[All blog posts]‎ > ‎

Assessing the role of (fossil and biomethane) gas in Ireland's Paris-aligned energy future

posted Nov 28, 2018, 7:31 AM by Paul Price   [ updated Nov 28, 2018, 9:01 AM ]

In this extended blog post we will look at two, highly contradictory, reports recently released on the future of natural gas (fossil methane) and biomethane in meeting Ireland’s future energy demand within long term decarbonisation objectives.

The first, McMullin et al. (2018), is a commissioned academic peer review (two of the IENETS team are co-authors) which concluded that plans to increase fossil gas dependence would be counter to Ireland’s commitment to aligning climate action with the Paris Agreement and would seriously undermine Irish long-term energy security compared to a wind and solar dominated energy system, combined with lower total energy use and renewable power-to-fuel (e.g., hydrogen or ammonia) for large scale (seasonal) energy storage.

The second report, a Long Term Resilience Study (hereafter we’ll call it the LTR Study) aiming to project future gas demand and examine the security of gas supply, was produced by Gas Networks Ireland (the Irish national gas network operator) and Eirgrid (the Irish national electricity transmission system operator), at the request of the Department of Communications Climate Action and Energy (DCCAE). Contrary to McMullin et al. and also at odds with ‘least cost’ studies previously produced for DCCAE for the National Mitigation Plan, the LTR Study advocates increased gas dependence, thereby inferring a pressing need for investment assessment of additional gas infrastructure (including a storage facilities and a floating Liquid Natural Gas terminal), a significant commitment to scaling up indigenous biomethane production and continued promotion of oil and gas exploration. However, as this blogpost analysis details, the LTR Study fails to address the national energy greenhouse gas emissions implications of such increased gas use within the necessary context of rapidly decarbonising the entire energy system. This failure to address these urgent decarbonisation in line with Ireland's commitment to the Paris Agreement fundamentally undermines the report’s projections and cost benefit analysis recommendations.

For the current IENETS project, projected gas supply and usage is highly relevant to aligning Ireland’s CO2 emissions and low carbon transition with equitably meeting Paris Agreement temperature targets and related global carbon budget. If projected emissions from proposed scenarios are likely to overshoot Ireland’s ‘fair share’ quota of the global carbon budget then Paris-aligned action would logically need to also include the costs of commitment to achieve planned carbon dioxide removal (CDR) from the atmosphere – using negative emissions technologies – to return Ireland’s nett cumulative emissions to its Paris-aligned quota level as soon as possible.

Two very different views of the future for gas

The LTR Study’s single mention of the Paris Agreement is that:

Ireland, in line with other EU member states, has signed up to the Paris Climate Change Agreement, and is fully committed to delivering on its climate change objectives within the current EU frameworks. p.8

The trailing caveat here, “within the current EU frameworks” is worth comment. Firstly, Ireland is an independent Party to the UNFCCC, so Ireland’s commitment to Paris is not solely through the EU. Additional national climate leadership by Ireland is not restricted to EU decisions and Ireland, as a full EU member state, can choose to advocate for higher EU ambition. Ireland has independently ratified the Paris Agreement and is therefore committed in any case to mitigation action aligned with meeting the agreement objectives, according to science and equity. Separately, EU frameworks are evolving such that the new National Energy and Climate Plans currently being produced by EU Member States will need to be show coherence with all relevant overarching targets, including the Paris agreement in particular.

In advocating continued and increased gas use the LTR Study cites the 2015 Energy White Paper Ireland’s Transition to a Low Carbon Energy Future, referencing it as a basis for stating that:

“as Ireland makes this transition the development of Ireland’s indigenous oil and gas resources has the potential to deliver significant and sustained benefits, particularly in terms of enhanced security of supply, import substitution, fiscal return and national and local economic development.” p.9

And then suggests that, therefore, further exploration for gas in Irish offshore is justified:

“there is presently significant interest in exploration for oil and gas offshore Ireland, following the 2015 Atlantic Margin Licensing Round. The discovery of a new indigenous gas source would reduce Ireland’s import dependency and diversify its gas supplies, thereby strengthening Ireland’s gas supply.” p.9

The LTR Study then describes a need for proposed infrastructure developments to improve the security of supply for gas and stresses an increasing economic importance of gas in future for electricity, transport and heating. In arguing that substantial continued reliance on natural gas specifically is critical and unavoidable (up to at least 2040) the LTR Study is very much in agreement with another report produced independently earlier this year by the Irish Academy of Engineering (IAE 2018).

