Why Niagara runs two ways: the treaty over the falls and the reservoir behind it

I. How the treaty splits the river

If you live in Niagara County, or anywhere upstate, some of the cheapest electricity in the country is made a few miles from the falls, and most people drive past the plant without knowing how it works. The Robert Moses Niagara Power Plant sits on the gorge in Lewiston, downstream of the brink. It turns the Niagara River into power without a dam across the falls themselves, and the reason the falls still look like falls is a treaty.

Since 1950 the United States and Canada have agreed, through the International Joint Commission (the binational body that oversees shared waters), on how much river has to go over the brink for the view and how much the two countries may pull aside for turbines. During the daytime tourist season, roughly April through mid-September in daylight hours, about 100,000 cubic feet per second must flow over the falls. At night and in the off-season that scenic minimum drops to around 50,000 cubic feet per second, which frees up more water for power, split evenly between the two countries.

II. The reservoir behind the plant

That schedule is the whole problem for an operator. When the view comes first, by day and in summer, less water is available to make electricity at exactly the hours air conditioners and offices want the most. When the view can give way, at night and in winter, there is more water than the plant needs. A plant that only ran the river as it arrived would waste the night and come up short in the afternoon.

NYPA's answer sits above the Robert Moses plant: the Lewiston reservoir, a forebay of roughly 1,900 acres on the escarpment. At night, when the treaty allows more diversion and demand is low, about a dozen pump-turbine units at the Lewiston Pump-Generating Plant run backward and push water uphill into the reservoir. During the afternoon peak they let it fall back down through the same machines to make power. That is pumped storage, the oldest and still the largest form of grid-scale energy storage. It makes no new energy (pumping uphill loses some of what you put in, on the order of a quarter), but it moves cheap night water to expensive afternoon hours. The reservoir borders Tuscarora Nation land, built over the nation's objections in the 1950s, a history worth knowing when you see it on a map.

III. What it means for your bill

Niagara is public power, and that shows up on bills in specific places. The main Robert Moses plant is rated at roughly 2,400 megawatts at last public report, with the Lewiston units adding a few hundred more, which makes the project one of the largest hydroelectric facilities in the country. Under long-standing state programs, blocks of low-cost Niagara hydropower are allocated through NYPA to upstate utilities for residential customers and to businesses that agree to keep jobs in the region.

How much of that reaches you is hard to pin down and depends on your utility and rate class. If you are a National Grid or NYSEG customer upstate, a small hydropower credit may already be folded into your rate, but it is rarely a line you can read off cleanly. Niagara's output also rides the river and the season, and NYISO, the state's grid operator, decides when the plant banks water and when it spends it. If someone quotes you an exact dollar figure for the Niagara discount on a typical bill, treat it with care.

IV. Worth watching this month

1. NYPA board materials, posted on nypa.gov, are where hydropower allocation decisions and any Niagara project updates usually surface, and most of them are routine.

2. The project's federal license runs to about 2057 at last public report, so near-term relicensing is not the story, but FERC's eLibrary is where any filing would appear if that changes.

3. Around mid-September each year the treaty's scenic minimum shifts toward the lower cold-season figure, which quietly frees more river for power into the winter.

4. NYISO's real-time dashboard shows hydro's share of state supply, worth a glance on the coldest, highest-demand afternoons.

5. The International Joint Commission posts updates from its Niagara board of control, and the annual ice-boom installation on the upper river each winter is routine but checkable.