Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland

Roberto Turconi, C. O'Dwyer, D. Flynn, Thomas Fruergaard Astrup

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The increase of renewable sources in the power sector is an important step towards more sustainable electricity production. However, introducing high shares of variable renewables, such as wind and solar, cause dispatchable power plants to vary their output to fulfill the remaining electrical demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11% reduction. Given that production technologies are typically modeled assuming steady-state operation at full load, as part of LCA of electricity generation, the efficiency reduction would result in large underestimation of emissions, e.g. up to 65% for an oil power plant. Overall, cycling emissions accounted for less than 7% of lifecycle CO2, NOx and SO2 emissions in the five scenarios considered: while not overbalancing the benefits from increasing wind energy, cycling emissions are not negligible and should be systematically included (i.e. by using emission factors per unit of fuel input rather than per unit of power generated). As the ability to cycle is an additional service provided by a power plant, it is also recommended that only units with similar roles (load following, mid merit, or base load) should be compared. The results showed that cycling emissions increased with the installed wind capacity, but decreased with the addition of storage. The latter benefits can, however, only be obtained if base-load electricity production shifts to a cleaner source than coal. Finally, the present study indicates that, in terms of emission reductions, the priority for Ireland is to phase out coal-based power plants. While investing in new storage capacity reduces system operating costs at high wind penetrations and limits cycling, the emissions reductions are somewhat negated when coupled with base load coal. © 2014.
Original languageEnglish
JournalApplied Energy
Volume131
Pages (from-to)1-8
Number of pages8
ISSN0306-2619
DOIs
Publication statusPublished - 2014

Keywords

  • Life cycle assessment (LCA)
  • Energy modeling
  • Power plant cycling
  • Wind power
  • Renewable energy system
  • Emission factors
  • Carbon dioxide
  • Coal
  • Emission control
  • Environmental impact
  • Fossil fuel power plants
  • Sulfur dioxide
  • Thermoelectric power plants
  • Coal based power plants
  • Electricity generation
  • Electricity production
  • Energy model
  • Life Cycle Assessment (LCA)
  • Renewable energy systems
  • Steady-state operation
  • Life cycle

Cite this

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title = "Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland",
abstract = "The increase of renewable sources in the power sector is an important step towards more sustainable electricity production. However, introducing high shares of variable renewables, such as wind and solar, cause dispatchable power plants to vary their output to fulfill the remaining electrical demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11{\%} reduction. Given that production technologies are typically modeled assuming steady-state operation at full load, as part of LCA of electricity generation, the efficiency reduction would result in large underestimation of emissions, e.g. up to 65{\%} for an oil power plant. Overall, cycling emissions accounted for less than 7{\%} of lifecycle CO2, NOx and SO2 emissions in the five scenarios considered: while not overbalancing the benefits from increasing wind energy, cycling emissions are not negligible and should be systematically included (i.e. by using emission factors per unit of fuel input rather than per unit of power generated). As the ability to cycle is an additional service provided by a power plant, it is also recommended that only units with similar roles (load following, mid merit, or base load) should be compared. The results showed that cycling emissions increased with the installed wind capacity, but decreased with the addition of storage. The latter benefits can, however, only be obtained if base-load electricity production shifts to a cleaner source than coal. Finally, the present study indicates that, in terms of emission reductions, the priority for Ireland is to phase out coal-based power plants. While investing in new storage capacity reduces system operating costs at high wind penetrations and limits cycling, the emissions reductions are somewhat negated when coupled with base load coal. {\circledC} 2014.",
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author = "Roberto Turconi and C. O'Dwyer and D. Flynn and Astrup, {Thomas Fruergaard}",
year = "2014",
doi = "10.1016/j.apenergy.2014.06.006",
language = "English",
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pages = "1--8",
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Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland. / Turconi, Roberto; O'Dwyer, C.; Flynn, D.; Astrup, Thomas Fruergaard.

In: Applied Energy, Vol. 131, 2014, p. 1-8.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland

AU - Turconi, Roberto

AU - O'Dwyer, C.

AU - Flynn, D.

AU - Astrup, Thomas Fruergaard

PY - 2014

Y1 - 2014

N2 - The increase of renewable sources in the power sector is an important step towards more sustainable electricity production. However, introducing high shares of variable renewables, such as wind and solar, cause dispatchable power plants to vary their output to fulfill the remaining electrical demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11% reduction. Given that production technologies are typically modeled assuming steady-state operation at full load, as part of LCA of electricity generation, the efficiency reduction would result in large underestimation of emissions, e.g. up to 65% for an oil power plant. Overall, cycling emissions accounted for less than 7% of lifecycle CO2, NOx and SO2 emissions in the five scenarios considered: while not overbalancing the benefits from increasing wind energy, cycling emissions are not negligible and should be systematically included (i.e. by using emission factors per unit of fuel input rather than per unit of power generated). As the ability to cycle is an additional service provided by a power plant, it is also recommended that only units with similar roles (load following, mid merit, or base load) should be compared. The results showed that cycling emissions increased with the installed wind capacity, but decreased with the addition of storage. The latter benefits can, however, only be obtained if base-load electricity production shifts to a cleaner source than coal. Finally, the present study indicates that, in terms of emission reductions, the priority for Ireland is to phase out coal-based power plants. While investing in new storage capacity reduces system operating costs at high wind penetrations and limits cycling, the emissions reductions are somewhat negated when coupled with base load coal. © 2014.

AB - The increase of renewable sources in the power sector is an important step towards more sustainable electricity production. However, introducing high shares of variable renewables, such as wind and solar, cause dispatchable power plants to vary their output to fulfill the remaining electrical demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11% reduction. Given that production technologies are typically modeled assuming steady-state operation at full load, as part of LCA of electricity generation, the efficiency reduction would result in large underestimation of emissions, e.g. up to 65% for an oil power plant. Overall, cycling emissions accounted for less than 7% of lifecycle CO2, NOx and SO2 emissions in the five scenarios considered: while not overbalancing the benefits from increasing wind energy, cycling emissions are not negligible and should be systematically included (i.e. by using emission factors per unit of fuel input rather than per unit of power generated). As the ability to cycle is an additional service provided by a power plant, it is also recommended that only units with similar roles (load following, mid merit, or base load) should be compared. The results showed that cycling emissions increased with the installed wind capacity, but decreased with the addition of storage. The latter benefits can, however, only be obtained if base-load electricity production shifts to a cleaner source than coal. Finally, the present study indicates that, in terms of emission reductions, the priority for Ireland is to phase out coal-based power plants. While investing in new storage capacity reduces system operating costs at high wind penetrations and limits cycling, the emissions reductions are somewhat negated when coupled with base load coal. © 2014.

KW - Life cycle assessment (LCA)

KW - Energy modeling

KW - Power plant cycling

KW - Wind power

KW - Renewable energy system

KW - Emission factors

KW - Carbon dioxide

KW - Coal

KW - Emission control

KW - Environmental impact

KW - Fossil fuel power plants

KW - Sulfur dioxide

KW - Thermoelectric power plants

KW - Coal based power plants

KW - Electricity generation

KW - Electricity production

KW - Energy model

KW - Life Cycle Assessment (LCA)

KW - Renewable energy systems

KW - Steady-state operation

KW - Life cycle

U2 - 10.1016/j.apenergy.2014.06.006

DO - 10.1016/j.apenergy.2014.06.006

M3 - Journal article

VL - 131

SP - 1

EP - 8

JO - Applied Energy

JF - Applied Energy

SN - 0306-2619

ER -