Commissioned by the Ecuadorean government to resolve a complex environmental issue confronting the Galapagos Islands, one that threatened the biological sanctuary’s UNESCO designation as a world heritage site, Siemens has developed a hybrid electricity generation system using renewable fuels that could serve as a model for clean power in decades to come.

The issue revolved around replacing the highly pollutive electric power system on Isabela Island, the largest of the national park’s 21 islands and the launch pad for tens of thousands of global tourists who each year take boat tours of the archipelago and its wondrous wildlife.

UNESCO was worried not only about the pollution but the risks incurred by the delivery of the plant’s diesel fuel by ship from the mainland 600 miles away. In recent years, two big fuel loads were spilled during the transfer from ship to power plant, fouling the island’s coastline and threatening the fragile ecosystem. The United Nations cultural agency put Ecuador on notice that a cleaner electric power solution had to be found or the Galapagos could lose its coveted “world patrimony” distinction.

Ecuador, with the key support from the German government, issued an invitation to global engineering companies to submit bids to design a reliable, environmentally clean system using renewable fuels, but the technical and logistical challenges of building and maintaining such as system on a remote island proved formidable. In the end, Siemens was the only bidder. Its proposal: A “hybrid” power plant that combined solar power generation with a biofuels power component that used a little known nut as its power source.

At just 1.2 MW of maximum capacity, Siemens’ proposal was for a power plant with a tiny fraction of the generational power the company is accustomed to building.

The hybrid’s system’s renewable technology consists of three main components: A 952-kW solar energy “farm” consisting of some 3,024 photovoltaic panels; a 1625 kW biodiesel generation system made up of five 325-kW generation sets, and a battery storage element can add 660 kW instantaneously when needed. Tying it all together is a unique control system that Siemens is showcasing at Isabela. It includes proprietary software to manage, among other functions, the energy flows to and from the batteries.

The system has been fully operational since October – but only after an extensive testing period at pilot projects in Ecuador and at a mock-up in Germany. Installing the project with its 600 tof machinery and construction material was a massive undertaking, made unusually complex by the fact that there are no quays or jetties in the Isabela island to which vessels can moor.

The new hybrid power plant has already delivered dramatic environmental benefits. Because it avoided burning 33,000 liters of diesel that fueled the old plant each month, the new power plant saved 88 t of CO2 emissions and one fuel delivery during October. Moreover, the new plant is much less noisy, operating at an average reduction of 30 dB, which is the perceived difference between a jigsaw and a conversation at low volume. And the system proved to be reliable, operating at 99% capacity.

A novel aspect of the project’s biodiesel component is its use of Jatropha, also known as Barbados nut, as the fuel source. The nut, which grows in tropical areas in several South American countries including Ecuador, consists of 40% oil that can be processed into a high quality biodiesel. But the nut heretofore was relatively untested and so more than 5,000 liters of the fuel were sent to Germany for prior testing before final approval. The entire system underwent a six-weeks trial at a mock-up near Hamburg last year, demonstrating the accurate operation of the plant even before being shipped to its final destination.

The special aspects of such a novel type hybrid power plant demand a high degree of reliability to power a complete island as a single source. Commissioning went without issues, and with the extensive R&D work invested into the development of the solution and the prolonged and intensive testing, Siemens was able to guarantee the performance of the hybrid power plant. A remote monitoring of the plant from Austin/Texas and Munich/Germany makes Siemens’ whole expertise in energy generation available to the local operators of the plant.

A Jatropha processing plant staffed by a local cooperative has been set up in Ecuador’s coastal region of Manabi to supply the new Isabela power plant with biofuel – which unlike fossil fuels would degrade relatively quickly if a spill during transport were to occur.

The result is a system that Siemens describes as unique in the world for its “high penetration,” a reference to the fact that the photovoltaic power the system generates during the day exceeds Isabela Island’s current power demand. In addition, excess PV energy generated will be stored in the battery system, allowing the complete shutdown of generation sets, providing daytime stability and giving the biodiesel power units time to start when the clouds come.

Source: Siemens