Flexible electric boilers as part of the energy system of the future
Chou, Chieh-en (2026)
Diplomityö
2026
School of Energy Systems, Energiatekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe20260719111671
https://urn.fi/URN:NBN:fi-fe20260719111671
Tiivistelmä
Decarbonising district heating through electrification is widely advocated, but its value within a carbon-neutral biomass combined heat and power (CHP) system is ambiguous. This thesis examines the cost and emissions effects of partial and full electrification of the Lappeenranta district heating system, and the role of the existing thermal energy storage (TES). An hourly linear programming model covering 1 March 2025 to 9 March 2026 is built using operational data from Lappeenrannan Energia, Nord Pool spot prices, and Fingrid hourly grid CO2 intensity. Five configurations are compared, from the current biomass CHP system with natural gas boilers to full electrification; the model is validated against measured operation and tested through sensitivity sweeps.
Partial electrification combined with the existing TES is the only configuration cheaper than the current system on total cost, saving 0.33 MEUR per year while reducing emissions by roughly 33%. This advantage is robust to plausible variation in electricity and gas prices. Full electrification achieves the lowest operating cost but, owing to its capital cost, requires a carbon price of 219 EUR/tCO2 to break even, while electrification without storage requires 511 EUR/tCO2. The emissions reduction comes from the fuel switch away from natural gas, not from storage, and full electrification emits more than the partial configurations because grid electricity displaces carbon-neutral biomass heat. The value of TES grows approximately 2.6-fold under electrification. The case for full electrification strengthens as carbon prices rise and the grid decarbonises.
Partial electrification combined with the existing TES is the only configuration cheaper than the current system on total cost, saving 0.33 MEUR per year while reducing emissions by roughly 33%. This advantage is robust to plausible variation in electricity and gas prices. Full electrification achieves the lowest operating cost but, owing to its capital cost, requires a carbon price of 219 EUR/tCO2 to break even, while electrification without storage requires 511 EUR/tCO2. The emissions reduction comes from the fuel switch away from natural gas, not from storage, and full electrification emits more than the partial configurations because grid electricity displaces carbon-neutral biomass heat. The value of TES grows approximately 2.6-fold under electrification. The case for full electrification strengthens as carbon prices rise and the grid decarbonises.