ULO Rates in Ontario: How Battery Storage Saves You Money on Hydro

What Are ULO Rates in Ontario?

Why Choose Home Battery Backup in Muskoka?

• Cost savings by utilizing ULO rates for charging.
• Reliable power supply during outages.
• Less reliance on the grid when paired with solar.
• Potential eligibility for HRSP rebates.

The Ultra-Low Overnight (ULO) plan is one of three Regulated Price Plan options for Ontario residential customers, alongside Time-of-Use and Tiered pricing. It was introduced by the Ontario Energy Board to encourage homeowners to shift electricity usage to overnight hours when demand on the grid is lowest.

Under the ULO plan, electricity prices vary dramatically depending on when you use power (Ontario Energy Board prices in effect November 1, 2026):

The key number: 3.7¢ vs. 37.7¢. The weekday on-peak price is about ten times the overnight price, and that gap is what a battery takes advantage of.

How Battery Storage Creates an Arbitrage Opportunity

Think of your home battery as a simple buy-low, sell-high machine for electricity:

1. Charge overnight (11 PM – 7 AM) — Your battery fills up at the ultra-low rate of 3.7¢/kWh.
2. Power your home during peak (4 PM – 9 PM weekdays) — Instead of buying electricity at 37.7¢/kWh from the grid, your home draws from the battery.
3. Keep the difference — Each kWh the battery supplies at peak was bought at the overnight price instead of the peak price (less some energy lost in charging and discharging).

In short: on the ULO plan a battery can charge overnight at 3.7¢/kWh and power the home during the 37.7¢/kWh weekday peak. How much that saves depends on how much you use at peak, your rate plan and the system size.

What Affects How Much You Save

Savings vary a lot from home to home. The main factors are:

• How much electricity you use from 4 to 9 p.m. on weekdays — a battery can only save at peak what your home would otherwise buy at peak
• Battery size — how much of that peak use the battery can cover
• Weekends and holidays — there is no on-peak price on those days
• Your rate plan — the gap between overnight and peak prices is largest on ULO
• Solar — panels can cover daytime use and help recharge the battery

An installer can look at your usage and give you an estimate for your home.

Who Qualifies for the ULO Rate Plan?

Ontario residential customers on the Regulated Price Plan can choose ULO through their local distribution company (LDC). Local utilities in this region include:

• Hydro One territory — covers much of rural Muskoka District and many cottage areas (some towns, such as parts of Bracebridge, Huntsville and Gravenhurst, are served by other local utilities)
• Alectra Utilities — serves parts of Barrie and surrounding areas
• InnPower — serves Innisfil
• Collus PowerStream / EPCOR — serves Collingwood and area

To switch to ULO, you contact your local utility and request the rate change. No special equipment is needed — your existing smart meter already records when you use power. Your utility can tell you when the change takes effect.

ULO + Battery: Cost and Payback

The installed cost of a battery depends on:

• Battery capacity (for example, a 13.5 kWh battery versus a smaller or multi-battery system)
• Whether solar is installed at the same time, and its size
• The electrical work, such as panel upgrades or a backup subpanel
• The site: where the equipment can go and how far it is from the panel

An installer quotes after seeing the home. Payback depends on your usage, rates, rebates and the price, so ask the installer for an estimate for your home. For how long a battery is covered and how much capacity it keeps, check the manufacturer's warranty for capacity and years.

What About Mid-Peak Hours?

A battery doesn't just save you money during peak hours. By programming your battery to also cover mid-peak hours (14.6¢/kWh), you can shift more of your use to the overnight price — useful if you have a larger battery that still has capacity after covering the peak window. The gap between mid-peak and overnight is much smaller than the gap between peak and overnight.

Smart battery systems like the Tesla Powerwall and Enphase IQ can be programmed to prioritize peak hours first, then extend into mid-peak as capacity allows. Your installer can configure this based on your household's specific usage pattern.

How to Get Started

Taking advantage of ULO + battery savings is a straightforward process:

1. Switch to ULO — Contact your utility (Hydro One, Alectra, etc.) and request the Ultra-Low Overnight rate plan. It's free.
2. Get a battery quote — Send your enquiry through muskokaenergystorage.ca and we pass it to an independent local installer for a no-obligation assessment
3. Check the HRSP rebate — The battery rebate (up to $5,000) applies only when the battery is installed with new solar, for up to $10,000 combined. Check Save on Energy for the current amounts and rules before you rely on them.
4. Let it run — Your battery charges overnight and powers the home during peak hours