However, strongly contesting these views, McMullin et al. in Is Natural Gas “Essential for Ireland’s Future Energy Security”? presents a highly critical analysis of the IAE’s report, a critique which now similarly applies in large part to the new LTR Study. While agreeing that relying on imported natural gas does result in very serious security-of-supply issues for the Irish energy system, McMullin et al. finds that:

  • Good faith commitment to the Paris Agreement requires far higher emission reduction rates than acknowledged by the IAE report (or, now, the LTR Study).

  • Displacing other fossil fuels in favour of increased use of gas will only escalate security-of-supply risk through escalating system reliance on a single fossil fuel.

  • Prioritising early exit from all fossil fuels, including gas, is now increasingly feasible, more certain in CO2 mitigation and more secure than a “gas bridge” transition.

  • Near-term and sustained energy demand reduction and progressive electrictrification of transport and heating would be critical to meeting a Paris-aligned pathway.

  • Excess wind and solar periods enable power-to-fuel (P2X) production of electrofuels: chemical gas or liquid storage of energy to ensure continuous, on-demand, energy supply.

  • All low and negative decarbonisation pathways are now extremely challenging, but rapid fossil fuel phase-out would deliver greater economic and social resilience.

  • Therefore, increases in (methane) gas dependence, new gas infrastructure and continued natural gas exploration are not advised for Ireland’s sustainability, economic development or energy-security objectives.

A key basis for these conclusions is the very limited time available for climate action given Ireland’s limited remaining CO2 quota, relative to the Paris global temperature targets. Note this is a quota allocation of total cumulative CO2 emissions because CO2 accumulates in the atmosphere to cause very long term warming. Our previous IENETS analysis concluded that precautionary climate risk management should be based on the low-end of an assessed scientific global carbon budget range, especially in light of Ireland’s significant land use emissions and high non-CO2 emissions (from agriculture) that are not projected to fall substantially. Allowing for even a minimal interpretation of meeting the “well below 2ºC” Paris temperature goal on a basis of equity, we assessed a “fair share” remaining CO2 quota for Ireland as a maximum of about 378 MtCO2 (80 tCO2 per capita) from 2015.

Based on a direct emissions analysis of SEAI fossil energy supply projections, Ireland’s continuing, high per capita energy CO2 emissions will exhaust this quota and Ireland will enter “carbon debt” by c. 2025, thereafter requiring (on a basis of good faith climate action) compensating negative emissions, in order to return to the quota level.

Therefore, based on this quota and current projections, all fossil and land use CO2 emissions from about 2025 onward will accumulate an increasing carbon debt or quota overshoot relative to Ireland’s good faith Paris commitments. This translates directly into an ill-defined but very high risk obligation imposed unilaterally on future Irish citizens as they must attempt to somehow reverse this overshoot by removing that excess CO2 from the atmosphere and return the associated carbon to secure (ultimately geological) storage. Further, this obligation will, by definition, may fall to be discharged against a background of severe societal stress due to intensifying climate disruption, locally and globally. Given good faith commitment to Paris-aligned climate mitigation and climate leadership, minimising this obligation, by minimising the extent of such carbon debt, is now a key imperative both for effective climate action and for protecting intergenerational trust and solidarity.

Having set out a cumulative CO2 framing for energy projections analysis, let’s look in more detail at the LTR Study in terms of annual emissions and the now binding constraints of conforming (in good faith) to a Paris-aligned cumulative CO2 quota.

