{MECH560} Homework 1 Description

pdf

School

McGill University *

*We aren’t endorsed by this school

Course

MISC

Subject

Mechanical Engineering

Date

Jan 9, 2024

Type

pdf

Pages

Uploaded by Twirox

MECH 560 FALL 2023 Research Report I Hydrogen as Energy Storage 1 Quick Facts This is an individual homework, worth 9% of the course grade. Choose your research task on myCourses (”first come, first serve”). If you have not signed up for a task by September 21, you will be assigned one. Due date: 11:59pm on October 7th, 2023 Deliverables: max. 2-page report (excluding references), to be submitted as PDF on my- Courses. Evaluation criteria (each 25%): – Quality and critical assessment of references. – Consideration of relevant aspects. – Clarity of report & calculations. – Conclusions Contact: manuel.sage@mail.mcgill.ca | mutahar.safdar@mail.mcgill.ca 2 Project Description 2.1 Background You work for a manufacturing company with a significant electricity demand. This high demand and the company’s reliance on the public grid pose challenges related to power outages and rising energy costs. To address these concerns, the company’s management is eager to enhance resilience while also reducing the carbon footprint. The solution that has piqued their interest is an energy storage for electricity, with a particular focus on hydrogen. Though hydrogen storage holds promise, it’s worth noting that only a handful of companies offer such solutions, and global prototypes are limited. This rarity could position your company as a pioneer in the field, which has garnered enthusiasm from the marketing department. However, it’s crucial to acknowledge the substantial uncertainties surrounding the feasibility of this project, both from an economic and technological perspective. Careful evaluation and planning will be essential in determining whether hydrogen could be a suitable energy storage for the company’s needs. 1

MECH 560 FALL 2023 Figure 1: The pipeline of an energy storage for electricity and its meaning with respect to hydrogen. 2.2 Task You are part of the engineering team tasked to conduct the first research on the feasibility of hydrogen as an energy storage solution for your company. The outcome of your initial work will determine whether the company further pursues the idea or not. Your report won’t be used for the final decision but rather as the first guide in a sequential process. Hence, the objective is a fair comparison of the available technology options (see below) based on the references you can find as well as assumptions and (ballpark) calculations you make. Energy storages for electricity can typically be divided into three stages: the conversion of energy/electricity into its stored status, the actual storage, and the re-conversion of stored energy back to electricity. Fig. 1 shows this pipeline and the relevance of its parts when it comes to hydrogen. Your task in this project is to choose one of the three stages of this pipeline and evaluate two competing options for this stage. Details for each part are presented in section 2.5. Independent of the task chosen, you will spend most of the project time researching through reports, articles, websites, etc. for relevant information. Choose a location within Canada for the storage and specify it in your report. Then, assess the retrieved information regarding its accu- racy/suitability for this project and use simple calculations based on general engineering knowledge to put it into perspective. Aspects that should be included in your thoughts/calculations are: The efficiencies of individual components and of your part of the pipeline. The capital expenditures (CAPEX) of the equipment/infrastructure needed. The operating expenses (OPEX) of the system (e.g. for fuel or maintenance). The levelized cost of storage (LCOS) per unit for your part of the pipeline. A simple example for Diesel generators is provided in section 3. You can assume a project lifetime of 20 years and a discount rate of 8%, leading to a capital recovery factor of 10.19%. This means that your calculations should account for the fact that the technology must operate for 20 years. 2.3 Report A concise report (max. 2 pages, references not included) is the only deliverable for this project. Use standard formatting (letter size, 11/12pt fonts, reasonable margins). The report can be formulated in bullet points, as long as your steps are clear. The report should include: 2

MECH 560 FALL 2023 A brief intro stating your starting point, i.e., the technology compared, the location chosen, and other relevant assumptions made. A step-by-step guide through the retrieved information and the calculations made, leading to your results. Use metric units and convert all currencies to Canadian dollars. Round reasonably. A conclusion in which you summarize and evaluate your findings. A list of your references at the end (properly formatted in a style of your choice - be consistent) 2.4 Other Information / Tips In general, focus on the differences between the technologies compared and their effect on efficiency and economic indicators. It’s okay to neglect aspects that are similar/identical. It’s a research project! Feel free to investigate aspects not covered by the project description and mention them in your report. Some reading to get you started: on LCOE and LCOS [1]; a comprehensive report on the future of hydrogen [2]. 3

