CC BY
9ELECTROLYSER BASED FUELLING STATIONS FOR VARIOUS PROJECTS IN EUROPE
A. Cloumann, K. Sollid
Norsk Hydro Electrolysers AS, Norway
Born in Notodden, Norway, the 26 of August 1955.
Educated as an Electrical and Electronic Engineer in Norway and Britain in 1983.
Worked for different engineering companies till 1997 when he joined Norsk Hydro Electrolysers AS.
He is currently holding the position of General Director of JSC «Hydro-electrolysers Russia».
Kjell Sollid
New solutions for fuel supply are required in connection with the introduction of fuel cell vehicles. Hydro is in the process of supplying electrolyser based fuelling stations for various projects in Europe. This paper will present some basic information on these fuel stations and will discuss future challenges with regard to space required, capacity, efficiency etc. for larger stations.
1. Introduction
Norsk Hydro ASA [NYSE: NHY] established 1905 is a leading supplier of oil and energy, light metals and plant nutrition. With more than 50000 employees the Oslo, Norway based company, operates in approximately 60 countries worldwide. The operations are divided into three main areas of experience:
■ Agri;
■ Aluminum;
■ Oil and Energy (including Renewables and Hydrogen).
With a global market share of six percent, Hydro Agri is the world's largest supplier of mineral fertilizers and has a strong presence in every part of the world. Hydro Agri has modern plants serving global and local markets and is a leader in products like ammonia and nitrogen fertilizers. In addition to plant nutrition, Hydro Agri markets industrial gases and nitrogen chemicals upgraded from co-production from the fertilizer production plants.
With the acquisition of the German aluminum company VAW in 2002, Hydro Aluminum steped up from a strong position in Europe to
one of the three major global aluminum companies with a total turnover in 2001 of 2.3 million tons of aluminum. In addition to the production and remelting of primary aluminum Norsk Hydro is boosting its role in rolled products and as a supplier of extruded products to the automotive and construction industries.
Norsk Hydro Oil and Energy is producing, processing and trading crude oil and oil products, natural gas, hydroelectric power and wind power to energy markets in the world. Our daily production is approximately 500.000 barrels of oil equivalents daily. In addition we have an annual production of some 6 bcm natural gas and 10 TWh of electricity.
The annual operating revenue of Norsk Hydro ASA is approximately 20 billion Euros. More information is available on www.hydro.com.
Norsk Hydro has considerable experience in producing and handling hydrogen since the mid 1920s. Hydrogen is part of everyday life in an number of Norsk Hydro activities like: ammonia production, hydrogen production, petrochemicals and of course in Norsk Hydro Electrolysers and the R&D departments of the Oil and Energy area.
Norsk Hydro investigated the utilization of hydrogen as a vehicle fuel in the early 1930s. Professor Halvorsen was engaged as a consultant to Norsk Hydro and managed the fuel research activities in Rjukan. The Erren motor, then produced in England was introduced as a hydrogen motor for vehicles. Norsk Hydro considered purchasing the license for the Erren motor, but instead acquired a vehicle with such a motor and tested it with various ammonia and hydrogen mixtures. The motor was hardly running and the inhabitants of Rjukan could observe how the test car could hardly make the steep hills in the area, sending an odor of ammonia through the streets. More power was achieved when adding petrol to the ammonia, but this resulted in the formation of hydrocyanic acid. Still the tests were continued for several years.
Norsk Hydro Electrolysers AS (NHEL) — a wholly owned subsidiary of Norsk Hydro — has its roots from those days and has been continuously developing electrolyser technologies and is today a world leading producer of alkaline elec-trolysers. More information is available at www.electrolysers.com.
2. Hydrogen — the challenge in establishing a new fuel
Hydrogen has gained an increasing focus in recent years due to the development of fuel cell technology both for distributed power applications and as a transportation fuel. Hydrogen is, as we all know, a clean zero emission fuel when used with fuel cells and may also secure the worlds energy supply utilizing a variety of energy resources and thus making us less dependant on crude oil.
As an energy company with access to crude oil, natural gas and renewable hydro-electric power, we do not see the rapid downturn for the traditional energy carriers. The crude oil based motor fuels will within the next ten years get considerable cleaner in regard to sulphur and other local emissions. Still the global emissions and the challenges regarding green house gases is not addressed with new fuel standards. And the need for energy — in particular for transportation is quite evident, when studying the IEA data for future energy supply.
In addition the resources to cover this demand are not always in political stable regions of the world.
Hydrogen, which can be produced from a number of energy sources, can contribute to a diversification of our energy supply, utilizing renewable resources as well as fossil sources available.