LTR Study gas relative to Ireland’s remaining Paris CO2 quota

The LTR Study states that:

“The median demand scenario is aligned with Ireland reaching long-term decarbonisation targets.” p.11

We can examine this statement using the LTR Study projections and translate them into emissions to compare with the national CO2 quota. The study gives two scenarios of future annual gas usage, median demand and high demand, as shown in Figure 4.4 of the study, reproduced below.

Using the Paris Agreement year of 2015 as a start point for long-term decarbonisation targets we can use SEAI projections for gas usage for the data up to 2024 that is missing from this chart. The LTR Study also includes a plan for rapidly increasing Irish indigenous production of biomethane. Energy from biomethane combustion is assumed to be carbon neutral under EU energy-emissions accounting and could displace the use of fossil natural gas.

[It is important to note that the EU’s approach to overall bioenergy carbon accounting has been very strongly contested by numerous scientific reviews and papers (EEA 2011; EASAC, 2018). But we set that aside for the current discussion, and also accept the best case projection for biomethane production proposed in the LTR Study, in order to allow the most generous possible assessment of its emissions implications.]

By charting the LTR Study gas energy projections we can then compare them with a modelled projection of notional least cost energy-emissions for the minimum ambition “CO2-80” pathway aiming for an 80% cut in emissions by 2050 compared to 1990 (Deane et. al 2013). This pathway was previously produced for DCCAE using the IrishTIMES energy system model to inform the National Mitigation Plan (2017) climate action measures. That projection (starting from 2005) gave higher gas usage in 2015 than actually came about, therefore to give an indicative comparison in the charts below we adjust the Deane et al. IrishTimes modelled gas pathway to start from the actual usage and then, from 2020, mirror the CO2-80 relative changes over time.

As a result, in the chart below, we see the gas-only energy projection for annual energy from 2015 onward for these alternatives. The biomethane production projection is shown as a dashed brown line – assuming linear increases between the LTR Study data points in its Table 6.1. The total gas demand from the LTR Study Fig. 4.4, including projected biomethane, is shown by the dashed blue (median demand) and red lines (high demand). Subtracting the biomethane energy from the projected total gas energy gives the projected use of natural fossil gas for the two scenarios in the solid lines: blue (median demand) and red (high demand).  

Looking at this chart, the projected rise in total gas demand for both LTR Study scenarios is far greater than the modelled ‘least cost’ CO2-80 pathway, which projects a 15% reduction in natural gas primary energy supply from 2010 to 2050. By comparison, the more stringent CO2-95% emissions pathway requires a far greater 73% reduction in natural gas primary energy supply by 2050. Further, if the projected production of carbon neutral biomethane does not materialise then the shortfall in total energy from gas would need to be replaced by some combination of demand reduction and zero carbon energy sources to avoid any increase in emissions from use of fossil fuel energy, including natural gas.

The corresponding chart of CO2 emissions is shown below. The brown dot-dash line shows a bioenergy credit for (temporary) CO2 removal from atmosphere , arising from the photosynthesis process in growing the biomass used to produce the biomethane, corresponding directly to the CO2 that is regenerated in subsequent biomethane combustion (normally simply returned back to atmosphere). The solid blue (median demand) and red lines (high demand) show the projected nett emissions from the combustion of all gas, allowing for the bioenergy credit. The dot-dash blue and red lines show the level of gross gas-combustion emissions for the LTR Study scenarios including biomethane consumption, but exclusive of the bioenergy credit.

As already noted, EU energy emissions accounting treats bioenergy combustion as carbon neutral – any bioenergy combustion emissions are assumed to be exactly compensated by the bioenergy credit. However, a quantified carbon balance for the energy use would depend on the actual sustainability criteria and land use accounting basis for assessing the bioenergy credit. If bioenergy is supplied on the basis of a lack of enforced sustainability criteria or without verifiable, detailed land use accounting and strict monitoring of anaerobic digestion plants for methane leakage then the amount of bioenergy credit accounted to compensate for biomethane combustion emissions may need to be validated or estimated to allow for net emissions.

