A microgrid requires three basic elements – generation, storage and a controller to manage the flows of electricity and for grid connected microgrids, islanding and reconnection to the main grid.
Generally, batteries or mechanical storage have proven the most popular form of storage in microgrids due to their more advanced development and wider availability. But with growing potential for longer term storage, particularly in more isolated areas, now we are also seeing the emergence of the hydrogen storage microgrid, with three examples at various stages of development in the last as many months.
‘Plug and play’ in Chile
The most advanced of these is what is claimed as the first ‘plug and play’ microgrid powered by solar PV and hydrogen-based storage, which has been installed by Enel Green Power in the Antofagasta region in northern Chile.
The microgrid comprises a 125kWp solar PV facility combined with a hybrid energy storage system including 450kWh of hydrogen storage and 132kWh of lithium-ion storage.
An innovative microgrid controller optimises the electricity flows produced by the PV modules between the two storage systems.
In this way, intermittent solar power is turned into a steady energy source, which can supply energy for 24 hours per day without the need for back-up diesel generators, according to an Enel statement.
Says Antonio Cammisecra, Head of Enel Green Power: “This groundbreaking project shows that it is possible to build fully renewables-powered microgrids capable of delivering efficient, zero-emission energy without interruptions.”
The microgrid was developed by Enel with the technological support of storage and microgrid specialist Electro Power Systems and is contributing to the energy needs of the camp which hosts the over 600 technicians working at Enel Green Power Chile’s Cerro Pabellón geothermal plant.
As a ‘plug and play’ system it can be moved to potentially any location and works both on-grid and off-grid.
The Cerro Pabellón facility is itself noteworthy, being both the first geothermal plant in South America and the world’s first high enthalpy, utility-scale geothermal plant to be built at high altitude (4,500m above sea level).
Testing hydrogen storage in Singapore
Another development which will have hydrogen storage as a key focus is a microgrid which is being developed on the island of Semakau, just off the coast of Singapore, as part of the Renewable Energy Integration Demonstrator-Singapore (REIDS) initiative.
Led by Nanyang Technological University (NTU) and including international energy companies Engie and Schneider Electric, the aim is to test and demonstrate in a microgrid the integration of solar, wind, tidal, diesel, storage and power-to-gas technologies.
In an interview on the project, Didier Holleaux, Executive Vice President at Engie, was quoted as saying that hydrogen has massive long-term potential.
“Batteries are fine for intraday, or a few hours, but if you produce energy in summer and need it in winter, or need it to last during a few cloudy days, then hydrogen would be the obvious solution,” he said.
Fuel cells like other technologies are on a declining cost path. However, for hydrogen storage to become commercially viable, the electrolysis process that breaks down water into hydrogen and oxygen, needs to become both much cheaper and more efficient, which Holleaux believes to be in the 10-15-year timeframe.
The REIDS microgrid, said to be the first in the region and the largest hybrid microgrid in the tropics, is envisaged to pave the way for the development of electrification solutions for off-grid communities, particularly on the hundreds of islands in the southeast Asian region.
Business park microgrid in Britain
With Dunsfold Park in southern England home to fuel cell developer AFC Energy, a hydrogen based microgrid would seem an obvious development for the business park, which already has a solar farm and is actively pursuing a clean energy strategy.
AFC Energy is about to commence ‘front end engineering and design’ work on a plan to install 1-1.5MW of hydrogen fuel cell capacity in a microgrid to meet the growing needs of the site’s residential and industrial redevelopment.
This includes the development of an initial 1,800 new homes and green space, which will co-exist with light industry.
The scheme expects to be supplied with ‘green hydrogen’ sourced locally from biomethane so that it is entirely renewable and clean.
“The introduction of hydrogen derived from renewable sources is a particular highlight of the proposed scheme,” says Adam Bond, AFC Energy’s Chief Executive Officer, noting that it offers the potential for national and international replicability.
AFC Energy also expects to install a hydrogen vehicle refuelling station, electric car recharging points sourced from hydrogen fuel cell generation and low grade heat integration.
Jim McAllister, Chief Executive of Dunsfold Park Ltd, adds: “We look forward to seeing the results of the FEED study and endorse the initiative’s full alignment with Dunsfold Park’s clean energy strategy which has permeated all of our redevelopment activities over the past few years.”
Other interesting aspects which should emerge for such projects are the delivery and ownership models, including a joint venture, which will be considered by AFC Energy and Dusnfold Park. Over a 20-year lifetime the project is expected to generate revenue in excess of £25m.