What might a Zero Carbon Gwynedd look like?

Updated 17th August to reflect updated Wales wide analysis.

Mae'r tudalen yma hefyd ar gael yn Cymraeg.

The following tries to answer this question by looking at Gwynedd within the context of the national ZeroCarbonBritain scenario developed by The Centre for Alternative Technology in Machynlleth. It looks at energy use in Gwynedd today, how much energy we generate from renewable energy in Gwynedd and how much we would need to build either here in Gwynedd or at a wider scale in order to supply Gwynedd's projected energy needs if we followed the ZeroCarbonBritain scenario.

The analysis here is based on the three summarised data tables below:

1. Gwynedd energy use, carbon emissions today.
2. Energy demand in a future Zero Carbon Gwynedd scenario
3. Renewable energy in Gwynedd today and how much more we would need either here in Gwynedd or imported from further afield to meet our projected share of ZeroCarbonBritain energy demand.

Energy and carbon in Gwynedd today

* Electricity supply on a national average basis is currently about 21% from wind, solar and hydro, 19% from nuclear, 11% from bioenergy (of which about half comes from drax wood chip’s). The remaining 49% is mostly gas power stations, plus a little from oil and coal.

* Primary energy estimate based on 1.36x factor difference between national primary and final energy figures. This covers thermal power station losses, grid losses, other conversion losses and energy industry own use [3].

These figures give us an idea for how much energy we use today, the exact figures and units are less important than the overall relative changes. We use a lot of energy today, we can save a lot of energy just by switching to more efficient technology such as heat pumps and electric vehicles. 35% of our electricity consumption is currently generated by local renewable energy in Gwynedd but electricity is only 20% of final energy demand.

Energy demand in a future ZeroCarbonGwynedd scenario

The following is based on a proportional share (by number of households) of the national ZeroCarbonBritain scenario [2], modelled using the open source ZeroCarbonBritain scenario tool.

Like most energy scenarios, ZeroCarbonBritain is a combination of changes on both the demand side and supply side of the energy system. It includes almost full electrification of heat and ground transport in order to make the most efficient use of zero carbon electricity. It is also particularly ambitious compared to other scenarios in reducing demand with building retrofit and behaviour change, it includes:

• 50% reduction in space heating demand through ambitious building retrofit. The practicality and cost effectivness of this in Gwynedd, especially given traditional stone buildings and wind blown rain is a key question.
• 30% reduction in miles travelled by car.
• 66% reduction in miles travelled by air.

Total primary energy demand is reduced by almost 50% compared to our energy use today.

Other scenarios such as the recently published 100% Renewable UK scenario are much less ambitious on reducing demand and compensate by building more supply. ZeroCarbonBritain also sources a relatively large share (23%) of it's energy supply from biomass energy, this uses 18% of total UK land area. It might be better to build more wind, solar and associated power-to-gas and liquid fuels infrastructure (with carbon recycling or direct air capture) so that we can free up more land for biodiversity.

An alternative higher demand, low biomass scenario simulated using the ZeroCarbonBritain scenario tool, reflecting 2018 levels of miles travelled by car and air, would require a primary energy supply of ~2620 GWh/yr [12] and final energy demand of ~1750 GWh/yr. The electricity supply requirement would increase from 1434 GWh/yr in the base scenario to ~2560 GWh/yr. This is a similar demand level to the 100% Renewable UK scenario (scaled down to a Gwynedd proportional share).

Electrification progress

While electrification of heat, transport and industry are key parts of both the ZeroCarbonBritain and 100% Renewable scenarios we are still only at the first few % points of the transition on the demand side.

Renewable Energy in Gwynedd today vs a future ZeroCarbonGwynedd scenario

Additional storage infrastructure is required to provide a complete working energy system that matches demand for every hour of every day. Gwynedd's share of national storage requirements based on the ZeroCarbonBritain model would very roughly be: 370 MWh high efficiency electricity storage, 50 MW of electrolysis, 40 GWh of hydrogen storage, 120 GWh of e-methane storage, 120 MW of backup gas turbine capacity. These are indicative figures to provide a more complete picture of what the model suggests is required [3]. We do already have two large pump hydro storage schemes: Dinorwig and Ffestiniog which have a combined storage capacity of 10.5 GWh and there is another proposed project at Glyn Rhonwy.

The following chart shows the recent historic generation output from renewable energy in Gwynedd. Extrapolating a linear trend suggests 465 GWh/yr of generation in 2050 or about 32% of the ZeroCarbonBritain based scenario value. At this rate of renewable deployment (+9.5 GWh/yr), it would take ~130 years to reach 1434 GWh/yr or 250 years to reach the higher demand scenario if the goal was to meet Gwynedd energy demand from within Gwynedd.