From these annual charts it is evident that even the median demand scenario of the LTR Study describes much higher gas supply and emissions rates than the notional least cost decarbonisation pathways described by IrishTIMES cost optimisation modelling previously commissioned by DCCAE. The difference between the IrishTimes and LTR Study scenario pathways would appear to suggest the LTR Study pathways are not aligned with the notional least cost decarbonisation, even for a (minimal) 80% CO2 reduction target by 2050. Although this economic modelling has similarly been produced for DCCAE to be ‘policy relevant’ it is not referenced in the LTR Study (nor, for that matter, in the IAE’s report).

Moving toward carbon quota analysis, cumulative CO2 emissions trajectories for gas only shows that, even if natural gas were the only fossil fuel in use and even if the projected carbon neutral biomethane production occurs, the LTR Study scenario natural gas usage alone would exhaust Ireland’s entire post-2015 carbon quota by about 2050. Of course, in reality, in the absence of radical, very near-term, reduction in fossil fuel use (not discussed in any material way in the LTR Study), the projected usage of oil, coal and peat, as well as gas, can be expected to exhaust the full quota even before 2025. As shown in the chart above, the natural gas usage projections of the LTR Study from 2025 to 2040 alone would then result in cumulative CO2 debt of 150 to 200 MtCO2, based on 9 to 15 MtCO2/yr annual emissions, requiring similar CDR, almost certainly dependent on using large scale geological CO2 storage, combined with either biogenic or technological removal of CO2 from atmosphere. However, the viability of such a sustained scale and quantity of negative emissions capacity would need to be assessed and costed within a full-energy-system cost-effectiveness analysis, under the constraint of meeting the required Paris-aligned nett cumulative CO2 quota.

Current government climate policy (based on the National Policy Position) suggests the use of nature-based land carbon sequestration (in forest and soil) to offset other land use (mainly agricultural) emissions. Therefore, any production of bioenergy will need to result in no additional land use emissions, particularly avoiding any nett additional N2O emissions by limiting or, ideally, decreasing total nitrogen fertiliser use in Ireland.

Carbon capture and storage (CCS) could possibly greatly reduce territorial emissions intensity of gas power plants by perhaps 90% assuming that investment in CO2 capture and storage infrastructure was achieved. If biogas or bioenergy combustion CO2 was captured and stored via CCS also then nett negative emissions could be achieved. The Irish Times energy system modelling for the National Mitigation Plan shows rapidly increasing amounts of gas CCS, but only from 2040 onward. Curiously, the LTR Study does not refer to CCS at all, even though Gas Networks Ireland and its parent company Ervia have been promoting the potential use of CCS for the gas-fired power stations in Co. Cork to take advantage of the geological storage potential of the now nearly exhausted Kinsale Gas Field. Estimated total CO2 storage capacity in the low pressure Kinsale field is 330 MtCO2, roughly the same as the gas-only CO2 emissions to 2050.

This carbon quota analysis suggests that to meet a precautionary Paris-aligned CO2 quota, CCS is needed as soon as possible if any fossil fuel use is planned after 2025, let alone increased gas use in addition to projected oil use. Inevitably, the energy penalty for CCS and the cost of additional infrastructure (capture plant, pipelines, injection and storage) add significant cost to future fossil fuel use, particularly if all CO2 released in Ireland by unabated combustion from 2025 will need to be compensated by subsequent permanent removals from atmosphere.

Decarbonising also implies gas+oil sector reductions

A key framing for the LTR Study is that:

”In the transition to a more sustainable future, and the phasing out of more carbon intensive fuels such as peat and coal, gas is likely to become increasingly important for electricity, transport and heating.”

This framing is commonly appealed to in the energy policy community, most particularly by those holding or responsible for significant existing natural gas assets or infrastructure. However, it is potentially misleading in terms of effective climate action. Above all, climate mitigation requires ongoing rapid reduction of absolute emissions, not just reductions in the carbon intensity of the different fossil fuels (or activities). Although the thermal combustion emission intensities of natural gas (205 g/kWh) and oil (264 g/kWh) are indeed lower than coal (341 g/kWh) and peat (415 g/kWh), total energy emissions in Ireland are dominated by oil (about 21 MtCO2/yr including jet kerosene) and gas (about 10 MtCO2/yr) whereas coal and peat already account for comparatively much smaller shares (about 6 MtCO2/yr and 3.5 MtCO2/yr respectively).

