Do you keep track of your KWh per month? If so, consider reading this page: https://www.pge.com/en_US/residential/rate-plans/rate-plan-o... and then plugging in the numbers. That will give you an idea.

For my house in Nov of 2014 the tiers were Tier 1: 15 cents/kwh Tier 2: 18 cents/kwh Tier 3: 26 cents/kwh Tier 4: 32 cents/kwh

And the baseline allowance is 10KWh a day (our house typically uses 24 - 28KWh per day.

Put those numbers in to your power bill and tell me what the number comes out to.