Photo-Voltaic (PV) cells are devices that convert sunlight to electricity, bypassing thermodynamic cycles and mechanical generators. PV stands for photo (light) and voltaic (electricity), whereby sunlight photons free electrons from common silicon.
There are four main types of PV applications.
- Consumer (e.g. on your house)
- Off-Grid (e.g. at your cabin or on your boat)
SPEC's PV System
In July, 2005, SPEC worked with the Vancouver Renewable Energy Co-operative to install solar panels (photo-voltaics) on the roof of the SPEC building in Kitsilano. With the generous support of a Green Building Fund grant, offered by VanCity and the Real Estate Foundation of BC, we were able to secure a 1.4 kilowatt system, capable of producing about 1.5 megawatt hours of electricity annually. This is about half of the annual power consumption in the building.
SPEC's system reduced greenhouse gas emissions by close to 800 kilogram per year. (This assumes that the system offsets the need for new generation in B.C. with a mix of 20 per cent coal, 70 per cent natural gas and 10 per cent large hydro. When compared to generation on the entire North American grid the reduction is over 900 kg).
More importantly, perhaps, we also installed a grid-tie that allowed us to sell power into the BC Hydro grid at times when the building was not drawing from the cells. This is a relatively new process in BC, and requires a net-metering agreement with BC Hydro and the installation of a special meter.
Is PV Right For You?
Photo-voltaic panels are not necessarily the renewable energy option of choice for Vancouver homeowners.
However, it would also make good public policy sense for public buildings to generate as much power as they can, whether by the use of photo-voltaics, or wind generators or solar hot water panels. Here, the payback may be measured in two ways: in the dollars saved directly on energy costs and in the reduction in peak energy demands that could be achieved, thereby reducing or delaying the need to build new major power generation facilities. In areas serviced by BC Hydro, the cost of public power remains lower than the cost of photo-voltaic generation--at present energy prices.
Homeowners looking for a cost-effective solar energy solution might want to consider solar hot water
systems, which can achieve financial payback in relatively short time frames, and are very affordable.
Solar Panel System FAQs
Following are some frequently asked questions concerning the solar panel system, provided courtesy of Vancouver Renewable Energy Co-operative. For more information, visit their site at www.vrec.ca
Are solar systems really viable in Vancouver where we get so much cloudy weather?
Germany has the largest installed solar electric base in the world (with 300 MW it recently surpassed Japan), yet many cities in Germany receive less sunlight than Vancouver. Vancouver receives 1919 hours of sunlight annually compared with 1837 in Berlin, 1680 in Munich and 1643 in Frankfurt.
How much will the system save?
BC has some of the cheapest electricity in the world. This system will save around $108.00 per year.
How long do the solar panels last?
Solar panels manufactured over 50 years ago are still producing power. The amount of power produced does diminish over time. The panels generally come with a 20 year warranty.
What is the payback for a system?
There are two different payback periods to consider. The energy payback is 2-4 years. This means that after 4 years the panels will have produced more energy than it took to manufacture them (the embedded energy).
Many people are also interested in the financial payback. However, many other products such as cars, entertainment systems and furniture are generally not purchased with payback in mind. In nations like Germany with good incentive programs the payback period can be less than 20 years. British Columbia lags behind many other places when it comes to promoting solar power.
The Sate of Washington has legislation pending that would pay producers up to 67 cents (Canadian) for solar electric power. This would mean a simple payback for this system of 11 years. Under current BC rates the payback period for this grid-tie system will be about 167 years. This is a "simple payback" that does not take in to account the rising cost of energy. As energy costs rise the payback period will shorten.
Isn't BC's energy already clean and green?
Although the majority of BC's power comes from hydroelectric dams, BC Hydro does import a portion of its power from coal-fired plants in Alberta. It is also important to realize that the Intergovernmental Panel on Climate Change is considering treating hydroelectric dams as a source of greenhouse gas emissions. And some politicians and industry leaders are advocating that BC generate power from coal and natural gas.
What about the fact that Solar PV isn't a firm source of power?
Although the annual production of a Solar PV system can be calculated fairly accurately the amount of power generated by a system does fluctuate greatly during a 24 hour period and from day to day depending upon the weather. However, non-firm sources of power make a good complement to hydroelectric dams which can reduce their production and save water when PV systems are producing power. PV systems also tend to complement wind turbines in British Columbia which are likely to produce more power in the winter when PV systems are producing less.