SMA Fuel Save Solution on Sint Eustatius – Excellent Performance Proven

After one year of operation, THEnergy analyzed the SMA Fuel Save Solution located on Sint Eustatius and summarized its performance in one word “excellent.”

After one year of operation, it was time to have a look at the outcomes. Were estimations about the performance of the system accurate? Did the system perform as well as it should? Did the wear and tear on the components match expectations? To answer these questions, SMA Sunbelt asked Dr. Thomas Hillig to analyze how the system performed. Hillig is the founder of the Dr. Thomas Hillig Energy Consulting, which assists companies in the renewable energy sector with consulting in sales, marketing and sustainability.


The hybrid system’s performance in numbers


A hybrid system’s performance is determined by simulations, which rely on assumptions being made. These assumptions are usually forecasts that, from looking at the past, estamet what the conditions will be like in the future.

A great impact on plant performance is caused by irradiation as it defines how much energy the solar system is able to deliver. The past year was not the sunniest one, which explains why the analysis shows an irradiation of 4.9% less than the forecast.
It is also important to consider consumption, as the overall system performance and savings increase the more energy from solar can directly be used. However, the amount actually consumed turned out to be 4.5% less than what was forecasted.

Albeit these non-optimal conditions, the plant performed excellently. The solar system produced more than expected. Despite irradiation being 4.9% less than anticipated, the solar system produced only 2.3% less energy. A great result.
Fuel savings reached 812,887 liters in the year reviewed, which is only 1.2% less thexpected – even better.

One of the most critical components is the battery as a higher ageing of the battery as the most expensive part of the system can be very costly. The batteries were forecasted to have a remaining battery capacity of 95.6% after the first year of operation. Measurement of the capacity after one year of operation showed that the battery performed much better with 98.7% remaining capacity.

You can find the complete performance analysis here (PDF).


Experiences from the first year of operation

First of all, Sint Eustatius is a really, really great hybrid system from a development point of view. For maintenance and tuning, there is a secure live connection between the hybrid system and SMA headquarters in Germany. Due to the time difference of -6 hours with Germany, we are able to comfortably put agreed optimizations and updates into place while solar production is still sleeping. At noon German time, solar production in the Caribbean powers up and the solar plant is at full power just before quitting time in Germany. This is a luxury unique to this site.

statia_cloudySint Eustatius is also an interesting plant because of where it is located (and not only because of dreamlike water and the generous people living there) and the hybrid system’s characteristics. The solar field is incredibly compact and there are nearly no statistical effects distributing cloud impact to different solar systems in the grid. Above that, cloud movement is often really fast as water all around barely slows wind down. So clouds appear within seconds, causing an immediate and extreme reduction in solar production. This would create a significant strain on the generators because always enough genset power would have to be kept online to cover each single solar break in. At this point the battery storage kicks in. As soon as solar production drops, the storage reacts immediately by pushing energy into the grid with a power of up to +-1MW. As a result, a 0.9MVA genset can run at idle power of 30% while 1.7MW of the load is present in the system.


Sint Eustatius a blueprint for the german energy transition


From the beginning, Germany’s grid utility companies have complained about grid stability as the use of renewable energies has grown. On the right you can see power production of one recent week in the German grid. While in Sint Eustatius the fluctuations in solar power were much more significant as there is little regional distribution AND the renewable share does not cap at 50% as it does in Germany, but instead goes up to 89%; AND there is no larger grid to import / export energy to balance out the fluctuations, Statia Utility Company (Stuco) still intends to raise the renewable share in their grid even further.

So, when a little Caribbean island like Sint Eustatius has the technology to cope with the difficult conditions presented given their location, why should a large European grid not be able to overcome its challenges? If you compare the diagrams, the difference in the level of challenges becomes clear.



Today, we are working on the next level of hybrid systems. While solar-diesel-hybrid systems today mainly reduce consumption with a generator there to cover spikes and to give the beat in the grid, we are developing means to completely turn off all gensets and let the battery storage entirely take over the grid. Again, Sint Eustatius may well be the place where we first implement this large step forward with a larger battery, even more solar and a grid forming industrial class battery inverter.

We will keep you updated on our development progress here.


Interested in the project? Check the video about the project (2016):

カリブ海のシント・ユースタティウス島: SMA燃料削減ソリューションによる持続可能な電力供給

Update 2017-07-13:

In the mean time, there were a lot of publications spreading this great success.
Here is a selection of publications:





More information

You can find all of our blog posts on the Fuel Save Solution here. It is a great source of information if you are interested in saving fuel or planning to integrate solar energy into your grid.

Do you have comments or questions? Great! Just use the comment field below. We look forward to receiving your comments and we will answer each question as best as we can.

You can find even more details on the Fuel Save Solution Product Website.

If you would like our experts to help you lay out your own Fuel Save Solution, just send us an email at

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