Therefore, although removing higher carbon intensity peat and coal from the energy supply is important, the future projected combined use of all fossil fuels is critical to any discussions of low carbon transition, including projections of future gas supply as in the LTR Study. As shown below, based on current policies and ESRI economic projections, SEAI project Ireland’s use of oil will not reduce (it may even increase) and gas use is projected to increase. Comparing with the previous charts, these SEAI projections are more in line with the high gas demand scenario. As before, the bioenergy credit is shown as negative emissions, without which the gross gas and total emissions are higher as shown by the orange and black dot-dash lines.

This chart shows additional emissions from gas and oil simply replacing the projected reduction in coal and peat emissions. Total nett emissions stay more or less unchanged (i.e., even if the bioenergy credit for biomethane is included). The most recent SEAI National Energy Projections to 2030, based on ESRI modelling, now show some reductions in energy CO2 by factoring in additional National Development Plan (NDP) and oil price assumptions but, as consequential rebound effects are not assessed by the SEAI, it is unclear to what extent spending cost savings from energy efficiency and conservation might result in emissions-causing activities likely to limit nett mitigation from policies.

For the same annual emissions but now looking at the cumulative CO2 emissions in total and by fuel compared to a Paris-aligned CO2 quota, in the chart below we can see Irish total cumulative emissions exceeding the national quota by 2024. A cumulative emissions pathway will only level out if the nett annual CO2 emissions go to zero, and nett negative emissions are required to then bring nett cumulative CO2 back down. The oil and gas lines continue upward because annual emissions are not going to zero, rather they are high and stable or increasing. Oil-related emissions alone are currently likely to emit a 2015-2035 total of 475 MtCO2, greater on its own than a 378 MtCO2 total CO2 quota, and gas could emit an additional 270 MtCO2 by 2035 in the high gas scenario.

As this chart makes clear, single fossil fuel or single sector analyses such as the gas and electricity-focused LTR Study are, on their own, insufficient to conclude that the scenarios given are “aligned with Ireland reaching long-term decarbonisation targets”. It seems evident that near-term reductions in the Ireland’s supply and demand for oil and gas combined are needed to limit the amount of CO2 quota overshoot and the scale of the corresponding tacit commitment to achieving subsequent nett negative emissions. Therefore, all carbon emitting fuels (especially oil) and technologies must be included in energy-emissions analysis of decarbonising Ireland’s entire energy system.

Based on the SEAI projections but using the LTR Study biomethane projection, the cumulative CO2 analysis shows that the projected rapid increase in biomethane production makes very little difference to cumulative CO2, even if achieved at the ambitious level suggested by the study. Although the gas energy-emissions projection in these charts is similar to the LTR Study high scenario, the median gas scenario would still have 2040 fossil fuel emissions of 9 MtCO2/year from gas alone (assuming zero nett climate emissions from sustainably produced biomethane) requiring the corresponding energy system analysis projections of oil, coal, peat and negative emissions in order to provide an appropriate decarbonisation assessment.

Paris-aligned energy choices require carbon quota analysis

In summary then, the LTR Study claim that its medium demands scenario is aligned with Ireland reaching long-term decarbonisation targets appears highly questionable in terms of Ireland’s fair share carbon quota and even in terms of published least cost analysis. The LTR Study’s cost-benefit analysis does not provide a comparison with the lower cost IrishTimes pathway, or include quota-alignment costs of carbon dioxide removal needed to compensate for unabated gas combustion (without CCS). Such costs would also need to include the upstream emissions related to natural gas, and the energy penalty of CCS. Similarly, the costs of assuring strict sustainability criteria for bioenergy are not stated. For example, biomethane produced from grass silage requires enforcement of limits on nitrogen fertiliser for grass growth and on fugitive methane emissions in in anaerobic digestion plants.