What is the goal? Local vs national
A goal of supplying Gwynedd energy demand from zero carbon energy within the Gwynedd boundary or near offshore is itself a goal that may or may not be the right one. It is usually better to take a wider view.

Wales as a whole is moving faster with a historical renewable build rate that would suggest reaching the ZeroCarbonBritain target in ~68 years and a pipeline of large scale renewable projects that should get us there even faster (Awel y mor, Mona/Morgan, Celtic sea floating wind & Morlais). We may even get to 70-90% of the standard ZeroCarbonBritain scenario target by 2035, with the renewables that are already in the pipeline. Leaving time to get to 100% by 2050. For a ZeroCarbonBritain scenario, Wales might require an additional ~7,200 GWh/yr of electricity generation beyond the existing pipeline. A higher demand scenario might need an additional ~25,500 GWh/yr. Could Gwynedd contribute to this meeting this shortfall?

Could we find an additional 1250 - 2400 GWh/yr of generation in Gwynedd?

If we did decide that we wanted to meet Gwynedd energy demand from generation within Gwynedd or that we want to make a substantial additional contribution to meet the Wales wide need for additional generation post 2035, the following gives an idea for how we might approach this.

• Hydro is our largest source of renewable electricity today, generating ~135 GWh/yr. Since 2014 hydro capacity has increased from 56 MW to 62 MW. The number of sites has increased from 40 to 120 and output has increased from ~100 GWh/yr to 135 GWh/yr. The number of sites being developed has slowed down significantly since the FIT support was withdrawn. It seems unlikely that generation can be increased significantly due to the limited number of sites and large number of schemes that have already been developed. A small number of additional sites may still be developed with benefit for communities and land owners but are unlikely to move the needle much at the wider Gwynedd scale.

• The 0.5 MW (~1.3 GWh/yr) Enlli Tidal project being developed with Nova Energy and Ynni Llyn was recently shelved due to "revenue support limitations and grid and cable routing constraints". Wave and tidal technology is still in it's infancy, perhaps technologies tested and proven over at Morlais could in future be used here in Gwynedd.

• The Solar PV potential in Gwynedd is theoretically quite high and could make a meaningful contribution, if we used 1% of land area for solar (25 km2) with a power installation density of 70 MW/km2 (similar to other large sites in Wales), this would result in ~1750 MW of capacity and 1686 GWh/yr of generation (11% capacity factor). This is equivalent to ~100 solar farms the size of Parciau just outside of Caernarfon (Parciau power density is ~56 MW/km2, area 0.25 km2). Alternatively the ZeroCarbonBritain scenario suggests a proportional share of just 166 MW (137 GWh/yr), or 4x current solar PV generation in Gwynedd. Solar is not quite as useful as wind as it does not generate as much in winter when electricity demand is highest, it requires significantly more long duration energy storage (e.g power-to-gas) to shift energy from summer to winter.

• Wind power should really be our preferred renewable energy. It generates more in winter than summer, providing a better match with higher winter demand and Gwynedd has a particularly good wind resource. Despite these advantages, we only generate ~13 GWh/yr from wind in Gwynedd today. Wind power development is significantly restricted with planning policy that does not really support the scale of wind power that would be required to make a significant contribution, the Gwynedd Council supplementary planning guidance states:

  "Policy C26: Proposals for wind turbine developments on sites within the Llŷn AONB will be refused. In other locations, only proposals for small scale or community or domestic based wind turbine developments will be approved".

  To meet the suggested ZeroCarbonBritain share of onshore wind would require an additonal 50 MW of wind capacity (130 GWh/yr). The smaller the turbine, the more turbines would be required e.g 16x 3MW turbines, 50x 1MW turbines or 500x 100kW wind turbines.

  To meet the suggested ZeroCarbonBritain share of offshore wind would require 260 MW (975 GWh/yr), this could be done with 26x 10 MW turbines or 52x 5 MW turbines. A wind farm of this size would be half the size of gwynt y mor.

  In the recent Dyffryn Peris Gwyrddni climate assembly there was general support for looking at the potential for community wind. Could a community initiative perhaps be developed to purse an onshore wind project for 50x 1MW turbines for 50 local communities, ensuring that the maximum benefit is returned to local communities?

Risks to achieving these generation goals

Opposition to development

• A significant amount of concern was raised during recent hydro development, especially amongst the local mountaineering community as expressed in a number of BMC articles and meetings [8]. Concerns ranged from the number of schemes being developed, the short term construction impacts, questions about the impacts on biodiversity alongside a wider principle of wanting to conserve naturally free-running rivers. These developments were all of a relativly small scale compared to earlier plants such as Cwm Dyli and Maentwrog, reflecting already strict requirements to minimise impacts which in turn reduced the generating potential of many schemes.

