Enlarge: „Food and Energy“ – the greenhouse and the transport vehicle, which was converted from diesel to biodiesel fueled

Since the Bahamas lacks oil and gas reserves, energy sources are currently still imported, a complex and costly process. Agriculture suffers from similar difficulties. There is a lack of fertile soil and, above all, opportunities for irrigation. This sector therefore also relies on imports. In addition, because the Bahamas is made out of islands, waste management is a challenge which any solution to provide a more independent power and food supply must tackle.

"Food and Energy" - a sustainable solution from Germany
To address this situation, SUNfarming GmbH and bioltec systems GmbH jointly developed a concept – the “Food and Energy” Hybrid Center. In 2018, the German companies were able to implement this in the Bahamas at a demonstration scale within the framework of the Renewable Energy Solutions Programme run by Deutsche Energie-Agentur (dena) – the German Energy Agency.

In the grounds of the Windsor High School in Albany near the capital Nassau, SUNfarming set up a hurricane-proof greenhouse fitted with photovoltaic modules. Here, thanks to solar-powered drip irrigation, vegetables, herbs and other produce are cultivated for use in the high school’s cafeteria. A control unit adjusts irrigation intervals to meet current needs. Depending on the status of the system, the generated solar power is either directly consumed, fed into the building network or stored in the battery system. In addition, there is a charging station for e-bikes and e-motorcycles.

The partner company bioltec contributed a further aspect of sustainability to the project – the utilisation of used cooking oil. The oil is obtained from the many cruise ships anchoring in Nassau and also from restaurants in the area and is used in the biofuel production conducted by “Bahamas Waste”. In the plant the used cooking oil is processed into biodiesel by local partner 700 Islands Energy. In a functional building set up beside the greenhouse, bioltec has installed a vegetable oil combined heat and power generation plant. The power produced by this generator flows into the overall system, and the heat is used to heat up the service water in the kitchen and sanitary facilities of the Windsor High School. bioltec has also modified an existing vehicle from local waste disposer “Bahamas Waste” so the truck (which collects the used cooking oil) can now itself be powered with biodiesel.

The energy transition on the curriculum
The partner institution for the project, the Windsor High School, has committed to sustainability. The new Hybrid Center will give the school and other educational establishments in the area the opportunity to demonstrate and teach sustainability, and over the longer term this will also give rise to new educational opportunities and job profiles. This fits perfectly with the school’s interdisciplinary approach to teaching and research and its goal to minimise its environmental footprint.

The ceremonial inauguration of the system was held on 10 December 2018. The almost 100 guests included local officials from politics and the economy, as well as from the education sector.

On the occasion of the opening, cooperation possibilities in teaching and research were discussed with representatives of the local universities.

Award from the Energy Globe Foundation
At the end of 2018, Sunfarming and bioltec applied for the "Energy Globe Award" together with their local partner, 700 Islands Energy (Bahamas) with the Hybrid Center "Food and Energy". The project was convincing and now the three companies have been awarded the national title "Energy Globe Award Winner Bahamas 2019" for their model project.

System Data (solar greenhouse): Hybrid Center with smart energy management system

Agricultural area	62m²
Module type	20 x solar panel SF VS300-60M DG 300 Wp
Inverter type	SMA STP 6000TL
Installed capacity	6 kWp
Annual yield	10.000 kWh

System data (combined heat and power generation plant)

CHP generation plant	Senertec Dachs NE HKA HR 5.3
Installed electrical capacity	5 kW
Installed thermal capacity	10 kW
Batteries	2 x Lithium-Ionen-Battery BMZ, ESS 7.0
Battery capacity	10 kW
Battery inverter type	3 x Victron Quattro, 3 x Victron Multi
Maximum annual electricity output with 24/7 operation	40.000 kWh
Maximum annual heat output with 24/7 operation	80.000 kWh
Used cooking oil biodiesel per annum with 24/7 operation	16.000 l