Renewable Gas : An Introduction

At first, I covered the usual ground – yes, many people are exploiting Biogas, and upgrading it to Biomethane to inject into the gas grid. Natural Gas is something like 75% to 85% methane, don’t you know ? They’re all fairly small projects at present, but it could scale up and replace several percent of the gas supplied.

And then there’s Renewable Hydrogen. One of the speakers mentioned “Power to Gas” :-

[…]

[Question from ARUP] “…your views on the role of gas in Germany ? Gas contracts – do they need to change with respect to Russia ?”

[Answer from German Energiewende presenter] “Gas has a role to play [as backup for renewables]. It needs to be interim [a bridge, a transition]. German business is quite happy with the relationship with Russia. If we’re going to have 80% renewable generation of electricity by 2050, what will be the 20% ? Russia believes that 20% will be in gas. Others, [flexible] lignite [generation]. I believe that by 2050, 100% renewable electricity is possible – the gas you will have will be biogenic [Biogas, Biomethane] – or synthesised by excess wind – Power to Gas. You can store gas for a long time – there’s a 30% cost in [energy] conversion – but this is achievable in the margins…”

[…]

I explained the two parts of Power to Gas to the young researcher after the seminar was over. First of all, the production of Renewable Hydrogen – hydrogen produced using methods that use no biological components. And then the methanation of Renewable Hydrogen to make Renewable Methane. And for methanation, you need carbon-rich gases.

The young man started to do internal calculations – leaps of thought. His brain almost audibly hummed. “And where do you get this carbon-rich gas from ?” he asked, “from Carbon Capture and Storage (CCS) ?” “From Carbon Capture and (Re)Utilisation (CCU)”, I explained.

I told him that ITM Power, together with a number of other industry players were looking at the prospects of injecting Renewable Hydrogen into the gas grid, which in addition to injected Biomethane, could total 10% to 15% of the gas supply – more if Renewable Methane were included. This would not be a small number. Again, I could almost hear the young man’s mind whirring.

Gas, we agreed, is the answer to backing up Renewable Electricity whilst capacity is being developed. And therefore, the decarbonisation of the gas supply is a useful goal.

[ NOTE : Of course, if carbon-rich gas feedstocks resulting from the combustion of fossil fuels are used in the methanation of Renewable Hydrogen, this would not create truly Renewable Methane. However, if a good proportion of “Power to Gas” gas is used in electricity generation, and the carbon-rich exhaust gases from that recycled, then eventually, the methane end product becomes more renewable. ]