University of Twente Student Theses


Feasibility Study of Power to Gas Technology at Twence

Bima Angunn Putra, A. (2015) Feasibility Study of Power to Gas Technology at Twence.

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Abstract:The business of selling electricity is becoming less profitable at Twence, as the wholesale electricity price tends to continuously drop. In responding to this problem, it is important for Twence to find any of new possibilities to create a business case that can offer benefits by using the low price electricity. For this purpose, Power to Gas (P2G) technology can be one of the candidates and it is becoming a topic of feasibility study at Twence. P2G is a potential business case at Twence. The P2G technology could be well collaborated with biomass/waste processing plant, thus it fits with the main business of Twence. The final products of P2G are also very flexible such as hydrogen, methane, or methanol. This flexibility makes P2G adaptable with the future energy market. In accordance to above, it is worthy to do an investigation regarding the possibility to apply P2G at Twence. During three months internship, several investigations have been done. The result of investigation is provided in this report in which the structure consist of the following chapters. Chapter 1 gives a brief introduction into the subject. First, a short description is given to the existing plants at Twence that are likely to have a relation with P2G. It is then followed by definition of problems, objectives, and methodology. The aim of investigation is to identify possible routes of P2G and to define probability operation scenarios as well as business case. To achieve the objective four methodologies are used: (1) literature reviews, (2) analysis of electricity price, (3) thermodynamic and flowsheet modeling, and (4) financial calculation. Chapter 2 provides a vision of the P2G technology. Basically, P2G takes important role in making a new sustainable carbon cycle. This cycle has a process that can convert CO2 to synthetic fuels. In addition, the fundamental theory of important reactions such as gasification, methanation, and methanol synthesis are introduced. Chapter 3 explains the summary of literature reviews. It mainly describes the state of the art of power to gas, the different routes of P2G, and the latest development of plasma gasification. The main result of this chapter is that Power to gas plays a role in the decarbonization scenario. In this scenario, P2G is more likely to act as a chemical converter instead of energy storage. As a chemical converter, P2G offers the routes of methanation or methanol synthesis from CO2, biomass, or waste. Through these routes, it is possible to create business cases of replacing fossil based chemicals/fuels. These renewable fuels can be distributed to mobility sector or industry. Chapter 4 provides analysis of spot electricity price using frequency curve. The data of the Netherlands, Sweden, Norway, and Denmark are taken for the analysis. As a result, it is revealed that the high penetration of wind based electricity production positively affects the electricity market price for P2G. This effect of high wind penetration is represented by Denmark spot price in comparison with the other three markets. From this result, it can be discussed that Dutch market will evolve toward a condition similar with DK1, because the Netherlands as well as other European countries has set a higher target of RE production for the next decades. Chapter 5 describes the process of making flowsheet model. In short, the flowsheet model was successfully created and it can be used for comparison analysis between different input variables, routes, or operation scenarios of P2G system. Chapter 6 presents the simple mass calculation using ideal stoichiometric ratio. The calculation is done to compare the difference between the output quaintly of methanation and methanol synthesis. From this chapter, it is concluded that the process of methanol synthesis is more efficient than methanation. Chapter 7 elaborates the route of methanol synthesis. Three scenarios are investigated: (1) methanol synthesis using CO2, (2) low yield methanol synthesis using biomass, (3) high yield methanol synthesis using biomass. From the investigation, it appears that the case no.2 is the most efficient process, because it has optimum methanol production while keeping the electrolyzer capacity at minimum value. In addition, it is also found that the use biomass (the biomass case) led to a higher production of methanol, compared to the use of waste (the waste case). Nevertheless, the waste feedstock has a negative price in which it may improve the net cash flow. In the end, further investigations about the financial feasibility of both the waste and biomass case shall be done. Chapter 8 presents the result of the financial calculation. The waste case shows a better result than the biomass case. In the waste case, profitable business case is noted (IRR>0), but the NPV has not fulfilled the Twence minimum requirement yet. Following this result, the sensitivity analysis is done to investigate which factor could significantly affect the value of NPV and IRR. It is found that NPV and IRR are sensitive to the investment cost of gasifier. Also, intermittent operation (winter summer cycle) has negative impact on NPV. This is because the growth of cash flow by intermittent operation does not compensate the larger capital cost. Chapter 9 explains the overall conclusion and recommendation. The conclusion combines all important messages and results from previous chapters. Most importantly, this study has revealed that the route of waste to methanol is the most feasible business case for Twence. Furthermore, The accomplishment of this study has opened various possibilities for further investigations such as the prediction of energy market, the improvement of the model accuracy, etc.
Item Type:Internship Report (Master)
Twence, the Netherlands
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Sustainable Energy Technology MSc (60443)
Keywords:Power to Gas routes, electricity market price, flowsheeting simulation, financial study
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