• A previous attempt to develop a 0.5 MW community wind turbine in Llanaelhaearn divided the local community and was ultimately rejected [9] [10]. The scheme had the potential to bring significant local investment but was opposed both by a portion of the community, Natural Resources Wales and Cadw. Gwynedd council's planning committee officers recommend the project be refused, saying it would have "a substantial harmful effect on the open feeling of the area" by creating an "alien and oppressive feature" for local residents. A more recent and larger 0.85 MW wind turbine near Boduan was however accepted, suggesting that it may not be impossible to develop such schemes. Is support for much larger schemes in Gwynedd possible? Could it be done in a way that achieves broad local support?

Grid contraints: Grid constraints are another key factor currently limiting the development of projects e.g Ynni Llyn tidal, proposals for offshore wind in Cardigan bay and onshore wind in mid wales. Some resolution to this issue will clearly be needed if we are to meet our zero carbon goals.

Other generation options

Nuclear: Trawsfynydd is of course one of the sites proposed for a 440 MW Rolls Royce Nuclear SMR, which at a capacity factor of 90% would generate 3470 GWh/yr 2.4x the ZCB renewable electricity target or 1.35x the Gwynedd higher demand scenario. On a Wales wide basis this project would take us from 87% to 99% of the lower demand target or from 53% to 61% of the high demand target. A recent report by the European Commission's Joint Research Centre highlighted that nuclear performs well on a large number of life cycle analysis metrics including a similar carbon intensity to wind [13].

There is still a lot of uncertainty around the likelihood of the Trawsfynydd project being built, given the UK Government decision to open a more competitive process for technology selection alongside pushing the final investment decision back to 2029. This suggests that the original early 2030 delivery dates are less likely. There is a big question as to how the next generation of nuclear projects will fare given past challenges, projects due for delivery before 2030 in Canada (BWRX-300) and the USA (Nuscale) should start to give a clearer indication.

CCS is another option that while less likely to be applicable in Gwynedd may play a part in a wider Wales scenario. There is a proposal to build a 350 MW Allam-Fetvedt Cycle natural gas CCS plant in Teeside that is based on an already working pilot plant in the US [11]. The technology itself is also useful for a 100% renewable scenario as it could make long duration energy storage with e-methane produced using renewable electricity more efficient.

There are other problems with these technologies and they do not yet have at least a recent history of tried and tested regular deployment in the same way that wind and solar have, suggesting caution on relying on their development at this stage. There are of course elements of 100% RE scenarios that are also at a similar early stage of development such as long duration energy storage with hydrogen or e-methane.

Questions

• What should our ambition be for increasing generation in Gwynedd in relation to expected demand?

• How do we balance conservation goals of the Llyn AONB and Snowdonia National Park with the scale of what zero carbon requires and the desire of local communities to benefit from the transition?

• Could a community initiative be developed to purse an onshore wind project for 50x 1MW turbines for 50 local communities? Could there be support for exploring offshore wind in the future?

• What will we achieve on the demand side? will we follow a trajectory that gets us closer to the ZeroCarbonBritain demand scenario or the higher demand 100% Renewable UK scenario?

Sources

1. UK local authority and regional greenhouse gas emissions national statistics, 2005 to 2020
2. Sub-national total final energy consumption data
3. ZeroCarbonBritain hourly energy model and scenario tool
4. Renewable electricity by local authority, 2014 to 2021
5. Based on 2.0 GWh el/yr [3] and 40% conversion efficiency.
6. Energy generation in Wales 2019
7. Energy use in Wales
8. https://www.thebmc.co.uk/hydropower-in-snowdonia-a-green-blessing-or-a-moneymaking-curse
9. https://www.bbc.co.uk/news/uk-wales-north-west-wales-29879600
10. https://www.dailypost.co.uk/news/north-wales-news/240ft-turbine-llyn-would-alien-2729722
11. https://www.imeche.org/news/news-article/inside-the-plans-for-the-uk-s-first-net-zero-power-plant
12. High demand primary energy estimate: 1312 TWh/yr national scenario modelled in ZCB tool × 55100 households 2018 ÷ 27600000 households 2018 = 2620 GWh/yr. 100% RE UK IAS scenario has primary renewable energy requirement at 1361 TWh/yr so in the same ball park.
13. Technical assessment of nuclear energy with respect to the ‘do no significant harm’ criteria of Regulation (EU) 2020/852 (‘Taxonomy Regulation’)