Hydrogen can also be a significant contributor to solving the anticipated CO2 emission problem if we still use fossil fuels as we do today.
The challenges with the new hydrogen economy are of course dependant on technological break through in hydrogen fuelled vehicles and public acceptance of hydrogen as tomorrow's fuel. The now started demonstration projects are of utmost importance for this acceptance, but indeed we do need the support from both central and local authorities.
At present there are only few fuelling stations in Europe, most of all dedicated to the demand of automotive companies for fuelling their prototype vehicles. The current demonstration projects in Europe are now unfolding their hydrogen production and of those the fuelling station delivered by Norsk Hydro Electrolysers for the ECTOS -project will be the very first public fuelling station in the western hemisphere.
The Icelandic initiative to abandon fossil fuels by 2030 is the basis for the Icelandic fuelling station in Reykjavik. The extraordinary step by this small country is of course, daring given the present technology status for fuel cells and hydrogen technologies.
3. Demonstration Filling station of today
At present the hydrogen economy is introduced through demonstration projects. This is already taking place in a number of places around the world, where filling stations are being built to supply small test fleet vehicles. The first demonstration filling stations were built mainly as hydrogen storage and filling stations. The hydrogen was supplied by trucks as liquid or compressed in bottles. This has worked well in order to enable testing of the actual vehicles, with less emphasis on the integration of hydrogen fuel supply.
More recently constructed filling stations or those now under construction will have an increased emphasis on fuel infrastructure in total,
including plant availability. Norsk Hydro Elec-trolysers are now involved in supplying «state of the art» filling stations for the following projects:
■ ECTOS (Ecological City Transport Europe), Reykjavik. Filling station to be delivered in April 2003 for operation of 3 fuel cell buses — it is already shipped!
■ CUTE (Clean Urban Transport for Europe). In this project 3 fuel cell buses inclusive filling station infrastructure will be operated in each of the 9 different cities in Europe. We will be supplying the filling station to Hamburg, Germany early this summer.
■ CEP (Clean Energy Partnership), Berlin. This is a partnership of car manufacturers, energy and industrial gas companies. And the filling station will be built in 2003-2004.
To describe the filling station, the ECTOS project in Reykjavik will be used as an example. The hydrogen filling station consists of four major components:
■ Production unit including gas purification,
■ Compression unit,
■ Hydrogen storage including valve distribution panel and
■ Dispenser as shown in the simplified flow chart below.
Fig. 2. Containerized electrolyser package producing 60 Nm3/hr at 15 bar g. It includes purification and drying equipment. The container is 9 m long
and reliable operation. For the filling station with storage pressure of 440 bar g an oil free diaphragm compressor is selected.
Downstream of the compressor a gas storage system is included. The storage system comprises of three independent storage banks to provide a three stage «de-canting» system to ensure that the bus, on-board vehicle storage tanks reach the
TR/RE — Transfer/Rectifier
EL/ES — Electrolyser Cell Block/Electrolyser Cell System DE/DR — Deoxidizer/Dryer BT — Buffertank
HC — High Pressure Compressor DP — Distribution Valve Panel GS — Gas Storage GD — Gas Dispenser
Fig. 1. Simplified flow chart of hydrogen filling station
3.1. Equipment description
Hydrogen will be generated in an electrolyser by splitting water into hydrogen and oxygen. The gases are generated at a pressure of 15 bar g and a capacity of 128 kg hydrogen/day (60 Nm3/hr). Oxygen will be vented to atmosphere. To operate the electrolyser a DC supply is required. A specially designed transformer is necessary to step down the incoming AC voltage to accommodate the required input voltage for the rectifier necessary for electrolyser capacity.
Downstream of the electrolyser gas purification equipment, i.e. deoxidizer and twin tower dryer are included for removal of traces of oxygen and moisture in the gas.
A high-pressure compressor is included as a complete skid mounted package to ensure safe
predetermined pressure without exceeding 85 °C. To ensure this, a mathematical model was built, and verified by experimental data. The pressure and temperature build-up for a simulated filling is shown in fig. 3.
Maximum utilization of the storage volume and the three-stage decanting sequence system is provided through a hydrogen fuel distribution panel.
A fuel gas dispenser will transfer high-pressure gaseous hydrogen, from the fuel station storage banks, to the storage tanks on-board the vehicle. The fuel gas dispenser will be similar to a conventional fuel dispenser and will be the mechanical interface between the hydrogen fuel station storage banks and the vehicle. Safety features and metering equipment will provide safe and reliable operation. The dispenser unit also
80
60
U
% 40 'S
L_
Q.
