| 31. |
- Beiron, Johanna, 1992, et al.
(författare)
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A Case Study of the Potential for CCS in Swedish Combined Heat and Power Plants
- 2021
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Ingår i: 15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021.
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Konferensbidrag (refereegranskat)abstract
- The global need to reduce anthropogenic CO2 emissions is imminent and might be facilitated by carbon capture and storage (CCS) technologies. Sweden has a goal to reach net-zero emissions by 2045, where negative emissions – and bio-CCS (BECCS) in particular - have been proposed as an important strategy to reach this target at the lowest cost. The Swedish district heating sector constitutes a large potential for BECCS since there is a large number of relatively large biogenic point sources of CO2 in the form of combined heat and power (CHP) plants burning biomass residues from the forest industry. This study provides a multi-level estimation of the impact and potential of CO2 capture and negative emissions in 110 existing Swedish biomass or waste-fired CHP plants, located in 78 local district heating systems. Process models of CHP steam cycles give the impact of absorption-based CCS integration on CHP plant heat and electricity production. The propagation of the plant-level impact to the unit commitment of CHP plants in district heating systems is modelled, and the potential for CO2 capture in each system is estimated. The results indicate that 45-70% of nominal steam cycle district heating generation is retained when integrating carbon capture, depending on the power-to-heat ratio; although the reduced heat output can be moderated by sacrificing electricity generation. In the district heating system context, CCS integration can lead to increased utilization and fuel use of CHP plants, in synergy with increased CO2 capture, but might also lead to greater need for peak heat and/or electricity generation. The total CO2 captured from the 45 CHP plants with modeled CO2 emissions exceeding 150 kton/year could be sufficient to meet a proposed target of 3-10 Mton/year of BECCS by Year 2045.
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| 32. |
- Beiron, Johanna, 1992, et al.
(författare)
-
A multiple system level modeling approach to coupled energy markets: Incentives for combined heat and power generation at the plant, city and regional energy system levels
- 2022
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- The energy system can be subdivided into interconnected structural levels with differing boundary conditions and objectives. For heat and power generation, these levels may be the: electricity price area (regional); heat price area (city); and production site (power plant). This work presents a multi-system modeling approach for the analysis of investments and operation of combined heat and power (CHP) plants, as optimized on a regional, city, or production site energy system level. The modeling framework, comprising three energy system optimization models at the respective levels, is applied to a case study of Sweden, electricity price area SE3. The modeling levels are optimized separately but linked through electricity and heat prices. The results show that optimized CHP plant investments and operation on the three levels can both align and differ, depending on conditions. With a low biomass price and moderate congestion in transmission capacity into the city, the results from the three levels generally align. Differences arise if the biomass price is increased, which impacts the competitiveness of CHP plants in the region, while city-level CHP investments are mainly determined by the local heat demand and less-sensitive to external changes. The differences indicate a risk for diverging expectations between system levels.
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| 33. |
- Beiron, Johanna, 1992, et al.
(författare)
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A techno-economic assessment of CO2 capture in biomass and waste-fired combined heat and power plants – A Swedish case study
- 2022
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 118
-
Tidskriftsartikel (refereegranskat)abstract
- The need to reduce global CO2 emissions is urgent and might be facilitated by carbon capture and storage (CCS) technologies. Sweden has a goal to reach net-zero emissions by 2045. Negative emissions and bio-CCS (BECCS) have been proposed as important strategies to reach this target at the lowest cost. The Swedish district heating sector constitutes a large potential for BECCS, with biogenic point sources of CO2 in the form of combined heat and power (CHP) plants that burn biomass residues from the forest industry. This study analyzes the potential of CO2 capture in 110 existing Swedish biomass or waste-fired CHP plants. Process models of CHP steam cycles give the impacts of absorption-based CCS on heat and electricity production, while a district heating system unit commitment model gives the impact on plant operation and the potential for CO2 capture. The results provide a cost for carbon capture and transport to the nearest harbor by truck: up to 19.3 MtCO2/year could be captured at a cost in the range of 45–125 €/tCO2, corresponding to around 40% of the total fossil fuel-based Swedish CO2 emissions. This would be sufficient to meet a proposed target of 3–10 Mt/year of BECCS by 2045.
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| 34. |
- Beiron, Johanna, 1992, et al.
