By DR. MIRIAM ACZEL
Cambodia has one of the lowest electrification rates in Southeast Asia: roughly half of Cambodia’s population does not have access to the electric grid. While the country has seen relatively strong economic growth over the last two decades, a majority of the population lives in under-resourced, rural areas. This has led to a large divide between those who live in the capital of Phnom Penh, nearly all of whom have electricity, and the more than half of Cambodia’s rural residents who do not have energy access. Those living without energy access and in under-resourced areas are also the most vulnerable to detrimental impacts of climate change, and, importantly, would gain the most from having access to electricity.
While solar-powered home systems have been installed in some Cambodian homes, the systems only serve a single household, and power from these single-home systems is not shared, leading to a loss of roughly one-third of the electricity generated by these systems.
Community Microgrids: A Scalable, Equitable Solution
Okra Solar has developed a creative solution, where the excess power not used by one household can be shared with the rest of the community. Thanks to Okra’s new DC mesh grid microgrid network, integrating both existing distribution, local power generation and storage, and smart data software, nearly 150,000 households in the rural village of Steung Chrov can now benefit from reliable access to clean, renewable energy. According to Okra Solar’s founder Afnan Hannan, the company is “unlocking the potential of villages and micro-entrepreneurs” through these ‘smart’ microgrids.
The project was funded through Cambodia’s Ministry of Mines and Energy along with support from the Electricity Authority of Cambodia and the United Nations Development Program.
Leveraging the Power of Connectivity
Okra Solar’s mesh grids combine both physical hardware, including solar panels, battery storage, and existing and new transmission equipment with a software management platform in order to create local peer-to-peer networks. Pairing these technologies and enabling connection between individual energy users allows remote monitoring of energy supply, demand, and usage, and lets users share locally-generated power from inexpensive individual home solar PV and battery storage systems. Although each individual household still operates as an independent energy consumer, mesh networks enable balancing energy needs and can dispatch power where needed—all in real time—thus providing an inexpensive solution for rural communities that lack connection to Cambodia’s electric grid. This innovative system minimizes unused energy ‘waste’ and provides an equitable way for sharing power, even in the most remote parts of the country.
Direct Current (DC) Mesh Grids vs. Alternating Current (AC)
According to Okra Solar operations manager Otteh Edubio, a key benefit of their system is that the DC mesh grid “can be installed for a fraction of the cost of a typical AC mini-grid.” In a centralized storage and generation system, there is often the need to ‘oversize’ the system—that is, to provide more power than is needed–in order to account for the energy demand of the entire community, as well as to compensate for electricity loss due to transmission at greater distances to remote households in the network. However, in a mesh microgrid system, electricity is both generated and used by individual households, with extra power shared with nearby homes.
AC is best for transmitting energy over long distances, which is why the AC system is the primary system used for distribution in a larger electric grid. However, for shorter distances, such as in the Steung Chrov village’s mesh grid, DC systems are ideal. Most appliances and wall outlets use DC, so using a DC grid avoids the need to convert from AC (used in transmission) to DC (for use), a conversion that leads to loss of roughly 10 percent of the energy. As a result, DC microgrids are more efficient than their AC counterparts.
In addition, according to Okra Solar’s estimates, the cost of developing DC microgrids is roughly 40% cheaper than installing traditional AC microgrid systems. This is thanks to lower costs of distribution and transmission: in an AC system with centralized power, larger, thicker cables are necessary for safely transmitting and distributing power over further distances from the generation location. However, in this DC mesh system, where power is distributed between neighboring homes, each with individual generation and storage systems, the distances are shorter and therefore the system can safely use cables roughly one-tenth of the thickness of those in a centralized AC system. Consequently, the transmission poles which carry the smaller wires can also be smaller and shorter than the transmission poles of the AC system. Finally, the modularity of the system enables connecting additional households and adding more generation and storage capacity without the need to restructure the network or add expensive infrastructure.
Okra Pod: Empowering Local Residents Through Electricity
Thanks to this mesh system, almost all the households in Steung Chrov have their own solar and battery system that can power small appliances. Okra Solar’s system uses the Okra Pod, a DC-to-DC controller system that converts the energy from the solar installations to a safer, lower voltage that is used to charge the batteries, enabling residents to plug in appliances including refrigerators, phone chargers, rice cookers, and lighting, and even charge electric scooters and bikes. In this way, the system provides critical services, increases community safety (particularly at nighttime), improves resident comfort, and promotes economic development and entrepreneurship through powering appliances necessary for home businesses.
Additionally, Okra Solar’s monitoring software can identify and communicate potential issues, which, combined with the much lower transmission voltage of the local systems, allow residents to fix problems themselves. Diagnosing and communicating problems among users and enabling local repairs not only reduces maintenance costs but also provides community employment opportunities.
Energy Access: A Key to Sustainable Development
Affordable, reliable access to sustainable energy—United Nations Sustainable Development Goal (SDG) 7—is critical for achieving many of the other SDGs, including poverty eradication, education, global health, and climate change mitigation, among others. This scalable, modular system serves as a model that can empower even the most remote rural communities with access to energy, thereby improving quality of life and promoting economic development and entrepreneurship.
Editor’s note: this article originally appeared on the EcoBlock blog
Dr. Miriam Aczel is the McQuown Postdoctoral Fellow at the California Institute for Energy & Environment (CIEE) at UC Berkeley, working on the Oakland Ecoblock project. She is also an Honorary Research Associate at Imperial College London’s Centre for Environmental Policy. Miriam earned her PhD at Imperial College London, where she was a President’s PhD Scholar. She is also co-founder and co-director of the Amir D. Aczel Foundation for Research and Education in Science and Mathematics, a nonprofit based in Cambodia.
Cover image credit: JustMe Moni via Pexels
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