| 1. |
- Abdollahi, Elnaz, et al.
(author)
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Potential profits from ancillary service markets
- 2023
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Reports (other academic/artistic)abstract
- In this deliverable from the SeCoHeat project, profits that can be made with 1 MWh of electricity production capacity on existing ancillary service markets are evaluated in 2020 and 2021. Profits are evaluated for four different marginal production costs corresponding to the following fuels for a CHP power plant: waste (assumed fuel price: 0 kr/MWh), recycled wood (10 kr/MWh), wood chips (20 kr/MWh) and wood pellets (30 kr/MWh). The results show that except for wood chips and wood pellets in 2020, the most profitable ancillary service markets are FFR (fast-frequency response) and aFRR down (automatic frequency restoration reserves for down-regulation). The reasons are that (1) producers don’t have to withhold capacity from the day-ahead market when their participate in these two markets and (2) producers get compensated for the capacity reserved for the ancillary service markets. For wood chips, the FFR market was the most profitable in 2020, followed by the mFRR down market (manual frequency restoration reserves for down-regulation). The reason for the mFRR down market to be more profitable than the aFRR down market for this fuel is that the profits from mFRR down depend on the avoided fuel costs, which are higher for wood chips than for waste and recycled wood. In 2021, all prices started increasing significantly, which decreased the relative profitability of the mFRR down compared to other markets. For wood pellets, the mFRR down market was also the second most profitable market in 2020, for the same reasons. The most profitable one in 2020 was the mFRR up market (manual frequency restoration reserves for up-regulation). The reason is that the higher fuel price of these two fuels entails low participation in the day-ahead market. Therefore, withholding capacity from the day-ahead market to be able to participate on the mFRR up market brings additional profits. In 2021, however, day-ahead prices started increasing significantly (a trend that continued into 2022) and the mFRR up market became the least profitable market for these two fuels. The profit evaluation performed in this deliverable is purely economic. It does not include the sector coupling to the heat sector (which entails limitation of the available electricity production capacity but also a possibility to store heat if storage is available) nor does it include other technical limitations such as ramp rates. These aspects will be considered in follow-up work in this project. This report has been compiled within the scope of the project SeCoHeat - Sector coupling of district heating with the electricity system: profitability and operation. The project is financed by the Research and Development Foundation of Göteborg Energi.
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| 2. |
- Hamon, Camille, et al.
(author)
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Profit estimation for district heating systems when participating in electricity and ancillary service markets
- 2023
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Reports (other academic/artistic)abstract
- Profits generated by district heating systems when participating in ancillary service markets in the electricity sector are studied in this report. An hourly scheduling model is developed to optimally schedule district heating units to meet the heat demand, minimize costs and maximize revenues from electricity markets. The output is used to evaluate the additional profits made by participating in the existing Swedish ancillary markets in addition to the day-ahead electricity market. Case studies are run in two district heating systems, one in Nyköping and one in Gothenburg, for the historical years of 2021 and 2022. Nyköping’s system is also used to evaluate potential profits from ancillary service markets in future scenarios for 2025, 2035 and 2045. Finally, Nyköping’s system is used to evaluate potential additional profits generated by two investments that enhance the flexibility that can be provided to the electricity sector: better CHP ramp rates and larger thermal storage. The analysis of the results shows, for both historical and future years, that participating in ancillary services brings about additional profits. These vary depending on the year, studied district heating system. Profits from electricity markets are shown to increase by up to 40% in Nyköping and 200% in Gothenburg when looking at the historical years. Doubling the CHP ramp rates ability for delivering ancillary services or doubling the size of the heat storage are shown to result in up to another 6% of additional profits. In the future scenarios, profits from electricity markets are shown to increase by up to 94%.
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| 3. |
- Hamon, Camille, et al.
