Thank you for having us, we are honored to get the opportunity to present our design to you today. I had the privilege to lead the group of graduate and undergraduate students from Washington State University that won the 2014 Hydrogen Student Design Contest. Also up here with me presenting our design is Jake Fisher, Simon Guo, Patrick Frome, and Mikko McFeely.
For this years design contest, the objective was to design a drop in hydrogen fuel station that could provide the infrastructure to support Fuel Cell Electric Vehicles. The biggest inhibitor is the cost to develop each fuel station. Current hydrogen stations range between $2 and $4 million each. To give you some perspective an average gasoline station costs anywhere from $1 to $2 million. The other key thing that was given to us in the project is that hydrogen could be delivered to the station for $7/kg as 200 bar or 3000 psi gas at ambient temperature or as a cryogenic liquid at 5 bar or 72.5 psi. The station had to be able to fill 25 vehicles per day and 2 vehicles simultaneously. It also had to be able to fill a vehicle with a 5 kg fuel tank to 700 bar or 10,000 psi in just 5 minutes. This is actually a very difficult metric to hit because as hydrogen gas is put into an empty fuel tank, it expands and heats up. The fuel tanks have a small operating temperature so if you fill to fast it will over heat and compromise the tank. So the hydrogen has to be cooled before it is delivered to the vehicle. For out design we store the hydrogen fuel at -40 C which happens to be -40 F. This allows us to fill a tank in 3-4 minutes. It also has to be transportable and have low maintenance. It will be operate autonomously and be monitored by a remote operator. So there is no hydrogen specialist at each station or it would simply be to expensive to operate. The station also has to be able to maintain the systems integrity if there is a 48hr power outage so that there is no danger to the public.
So I’m going to tell you a story about Joe. Joe is a typical small business owner who owns a gas station. Now Joe is a business man. He hears about these ne fangled cars that are coming out that run on hydrogen. Being a business man, Joe see’s an opportunity to expand his customer base.
Joe’s biggest concern is the cost. He can’t afford to invest everything he has into a new hydrogen station but if he can add one for a reasonable cost it may be worth the investment.
He also doesn’t want to have to do any maintenance on this new fuel station. Joe doesn’t know a lot about hydrogen and doesn’t want to have to check this station every morning to make sure it’s operating correctly. He just wants the station to be dropped off and be self sufficient.
Joe doesn’t have a lot of extra space at his gas station so the hydrogen fuel station needs to be compact. He also doesn’t want to have to dig up his existing lot to put it in. If demand isn’t what he initially anticipated, he wants to be able to remove the hydrogen station and resume his normal day-to-day operation.
Ultimately, joe want to expand his customer base so he has more people coming to his gas station to get fuel, which brings more people into his station to buy coffee and doughnuts and energy drinks which all equates to more profit for Joe.
We took all these considerations and determined that having liquid hydrogen delivered to the fuel station was the most viable, and cheapest option. By using liquid hydrogen, you can take advantage of the cryogenic temperatures to keep the hydrogen cold before fueling vehicles. Also by taking a small amount of liquid hydrogen and sealing it in a high pressure cylinder, we can achieve pressures of 17,000 psi to top off fuel tanks. This reduces the amount of active compression necessary by a hydrogen compressor. Liquid hydrogen delivered at 5 bar also has 4 times the density of hydrogen delivered at 200 bar. Utilizing liquid hydrogen allows for a much more compact station. 80-90% of all non-pipeline hydrogen is delivered via cryogenic liquid tanker so the delivery infrastructure is already in place.
We looked at these considerations when designing a drop in fuel station. Safety is the most important design consideration. Our system used both cryogenic liquid hydrogen and high pressure gaseous hydrogen so we need to take the necessary safety precautions to ensure safety. We also wanted our system to be completely contained within a standard ISO40 shipping contained. So the fuel station can be trucked in via semi truck, unhooked and left to operate independently. We also have a large liquid hydrogen storage tank so we need to consider boil off and cryogenic compatible components. We want to utilize autogenous pressurization to reduce the energy associated with active high pressure compressors. Any excess hydrogen boil off will be utilized to generate electricity through a fuel cell. These fuel cells will also be used to monitor the system if the grid power goes out so the system is continuously monitored.