(författare)
-
An assessment of the flexibility of combined heat and power plants in power systems with high shares of intermittent power sources
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is an urgent need to reduce anthropogenic CO2 emissions from the power sector as a climate change mitigating strategy. Thus, the share of renewable energy sources in power systems, for example wind power, is increasing. However, the variability in wind power generation poses a challenge to conventional thermal power plants, as well as yielding volatile electricity prices. Once in place, wind power with low operating cost will replace higher-cost electricity generation units in the merit order, while during low-wind periods the need for thermal plants remains. Traditionally designed for stable base load, thermal power plants might thus face a future with new demands for flexible operation to stay competitive. Combined heat and power (CHP) plants are thermal power plants that produce electricity and district heating simultaneously and, depending on plant type and fuel, they have different possibilities to vary the ratio between power and heat production. However, technical constraints place limitations on flexibility, including ramp rates and efficiency. The interconnection between the power and heat markets provides additional opportunities for load variation management. With the comparably slower dynamics of the heat market, and the possibility to store thermal energy, prospects of adapting to new and profitable operating strategies that can aid the balancing of the power system arise. This study focuses on how CHP plants can provide flexibility in a scenario with fluctuating power demand and associated volatility in electricity prices. Plant and market dynamics are analyzed to estimate the need for flexibility, and what is required of CHP units in terms of operation to meet these requirements. A CHP plant is modelled in detail with a boiler, steam cycle and its link to the district heating system, both under steady state and transient conditions, using the softwares Ebsilon and Dymola, respectively. The models are validated against operational data from a Swedish CHP plant. Transient responses to load ramps are characterized, as well as the flexibility in power-to-heat ratio, and their effects on efficiency.
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| 35. |
- Beiron, Johanna, 1992, et al.
(författare)
-
Carbon capture from combined heat and power plants – Impact on the supply and cost of electricity and district heating in cities
- 2023
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Ingår i: International Journal of Greenhouse Gas Control. - 1750-5836. ; 129
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Tidskriftsartikel (refereegranskat)abstract
- The capture and storage of biogenic CO2 emissions from large point sources, such as biomass-combusting combined heat and power (CHP) plants, can contribute to climate change mitigation and provide carbon-negative electricity while supplying district heating in urban areas. This work investigates the impact of retrofitting CO2 capture processes to CHP plants in a city energy system context. An energy system optimization model is applied to a case study of the city Västerås, Sweden, with scenarios involving two existing CHP plants in the city, retrofitted with either a heat-driven (MEA) or an electricity-driven (HPC) carbon capture process. The results show that the CHP plants might be retrofitted with either option without significantly impacting the district heating system operation or the marginal costs of electricity and district heating in the city. The MEA process mainly causes a reduction in district heating output (up to 30% decrease on an annual basis), which can be offset by heat recovery from the capture unit. The electrified HPC process does not impact the CHP plant steam cycle but implies increased import of electricity to the city (up to 44% increase annually) compared to a reference scenario.
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| 36. |
- Beiron, Johanna, 1992, et al.
(författare)
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Combined heat and power operational modes for increased product flexibility in a waste incineration plant
- 2020
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 202
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Tidskriftsartikel (refereegranskat)abstract
- The expected strong expansion of wind power may cause challenges for the electricity system in terms of grid stability, power balance, and increased electricity price volatility. This paper analyses how the new market conditions impact the operational pattern and revenue of a combined heat and power (CHP) plant. The work focuses on product flexibility that enables varied ratios between products; and thermal flexibility, to shift load in time given the differing timescales of heat and power demand. Product flexibility is given by five operational modes: conventional CHP, heat-only, CHP plus frequency response, condensing, and condensing plus frequency response. Optimization and process modeling are combined to study the plant dispatch in current and future electricity market scenarios and with thermal flexibility. The results indicate that load-shifting of heat generation together with condensing operation can increase revenue up to 4.5 M€ and plant utilization up to 100% for a 50 MWel waste-fired plant; but requires a thermal energy storage to meet hourly heat demand. The electricity price profile impacts both the revenue and operational patterns, with low-price periods favoring increased heat generation and frequency response delivery. High average electricity price and price volatility results in increased profitability of product and thermal flexibility.
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| 37. |
- Beiron, Johanna, 1992, et al.
