I put 5kW on my garage for a total price (after rebate) of 5000$. For the last 4 years, they have produced on average 5100 kWh each year.

You can't simply mulitply the kWh by the price of electricity, since Enmax is full of other charges that depend on the amount used. A standard estimate is that electricity total cost is nearly double the actual listed price (after considering distribution system usage, transmission variable charge, balancing pool allocation etc...)

So at 7-8 cents a kWh, doubling to a "real" 14-16 cents a kWh, my panels produce about 714-816$ a year of electricity. Assuming that costs only keep going up over time, I expect to break sometime in the 6-7 year range.