Definition of Hybrid Systems
Hybrid Systems are the simultaneous integration or combination of different power sources such as the photovoltaic system, the Grid (Electricité Du Liban), the batteries and the back-up generators.
The logic operation mode of a Hybrid PV system proposed by DCE is as follows:
(1) Sunny period & grid ON: The consumption priority is from the power generated by the solar panels. In case of production surplus the panels will charge the battery pack, and when the batteries are fully charged (100%) the production surplus will be injected into the public power grid. (NB. an electrical net-metering counter should be available for grid feeding)
(2) Sunny period & grid OFF: The consumption priority is from the power generated by the solar panels. In case of extra demand the battery pack will satisfy the needed energy as back-up. (NB. During grid failure, the surplus solar energy production cannot be injected into the public power grid).
(3) No sunny period & grid ON: The consumption is from the public power grid simultaneously charging the battery packs if needed.
(4) No sunny period & grid OFF: The consumption is fulfilled by the battery pack. In case of additional demand is needed and the battery packs is at its lower level then the diesel generator will be turned ON.
Consumption priority: Knowing that the solar management system is capable of combining the energy sources, the order of priority of the energy sources is always as follows:
1- Photovoltaic panels
2- Utility company (public grid)
3- Battery pack
4- Diesel generator
Residential Hybrid System:
These systems are addressed to residential facilities whose electrical energy sources are the grid and the generators and the power peak demand is below 40KW
• Considerable large cutoff periods.
• Low quality grid power.
• Increasing cost of fuel and the cost of generator subscription.
Photovoltaic System Advantages:
• Decreasing cost of Photovoltaic Systems in addition to BANQUE DU LIBAN subsidized loan with very low rate of interest.
• Prolonged yearly sunny period (290 days in Beirut, 320 days in Inland region).
• Minimum maintenance is required.
• Clean Continuous and stable internal electrical grid.
In order to size a proper photovoltaic system for a facility Durable Construction & Energy engineers make a site visit in order to determine the actual consumption of the facility and to determine its consumption profile. Following to the site visit an engineering study will be conducted in order to size the PV array (number of panels required), the inverters and the batteries.
The purpose of the installation is reducing to the minimum the consumption of non-renewable energy sources such as diesel generators during cutoff hours and to reduce as much as possible the grid consumption by replacing the grid by an energy supplied by the panels. In addition to all the above, the installation of photovoltaic systems reduces the green gas emissions which contribute significantly in the air pollution.
Durable Construction & Energy recommend AC coupling systems since they are more efficient and reliable. Please refer to “AC coupling vs. DC coupling”.
Comfort and constant monitoring and smart phone applications are available with Web communication interface. Be always informed of you system whenever you require.