Island hybrid PV-battery plant with excellent performance

10/19/17, 11:00 AM -

The performance of a hybrid PV-energy storage system on the Dutch Caribean island Sint Eustatius exceeds expectations. The island utility plans to expand the plant and switch-off remaining diesel generators in the near future.

Island utility Stuco plans to expand the hybrid PV-battery plant on the Caribean island of Sint Eustatius and switch-off diesel generators in the near future
Island utility Stuco plans to expand the hybrid PV-battery plant on the Caribean island of Sint Eustatius and switch-off diesel generators in the near future

SMA Sunbelt Energy commissioned a 1.89 MW solar PV and 1 MW / 572 kWh Li-Ion battery energy storage system, in 2016. The objective of the retrofitted renewable energy plant is to reduce the diesel consumption of existing diesel generators. THEnergy has performed a data analysis for the first year of operations. Large-scale hybrid systems are rather complex and for island utilities it is difficult to fully assess the outcome of hybridizing their diesel power plants with solar power plants on fuel consumption. They typically rely on the calculations of the manufacturers or on rather costly third-party studies.

3.4 percent higher diesel savings than forecasted

In the case of Sint Eustatius, the performance of the plants exceeds the forecasts after one year. The share of solar energy on the island energy mix was higher than predicted for the first year of operations. The solar energy produced was 3,126 MWh. Relative diesel savings were 812,887 liters, 3.4% higher than forecasted: diesel consumption was reduced by 62 l/MWh instead of 60 l/MWh. These additional savings are particularly remarkable as solar irradiation during the year was 4.9 percent below average due to local weather conditions. Even the total savings in diesel were in line with those forecasted. This is also reflected in the slightly higher than expected performance ratio of the solar PV plant.

Actual battery degradation of only 1 percent

The analysis also shows positive findings for battery performance. While a degradation of 4 percent was expected, the actual degradation after the first year was 1 percent with a battery health of 99 percent.  The battery energy throughput was 148 MWh. It is realistic to assume that with normal weather conditions, and the extremely low degradation of the battery energy storage system, the future performance of the plant will be even better than during the first year.

Utility plans to add 2.25 MW PV and 4.4 MW energy storage

The outstanding results of the new system are also the main reason for the island utility deciding to expand the plant in the near future by adding 2.25 MW of solar power, and 4.4 MW / 5.2 MWh of battery energy storage. As Fred Cuvalay, CEO of Stuco explained: “We are fully convinced of SMA Sunbelt, which is particularly important, as in this next step we will switch off our diesel gensets during sunny days and will fully rely on renewables”.

Positive signal for other islands

Thomas Hillig, the Managing Director of THEnergy also made the following comments on the exciting results: “Large PV-battery diesel hybrid plants are still relatively new. On islands in particular, the reliability of the supplier is a key success factor. Bad planning and technical issues may lead to huge consequential costs. This project will also be a signal to other islands of what can be achieved by integrating renewable energy.” (HCN)

Read more about enery storage

Stay informed, get our free newsletter twice a week, register here

More useful information: