5 ms·
There are a couple of things at play here. So first, if you need to do 'work', then definitely just use electricity directly to do the job, which is much more
by DavidPBL 5y ago
There are a couple of things at play here.
So first, if you need to do 'work', then definitely just use electricity directly to do the job, which is much more efficient.
I agree it wouldnt make sense to split natural gas (into CO2 + H2) and then recombine it back into ethanol, although oil companies would love to do this as they have billions in stranded assets in the form of natural gas.
Ideally you couple some process that generates CO2 (not from burning fossil fuels) with renewable electricity to recycle that carbon back into useful chemicals to displace petroleum derived chemicals. Two examples of this would be cement manufacture and industrial brewing. But yes you need an external energy input, like with most things.
As a side note, the impact of this depends on where you get your energy (renewable of course) and your carbon. Some companies have caught onto this. For example Unilever created a carbon 'rainbow' to separate the types of carbon. Recycling renewable carbon is the goal here.
- IgorPartola 5y ago> So first, if you need to do 'work', then definitely just use electricity directly to do the job, which is much more efficient. Pardon me but this doesn’t sound right. If you want to generate heat, burning natural gas is going to be a lot more efficient overall than first burning natural gas at a power plant then transmitting electricity to your facility to convert it to heat. Similarly with rotational energy, etc. Your second point stands: if you power your process by solar, wind, or hydro you could get ahead of CO2.
- DavidPBL 5y agoI may have misused the term 'work' here. I was trying to describe the displacement of an object through the actions of something like a motor. You can achieve that by burning fuels (combustion engine), or steam, or an electric motor. I was trying to allude to the latter being the most efficient.
- IgorPartola 5y agoNo I know what you mean by “work”, my degree is in physics. What I think is not clear is what you mean by “efficient”.
- DavidPBL 5y agoGotcha, I reread what you wrote andit makes more sense to me now. What are your thoughts on using renewable electricity for heating applications as a way to displace burning of fossil fuels?
- IgorPartola 5y agoI mean obviously if you use something like solar or wind it will not produce CO2 so any CO2 your process extracts will be a net gain. If you use it to make ethanol that then gets burned you’ll just be putting CO2 back into the air. If you make construction bricks with it, you won’t. Solar can also be used to heat things more directly than first converting to electricity (and taking a big loss on that), but then you really are subject to when the sun shines. But if you put your facility in a desert in Arizona you’ll probably do quite a bit with a set of mirrors used to heat specific objects.
- DavidPBL 5y agoI should have been more specific. I was trying to ask about generating renewable energy and then using that at some other site for heating purposes. What kind of efficiency does electricity to heat get you compared to just burning fossil fuels on site? I am not sure if that is the best way of asking this question.
- IgorPartola 5y agoI am not an expert on this but my understanding is that a fossil file plant wastes something like 60% of its energy as lost heat. There is also transmission losses. Whereas an oil or gas heater can get to like 97% efficiency in heating water when on site. Hell, you could get heat for free by just removing it from the smoke stack of a coal fired power plant.
- semi-extrinsic 5y agoHow do you see the scaling up to multiple gigatonnes per year? For me that has alwayd been the hard part to understand about CCU, where is there a market large enough to absorb that volume? And where the product does not get burnt or emitted anyway in the end?
- PaulHoule 5y agoThere is a huge amount of talk about things like this or CarbFix which all seem secondary to the "capture CO2 at some generic capture point and pump it into a saline aquifer" approach which seems to be pretty scalable. Even though the technology is on the shelf it's not being deployed largely because there is no financial incentive to do so... Yet the widespread use of this technology really needs to be happening now if we want any of these carbon capture things to happen.
- DavidPBL 5y agoI find it ironic that carbon capture and storage technology was originally (might be wrong here) developed for enhanced oil recovery (EOR). But yes we really need better systems to incentivize the capture and storage or utilisation of CO2. Carbon taxes a great place to start.
- PaulHoule 5y agoYou can drill in Texas and find CO2 underground and people used this for advanced oil recovery before it was captured at power plants. It is a use of CO2 that people will pay for.
- DavidPBL 5y agoDidn't know that! I assumed it was always captured elsewhere. As we find new profitable uses for CO2 the demand for it will increase, which should help create new carbon value chains.
- DavidPBL 5y ago