September 10, 2010
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PV Stand Alone / Remote Power Applications

Technology Name:

Photovoltaics - Stand Alone/Remote applications

Date Introduced in the market:

1970s

Maturity of the technology:

Established industry with continuous growth over 5+ years.

Type of energy that can be produced (i.e. thermal, electrical):

Electric

Typical applications:

To provide electricity for remote applications where there is no grid service.
To provide mobile electricity to areas where there is no grid service.
Examples:
Water pumping, irrigation
Electric fencing, livestock management
Village power - for small appliances such as tv's, radio, lighting
Water desalination and purification
Remote refrigeration
Battery charging
Off grid homes, cabins
Security lighting
RV ancillary power needs
Power tools, refrigerators, automatic gate openers, automatic feeders, fans, motors, radios, and lighting are all examples of electric loads that can be powered by a properly designed stand alone PV system.

PV is generally not an economical choice for heating or cooling loads such as electric ovens or electric water heaters.

Range of possible dimensions and sizing considerations for the system:

The main components of an off grid PV system will vary depending on the application of the PV system. Systems can be as simple as a PV panel wired to a DC motor, for example for some water pumping purposes. Systems can be designed to provide DC power, AC power or both, with or without battery storage, in combination with other power sources such as wind turbines and diesel generators. For most agricultural applications, stand alone PV systems will range from a few watts to several kW of PV capacity. Sizing considerations will include the application, total and peak (most at one time) power requirements, climate, solar exposure and resource.

Components of a stand alone PV system can include the PV module and mounting system, wiring, PV controller, battery charge controller, inverter, battery bank, meters, DC and or AC power panel disconnects.

PV systems are module based. If you plan to add PV panels to your system over time, be sure to size the rest of your system (inverter and wire) to manage the additional panels. Energy efficiency and conservation are vital considerations before designing a PV system to meet your power needs. For every dollar spent on energy efficiency and conservation, 3-5 dollars on PV panels is saved.

Inverter:

When sizing an inverter for a PV system it is important to know your peak power consumption. If you plan to add loads to your system be sure to get an inverter that can handle the peak demand.

Batteries:

Deep cycle batteries are usually used with PV systems. They are longer lasting and withstand deeper discharges than gel or automotive batteries. Batteries are available on the market that are designed to work with PV systems. Battery capacity is measured in amp hours. The amount of amp hours you will need in your battery bank will be determined by the number of cloudy days you experience in a row, whether or not you have a back up power source, load requirements and PV power production capacity.

Range of performance of the technology per unit installed:

In Canada, if installed on a fixed mount with a clear southern exposure, expect approx 1-1.3 MWh/kW installed/year. More electricity can be expected if PV panels are mounted on a tracker.

Range of costs per unit of energy and per system (installed, and maintenance costs):

PV systems in Canada cost about $9-12/watt installed.
Enquire about maintenance contracts from your system designer and installer. While maintenance is minimal, expect to pay electrician rates if maintenance is required.

Expected Pay-Back:

For many off grid/remote PV systems, PV is a cheaper alternative than bringing the grid to the load from the beginning. The economics will depend on the application, the energy resource being offset, and how other attributes of the system are valued. For example, a PV system can significantly reduce maintenance time on a generator, and reliable power for a critical load can save money when grid outages are frequent. PV systems are often a more expensive capital investment than other power generation equipment.

Design, Installation, Maintenance & Operation of an Off grid solar system:

 

Design of an off grid solar system:

Expertise/knowledge required can include: PV system design, electrical, mechanical, general construction.

Installation of an off grid solar system:

Expertise/knowledge required, to implement a project, can include: electrical, mechanical, general construction skills, roofing. A certified electrician may be required.

Maintenance of an off grid solar system:

Maintenance of an off grid PV system is minimal but will depend on type of system. Batteries require regular maintenance.
Expertise/knowledge required can include electrical, mechanical.

Operation of an off grid solar system:

Can be monitored and operated by user with instruction from retailer/contractor/installer.

Training for designers and installers:

CanSIA is working with colleges to implement training programs for designers and installers of PV systems, based on the North American Board of Certified Energy Professionals. A wide variety of training opportunities exist from online courses and free information to hands on workshops and college courses. See www.cansia.ca for more information.

Range of Operational & Maintenance requirements:

Requires only periodic monitoring and maintenance to ensure proper functioning.

Potential problems or challenges:
System performance:

 

Other considerations:

Investigate Maintenance contracts or warrantees.
Ensure system is designed for climate and electric load.
Ensure southern exposure clear of obstructions between the hours of 10 AM and 3 PM or longer.

Permitting:

An electrical inspection may be required. Check with your local permitting office for potential requirements.

Range of warranties and life expectancy of the systems:
Warranties:

PV panels: 20-30 years
Inverter: 5-10 years
Batteries: 1-5 years
Turn key systems may come with a warranty.

Life Expectancy:

PV panels: 30 years +
Inverter: 10 years +
Batteries: 5-10 years

Solar Resources Assessment:

Site specific solar resources can be measured by visual techniques and inspection or through commercially available solar site analysis tools. The U.S. National Renewable Energy Laboratory has extensive solar radiation resource information http://www.nrel.gov/rredc/. Links to Canadian solar radiation data can be found at http://www.canren.gc.ca/resou_asse/index.asp?CaId=55&PgId=452

Canadian Solar Resource maps are available at: http://atlas.nrcan.gc.ca/ and https://glfc.cfsnet.nfis.org/

Back up generators:

For critical loads or cottage systems, a back up generator is usually recommended.

Software/Tools available to do prefeasibility level study:

RETScreen (www.retscreen.net) is a free software from NRCan that can assist with sizing a renewable energy system. It had been developed for prefeasibility level study. Be sure to consult a professional PV system designer before purchasing a stand alone PV system.

Links to other sources of information:


Sources of supply (in Canada):

Check CanSIA's website for contact information for suppliers and installers in your area. www.cansia.ca

Énergie Solaire Québec sells for a small fee (free with membership) a list of renewable energy suppliers and businesses in Quebec. http://www.esq.qc.ca/

Recommendations on how to proceed with a project development:

Contact CanSIA: check their database for a local installer.
Finding a contractor: As when hiring any contractor, ask for references from other clients or examples of their work and past experience.
Ensure you have the necessary permits and the inspector is familiar with your plans before construction.
Check the links above for more information.
Check for local incentives, rebates, etc., to offset the cost of installation; local renewable energy associations such as CanSIA will be able to help with this.


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Created: 02-18-2008
Modified: 04-03-2008