Ireland's transition to a low-carbon energy future

Authors: Professor Brian Ó Gallachóir and Dr Paul Deane, Environmental Research Institute, University College Cork A key challenge in achieving a successful transition to a low carbon future is implementing the correct suite of policy measures that are based on robust evidence. Today’s policymakers across the world draw on a number of tools to inform long-range climate mitigation and energy policy choices and one powerful set of tools are called integrated energy system models. We in University College Cork (UCC) have developed an integrated energy systems model for Ireland called the ‘Irish TIMES’ over the past eight years, with funding from the Environmental Protection Agency and the Sustainable Energy Authority of Ireland. TIMES is a techno-economic optimisation framework developed over the past 40 years through an International Energy Agency co-ordinated international collaboration that generates future energy system pathways to meet our energy needs at least cost, subject to a number of defined constraints. TIMES models are used in more than 70 countries worldwide (including a number of EU member states) to inform energy and climate policy. The project in Ireland has involved wider collaboration with the Economic and Social Research Institute on the economic drivers and macroeconomic implications and with Teagasc and University College Dublin on including agriculture systems and exploring land use competition.

Model's key strength is that it considers all modes of energy

The model’s key strength (in addition to the international network of expertise and continued methodological improvements) is that it considers all modes of energy (electricity, heating and transport) across all sectors of the economy in an integrated fashion rather than treating individual modes or sectors in isolation, which can lead to sub-optimal solutions. More importantly, in using the model we don’t optimise for direct energy use, instead we optimise for energy service demands (that is, the utility we get from energy use) such as lighting, heating, passenger kilometres, tonnes of steel and cement etc. This is significant because as a society we don’t intentionally use energy, but rather have requirements for mobility, lighting, goods and so on. This is a useful distinction of TIMES and allows us to evaluate a large number of technologies to meet these demands at the least cost. In all we consider a wide range of more than 1,300 technologies in the time frame to 2050 from light bulbs, cars, fridges, heaters, boilers, power plants, bio refineries etc. Note that elements such as insulations and retrofitting are also included as proxy technologies. Technologies effectively compete with each other over time in order to meet our energy services such that the overall costs to society are minimised and any policy constraints are simultaneously met. It allows us to explore, for example, whether our future mobility needs will be met by biogas-powered vehicles, or wind-powered electric vehicles, or hydrogen-fuelled vehicles, not in an isolated but in an integrated manner, within the context of the overall energy system evolution.

Modelling the energy system within the wider economy delivers rich insights

Modelling the energy system within the wider economy delivers rich insights and provides a consistent framework to analyse policy choices. In the absence of such a modelling framework decisions about policy choices become much more challenging, as do negotiations with the European Union (regarding member state targets to deliver an overall EU ambition). We must be careful not to fall into the trap of thinking that these models (or indeed any models) can ‘predict’ the future or that the more complex a model is the better it is. Both these statements are not true and in UCC we are always mindful of the modeller’s mantra that ‘all models are wrong, but some are useful’. We don’t do predictions; instead we model a range of scenarios of possible futures (including a range of economic growth levels, changes in technology prices and timing of availability, reduced access to energy imports, etc). Scrutinising the results of this scenario analysis provides useful insights into the interaction between technologies, timing of technology deployment, resource availability and climate policy ambition. Complexity is unavoidable in such large models but complexity has to be balanced with the inherent uncertainty in long-range inputs such as fuel prices and macroeconomic estimations.