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

MECH 560 FALL 2023 2.5 The Hydrogen Pipeline Choose only one option from the subsections 2.5.1 - 2.5.3. 2.5.1 Option 1: How to obtain H2? This subtask deals with the question how the company can obtain the desired hydrogen. You will analyze and compare two alternative ways: (1) purchasing the hydrogen from an external source and transporting it to your company and (2) generating it on site through an electrolyser. As shown in figure 2, multiple approaches are possible within these two ways. For example, your company could decide to purchase green, blue, or gray hydrogen, and the transport could be managed via tankers or pipelines. The electrolyser on the other hand, could be operated with electricity from the public grid or directly from renewables installed by your company. You are free to choose among these options as long as you investigate one option for each alternative. SIZING: The storage should supply 3 MW of electrical power for a 24h period per week. Thus, 72 MWh of electrical energy are required at the output. Assume that the combined efficiency of all processes following your part is 35%. Then, you need to provide hydrogen containing 72 MWh / 0.35 = 206 MWh of energy per week . However, your LCOS calculation should be based on the 72 MWh of weekly provided electricity. Additional notes, assumptions, and hints: Use the lower heating value (LHV) of hydrogen, which is 33.33 kWh/kg. Electrolysers require direct current, consider the cost & efficiency of rectifiers in your calcula- tion. If you choose to fuel your electrolyser with renewables, research the levelized cost of energy (LCOE) for comparable renewable projects and use it for your calculations (cite!). There is no need to determine CAPEX/OPEX of the renewables. Figure 2: The two main ways to obtain H2. The red box shows the scope of the task. 4

MECH 560 FALL 2023 2.5.2 Option 2: How to store H2? This subtask deals with storing the hydrogen that was produced in the previous step. You will analyze and compare two alternative ways: (1) storing the hydrogen in tanks above the ground and (2) storing it underground, for example in depleted gas wells or in salt taverns (see fig. 3). Storing hydrogen usually requires compressing it beforehand. Consider the cost (CAPEX and OPEX) as well as the efficiency of the compression step in your calculations. SIZING: The storage should supply 3 MW of electrical power for a 24h period per week. Thus, 72 MWh of electrical energy are required at the output. Assume that the combined efficiency of all processes following your part is 50%. Then, you need to store hydrogen containing 72 MWh / 0.5 = 144 MWh of energy per week . However, your LCOS calculation should be based on the 72 MWh of weekly provided electricity. Additional notes, assumptions, and hints: Use the lower heating value (LHV) of hydrogen, which is 33.33 kWh/kg. Assume that the hydrogen provided in the previous step costed 10/kg (for OPEX). Comment on the feasibility of an underground storage on the chosen location. Consider losses due to leakage (if applicable). Figure 3: Two ways to store H2. The red box shows the scope of the task. 5

MECH 560 FALL 2023 2.5.3 Option 3: How to generate electricity from H2? This subtask deals with generating electricity from the hydrogen that was produced and stored in the previous steps. You will analyze and compare two alternative ways: (1) burning hydrogen in a gas turbine and (2) using fuel cells. As fuel cells produce direct current electricity, consider the cost and efficiency of the inverters required to provide alternating current to the company. SIZING: The storage should supply 3 MW of electrical power for a 24h period per week. Thus, 72 MWh of electrical energy are required at the output per week . During peaks the demand can raise up to 10 MW (3 MW is the average and 10 MW the max) and so the installed capacity must be greater than or equal to 10 MW. Additional notes, assumptions, and hints: Use the lower heating value (LHV) of hydrogen, which is 33.33 kWh/kg. Assume that the hydrogen provided in the previous step costed 20/kg (for OPEX). Comment on the feasibility of burning hydrogen in a gas turbine. Different types of fuel cells exist with different properties. Try to be consistent with the parameters you choose. Figure 4: Two ways to generate electricity from H2. The red box shows the scope of the task. 6

