If you are concerned about CO2 emissions from hydroponics, I have bad news for you regarding every other activity in an industrial society that consumes electrical power or requires heat. They all produce enormous amounts of CO2. That is why global warming is happening.

If you would like that to stop happening, I would suggest working on a ban on petroleum drilling, or a carbon tax.

They were going to burn it for heat anyway. This produces less CO2 than getting it from a tank.