Samoa could inch very close to its goal of running on 100 per cent renewable energy by 2025, but it would take more than $600 million in investment to reduce its reliance on fuel imports, new research has found. 

A researcher and lecturer from the National University of Samoa, Tupuivao Vaiaso, says Samoa could feasibly run on just over 90 per cent renewable energy by 2025. 

Mr. Vaiaso has recently completely his Master's degree in science at the University of Otago, where he undertook a techno-economic analysis of Samoa’s stated national policy of achieving 100 per cent renewable energy by 2025.

Analysing historical data on the country’s energy use, he found with an investment of nearly US$176.3 million (T$643.83 million), Samoa could reduce its reliance on diesel fuel from 60 to 7.5 per cent.

“It is technically feasible to get close to 100 per cent renewable electricity using a combination of solar hydro, and stored solar energy,” said Mr. Vaiaso, with just 7.5 per cent of electricity produced by diesel. 

The major factors in reducing Samoa’s diesel reliance is increasing solar energy use sevenfold and investing in at least US$22 million (T$57.9 million) worth of energy storage to capture all the excess energy that solar would reap.

Such a reform would be a win for the climate, Mr. Vaiaso said, but also for Samoa’s independence and resilience, not having to wait on expensive and potentially precarious shipments of diesel from overseas. 

A cheap but environmentally impactful option for energy storage is a hydro-dam, Mr. Vaiaso said, but the simpler option is batteries which have been getting dramatically cheaper over the decade thanks to its rising popularity.

Today batteries cost US$200 (T$526) per kilowatt hour. At a minimum, he has calculated Samoa needs at least 110 megawatt hours of storage, costing at least $22 million (T$57.9 million). That cost could get lower still, however.

Mr. Vaiaso said he was drawn to study Samoa’s capacity for renewable energy because of how global the issue has become in light of the damaging effects of fossil fuels on the climate. 

With the Government of Samoa’s deadline for 100 per cent renewable energy production nearing, he was eager to review what it would take to meet the policy aim.

But like many researchers, the scientist came up against a lack of reported data. 

The Ministry of Finance’s latest report on Samoa’s energy production is from 2015. And Mr. Vaiaso was able to get time-series data on energy use from the Electric Power Corporation for two years, which was enough to figure out how Samoa consumes energy and to what extent it can afford to lose diesel.

That delay likely accounts for the discrepancy between Mr. Vaiaso's analysis of the country's current reliance on fossil fuels of about 60 per cent and the Electric Power Corporation's claim last September that the nation was now running on 50 per cent renewables. 

The data clearly shows when Samoa uses the most versus the least power, and how much is generated from hydropower, solar power and diesel. 

Mr. Vaiaso found the country could successfully use power generated from hydropower and solar power for just about the entire day, switching to storage in the evening and back again in the early hours of the morning.

But because batteries, while cheaper than a decade ago are still expensive, there is at least an hour between one and two in the morning when the storage will run out, and power will need another source to be maintained.

Currently he believes the storage is too expensive to buy to cover that gap, and so it has to be covered by has to be diesel at this stage.

“Hydro is not sufficient to meet the [unmet demand] so in the study I have assumed that is the bit is where diesel comes in, or if we are going 100 per cent then something needs to fill that gap,” Mr. Vaiaso said.

Of all the renewable energy options, solar energy was Mr. Vaiaso’s top pick because it so effective in Samoa. Days are long all year round, and even the bad weather in the wet season isn’t strong enough to dampen the efficacy of solar panels, he said.

Samoa can generate five kilowatt hours per square metre of solar panels, he said.

Based on a variety of scenarios, Mr. Vaiaso calculates Samoa needs to get somewhere between 28 and 37 per cent of its energy production from solar, and 17 to 30 per cent in solar storage. 

The remaining 25 to 40 per cent could come from hydropower, but most of his scenarios do not include increasing hydropower in the country because of its rivers’ capacity for generating power.

“The resource is property that is a challenge, it’s the variability. It’s not there when you need it,” he said. 

Mr. Vaiaso says he is yet to show the Electric Power Corporation the results of his analysis.