Your electricity rate
changes by the hour.
Here's how to use that.
Time-of-use rates charge more during peak hours — typically 4-9pm on weekdays — and less at night and on weekends. If you have solar, batteries, or an EV, this changes your savings math significantly.
Your utility charges more
when everyone needs power
at the same time.
Traditional electricity rates charge the same amount per kWh regardless of when you use it. Time-of-use rates charge different amounts depending on the time of day — reflecting the actual cost of generating and delivering electricity when demand is high.
Peak hours (usually 4-9pm on weekdays) cost more because everyone is home from work, running air conditioning, cooking dinner, and charging devices simultaneously. Off-peak hours (typically nights, mornings, and weekends) cost less because demand is low and there's more available capacity.
Rate examples are approximate, reflect 2026 rate schedules, and change periodically. Verify your current rate at your utility's website.
Most people don't know
if they're on TOU rates.
Here's how to find out.
TOU rates are often opt-in in most states — meaning you need to request them. In some states they're becoming the default, particularly for EV owners and solar homeowners.
TOU rates change when
your solar saves you the most.
Without TOU: every kWh your solar panel generates saves you the flat rate (roughly $0.13/kWh in Colorado).
With TOU: a kWh generated at noon (off-peak) saves you less (~$0.08/kWh) but a kWh generated at 4pm (entering peak hours) saves you more (~$0.20/kWh).
The practical implication: solar panels facing west — and therefore generating more power in the late afternoon — are more valuable on TOU rates than panels facing south, because they generate power during the more expensive peak hours.
For net metering: if your utility uses TOU-based net metering, the credit you receive for exported solar power varies by time of day — typically more credit for power exported during peak hours.
TOU rates are the reason
batteries make financial
sense without VPP.
The basic battery arbitrage strategy: charge during off-peak hours (cheap electricity), discharge during peak hours (expensive electricity). The difference in rates is your savings.
Peak discharge saves: $0.2034/kWh
Net arbitrage value: ~$0.125/kWh
A 13.5 kWh battery cycling once daily generates approximately:
0.125 × 13.5 × 365 = ~$616/year in TOU arbitrage savings alone — before any VPP enrollment.
This is why battery payback calculations that don't account for TOU rates are often wildly pessimistic. A battery on a flat rate saves far less than a battery on TOU rates.
Charging your EV at night
instead of 6pm can save
$300-600 per year.
The most actionable TOU tip for EV owners: never charge during peak hours if you can avoid it. Schedule charging to start after 9pm or before 7am — when rates are lowest.
Off-peak charging (11pm): $0.0785/kWh = $5.10 per full charge
Savings per charge: $8.12
Annual savings (charging 3x/week): ~$1,266/year
Most EVs allow scheduled charging — set your car to start charging after 9pm and capture this saving automatically.