, so if a cubic metre of a 70/30 blend is combusted the energy released is 0.7 x 35.8 + 0.3 x 10.8 = 28.3 million Joules.
That means that you have to burn 1.26 cubic metres of the 70/30 blend to achieve the same amount of energy production.
Thus 1.26 x 0.7 cubic metres of natural gas will now have to be combusted i.e. 0.88 cubic metres. The upshot is therefore a 12% reduction in CO2 not 30%.
There has been much reporting of the 80/20 natural gas/hydrogen blend for domestic heating. At that combination no modification is needed to domestic boilers.
If the 80/20 ratio is used the CO2 saving is only 7%.
Whilst any reduction in CO2 is to be welcomed, I’m not sure that most people understand the extent of the CO2 reduction through hydrogen blending.
The motivation for the Humberside cluster is very laudable but I have concerns that the UK taxpayer will fund work that demonstrates the obvious – the technologies are all in place but the business case is not.
I make no apologies for being a stuck record. Unless there is a meaningful cost attributed to CO2 and other harmful emissions, the Humberside study outcome is pre-determined.
Tom Baxter is visiting professor of chemical engineering at Strathclyde University and a retired technical director at Genesis Oil and Gas Consultants