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

MECH 560 FALL 2023 3 Example 3.1 Intro/Assumptions This example investigates the cost of using Diesel generator set (genset) as backup power source for the company. The location is assumed to be Calgary, Alberta. USD to CAD conversion rate of 1:1.35. Cost of land usage is neglected since insignificant compared to other cost. 3.2 Calculations CAPEX (Genset): The cost of installing a Diesel genset, i.e. motor and generator, is 1,080/kW (US 800/kW in [3]). For 10 MW installed capacity, this results in 10.8M. OPEX (Fuel): Assuming 20 gensets with each 500 kW are installed, 6 of them run on average to meet the 3 MW requirement. The genset chosen consumes 118.1 liters of Diesel per hour at 500 kW [4]. For 6 generators and 24h of operation this results in 17,006 liters of Diesel per week. Taking Calgary’s current Diesel price of 1.61/liter [5] and multiplying by 52 weeks/year, the yearly fuel costs are 1.419M. CAPEX (Tanks): From the previous point we know that we need a storage capacity of 17,006 liters. In [6], a 1000 gallon Diesel tank is priced at 49,950 (US 37,000). 5 of such tanks are required to store the weekly amount of Diesel needed, totaling to 249,750. OPEX (O&M): According to [3], the expected lifetime of a genset is 20 years, so no replacement cost occur. Degradation is also not a severe issue for Diesel gensets, but O&M is necessary to keep the units operable. [3] assesses the lifetime O&M cost to be 547/kW (US 405/kW). With a 20 year lifetime, this corresponds to 27/kW/year and 273,375/year for the installed 10 MW. Table 1 summarizes the results obtained so far. The yearly contribution of CAPEX was computed using a capital recovery factor of 0.10185. Dividing the the total yearly cost by the yearly supplied energy of the genset, a LCOS of 753/MWh is obtained. Efficiency: The efficiency can be calculated through the fuel consumption rate at 500 kW electric output. In one hour, the genset burns 118.1 liters of Diesel [4] and provides 500 kWh of electricity. The energy content in the Diesel is 1224 kWh (LHV of Diesel: 43.4 MJ/kg = 12.06 kWh/kg, density: 0.86kg/liter). Thus, we have 500 kWh / 1224 kWh and an efficiency of 40.84%. Table 1: Summary of calculation results. CAPEX OPEX Combined Levelized cost Genset: 10.8M Fuel: 1.419M Yearly CAPEX: 1.125M Weekly energy: 72MWh Tanks: 249,750 O&M: 273,375 OPEX: 1.693M Yearly energy: 3744MWh Sum: 11.05M Sum: 1.693M Total yearly cost: 2.819M LCOS: 753/MWh 7

MECH 560 FALL 2023 3.3 Conclusions The average wholesale price of electricity in Alberta was 163/MWh for 2022 [7]. The LCOS of the Diesel gensets for this project is 4.6 times more expensive. This price difference seems reasonable for a backup power source and should be put in perspective to the potential losses due to black outs. Diesel gensets are generally well established and reliable ( > 90% [3]). However, increasing fuel prices could make this option less attractive in the future. In addition, Diesel gensets emit significant amounts of greenhouse gases and are thus not suitable to reduce the company’s carbon footprint. References [1] US EIA, “Levelized cost of new generation resources in the annual energy outlook 2022,” Washington DC: US Energy Information Administration , 2022. [Online]. Available: https: //www.eia.gov/outlooks/aeo/pdf/electricity_generation.pdf . [2] IEA, “The future of hydrogen,” Paris: International Energy Agency , 2019. [Online]. Available: https://www.iea.org/reports/the-future-of-hydrogen . [3] S. J. Ericson and D. R. Olis, “A comparison of fuel choice for backup generators,” National Renewable Energy Lab.(NREL), Golden, CO (United States), Tech. Rep., 2019. [Online]. Avail- able: https://www.nrel.gov/docs/fy19osti/72509.pdf . [4] Generac, “Md500 industrial diesel generator set,” Generac Power Systems, Inc, Tech. Rep., 2019. [Online]. Available: https://www.nrel.gov/docs/fy19osti/72509.pdf . [5] Natural Resources Canada. “Average retail fuel prices in calgary.” (2023), [Online]. Avail- able: https://www2.nrcan.gc.ca/eneene/sources/pripri/prices_byfuel_e.cfm? locationName=Calgary#priceGraph (visited on 09/09/2023). [6] Squaw Valley Public Service District. “Convault replacement.” (2018), [Online]. Available: https://www.ovpsd.org/sites/default/files/F-4%20Convault%20Replacement.pdf (visited on 09/09/2023). [7] Alberta Electric System Operator. “Market and system reporting.” (2021), [Online]. Available: https://www.aeso.ca/market/market-and-system-reporting (visited on 09/09/2023). 8