Balance of System (BOS):
In a photovoltaic energy system, the solar panel is the queen of the system. All other parts which contribute to the functioning comprise the “balance of system” usually denoted by the acronym (BOS). These will include the:
- Wiring.
- Switches.
- Mounting system-mostly needed for supporting the panels but may house other allied equipment.
- One or many solar inverters- for converting the DC produced by the panels to AC suitable for use or grid connection.
- Battery bank- Required with sufficient capacity if grid connection is not available (stand-alone systems). Excess Energy must be stored for use when the sun is not available.
- Battery charger- Charges batteries from solar energy. Maximum Power Point Tracking (MPPT) chargers adjust the current so as to pass maximum power to the battery under given solar output conditions.
- Inverters- Invert DC to AC.
- Junction boxes with fuses and relays.
- Power conditioners- Ensure that the inverter output is well regulated and free of sags, surges and spikes.
- Metering system- In the case of grid-connected systems to record flow of energy from and to the grid.
Optional equipment, depending on nature and scope of the system, may include:
- GPS Solar tracker- To keep the panel always positioned for receiving maximum energy from the sun.
- Power management software- Will be required in larger systems using multiple strings of panels and inverters, and possibly feeding multiple loads. The software may control alarms for out-of-tolerance conditions, take autonomous switching actions.
- Solar concentrator.
- Solar irradiance sensors- These are normally justified in large commercial systems for maintenance and monitoring purposes.
- Wind speed sensors.
- lenses or optical mirrors (CPV system only)-For concentration of the beam.
- Or accessories specific to the installation and owner requirements.
Balance of Plant
A similar term to Balance of System is “Balance of plant (BOP)” which is generally used in the context of power engineering and applies to all the supporting components and systems of the power plant which are needed to produce the energy. These may include suitable transformers, inverters, cabling, switching and control equipment, protection equipment, power conditioners, support structures, etc., depending on the type of plant.
Cost of BOS
Cost of Balance of System will include the cost of the hardware (and software, if applicable), labor, permitting Interconnection and Inspection (PII) fees, and any other fees that may apply. For large commercial solar systems, the cost of BOS may include the cost of land and building, etc. The cost of BOS can be about two thirds of the total cost.
Downward Trend
While the cost of solar panels is coming down appreciably, the cost of BOS is not showing the same rate of decline. It is understandable because extra effort has gone into the solar cell technology. The solar cell technology is still evolving and improving, and costs are being reduced fast. The balance of systems consists mostly of items which are not specific to solar technology. As an example, the mounting structures are quite usual and the technology may already be mature, benefitting little from further innovation and research.
A Solar PV Balance-of-System or BOS refers to the components and equipment that move DC energy produced by solar panels through the conversion system which in turn produces AC electricity.
Most often, BOS refers to all components of a PV system other than the modules. In addition to inverters and racking, this includes the cables/wires, switches, enclosures, fuses, ground fault detectors, and more. BOS applies to all types of solar applications.
What to look for:
- Solor Mapping to target solar power or photovoltaic potential per day, by location.
- Review utility bills with a prospective customer to help them better understand energy usage and fluctuations as well as how much they pay per kilowatt-hour.
- Inspect and recommend insulation to increase energy efficiency and rebate opportunities.
- Estimate and compare costs for rooftop and ground-mounted solar PV panels, based on optimum southern exposure.
- Calculate ways to install a solar system to determine which balance-of-systems components will be optional and which will be necessary.
What does balance-of-system mean?
BOS components include the majority of the pieces, which make up roughly 10%-50% of solar purchasing and installation costs and account for the majority of maintenance requirements. Essentially it is through the balance-of-system components that we: control cost, increase efficiency, and modernize solar PV systems.
Costs are steadily decreasing with regard to solar panels and inverters (formerly 50% of solar PV investment costs).
Some key cost reduction aspects to consider are:
a. Bundled BOS systems (one-supplier or manufacturer) vs. gathered (several)
b. Installation – Rooftop vs. Ground-Mounted
c. Electrical Components
d. Interconnectivity / Equipment Compatibility.
With the right knowledge, a solar PV systems provider can guide consumer interest where state incentives and federal rebates apply to total expenditure, lower costs where rebates and incentives are not applicable, and focus on BOS efficiency within design planning and implementation.
Balance-of-systems cost and efficiency can enable business growth by way of:
a. Expansion into new sectors (i.e. Government, Schools, Non-profit, Agricultural)
b. Word of mouth recommendations
c. Creating new jobs and business locations
d. Increase training and development resources
A Solar PV Balance-of-System or BOS refers to the components and equipment that move DC energy produced by solar panels through the conversion system which in turn produces AC electricity.
Most often, BOS refers to all components of a PV system other than the modules. In addition to inverters and racking, this includes the cables/wires, switches, enclosures, fuses, ground fault detectors, and more. BOS applies to all types of solar applications.
What to look for:
- Solor Mapping to target solar power or photovoltaic potential per day, by location.
- Review utility bills with a prospective customer to help them better understand energy usage and fluctuations as well as how much they pay per kilowatt-hour.
- Inspect and recommend insulation to increase energy efficiency and rebate opportunities.
- Estimate and compare costs for rooftop and ground-mounted solar PV panels, based on optimum southern exposure.
- Calculate ways to install a solar system to determine which balance-of-systems components will be optional and which will be necessary.
What does balance-of-system mean?
BOS components include the majority of the pieces, which make up roughly 10%-50% of solar purchasing and installation costs and account for the majority of maintenance requirements. Essentially it is through the balance-of-system components that we: control cost, increase efficiency, and modernize solar PV systems.
Costs are steadily decreasing with regard to solar panels and inverters (formerly 50% of solar PV investment costs).
Some key cost reduction aspects to consider are:
a. Bundled BOS systems (one-supplier or manufacturer) vs. gathered (several)
b. Installation – Rooftop vs. Ground-Mounted
c. Electrical Components
d. Interconnectivity / Equipment Compatibility.
With the right knowledge, a solar PV systems provider can guide consumer interest where state incentives and federal rebates apply to total expenditure, lower costs where rebates and incentives are not applicable, and focus on BOS efficiency within design planning and implementation.
Balance-of-systems cost and efficiency can enable business growth by way of:
a. Expansion into new sectors (i.e. Government, Schools, Non-profit, Agricultural)
b. Word of mouth recommendations
c. Creating new jobs and business locations
d. Increase training and development resources