So this may be the most important slide in the entire presentation. This schematic shows how the fuel station actually operates. So we have all the main components of the system. The 3000 gallon cryogenic bulk liquid storage tank is at the top, then there are 3 high pressure, a 6,000 psi compressor, the medium pressure tank, and the liquid cooling bath that that keeps the high pressure and medium pressure tanks cool. So I will walk you through the fueling process for one vehicle. We start out assuming that all the tank in the station are fully charged and the vehicle comes in with a quarter tank. Fuel will first be dispensed from the medium pressure tank. The medium pressure tank will always fill the vehicle to 75%, then the high pressure tank will then top off the vehicle to 700 bar. From there the high pressure tank must be evacuated to refuel with liquid in order to autogenously pressurize. So using the pressure gradient we can move some of the hydrogen from the high pressure tank directly into the MP tank. The rest must be run through a compressor to fill the medium pressure tank. Now the high pressure tank can be filled with liquid, sealed off, heated up to -40 C which equates to a pressure of 17,000 psi. Any boil-off hydrogen from the liquid storage tank will be stored in a low pressure tank where it can be used to run a fuel cell or recharge the medium pressure tank. Now this system does assume an average vehicle coming in with a quarter tank. If that isn’t the case the low pressure tank acts as a buffer volume that can store or provide additional hydrogen as needed.
This is an example of the system interface that a remote operator would be using for each fuel station. I apologize for how busy this slide is. So the left side is just the system diagram from the previous slide. The important part of this slide is the left hand slide. This shows the temperature and pressure of each tank and which valves are open instantaneously so a remote operator can monitor every aspect of the system to ensure it is operating correctly. If there is an issue with any of the components, such as an overheated tank, a warning message will appear and alert the operator to check the system and take appropriate actions.
The customer will interact with the fuel station via a standard touch screen tablet. Similar to a gasoline station, the user will select the method of payment, and a brief instruction on the nozzle operation will appear. The customer will be able to instantly monitor the fuel level and cost of the interaction. Environmentally friendly options for the reciept are provided. If at anytime the customer has a question or is concerned about the systems safety, the information tab allows for a live video chat with a technician and has the option of activating emergency shutdown procedures.
This system has been designed to be as safe as possible. Each tank is fitted with a pressure relief valve to ensure they to not over pressurize. The trailer is ventilated with industrial fans to prevent a concentration of hydrogen within the station. The system will be continuously monitored in real time to allow a remote operator control over the system in a malfunction. Fuel cells provide power to emergency and monitoring system in the event of main grid power failure. The container is outfitted with state-of-the-art fire suppression and emergency warning systems to alert the public, local authorities, and the remote operators in the event of an emergency. If all other systems fail, the container is outfitted with an explosion relief panel to direct any explosions or in a safe direction away from people and property.
Another part of this contest was to find a location where we could put this station and figure out what permits and regulations we would need to follow. We chose to site our station in a parking lot on the Washington State University campus. Being a university, they are more open to work with students on competitions and are more open to new and emerging technologies. The site we chose already has gasoline pumps on site so the location acts as a gas station for the university vehicles. Our design meets all of the national fire codes and regulations and is in accordance with the Washington Administrative Code which adds additional amendments to the national codes for the state of Washington. So since it is within the Washington state codes, which tend to be some of the strictest in the country, it is likely in accordance with other state’s regulations. If you look at the siting diagram, you can see that the locations is wide open which leaves plenty of room for vehicles and refuelers to access the station. The container is also lined with 2 hour fire resistant walls to help reduce these setback distances even farther. If we zoom in on the fuel station, we can see the layout of equipment in the container. All the mechanical and electrical equipment is located at one end of the trailer away from the hydrogen to further increase the safety of the system.