E ^20
— tank — bus — inner wall outer wall
//
{/
N
100 200 300 time [s]
400
fighting services and provide an easy means for escape of persons in the event of an emergency.
The electrolyser and compressor are delivered in two separate containers. Our safety concept is based on IEC 60079-10 for zone classification with all the equipment used, certified for applicable area as shown in the figure below.
Fig. 3. Temperature and pressure build-up with the 3 bank storage system
has it's own PLC unit, to provide metering of the hydrogen gas fuel, supplied to the vehicle, pressure monitoring and communication with the filling station control system. The plant is delivered complete with an integrated PLC system for safe and unattended operation. Necessary gas quality analyzers and gas detectors are included.
3.2. Safety
Safety aspects are given great attention within our company, for the design and construction of the filling station. Norsk Hydro is actively participating in a number of ongoing international projects, to establish practical standards and safety guidelines for filling station design. In general, care is taken with regard to location of hydrogen equipment, relative to source of fuel including pipelines and bulk storage flammable gases and liquids. All equipment is selected for simple and safe operation and maintenance. In addition all equipment will be readily accessible for fire
Fig. 4. Containerized electrolyser without wall panels showing the electrolyser unit separated by a wall into hazardous and non hazardous area
The European Industrial Gases Council IGC has given guidelines for compression, purification and storage of hydrogen. This document IGC 15/96 E/F/D together with NFPA 50A have been used for determining safety distances.
Both the electrolyser and the compressor container are equipped with double fire detection system consisting of UV and smoke detectors together with gas leakage detector in hazardous area. The complete filling station excluding the dispenser has a fence around to limit public access.
4. Challenges for future filling stations
By designing the future public filling station, the filling pattern (load profiles) and electricity cost will play an important role in determining the production and storage capacity. Experience from our demonstration projects, together with our R&D work in designing of future filling stations, showed clearly that huge storage volumes could render the location of sites difficult, considering stringent size limitations, as is the case on existing petrol stations. This led to the question «to what degree the storage capacity can be reduced by increasing the production capacity, above the expected daily average consumption, to minimize the capital and operating costs».
The influence and the connections of the different parameters with regards to storage and production capacity are shown in the figure below. This paper focuses only on filling stations with on-site water electrolysis but many aspects are also valid for other hydrogen production technologies.
Fig. 5. Different parameters influencing the optimization of a future filling station
4.1. Space and storage
A typical full scale filling station may have a layout as indicated below. The production capacity for this station matches the daily average consumption. One can see that the storage capacity occupies nearly 50% of the site, posing a possible hazard because of the large hydrogen volume stored. This very important fact will be given great attention since many of the filling stations are located in densely populated areas.
Fig. 6. A conceptual layout of a future hydrogen filling station
From our simulation work we know that additional production capacity will result in significantly reduced volume of gas stored on the site with accordingly reduction in space required. The ultimate saving is when a 3 bank system is used, with a 4 bank system or higher, the space required is virtually unchanged as shown in fig. 7.
We also notice that min space is occupied for a 3 bank system when excess production capacity is 100 % with the advantage of having almost no gas stored on site.
Fig. 7. Space or area trends for car filling station
A similar exercise has also been done for the equipment cost as function of the production capacity. As shown on fig. 8 the highest savings in increasing the production capacity are when a 3 bank storage system is used. The minimum total investment cost is approx. at 50% excess production capacity. By increasing the number of banks the excess production capacity can be reduced.
Fig. 8. Equipment cost trends for car refueling
4.2. More compact technologies/solutions
For further reduction of costs it is necessary to introduce more space and cost effective equipment. For storage we refer to technologies like metal hydrides and carbon nano fibers, which are out of the scope of this paper.
For hydrogen production technologfy Norsk Hydro together with our German partner MTU are now developing new revolutionizing high efficient electrolyser. This new unit will operate at 30 bar g, with high current density resulting in a compact design and favorable cost target and energy consumption. Typically a 500 Nm3/h elec-trolyser will be accommodated in a standard container. The preliminary data for this high efficient electrolyser is given below.
Alkaline bipolar type electrolyser
Operating pressure: 30 bar g
Operating temperature: 80 0C
Current density: 8-10 kA/m2
Energy Consumption: 4.1 kWh/ Nm3/h at 8 kA/m2
Capacity range: 460-574 nm3/h
Operational range: 10-100%
Foot print: 2.5 x 2.3 x 3.0 m
Fig. 9. The first generation high efficient pressure electrolyser
5. Future challenges for hydrogen supply
Another challenge, is the establishment of a sufficient infrastructure for the market breakthrough of hydrogen for transportation.
