Among the many projects that are currently being undertaken in Tuvalu one is the plan to make the Funafuti electricity grid run off 100% renewable energy by 2020. This decision I suspect was made out of a desire for greater energy independence and cost savings as much as an environmental one with the grid reliant on diesel shipped in from Fiji that can be unreliable and expensive. With an average daytime island load of around 1MW the capacity is very small on a world scale but what makes it interesting is how to ensure this micro-grid remains stable during both the transition to 100%, reaching the target and ensuring the grid has the ability to grow and adapt to changing needs of the island. How to do this in the harsh marine climate in a culture where maintenance is not strongly integrated in the culture provides additional challenges.
Currently there are three solar systems on the grid: the one donated by the Russians at the southern end of the runway is a 45kW system that was to power the desalination plant (that is no longer operable) but the solar still reliabley pumps power into the network; the second two were donated by the Japanese, one located on the sports field grandstand and the second is in the yard of the Public Works Department (PWD) and is supposed to feed the operational desalination plant.
The sports field 40kW system (admittedly the oldest of the three) has rocks sitting on the solar panels, which judging from the nearby panels with holes in them, were thrown their by bored youth.
The PWD 62kW system is in reasonable condition but large portions of it shaded by tree growth that has not been trimmed. Unfortunately neither of these are working and highlight the biggest hurdle to any technology project in the pacific. Even a technology with as little maintenance requirements as solar cannot escape the fate of disintegrating in the harsh marine environment or becoming inoperable without minimal care.
In 2015 we see two more solar projects being installed on Funafuti. One funded by MFAT involves both the Government and the Media Building covered in a combined 170kW simple grid connected system. The second is funded by the Government of the United Arab Emirates and managed by Masdar and consists of 500kW spread between the TEC power station site, Princess Margaret Hospital roof and the Wharf Warehouse building. Combined these systems bring the total (operational) capacity of solar on the grid to 710kW.
This is very high penetration for a grid this size and represents what we would consider a transition phase for the grid. To ensure the grid remains stable 350kW of the solar is controlled (rather than feeding passively onto the grid). The control system is hooked up with the diesel generator control system. The grid load is monitored and the control system can prioritise fuel saving (minimising generator load) while ensuring the generators are operating at an acceptable level (turning down the solar at particular vulnerable times).
Next year the World Bank will take this control system and the grid integration to a new level with plans to add a further solar, potentially wind and a battery bank to take Funafuti to a 100% renewable electricity network. But we are all left with the question how do we design and install our systems and work with the Tuvalu Electricity Corporation (TEC) to reduce the likelihood that these new systems too will end unmaintained and failing.