Hi Spid,The CO2 produced from oil or gas fields varies...

Hi Spid,
The CO2 produced from oil or gas fields varies considerably, but is often up to 30%. I have no idea how many wells are powered by renewables , but would guess there'd be very few.
It is the fugitive emissions from fossil fuel sources, (so far uncontrolled with no technology proved workable) that proponents of renewables use to disqualify the use of fossil fuels in the production of "green hydrogen".
In the case of the Hazer process using biogas.as a feedstock the conversion of the CH4, storing the carbon as graphite, is more than enough to offset any carbon created from the very small amount of iron ore used. in fact their process is carbon negative.
I'm all in favour of blue hydrogen as I believe the future demand for hydrogen will far exceed renewable's ability to deliver enough and at an economical price.