(author)
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Review of current and future heat- and electricity-related products and their relevance for district heating companies
- 2023
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Reports (other academic/artistic)abstract
- A review of sector coupling possibilities between the heat and electricity sectors in Sweden is made in this report. First, a review of the way the heat sector works in Denmark, Finland and Sweden works is performed. Finland and Sweden have similar setups with deregulated heat sectors in which district heating companies set their billing price freely considering different cost factors, including costs for alternative technologies to which consumers could switch. Denmark has had a more regulated approach with prices being reviewed by the regulator. The sector coupling between the electricity sector in Denmark has been stronger than in both Sweden and Finland. District heating companies had an obligation until 2019 to participate in both the day-ahead market and the balancing market (mFRR). CHP plants in Denmark have also participated to frequency regulation (aFRR). There is still a non-negligible share of CHP plants in Denmark running on fossil fuels such as natural gas and coal. Large investments in heat pumps, biofuels and solar thermal facilities have been identified as alternatives to these CHP plants to enable a fossil free heating sector. Second, the current electricity and ancillary service markets in Sweden are described. Recent experiences with local and regional flexibility markets in Sweden are reviewed. District heating companies are particularly well-fitted for participating in these markets thanks to their geographical location close to the electric consumption centres in the cities. Third, a review of the state-of-the-art research on the participation of district heating systems to the electricity and ancillary service markets is performed. It is shown that the flexibility in district heating systems that can be used in the electricity sector can take many forms: changes in the electricity production / consumption of heat production units, by-product usage of the excess heat (e.g. fuel drying), thermal storage in water tanks or other kinds of storage facilities, thermal storage in the pipeline network and thermal storage at the customers’ site (for example in buildings). Research on the technical capabilities shows that many units in the district heating systems can fulfil the requirements for delivering ancillary services. Many research works have identified possible economical gains by participating in more markets on the electricity side (for example ancillary service markets). However, many research works in this field have focused on single CHP plants instead of considering the whole portfolio of units in the district heating systems. To get a more detailed assessment of the profitability of increasing the participation of district heating companies in the electricity sector, it is advocated to develop operational planning and operations tools for district heating systems that can capture the hourly variability of prices of the electricity and ancillary service markets, as well as consider the order in which decisions have to be taken on these markets (i.e. the time order in which the different markets operate). These tools will be developed in the coming work in the project.
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| 4. |
- Hamon, Camille, et al.
(author)
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Sector coupling of district heating with the electricity system: profitability and operations (SeCoHeat)
- 2023
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Reports (other academic/artistic)abstract
- District heating systems can play key roles in the energy transition. The transition to a production mix based on renewable intermittent generation will create a larger need for ancillary services including frequency-regulation services. District heating systems typically participate in the wholesale electricity market (the so-called day-ahead market) today but do not, in general, participate in ancillary service markets. Previous studies have shown that it is technically possible to participate in these markets and that district heating systems have a role to play in these markets in the future. This requires investigating how further integration of district heating systems with the electrical grids and markets will impact operation and planning of these units. In addition, while it may be beneficial on a system level for district heating systems to participate in ancillary service markets, district heating system owners and operators will only do so if there are economic incentives to do so. The SeCoHeat project has therefore explored topics related to the profitability for individual district heating systems to participate in other electricity markets than just the day-ahead market, such as ancillary service markets. Studying sector coupling between the heat and electricity systems requires a thorough understanding of both sectors. This project has contributed to this by bringing together experts from both sides which has led to fruitful knowledge exchanges. Furthermore, some deliverables from the SeCoHeat project have been especially written to provide introduction about the heat sector to experts from the electricity sector, and vice versa. This includes an overview of the electricity markets in which district heating systems can participate, the technical requirements to participate in these markets and explanations about how profitability of participating in these markets can be computed. This also includes explanations about how the flexibility on the heat side can be sourced and provided to the electricity system and what limits this flexibility. Another important contribution of this project is the development of a Python-based open model for scheduling district system units on an hourly basis to minimize heat and electricity production costs while maximising revenues from several electricity markets. This model has been used in this project to evaluate the additional profits of participating in ancillary service markets. The results show that substantial additional profits can be made by doing so, both in historical years and in scenarios for future years. This report is a guide to the separate deliverables produced within this project. It offers an overview of the goals, methods and results from the project. The interested reader is referred to detailed descriptions in the corresponding deliverables. The SeCoHeat project was funded by Göteborg Energi AB:s stiftelse för forskning och utveckling. The work has been performed by RISE with the support of reference group members from Göteborg Energi, Vattenfall, Svenska kraftnät, IVL Svenska Miljöinstitutet, Chalmers and Profu.