Multidimensional and intricate nature of energy systems

In the absence of a modelling framework, any analysis of the energy system over the coming decades reverts to educated guesswork, due to the multidimensional and intricate nature of energy systems. The outputs from TIMES capture the scale of the challenge ahead and also point to a number of areas of opportunity for Ireland as it transitions to a low carbon future. [caption id="attachment_27945" align="alignright" width="300"]

Figure 1: Ireland’s energy supply and demand in 2050 with a no ambition scenario[/caption] Let us examine two specific 2050 scenarios from a wider range of results from TIMES. The first scenario is one where no specific ambition to reduce emission is assumed. While this is not realistic as the EU-ETS and other policy instruments are in place, it provides a useful counterfactual. The Sankey diagram below captures the origin of primary energy inputs on the left, fuel types and energy transformation in the middle and final energy consumption by sector on the right. In this scenario with no specific ambition, the 2050 energy system looks broadly similar to today’s with a high reliance on imported fossil fuels and a small (10 per cent) contribution from renewable energy (compared with 8.6 per cent in 2014). Total final consumption in 2050 is 170 TWh (growing from 134 TWh in 2014) with electricity accounting for 17 per cent of final consumption, compared with 19 per cent today. Transport is dominated by imported oil and home heating is provided by oil and gas. The services sector uses electricity and gas and industry energy use is split roughly equally between gas, oil and electricity. [caption id="attachment_27946" align="alignright" width="300"]

Figure 2: Ireland’s energy supply and demand in 2050 with in a low carbon future (80% reduction in CO2 compared with 1990). This scenario assumes access to sustainable bioenergy imports and carbon capture and storage technology.[/caption] Now let’s look at an alternative scenario, a low carbon energy system in which CO₂ emissions are 80 per cent lower than 1990 levels. This scenario excludes the large share (30 per cent) of GHG emissions caused by agriculture, aligning with current national climate mitigation policy targets of at least an 80 per cent reduction in the energy system in parallel with carbon neutrality in agriculture. In this specific scenario, we assume that Ireland has access to imports of sustainable bioenergy and that the ability of the electricity grid to absorb variable renewables such as wind and solar is limited to 50 per cent on an annual basis (this is a proxy for a system non-synchronous penetration [SNSP] limit of 75 per cent). We also assume that carbon capture and storage (CCS) is commercially available as a technology by 2050. These assumptions are of course very uncertain and contentious, and comparisons with additional scenarios in which we assume limited bioenergy imports and delays in CCS technology maturity provide useful insights on the implications of technology risk and security of supply for Ireland.

Full electrification of the private car fleet

In this alternative 2050, we see a very different Ireland. Total final consumption is significantly lower (134 TWh), highlighting the important role of energy efficiency. We see full electrification of the private car fleet and thus high use of electricity in transport, but we also see a high usage of biofuel in transport for light goods vehicles and biogas CNG for heavy good vehicles. We see a strong exploitation of indigenous (gaseous and solid) bioenergy but also strong imports of sustainable (solid and liquid) bioenergy which brings security of supply into question. We see a greater electrification of heating in the residential sectors primarily through heat pumps, coupled with the stronger levels of retrofitting and expansion of gas and biogas into the sector. Electricity represents 25 per cent of final energy use, half of which is provided by a full uptake of Ireland’s onshore wind resource and some PV is deployed after 2030, but variable renewable electricity generation is capped because of the grid constraint on SNSP. We also see significant use of natural gas through carbon capture and storage in the sector. Looking at this specific scenario, it is clear that there is significant uncertainty around CCS and bioenergy imports. In scenarios where CCS is not available, the system switches to more bioenergy imports. In scenarios where bioenergy imports are not allowed, the system selects a more expensive option of further electrification, some of which is used to produce hydrogen for freight transport. If we exclude both of these options, limit the land available for indigenous bioenergy and limit the electricity grid to an SNSP of 75 per cent then the model cannot find an energy system that delivers the 80 per cent emissions reduction required. Other options that we are currently evaluating are massive electrical interconnection to Europe (and within Europe) and also an option where nuclear energy is available. These are works in progress and will be available during the year. Summing up some of the important points from the TIMES modelling exercise for Ireland:

The decarbonisation challenge is very significant;
Beware of silver bullets, there are none;
High level policy signals on targets are strong;
Measures and action are now critical;
We need an urgent focus on heat and transport - we need everybody on board;
There are significant opportunities.

Prof Brian Ó Gallachóir presented a talk on ‘Ireland’s Transition to a Low Carbon Energy Future’ at a joint meeting of Engineers Ireland Energy and Environment Division and the Energy Institute