There seems to be a commonly accepted expectation that a new fuel should be liquid and with an infrastructure similar to the one we have today. Some people believe, that the infrastructure solutions for methanol are easily resolved, whereas hydrogen is a much bigger challenge. Of course any new fuel is a considerable challenge. For methanol also considerable investments would be necessary both for production and storage facilities and dispensing units at current fuelling facilities.
When evaluating the advantages and disadvantages of different fuel alternatives the present de facto requisites of a long term infrastructure must be considered, and of course also the environmental and security aspects of each alternative.
First, let us consider the options for building up an infrastructure:
■ Centralized hydrogen production from natural gas and where applicable with carbon sequestration and thus a clean fuel alternative.
■ Centralized hydrogen production from crude oil fuels or coal.
For both alternatives, purifying facilities are required in order to get a sufficient fuel quality for fuel cells. Both alternatives also require transportation of hydrogen to the fuelling stations with either pipelines or trucks, gaseous or liquefied. The advantage of these alternatives is that large scale production units and in many cases existing facilities, which today produce hydrogen for other purposes — like our own ammonia plants, can be used. This is in fact the traditional means of fuel supply to our current gasoline and diesel fuelled vehicles. This also implies considerable investments in production facilities, transportation, fuel storage and fuel dispensing units.
Another option is that of networked facilities, the grid free, wireless and distributed system — as is our choice in PCs, cell phones, new power supply solutions. We should indeed consider the distributed fuel supply as a serious option — not instead, but in addition to the grid related system.
The current options are:
■ Distributed hydrogen production with small scale gas reforming, utilizing existing natural gas pipelines.
■ Distributed hydrogen production with elec-trolysers utilizing existing power and water supply.
This will enable the step by step building of infrastructure in line with the market and the fuel demand by currently rather few hydrogen fuelled vehicles. These alternatives will secure state of the art facilities without over investment and with flexibility for later enlargements or changes in technology.
The roadmaps developed by the TES in Germany and by the DOE in the US are promising for a joint effort to establish a new infrastructure. Most of all there is a continuous need for close cooperation between authorities and industrial companies across industrial boundaries to achieve good and lasting solutions. The fuel choice cannot be made by the automotive industry or the fuel suppliers alone.
6. Summary
The world primary energy demand is expected to increase by about 66% from year 2000 to 2030. Hydrogen, which can be produced from a number of energy sources, will most likely contribute to a diversification of our energy supply, utilizing renewable resources as well as fossil sources available. Hydrogen can also be a significant contributor to solving the anticipated CO2 emission problem, if we still use the amount of fossil fuels as we do today.
At present the hydrogen economy has been introduced through demonstration projects. We are involved in supplying «state of the art» filling stations for the following projects in Europe:
■ ECTOS (Ecological City Transport Europe), Reykjavik, Iceland.
■ CUTE (Clean Urban Transport for Europe), Hamburg, Germany.
■ CEP (Clean Energy Partnership), Berlin, Germany.
This paper describes basic details about these filling stations. Fast filling management, to ensure that we reach the predetermined pressure in the vehicle storage tank without exceeding 85 oC, has been given much attention together with the safety aspect.
Experience from our demonstration projects show that there is a great challenge in limiting storage capacity on site. By taking into consideration the variation in the filling pattern (load profile), we can conclude that additional production capacity will result in significantly reduced volume of gas stored on the site with accordingly reduction in space required. New more energy efficient and space saving hydrogen generators will also contribute in the same way.
The main challenge for the hydrogen economy will be to establish a sufficient infrastructure for the market breakthrough for transportation. Here exist various options like:
■ Centralized hydrogen production from natural gas with possible carbon sequestration.
■ Centralized hydrogen production from crude oil or coal.
■ Distributed hydrogen production with small scale gas reformers.
■ Distributed hydrogen production with elec-trolysers.
The last two options have an advantage since these enable us to build up the infrastructure step by step with moderate costs. The first two will be of more interest when larger volumes are required.
7. Acknowledgement
The authors would like to tank the following colleagues for the contribution:
■ Dr.Vera Ingunn Moe, Hydro Energi;
■ Henrik Solgaard Andersen, O&E Research Centre;
■ Jan Schelling, Norsk Hydro, O&E Research Centre;
■ Pal Kittilsen, Norsk Hydro, O&E Research Centre;
■ Iain Alexander Russell, Norsk Hydro Elec-trolysers AS.
