Supplying Power Where Power is Due: Annobon Island Microgrid

Aug. 20, 2015
Darren Hammel of Princeton Power Systems explains the changes that the Annobon Island microgrid will bring to this Equatorial Guinea community.

Darren Hammell, Princeton Power Systems

With electricity only five hours a day, Annobon Island is much like many other remote areas of the developing world. Darren Hammel of Princeton Power Systems explains the changes that the Annobon Island microgrid will bring to this Equatorial Guinea community.

Annobon Island is the southern-most island of Equatorial Guinea off the coast of west central Africa. The island has a population of approximately 5,000 residents, with limited access to reliable electricity. In 2014, residents of Annobon Island had access to electricity for about five hours per day, if at all, and even then the electricity did not come cheap as they would spend an average of 15-20 percent of their annual income on supplemental power.

Unfortunately, the scenario on Annobon Island is fairly common throughout the developing world, especially on islands. The quickest and most convenient way to bring electricity to remote areas is with a diesel generator. They are widely available nearly everywhere on the planet, and reasonable cheap to buy and install. The problem comes with the long-term operation of these generators, which can be very expensive, particularly in locations that do not have easy access to the refined diesel fuel that the generators need to run. Furthermore, these generators are loud, polluting, burn significant volumes of fuel, and must be frequently monitored, maintained, and overhauled. Overall, this leads to diesel generators being a very expensive way to generate electricity.

What’s worse, generators are typically oversized for the average amount of power they provide, which makes them run inefficiently, burn more fuel, and need more maintenance. Finally, with many mechanical moving parts they are prone to break-downs and are tough to count on for reliable electricity, especially in warm temperatures.

One new solution to this issue relies on solar energy, advanced batteries, and advanced power electronics and controllers to create a “microgrid” to supply a village or an entire island with reliable and cost-effective electricity. As the technology to do this reliable and cost-effectively has only recently become available, it requires strong leadership and political will to develop microgrid projects at large scale. Annobon’s President Obiang Nguema had a vision to raise the quality of life for the residents by filling the need for an energy solution that would provide them with electricity for 24 hours a day seven days a week, and after consulting with industry came across solar microgrid technology as an optimal solution. Princeton Power Systems stepped in with the technology and capabilities to prove that one does not have to live on the mainland to enjoy the benefits of affordable, reliable, low-pollution electricity.

Princeton Power Systems, based out of Lawrenceville, New Jersey, opened doors in 2001. The company has extensive experience with microgrids having developed perhaps the highest profile solar microgrid in the world for the US National Park Service on Alcatraz Island in the San Francisco Bay, plus many other projects with customers across the United States, the Caribbean, Europe, and Africa. Princeton’s UL and CE-certified power electronics are used worldwide in advanced battery operations both tied to the electric grid and offgrid, with built-in smart functions for ancillary services.

The company’s project on Alcatraz, off the coast of California, is similar to the Annobon Island situation in the sense that they are both isolated from central power grids and Alcatraz previously ran entirely on diesel-fueled generators, which drove a significant amount of operating costs and pollutants for the Golden Gate Recreational area that manages the island. The Alcatraz Microgrid has been operating reliable for nearly three years, since the project was commissioned in 2012. During that time, the amount of diesel fuel consumed on the island has dropped by over 50 percent, reducing the number of fuel-resupply ferries that go out to the island by almost 75%. The resulting cost savings, emission savings, and improved electric grid reliability have made the project a success for the Park Service.

In collaboration with the project developer and partners, Princeton Power Systems began the build-out of a 5-MW self-sufficient solar microgrid on Annobon Island, consisting of 20,000 solar panels split into three geographically-separated arrays, three large-scale advanced battery banks, and redundant generators. The microgrid is enabled by Princeton Power Systems 250 kW battery integrated inverters (BIGI), twenty of which are installed across the island to condition the power from the solar arrays and batteries, and to manage power flow between the different sources and loads. The BIGI-250 is the world’s first multi-port, DC-coupled power converter designed for cost-effective solar and battery microgrids like the one on Annobon.

The BIGI-250 operates both on-grid and off-grid and features built-in smart functions, such as demand peak shaving, photovoltaic (PV) ramp rate control and area frequency regulation (AFR). It includes a droop control algorithm that allows multiple power converters to synchronize on an AC-microgrid along with diesel generators and without dedicated communication lines between the converters. This control method allows inverters to drop off-line or communications to go down without affecting the reliability of the electric grid.

The control structure is based on Princeton’s Energy Management Operating System (EMOSTM) and four EMOS-Hub controllers placed around the island. There is one EMOS-Hub located near the mouth of the island’s inactive volcano, another near the island’s airport, one near the island’s only hotel and the fourth master controller near the southern tip to coordinate between all of the locations and support three small villages.  The island-wide microgrid EMOS controllers allow remote control and monitoring of the power system, and allows remote maintenance and software upgrades as needed.

“Today over 1 billion people are without power. We are taking our experience in microgrids from Alcatraz Island, the US Department of Defense and private sector customers to now apply it to improving quality of life for people in rural areas where grid connected power does not exist or is not reliable,” said Ken McCauley, president and CEO Princeton Power Systems.

The island-wide microgrid on Annobon will provide reliable, predictable power, supply enough electricity to handle 100 percent of the island’s current energy demand, and will be the largest self-sufficient solar project on the continent of Africa. Solar power with advanced batteries provides a cost-effective way to bring electricity to islands and remote areas with much lower emissions than fossil-fuel generators. Modern solar panels are far more efficient and cost-effective than their predecessors, and advanced batteries that can support the daily charging and discharging required for microgrid operation are just now becoming widely commercially available. The electronics and controls required to manage these assets has been demonstrated for several years in projects including the Alcatraz Microgrid.

The Annobon project is a part of Equitorial Guinea’s National Economic Development Plan Horizon 2020, which aims to make Equitorial Guinea an “emerging economy” while accelerating its development and democratization by 2020.  Along, with a much needed power supply, the microgrid will enable the development of multiple industries on the island, therefore, providing residents more jobs and significantly raise the standard of living.

Darren Hammell is co-founder and chief strategy officer at Princeton Power Systems.

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