One Year Later: How Alina Eneji saved 40% per connection using a Hub & Spoke mesh-grid

A Case Study
Tim Ha
September 15, 2023
“It's been a journey. We started with energizing 35 households and now are energizing over 1,000. This would not have been possible without the support of our stakeholders and the mesh-grid technology we’re leveraging from Okra. I am extremely grateful for the partnership and look forward to the continued collaboration“ - Driko Ducasse, CEO Alina Enéji


Challenge: Alina Eneji´s project financing model required further reduction in cost per connection to prove financial viability and scale up to 700hh

Solution: They installed a “Hub & Spoke” mesh-grid topology, which has battery and generation capacity installed at “Hub” households who receive primary service. Any excess power generated is shared to nearby “Spoke” households for secondary service.  

Result: Utilization rose markedly as a result of switching to this approach, along with reducing the cost per connection as expected. The Hub & Spoke implementation has not only enabled productive usage for the community’s Hubs, but also facilitated cost-effective electrification for lower tier consumers.

The Challenge

After our pilot project with Alina Eneji was successful in connecting 35 households to electricity, new objectives were drawn up to ensure longer term project viability. These were:

  1. Lower the cost per connection: Although already lower than a mini-grid serving the same amount of energy demand, the project payback period target was updated to be below 5 years. Under the current tariff  structure, this couldn’t be achieved.
  2. Profitably capture the low tier of consumers who demand less than 200Wh/day, who were previously difficult to justify a full connection for.
  3. Increase Average Revenue Per User (ARPU): to improve the efficiency of the capex investment and total project profitability.

This is what led Alina Enèji to go for a “Hub & Spoke” implementation of the mesh-grid that enabled an average daily load of 440 Wh/day with around 1.5 days of battery autonomy. This follow-on case study aims to determine whether the objectives have been achieved.

Solution: The Hub & Spoke

We observed that certain households in the community tend to use many times the energy of their neighbors - to power mills, freezers and other productive uses. However, the majority of households tend to require a lot less energy, for basic household usage such as charging up smartphones, and using lights and fans. It was hypothesized that in order to serve the lowest energy consumers while building a commercially sustainable model, high energy consuming households should be prioritized as “Hub” systems, and excess power could be shared to nearby low consumption residential users, to be known as "Spokes". 

Each Hub system uses a large battery and panel to power productive appliances. Additional households can be connected to the Hub household as a Spoke. Spokes are simply another Okra Pod that connects to the Hub’s battery and doesn’t require any generation or storage assets. See below for a diagram of the Hub and Spoke topology.

Hub & Spoke topology. See here for more detailed information.

Using this method, it was possible to improve utilization of assets while prioritizing the high energy consuming Hub users. Hubs were interconnected to each other, increasing network reliability, and Spokes can be upgraded to a Hub in a modular fashion when their consumption warrants further capex investment. For this project, there was a target of 1,000Wh/day for Hub users and 200Wh/day for Spoke users. 

The Results

As of August 2023, the 300 household scale-up project has been deployed for over one year. The Hub & Spoke implementation has enabled both productive usage for the community’s Hubs as well as cost-effective electrification for lower tier consumers. Below, the scale-up project breakdown is shown in comparison to the 35 household pilot project. 

Note: 90 Spokes in the scale-up project were installed with a Small Mesh-grid Kit at every household, rather than in a Hub and Spoke configuration. They have been included with the Spokes in the above table because they are also low energy consumers.

Notably, the landed cost has decreased around 40% from $818 to $488 per connection while the Daily Average Load and ARPU decreased slightly. The (landed) capex cost has reduced due to the reduction of installed assets, as multiple homes can now share one large system - reducing the cost per kWh for batteries. Hub households were selected on the basis that they either already had some form of productive appliance or would be happy to finance a productive appliance such as a freezer, leading to high energy consumption. 

The slight reduction in ARPU could be attributed to challenging macroeconomic conditions that are currently present in Haiti and the fact that previously economically “unviable” households were also connected as Spoke households. The OPEX for the 300 household phase of the project is approximately $1.80 USD per household per month.

This project showed that, by focusing on higher consuming users, the Hubs, a financially sound model could be developed. Additionally, excess energy from the Hubs could be used to bring power to the nearby low consuming Spokes while keeping the average capex connection per house low. 

Graphic comparison between projects before and after installing Hub & Spoke.

Without Hub and Spoke, Alina Enèji would not have a viable business model for electrifying this village (since the majority of homes are lower tier consumers). Now, any home with the capability to use over 200 Wh/day has the potential to produce sustainable revenue as a Spoke, meaning that the whole village is able to be electrified.

Next Steps

With this successful implementation in mind, Alina Enèji has already deployed another 700 households and has committed to a further 5,000 households, all using the Hub & Spoke topology. The Hub & Spoke topology also allows Spokes to be upgraded to Hubs over time as their energy demand increases, so these next phases will also include some households scaling up in this fashion.

The project in Haiti is proud to have been supported by GEAPP and Alina Enèji looks forward to energizing tens of thousands more homes in Haiti in the coming years.

After a stint in the world of Electrical Engineering, Tim tapped into his creative side and worked as a freelance photographer and filmmaker in Cambodia for three years, with a focus on short documentaries for NGO’s. Now he’s able to combine his technical engineering skills with his love for telling stories and creating content at Okra.