(författare)
-
Dynamic modeling for assessment of steam cycle operation in waste-fired combined heat and power plants
- 2019
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 198
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Tidskriftsartikel (refereegranskat)abstract
- As the share of non-dispatchable energy sources in power systems increases, thermal power plants are expected to experience load variations to a greater extent. Waste-fired combined heat and power has multiple products and is today primarily operated for waste incineration and to generate heat. To consider load variations in the power demand at these plants may be a way to provide system services and obtain revenue, however, the transient interaction between power and district heating generation for the type of steam systems used should be studied. This work describes the transient characteristics and timescales of cogeneration steam cycles to discuss the operational interactions between power and district heating generation. A dynamic model of the steam cycle of a 48 MW waste-fired combined heat and power plant is developed using physical equations and the modeling language Modelica. The model is successfully validated quantitatively for both steady-state and transient operation with data from a reference plant and is shown capable of characterizing the internal dynamics of combined heat and power plant processes. Simulations are performed to analyze steam cycle responses to step changes, ramps and sinusoidal disturbances of boiler load changes and variability in district heating inlet temperature and flow. The results give insight on the process timescales for the specific case studied; for example, with the present design a 10% boiler load change requires up to 15 min for responses to settle, while the corresponding time for a 10% change in district heating flow or temperature show settling times within 5 min. Furthermore, increasing the boiler ramp rate from 2 to 4%/min could reduce the rise time of power generation by 42%, which could be of economic significance in day-ahead power markets.
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| 38. |
- Beiron, Johanna, 1992, et al.
(författare)
-
Enhancement of CO2 Absorption in Water through pH Control and Carbonic Anhydrase - A Technical Assessment
- 2019
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 58:31, s. 14275-14283
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides an industrial-scale technical assessment of absorption of CO2 in water to react into bicarbonate (HCO3−), with the goal of storing HCO3− in the oceans as a carbon sequestration technology. A potential advantage of the process is that it will not require a CO2 transport and storage infrastructure that will be expensive for small-scale and remote emission sources. Process simulations are utilized to estimate absorber column length and for mass flow estimations of water and base required for a target capture rate of 90%. The results indicate that the process is technically feasible under specific conditions, with pH regulation being highly important, although the demand for base represents a limiting factor. Yet, a potential niche for the process is CO2 capture at smaller plants emitting small amounts of CO2.
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| 39. |
- Beiron, Johanna, 1992, et al.
(författare)
-
Flexibility provision by combined heat and power plants – An evaluation of benefits from a plant and system perspective
- 2022
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Ingår i: Energy Conversion and Management: X. - : Elsevier BV. - 2590-1745. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Variable renewable electricity generation is likely to constitute a large share of future electricity systems. In such electricity systems, the cost and resource efficiency can be improved by employing strategies to manage variations. This work investigates combined heat and power (CHP) plant flexibility as a variation management strategy in an energy system context, considering the operation and cost-competitiveness of CHP plants. An energy system optimization model with detailed representation of CHP plant flexibility is applied, covering the electricity and district heating sectors in one Swedish electricity price area. The results show that investments in CHP plants are dimensioned based on the demand for district heating rather than electricity. In the system studied, this implies that CHP plant capacity is small relative to electricity system variations, and variation management using CHP plants has a weak impact on the total system cost of supplying electricity and district heating. However, flexibility measures increase CHP plant competitiveness in scenarios with low system flexibility (assuming low availability of hydropower or no thermal energy storage) although investments in CHP capacity are sensitive to fuel cost. It is found that while district heating is the dominant CHP product (constituting 50%–90% of the annual CHP energy output), the dispatchable electricity supply has a high value and comprises around 60% of the annual CHP plant revenue. In all scenarios, operational flexibility of the boiler is more valuable than a flexible steam cycle power-to-heat ratio.
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| 40. |
- Beiron, Johanna, 1992, et al.
(författare)
-
Flexible operation of a combined cycle cogeneration plant - A techno-economic assessment
- 2020
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 278
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Tidskriftsartikel (refereegranskat)abstract
- The need for flexibility in combined heat and power (CHP) plants is expected to increase due to the strong expansion of wind power in electricity systems. Cost-effective strategies to enhance the flexibility of CHP operation are therefore needed. This paper analyzes three types of flexibility measures for a combined cycle CHP plant and their relative impact on the plant operation and revenue. The types of flexibility are: operational flexibility of the fuel conversion system, product flexibility with variable plant product ratios (heat/electricity/primary frequency response), and thermal flexibility in a district heating network. A modeling framework consisting of steady-state and dynamic process simulation models and optimization model is developed to combine static, dynamic, technical and economic perspectives on flexibility. A reference plant serves as a basis for the process model development and validation, and an energy system model provides input profiles for future electricity price scenarios. The results indicate that product flexibility and thermal flexibility have the highest value for the cogeneration plant (up to 16.5 M€ increased revenue for a 250 MWel plant), while operational flexibility (ramp rate) has a comparatively small impact (<1.4 M€). A wide load span and plant versatility, e.g. electricity and heat generating potential between 0 and 139% of nominal capacity, is beneficial in future energy system contexts, but has a marginal value in the current system. Electricity price volatility is a main driver that increases the value of flexibility and promotes operating strategies that follow the electricity price profile rather than the heat demand.
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