Hydrogen’s main future use as a clean energy vector has to do with its coupling to inherently intermittent renewable energy sources, such as wind or solar, which will play an increasingly important role in the world’s energy matrixes. These days, a lot is talked about the hydrogen economy, hydrogen systems and others. However, the reality indicates that as up to date there are relatively few energy systems in the world that use hydrogen as an energy vector. Hydrogen is still today produced mainly from hydrocarbons (primarily gas and coal) and used in the petrochemical and agricultural industries (e.g. not as a secondary energy source).
Nevertheless, the development of small-scale demonstration and niche-market commercial projects that make use of hydrogen as an energy vector for renewable energy sources can aid in a more rapid growth of the required hydrogen infrastructure and know-how that will be needed in the long-term. In particular, hydrogen based stand alone power systems’ market potential has been studied and assessed. Future perspectives are promising, provided that technical, socioeconomic, financial and other barriers are either eliminated or reduced, both by public as well as by private efforts.
In wind-hydrogen systems (as opposed to general renewable-hydrogen systems) a clear differentiation must be made in order to correctly analyze and compare them: whether they are grid connected or not. In the first case, the back-up of a frequency and voltage stable, usually fossil fueled powered, grid (most the times with no more than 10% penetration of wind energy) allows for a relatively easy connection of wind turbines and electrolyzers. Under these conditions, electrolyzers operate at almost constant power and high efficiencies using mature technologies. On the other hand, operation of an isolated wind-hydrogen system is far more difficult. The most important challenges are: system integration and energy efficiency issues, electrolyzers operating at variable loads, and the obvious non-controllable intermittent nature of wind power output.
Examples of grid-connected wind-hydrogen projects are in consequence more abundant today, since they require less investment on a per kilowatt basis and face fewer technical difficulties. The University of Applied Sciences in Germany (Fachhochschule Stralsund) operates a 100wind turbine coupled with a 20pressurized electrolyzer. Presently the system has still the back-up of a grid but studies and research efforts are directed towards the isolated operation of the couple. The Argentinean experimental hydrogen production plant is currently being built in Pico Truncado, Santa Cruz. It will serve as a demonstration, research and education facility. Currently, it has 20thermal generation, two 600wind turbines and two more to follow. On a first stage it will have a 5electrolyzer that consequently operates at invariable power and a 5fuel cell as well as hydrogen and oxygen storage systems. One goal of this unique experience in Latin America is to provide hydrogen to the town’s public transportation system (buses that will run on hydrogen ICEs - Internal Combustion Engines).
A larger scale grid-connected wind-hydrogen project is being carried out by United Kingdom’s Wind Hydrogen Ltd. in association with ACME group. Despite Scottish Shetlands islands’ great wind potential, current wind installed capacity totals only 4which complements the diesel and gas power by 8% to the islands’ electricity needs. The goal of the project is to develop a 90 MW wind-hydrogen scheme, thus providing 100% of the islands’ demand, balanced by adjustable load hydrogen electrolysis and dispatchable generation. Excess hydrogen will also be used for local public transportation. The development aims to demonstrate how intermittent wind power can be moderated to match consumer demand.
The most significant isolated wind-hydrogen system currently operational is being developed at Utsira Island, in Norway, by Norsk Hydro and Enercon. The small wind-swept island has 240 inhabitants. Ten households are supplied by a stand-alone 100% wind-hydrogen system, which includes two 600wind turbines, a 48electrolyzer, a 10fuel cell and a 55hydrogen ICE, a 24003 hydrogen storage tank (standard temperature and pressure (STP)), among other components and equipment. The ultimate goal of the project is to demonstrate the feasibility of totally renewable self-contained energy systems. Achievements totally aligned with the world’s sustainable development objectives.
It is also worth mentioning a project that is currently in a feasibility study stage in Cholila, Chubut Province, Argentina. It is an adaptation of the former Hacienda project, developed by the AAEE together with Fachhochschule Stralsund. It will consist of a 100% renewable hydrogen based energy system for an isolated tourist real-estate development. Once fully implemented, it will have two 600wind turbines, a 100pressurized electrolyzer and a 120 kW hydraulic turbine, besides hydrogen ICEs and storage tanks. It will cover both heat and power needs to almost fifty households. It would be a breakthrough in demonstrating the technical and socioeconomic feasibility of these types of experience in developing countries. It will be completely off-grid.
Last but not least, probably the world’s first totally renewable hydrogen-based large scale economy will be established in Iceland. Carried out by Icelandic New Energy (a multinational joint-venture between VistOrka, DaimlerChrysler, Norsk Hydro and Shell Hydrogen) in 25 to 50 years time they expect to fully convert Island from fossil fuels to hydrogen. An ambitious but yet feasible goal, this project will certainly open up a wide new range of opportunities and challenges in the transition to a completely new world energy matrix.
Wind-Hydrogen applications can also be useful as stabilizers for grid connected wind farms, i.e. the power balancing ability may reduce the backup needed by conventional generation resources in the future.
Market potential analysis for the introduction of hydrogen energy systems in stand alone power systems.
http://www.hsaps.ife.no
Utsira project.
http://www.hydro.com/en/our_business/oil_energy/new_energy/hydrogen/winds_change.html
UK’s large-scale wind-hydrogen systems.
http://www.wind-hydrogen.com/
Iceland’s hydrogen economy.
http://www.newenergy.is
The Martín García Island Proposal: An Example of Clean Energy Systems for Islands and Other Isolated Locations
http://www.renewables2004.de/en/programme/side_events_details.asp?TblSideEventsID=236
The Cholila Project
http://www.argentinaeolica.org.ar/