Unfortunately none of the economists in our group could make it today so I will attempt to explain the analysis that they conducted to come up with our price model. Our model considers all costs, including opportunity costs. The key costs in our system is the fixed cost of $423,000, this includes all the equipment and permitting costs. The other main cost is the monthly costs that include electrical power and cooling water from the main grid as well as maintenance costs associated with the system. We have not included the cost of a remote operator or the man hours required to assemble this system. We show the minimum price the fuel most be sold at given two factors: required rate of return and demanded for hydrogen in kg. This allows us to determine the minimum price given any quantity demanded/required rate of return assumptions.
Our results show that hydrogen can become comparable to the current cost of gasoline. So on the left we have the required return, then the monthly demand. So a demand of 3000 kg is equivalent to 25 vehicles a day and 6000 kg on the bottom equates to 50 vehicles a day. And you can see that the cost per tank, which is roughly 300 miles so comparable to current passenger cars, is highly dependent on the monthly demand, not the rate off return. So if fuel station accommodate just 50 vehicles a day, they can dispense fuel for about $48 per 300 mile tank. This is very comparable to gasoline and will be a much more stable price. This plot shows how the cost varies with the monthly demand and the rate of return. This plot is asymptotic though. It does start to level off at a little over $9/kg after a monthly demand of 6000kg.
In conclusion, a hydrogen fuel station has been design for $423,000. This design utilizes the existing liquid hydrogen infrastructure that is well established and already in place. It utilizes the properties of liquid hydrogen to autogenous pressurize the high pressure tanks and reduce the amount of active compression by a compressor. The system is inherently safe and uses state-of-the-art emergency systems to ensure public safety as well as equipment safety. And finally, this system is made from entirely commercially available parts. This system could be built today!
Designing a Drop-in Hydrogen Fueling Station
Designing a Drop-in Hydrogen Fueling Station
2014 Hydrogen Student Design Contest
Long Beach, CA
May 8, 2014
In this presentation…
1. Project Scope
2. Customer Attributes
3. Liquid H2 Delivery
4. Station Design
5. User Interface
6. Safety Features
7. Site Logistics
8. Economic Analysis
• Low cost – current H2 stations are $2- 4 million each
• Hydrogen delivered for $7/kg
• Fuel 2 vehicles simultaneously, 25 vehicles per day
• 5 minute fill time for 700 bar, 5 kg fuel tank
• Low maintenance
• Operated and monitored remotely
• Hydrogen storage should withstand 48 hr shutdown
2014 HYDROGEN STUDENT DESIGN CONTEST
DEVELOPMENT OF DESIGN FOR A DROP-IN HYDROGEN FUELING STATION TO
SUPPORT THE EARLY MARKET BUILD-OUT OF HYDROGEN INFRASTRUCTURE
Key Rules and Guidelines:
Design with the Customer in Mind
Low Cost No
• Lowest cost
• Low energy demand
• Minimizes equipment
• Utilizes thermal properties
4 times the density of delivered gas
• Existing infrastructure
80-90% of all non-pipeline H2 delivered by
cryogenic liquid tankers.1
1 Technology Transition Corporation (TTC). (22 March 2010).
Hydrogen and Fuel Cells: The U.S. Market Report.
Image from www.worldindustrialreporter.com
liquid H2gaseous H2
Designing a Drop-in Hydrogen Fuel Station
Image from www.hypercompeng.com
Image from www.chartindustries.com
• Liquid H2 Storage
• Autogenous Pressurization
• Hydrogen Boil-off
Images from www.firelite.com
•Located on WSU campus
•Existing gasoline station
•Easy access for vehicles
•Fire resistant walls
reduce setback distances
Pump 1 Pump 2
• Explicit and implicit costs considered:
– Fixed cost = $423,000 (all equipment)
– Monthly costs = $735 (power, water, maintenance –
– Discount rate
– Risk premium for the owner
• Price (P) model [$/kg]
– Monthly Demand (D)
– Rate of Return (RR)
Required Return Monthly Demand
Price per 5 kg or
300 miles ($)
10% 3000 11.31 56.55
30% 3000 11.62 58.10
10% 6000 9.62 48.10
30% 6000 9.78 48.90
Economics – Results
• Total equipment cost = $423,000
• Utilizes established liquid hydrogen infrastructure
• Autogenous pressurization
• System designed to be inherently safe
• This design could be built today!