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Development of an open-source load management system for community based renewable energy systems

The Smart Grids for Small Grids project aimed to improve the efficiency and reliability of small-scale renewable energy mini-grids using open source load management devices to monitor and control energy use in communities. The project addressed the intermittent energy use in many off-grid environments, where it is common for communities to experience a power deficit during peak consumption hours and a large power surplus during off- peak hours. Power deficits can lead to service interruptions at times when electricity is most needed, while off-peak surpluses reduce the financial viability of the system as the energy does not generate any value for community members.

Throughout the project, Green Empowerment’s partner organisations, Sibat in the Philippines and Tonibung in Malaysia, worked with indigenous communities that were selected because their micro hydropower mini-grids were experiencing low load factors or overloads.

Technology, Operations & Maintenance

Three communication technologies were tested to solve demand-side management problems in mini-grids by providing consumers with real-time information about available system capacity and making automated control decisions using hardware attached to specific devices. Finally, a modified firmware build of the open source Bluebird Electronic Load Controller (ELC) was implemented, which modulates the system frequency with the actual load factor.

New modular printed circuit boards have been developed that contain various functional components. For the purposes of this project, the modules could be configured as two different devices: (1) a comprehensive monitoring tool for data collection that provides half-second resolution data on multiple electrical parameters; (2) and an appliance control technology that continuously monitors the electrical system frequency and calculates the available power, thereby informing switching hardware that activates or deactivates the connected appliance, such as a washing machine or freezer.

Financial Management

Different use cases have been considered to cover the costs long-term: the perspective of the potential manufacturers such as Sibat and Tonibung, the perspective of the community owned energy utility, and that of potential private entrepreneurs residing within the community.

According to this modelling, the most viable strategy would be to bundle appliance controllers with productive end-use appliances that can create marketable products or services, such as making ice or offering laundry services. These micro-enterprises would then be run by community members to generate revenue to offset the cost of the controllers, while providing the benefits of energy use.

Environmental Issues

Load management devices reduce power outages and provide more reliable energy services from renewable energy mini-grids, thereby reducing the reliance on fossil fuels such as diesel generators and increasing the acceptance and acceleration of the technology. They maximise existing micro- hydro systems and ensure that the electricity generated is used more efficiently. Last but not least, better maintenance makes the systems last longer.

Social Issues

As the project focused on technology assessment, research, development and testing, no social impacts were expected. However, the project took into account the livelihoods of community members, their aspirations and ownership of appliances. As a result, appliances that could have a significant impact on the overall system load and that were a priority for consumers were included in the field tests of pilot communities. The project also held discussions with the micro-utility committees about the technologies and types of businesses that could use additional energy to generate value for the community. The results of the field tests showed the potential for future social impact through increased use of refrigerators or ice machines and pay-per-use washing machines, which generate income for community members.

Results

The measurement systems provide good quality, high resolution data and, when combined with SD card storage, are a perfect solution for collecting data from systems outside of cellular coverage. This data can be used for maintenance, troubleshooting, research and educational purposes, particularly in relation to community load profiles. They could also form the basis of an open source energy meter or similar device with some further development. The digital communication technologies developed also should be seen as building blocks, either for further refinement for load management purposes, or for use in other applications where either range or data rate are less of an issue. The appliance controllers with frequency monitoring functions are effective in determining the available capacity and are electrically compatible with a wide range of appliances. However, manufacturing costs remain a challenge, as do application range and system compatibility. Community feedback has also been positive, particularly for the ‘traffic light’ load indicators in the appliance controller, which are intended to inform their own manual appliance usage. There are questions about the suitability of shared-use appliances in the pilot communities, which favoured domestic use. Shared use appliances are likely to be more successful in less developed communities.

Replicability

Project partners Tonibung and Sibat have developed localised ideas for applying the technologies and knowledge gained in their programme regions. They have incorporated these into their organisational plans, which Green Empowerment will continue to support. In addition, the project has documented its developed technologies and research findings on a dedicated page on elcwiki.info and held a webinar to disseminate the project findings with the aim of to stimulate interest in collaboration and further development.

Lessons Learned

1. Collaboration with local partners and communities matters: Using local knowledge and networks of community members was invaluable.

2. Effective communication with multiple, appropriate tools and channels is vital: The various channels, such as the wiki-based online instructions, worked well to communicate the circuit board assembly process to the partners’ staff. They in turn provided helpful feedback to improve the comprehensibility of the instructions.

3. Time management is a critical element: Another key learning from this project was how necessary it is to provide sufficient time for project implementation, especially for data collection and procurement.

4. A modular approach allows for troubleshooting and making sub-circuits of the overall system without having to redesign and manufacture a completely new system board. This saved time and resources during the crucial testing phase. It also allowed to implement common areas of functionality as building blocks that could be reused in multiple applications.

5. Use of open-source technology improves data analysis: The use of Sparkfun’s low-cost OpenLog device allowed the large capacity of micro-SD cards to store the large number of parameters at the required resolution offline. Python was used for analysing the load profiles of rural communities and informing the system maintenance and troubleshooting of local partners.

6. Technology limitations: Building a high data rate network over several kilometres was a particular challenge, compounded by infrastructure cost constraints and the desire for local manufacturing.

You can find the detailed case study for download at the top of the page!