Technology
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Grid tied applications were once a very small percentage of Photovoltaic (PV) applications. Over the past several years, grid tied PV has grown rapidly and now makes up the vast majority of PV installations world wide. The growth is due in part to an ongoing reduction in the cost of PV, and to an increase in government targets and incentive programs to promote clean, renewable energy production. Growing awareness of the potential of PV, education and training opportunities have also fuelled the growth. Globally, grid connected PV installations increased from 2 GW to 3.1 GW from 2004 to 2005. Meanwhile, total PV installed, including grid connected and off grid systems, increased from 4 GW in 2004 to 5.4 GW in 2005. The one year growth of 55% represents an increase from 200,000 to 650,000 homes with grid tied solar PV installations. (www.ren21.net). The majority of grid tied PV installations are in Germany, Japan and the U.S. (mostly California), with Spain making rapid increases.
The market for grid tied PV systems is only beginning in Canada with about 100 systems installed/year. The largest growth in grid tied PV in Canada has been in Ontario, due to a new policy improving the terms for system owners. The policy, called a "Standard Offer Program", is similar to the policies used in jurisdictions such as Germany and Spain.
While PV provides but a fraction of global electricity demand today, the potential is great and growth is expected to continue at rates of 30% or above globally for the foreseeable future. Growth is expected in household sized applications, large power plant scale systems (see PV power plants - link), and building integrated photovoltaics (BIPV). The latter refers to systems that integrate photovoltaic panels into the building structure, e.g. roofing, windows). Rapid growth in PV installations is driving greater investments in research and development. Researchers are looking to increase the efficiency of PV, diversify the applications and use different materials to drive down cost and increase the potential uses for PV. Currently, the PV panels account for 70% or more of the installed cost of a PV system.
Residential or farm-sized grid tied PV systems are usually 1-5 kW with larger farm, commercial or industrial sized grid tied systems can be up to about 100 kW. Size is often a function of space and investment dollars available. Grid tied systems today are high voltage (up to about 600 volts) systems with PV panels attached to roofs, ground mounts, poles or as roofing material, depending on the type of PV panel chosen. The panels produce direct current electricity. The panels are wired to an inverter that changes the Direct Current (DC) electricity to Alternating Current (AC) to match the electricity grid. Systems also include disconnects for safety and meters to measure the electricity produced.
Modified: 02-18-2008