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| 5. |
- Lahdelma, Risto, et al.
(author)
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Optimization and Multicriteria Evaluation of District Heat Production and Storage
- 2019
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In: Multiple Criteria Decision Making. - Cham : Springer Nature. ; , s. 371-396
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Book chapter (other academic/artistic)abstract
- Climate change mitigation policy requires reducing dependence on fossil fuels and transition to low carbon energy production in district heating (DH). We study here inclusion of two kinds of renewable energy to a CHP based DH system in Finland: solar heat and ground source heat. In addition, we apply heat storages to balance the gap between production and fluctuating demand. The optimal operation of the extended systems is determined by a simulation and optimization model to minimize the operating costs. We evaluate the different possible extensions in terms of multiple economic, technical and environmental criteria using Stochastic Multicriteria Acceptability Analysis (SMAA). The results show that under Finnish conditions, ground source heat is more favourable than solar heat for DH.
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| 6. |
- Wang, Haichao, et al.
(author)
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Heat-power peak shaving and wind power accommodation of combined heat and power plant with thermal energy storage and electric heat pump
- 2023
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In: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 297
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Journal article (peer-reviewed)abstract
- Wind power curtailment becomes a major problem in many countries. The wind accommodation mechanisms and energy saving potentials for the combined heat and power plant with thermal energy storage, electric heat pump and both should be evaluated more systematically and accurately to accommodate more wind power. Heat-power peak shaving capacities for thermal energy storage, electric heat pump and both are analyzed using a graphical method, while the operation strategy is proposed to maximize wind accommodation. A simulation model for wind power accommodation considering the energy balances and constraints of all production units is developed based on EnergyPRO. A regional energy supply system in Jilin Province, China is selected as the case study, where the influences of different peak shaving technologies and their parameters on the wind accommodation and energy saving are studied. The wind curtailment ratio is reduced from 20.31% to 13.04% and 7.51% with thermal energy storage and electric heat pump respectively, and it is further reduced to 4.21% with both. Systems with electric heat pump can save energy from 1.1% to 5.8% with different parameters of the peak shaving devices. It was found that electric heat pump has better accommodation capability than that of thermal energy storage. Wind accommodation can be improved by adding thermal energy storage to electric heat pump, but the effect gradually decreases as the storage size increases. Electric heat pump can increase the system’s energy efficiency, but it is not always energy efficient by adding thermal energy storage to electric heat pump. In fact, thermal energy storage should not be too large, otherwise the system’s energy efficiency will be reduced.
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| 7. |
- Wang, Haichao, et al.
(author)
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Study on the performance of a forced convection low temperature radiator for district heating
- 2023
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In: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 283
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Journal article (peer-reviewed)abstract
- Low temperature district heating has significant advantages in energy efficiency, but a huge amount of existing radiators lack the capabilities for low-temperate heating. The innovation of this study is to develop an optimal and techno-economic method to improve the heating power of existing radiator by mounting a small fan considering different hydraulic connection modes. An experimental test rig was designed to study the optimal installation positions and angles of the fan. For a dormitory room in China, a computational fluid dynamics (CFD) model was developed and verified. The model was used to determine the lowest supply temperature of the radiator. Results show that the fan should be placed in a position and angle that blows air over the hottest surface of the radiator i.e. the hot center. The lowest supply temperatures before and after installing the fan are 42.3 °C and 39.5 °C. The response speed is increased by 28%, stability time is shortened by 13%, while the maximum indoor temperature difference is reduced by 15% and the maximum indoor air velocity is reduced by 0.07 m/s. Payback time is 63 days for case study, indicating a good economic feasibility. The method is beneficial to both the heat plant and users.
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