Most energy scenarios assume the rapid expansion of renewables, but it is sometimes claimed that Carbon Capture and Storage (CCS) is also needed to get to Net Zero Carbon. There are many plans and expectations, but so far no CCS system has proved viable at scale, and, although some tests have been made e.g. of carbon storage, the full thing is still some way off, with plenty of teething problems.
Nevertheless, the UK has earmarked £22bn for CCS development- a major commitment. That has not met with unalloyed support given that it is still all about using fossil fuel fossil and is an unproven technology with unknown costs. But, for good or ill, NZT Power, off the NE coast of the UK, seems likely to be the world’s first full scale gas-fired power plant with carbon capture & storage. Its start-up is expected in 2028- though a rival project on the NW coast is also now pushing ahead, with £2bn allocated. However, neither are done deals - there may yet be technical problems and objections. For example, there will still be some emissions from these fossil fired plants, even if they have CCS, and that worries some critics. Some also distrust the whole idea of, basically, shoving stuff under the mat to hide it. Indeed, there has been quite widespread concern about whether CCS was really a viable way ahead for fossil carbon reduction and climate protection.
The main motivation behind CCS seems to be to provide a way to keep using fossil fuel, which not everyone thinks is a good plan, not least since renewables are arguably a better option- and CCS may slow their development. However, there are some more subtle arguments for CCS. Firstly, renewables may take time to fully develop, although that may be a self-fulfilling prophecy if CCS gets supported in preference. More convolutedly, it is argued that the captured CO2 can actually be valuable with some of the CO2 possibly being turned into fuel (using green hydrogen) – so it’s then called CCSU i.e. CCS plus utilization. That is possible, but it seems likely to be very expensive. Much more so than just generating energy from renewables. If we have some zero-carbon green hydrogen, then use it, don’t convert it into a synthetic hydro-carbon fuel to create more CO2 again when is burnt. Like CCS in general, it all seems technically inelegant.
What about other the idea of carbon capture from the air ? Most mechanical/chemical carbon removal options, like Direct Air Capture, seem likely to be even more expensive, given that the percentage of CO2 in the air is so low, so that they are very energy using. Re-forestation & organic bio-capture seem simpler, cheaper options. But, sadly, the UK may not have enough room to compensate for continued emissions from burning fossil fuels in this way. The same is true for another idea- extracting carbon from sea water. There is typically over 150 times more CO2 absorbed in the seas than in the air, so extracting it should be easier and use less energy, but it still has to go somewhere- and stay put forever. Unless we can find a sensible use for it.
It could be carbon negative, but land use would also be a problem for another option, Biomass Energy with Carbon Capture and Storage (BECCS), if biomass growing and CO2 storing was carried out on a large sale. And of course the CO2 is still going to end up being stuffed into rock strata deep underground or undersea, in the hope that it will stay put forever. Or be used to make synfuel with green hydrogen- so called BECCUS.
While there may a few industrial processes where CO2 production is unavoidable and where it would be reasonable to opt for carbon capture, the idea of using valuable green hydrogen to make this CO2 into a new fuel seems suboptimal economically and environmentally. By contrast, pushing ahead with the use of zero carbon renewables directly in every sector possible, seems to make more sense. Wind and solar look at present to be the main renewable energy options, with the CfD system being successful at pushing them ahead. They are land using, but they generate far more power per acre than photosynthesis-based biomass production. There may be a role for green energy production from agricultural and domestic biomass waste, since no new land is used to make this and of course wind farm and agri-voltaic solar farms can co-exist with farming. And looking further ahead, wave and tidal stream power do not need any land directly – unlike hydro. Geothermal energy is also not very land using.
The real land use problem that we face is more to do with finding acceptable sites and designs for power transmission pylons. To the extent that some renewables can deliver power direct to local users (e.g. roof-top PV) and some can be used heating (direct or stored solar heat) or green gas grids (local heat nets), the need for power grids can be reduced. End-use efficiency can also reduce demand.
I think that all these aspects need urgent attention. But given that, even with local storage and energy saving, local green energy supply and local energy demand will both vary at times, on occasion substantially, we will need power grids for balancing. Some can be underground, although that is very expensive. Some can be offshore, which is also very expensive. So, we have an issue- concerns about local visual impacts. If we want green power it has to be faced- unless we are prepared to use less of it some of the time, which might be a necessary trade off if you do not like pylons. Unless Labours ‘bribe’ of money for local residents to accept them works. That may be less contentious if it is set in the context of wider debate about ‘locational pricing’, although that has also proved to be contentious, leading to an as yet unresolved debate.
Concerns about local environmental impacts may in some cases be about more than just about cherished views and amenity loss, and may slow down green energy deployment. In which case what can be done to avoid climate change? Carbon capture & storage won’t be enough on its own, so some look in desperation to other so-called geo-engineering ideas. For example, aerosol/micro particle injection into the upper atmosphere, or even putting giant sunshades in deep space orbit, so as to block the sunlight? (shouldn't we just use it instead?) Most of them have been opposed by greens, especially those potentially leading to irreversible modification of the ecosystem. But there is now more than hint that, if they are told often enough that renewables can’t deliver, even greens may succumb to quite wild ideas. That may have already happened in some cases with carbon capture and carbon removal, and it may also be why nuclear is now getting more support in some places - the USA especially. Mind you, politics are so polarised in the US these day, almost anything is possible, not much of it good. Chemtrail conspiracies anyone?
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