Cost Study for Manufacturing of Solid Oxide Fuel Cell Power Systems

Abstract

Executive SummarySolid oxide fuel cell (SOFC) power systems can be designed to produce electricity from fossil fuels at extremely high net efficiencies, approaching 70%. However, in order to penetrate commercial markets to an extent that significantly impacts world fuel consumption, their cost will need to be competitive with alternative generating systems, such as gas turbines.This report discusses a cost model developed at PNNL to estimate the manufacturing cost of SOFC power systems sized for ground-based distributed generation. The power system design was developed at PNNL in a study on the feasibility of using SOFC power systems on more electric aircraft to replace the main engine-mounted electrical generators [Whyatt and Chick, 2012]. We chose to study that design because the projected efficiency was high (70%) and the generating capacity was suitable for groundbased distributed generation (270 kW).The electricity costs for a mass manufactured solid oxide fuel cell could be competitive with centralized power production plants with costs estimated to be in the $0.07-0.08/kWh range based on a cost model using a standard approach to manufacturing solid oxide fuel cells. A process flow sheet was developed to understand the steps required to manufacture the units, as well as to estimate the materials, equipment, and labor required to make them. Equipment was sized to meet a production volume of 10,000 units per year. Appropriate material and equipment prices were collected.A sputtering approach was also examined using the model to project the decreases in costs associated with the process. The process not only reduces material costs but increases the power density of the fuel cell by 50%. The increased power density reduces the number of repeat units required to make up the 270 kW fuel cell stack. Stack costs decreased by 33%. However, due the BOP and the remainder of costs associated in power system manufacturing and installation, the cost of electricity was only reduced by $0.002/kWh.In addition, to the 10,000 units per year production scale model was adjusted to reflect the costs of production at 50, 250, 1000 and 4000 units of production per year. Material prices were adjusted to reflect purchase levels. Machinery and labor were adjusted to reflect the production scale.

A Direct Manufacturing Cost Model for Solid‐Oxide Fuel Cell Stacks

“…Quantities of slurry to mill per day are estimated based on number of cells casted per day and slurry weight of each layer. In reality, evaporation rates may be expected to be faster than the ones considered in this study since water evaporates more slowly than most organic solvents as n-butyl acetate or 2-butoxyethanol [33]. Assuming that the ratio of the freshly deposited layer thickness to the dried tape thickness is two [32] and multiplying this freshly deposited layer thickness by its corresponding liquid density it was possible to obtain the quantity of liquid removed per unit area.…”

“…The method of creating a glass seal considered in this study is adopted from a PNNL study [33]: (i) ball milling of the glass paste; (ii) dispensing of the paste on EEA cell perimeter by means of a dispensing robot; (iii) placing of the cell onto the frame; (iv) placing of a weighted plate onto the cell; (v) loading of the piece in the annealing furnace; and (vi) annealing in furnace under a static load (450 to 2,200 N). The annealing process includes four steps: (i) heating up to 600°C with a heating rate of 3°C min -1 ; (ii) heating up to 750°C with a heating rate of 5°C min -1 ; (iii) holding at 750°C for 60 min; and (iv) cooling to 50°C with a cooling rate of 15°C min -1 .…”

Three dimensional printing of components and functional devices for energy and environmental applications

“…Solid oxide fuel/electrolysis cells and stacks are geometrically complex multi-material devices based on functional ceramics. According to a recent report, 22 more than one hundred steps are required to fabricate a complete SOFC stack using traditional manufacturing processes (tape casting, punching, screen-printing, laminating, stacking or firing). This huge number of steps, some of them requiring manual input, makes the fabrication of these devices a very complex task with low reliability and complicated design for manufacturing directly associated with a long time to market.…”

Domestic hydrogen installation in Poland – technical and economic analysis

“…Fuel cell stack costs have been approximated based on [8,9] as 2 500 €/kW. The cost of a single wind turbine with nominal power is 1 900 €, PV installation with the power of 3.5 kW -6 300 € [10].…”