Rooftop Solar Costs Analysed
I am delivering on my promise to write an article with the real costs and benefits of rooftop solar for homeowners. This is based on costs and solar production to be expected in the Greater Toronto Area.
As everyone interested in renewable energy knows, there are no incentives available to help defray the costs so what this article is about is whether a reasonable person can justify the investment based on the costs. I am not considering other reasons such as environmental benefit in this article.
Crystal ball gazing is necessarily involved as several assumptions must be made. I welcome comments on the assumptions I have made and would be happy to send anyone my simple spreadsheet so you can change the inputs and see how it affects the result.
1. The roof is sloped 20-40 degrees and faces South (between SE and SW).
2. The roof surface is asphalt shingles or steel with a remaining lifetime of 25 years.
3. There are no trees, buildings, or other objects that cast shade on the array between 9 AM and 4PM.
4. Maintenance cost including insurance is 2% of the original cost for each of the 25 years lifespan.
5. Cost of money is 3% of the original cost for each of the 25 years lifespan.
6. Cost of electricity that would have been paid to your LDC is $0.10 per kWh in year 1 and increases by 5% every year for 25 years. The median cost with this assumption is $0.17 per kWh and is used in this example.
7. Cost for a turnkey installation is $2.00 per Watt plus HST of 13%.
5 kW System
Electricity produced (25 Years): 15,0000 kWh
Initial Cost $10,000.00
HST $ 1,300.00
Avoided cost of Hydro from your LDC $25,500.00
Total cost of ownership (25 Years) $23,800.00
NET SAVINGS (25 YRS) : $1,700.00
7 kW System
Electricity Produced (25 years): 21,0000 kWh
Initial Cost $14,000.00
HST $ 1,820.00
Avoided cost of Hydro from your LDC $35,700.00
Total Cost of ownership (25 years) $33,320.00
NET SAVINGS (25 YRS) : $2,380.00
10 kW System
Electricity produced (25 Years): 30,0000 kWh
Initial Cost $20,000.00
HST $ 2,600.00
Avoided cost of Hydro from your LDC $51,000.00
Total Cost of Ownership (25 years)$47,600.00
NET SAVINGS (25 YRS) : $3,400.00
After taking into account the real costs of ownership, even perhaps over-estimating the cost of insurance and maintenance, its clear that rooftop home solar without benefit of government incentives is at least a break-even proposition for optimum sites.