In the absence of a whole energy-emissions system analysis, the LTR Study is too narrowly focused on gas and electricity to make this claim. It also overlooks both ‘least cost’ decarbonisation analysis previously produced for DCCAE (Deane et al. 2013) and Paris-relevant cumulative carbon budget analysis (Price et al. 2018; Glynn et al. 2018). If energy emissions reduction is indeed the imperative that it is generally claimed to be, by government and in reports such as the LTR Study, then policies must, with high certainty, deliver a near- and long-term pathway of emissions reductions.

As McMullin et al. points out, there are also the costs of energy-supply risk in over-reliance on imported gas supply, and in the highly uncertain presumption of future discovery of more natural gas. Furthermore, there is the uncertain but multi-generational risk and long-term cost to our future of failing to restrict emissions in line with the Paris targets. In this context, nett zero or negative carbon energy should logically have an even higher energy and climate policy priority than short horizon energy security or current cost. Omitting costs skews cost benefit analysis, making options appear far less costly than they are within a system analysis demanding Paris-alignment of system decarbonisation.  

Viable options to stay within 1.5ºC or well below 2ºC are becoming ever more urgent, even with radical emission reduction and some limited commitment to nett negative emissions. As nuclear energy has been ruled out to date in Ireland and CO2 quota analysis shows continued fossil fuel dependence must rapidly come to an end, the only viable answer appears to be near-term and sustained energy demand reduction, combined with rapid roll-out of a 100% renewables energy system, primarily based on wind and solar generated electricity with a range of battery and pumped hydro for short-term grid balancing and chemical energy storage to provide seasonal or even multiannual security of supply.

McMullin et al. concludes that:

While the electrofuel storage element of this pathway is challenging in terms of technology maturity and immediate investment cost, this is true of all decarbonisation pathways that might credibly be commensurate with meeting the Paris climate goals; but this pathway has the unique advantages of high confidence in the effectiveness of decarbonisation and relatively rapid achievement of very high national energy security. Such a rapid fossil fuel phase out would additionally bring very significant co-benefits in balance of payments and overall national social and economic resilience.

Energy and climate policy requires a broad basis for the increasingly difficult energy and climate choices society and government now have to make. To be ‘policy relevant’, study scenarios and cost benefit analyses need to address cumulative emission quota analysis and how conclusions will assist in meeting a Paris-aligned energy and emissions pathway for Ireland. Cost-effectiveness analysis, as demanded by the Climate Act and as described by the Public Spending Code, requires such a Paris-aligned “national transition objective” to be defined and met by collective climate and energy policy. Without this overarching system perspective both costs and risks are likely to be greatly underestimated by narrowly focused or short-term studies.

Radical energy conservation measures to cut near-term fossil fuel use and early investments in large scale wind and solar with electrofuel back up, may be apparently expensive in the current absence of strong carbon management, but in a cost-effectiveness context aligned with meeting Paris commitments, thus requiring a national “fair share” cumulative CO2 quota to be met without fail, they may well be the optimal choice.


DCCAE, 2017. National Mitigation Plan 2017. pp.1–200.

Deane, P. et al., 2013. Technical support on developing low carbon sector roadmaps for Ireland Low Carbon Energy Roadmap for Ireland. ESRI e4sma UCC.

Gas Networks Ireland and EirGrid, 2018. Long Term Resilience Study 2018. Pp.1–42.

Glynn, J. et al., 2018. Zero carbon energy system pathways for Ireland consistent with the Paris Agreement. Climate Policy, 52, pp.1–13.

Government of Ireland, 2015. Climate Action and Low Carbon Development Act 2015. pp.1–25.

IAE (2018) Natural Gas: Essential for Ireland’s Future Energy Security. Irish Academy of Engineering. Jul 2018.

McMullin B, Price P, Carton J, Anderson K, 2018. Is Natural Gas “Essential for Ireland’s Future Energy Security”? Pp.1–21.