Energy systems · Scenario modelling · LEAP · Germany
Scenario-based 3E modelling of Germany’s electricity system from 2022 to 2045 using LEAP, comparing NDC 2030 policy targets against a nuclear recommissioning pathway on cost, CO&sub2; and social cost of the technology system.
Evidence dashboard
Would recommissioning recently closed nuclear capacity improve Germany's 2045 electricity-system decarbonisation pathway compared with the NDC trajectory, and what cost premium would that imply?
The LEAP model linked key assumptions, demand branches, transformation losses and electricity-generation technologies. Demand was projected by sector while technology branches carried capacity, efficiency, cost, lifetime and emissions assumptions.
The nuclear recommissioning pathway cuts post-2038 gas dependence and drives electricity-sector CO2 close to zero by 2045, but carries a modest social-cost premium due to higher nuclear CAPEX and O&M.
Electricity demand grows from 1,742 million GJ in 2022 to 2,488 million GJ in 2045, with transport rising from 53 to 365 million GJ.
Nuclear waste disposal costs, plant recommissioning feasibility and geopolitical fuel-price uncertainty require deeper treatment. The useful evidence is the scenario discipline: public assumptions, explicit technology parameters and transparent cost-carbon trade-offs.
Germany is Europe’s largest economy (GDP $4.07 trillion, 2022) and its biggest CO&sub2; emitter — 675 million tonnes in 2021, of which electricity and heat accounted for 356 million tonnes (53%). Despite the Energiewende and the Federal Climate Change Act (climate neutrality by 2045, 80% renewable electricity by 2030), Germany is not on track. It has phased out nuclear, is expanding LNG infrastructure, and coal remained the largest single electricity source as recently as 2022 at 20.1% of generation.
The research question: would recommissioning recently decommissioned nuclear plants be more cost-efficient and bring Germany closer to its CO&sub2; reduction targets than following the existing NDC pathway?
Germany’s 2022 gross electricity production was 571.3 billion kWh. The mix that the model had to project forward:
Reaching 80% renewable electricity by 2030 from a 44% base in 2022, while simultaneously phasing out nuclear, required a massive and rapid build-out of wind and solar — a pace Germany was not achieving as of the modelling baseline.
The model has four branches: Key Assumptions, Demand, Transformation, and Resources. Electricity is the sole energy carrier across all demand sub-branches. The transformation sector covers Transmission and Distribution (losses starting at 5%, reducing to 3.5% by 2045) and Electricity Generation (11 aggregated technology processes). Shortfall is handled by imports.
Key assumptions: industry demand +1.3%/yr (GDP growth rate); household demand −0.6%/yr (falling household count + efficiency gains); population −0.525%/yr; income +1.5%/yr; household size 2 persons. Transport modelled explicitly with EVs growing from 1.04 million (2022) to 15 million (2030) to 25 million (2045); rail electrification from 54% to 95% of network by 2045.
All 11 technologies were parameterised from industry and literature sources with capacity, fuel cost, efficiency, availability, lifetime, CAPEX and O&M:
Nuclear’s merit order was adjusted to 2 (ahead of oil) in the own scenario to facilitate dispatch between 2024 and 2038, aligning with the government’s commitment to retire coal and oil by 2038.
The own scenario recommissions eleven plants decommissioned within the last five years, adding approximately 12.074 GW of capacity. The targeted plants include Brokdorf (1,410 MW, shut 2021), Grohnde (1,360 MW, shut 2021), Gundremmingen B (1,284 MW, shut 2017), Gundremmingen C (1,288 MW, shut 2021), Emsland (1,335 MW, shut April 2023), Isar 2 (1,410 MW, shut April 2023) and Neckarwestheim 2 (1,310 MW, shut April 2023).
Households fall from 503 to 419 million GJ as household numbers shrink and efficiency improves. Commercial grows from 457 to 723 million GJ. Transport is the fastest-growing sector by far, as electrification of road vehicles and rail absorbs a large share of new electricity demand.
Coal was the largest CO&sub2; source in 2022 at 270 million metric tonnes. Both scenarios show declining coal emissions as plants retire by 2038. The divergence comes after 2038: the NDC scenario fills the gap with imported natural gas, keeping emissions non-zero; the own scenario fills it with nuclear and renewables, driving electricity-sector CO&sub2; to near zero.
The social cost premium of the nuclear scenario (+2.21% by 2045) is driven primarily by nuclear’s higher CAPEX ($2,800M/GW vs. $1,200M/GW for gas) and O&M ($109.52M/GW/yr). Solar and wind remain the largest social cost contributors in both scenarios due to their scale of deployment. The NDC scenario avoids the nuclear CAPEX but incurs ongoing high fuel costs from gas imports — increasingly from Russia’s neighbours post-Ukraine invasion — which are price-exposed and carbon-intensive.
On SDG 7 and energy poverty: Germany’s decarbonisation path risks “technology poverty” as consumers face mandates to upgrade end-use equipment. The EEG surcharge exemptions for renewable self-supply and the Energiewende’s community energy provisions partially mitigate this, but the transition’s distributional impacts require continued policy attention.
Five key policies frame the scenarios: the Federal Climate Change Act (2019 — climate neutrality 2045, negative emissions 2050); the Easter Package (2022 — accelerated renewable permitting); the Climate Action Program 2030 (2019 — CO&sub2; pricing for transport and heat, coal phase-out 2038); the Renewable Energy Sources Act (2000 — 80% renewable electricity by 2030); and the Energy Efficiency Strategy 2050 (2019 — 30% lower consumption by 2030 vs 2008). As of 2022, only 56.9% of Germany’s SDG targets were achieved or on track; 34.7% were worsening.
Relevance
This project demonstrates integrated 3E analysis: connecting demand projections across four sectors, technology cost data for eleven generation types, merit-order dispatch modelling and carbon accounting in a single scenario comparison. The nuclear recommissioning question is a live policy debate across Europe — Germany, Belgium, Sweden, the Netherlands and the UK have all reconsidered their nuclear phase-out positions since 2022.
The methodology of building credible scenarios from public data, parameterising technologies transparently, and comparing outcomes on cost, emissions and social cost is directly transferable to energy system planning, carbon strategy or policy assessment roles.