Denis Caron flicks the light switch in the old building at the far eastern end of the Androscoggin Mill, illuminating two big hydroelectric generators a floor below.

Only one is spinning, pushing out a mere 380 kilowatt-hours of electrical power, a quarter of what the building was capable of at its peak. But with the flow of water through Lewiston’s canal kept at 150 cubic feet per second, it’s as much electricity as the generator is capable of making.

Even so, Caron estimates that 380 kilowatt-hours is enough to provide electricity to 30 homes for a day.

But that electricity doesn’t directly power anything nearby – not even the lights of the generator building.

Alternating Currents: What’s watt

Click here for our interactive graphic and video.

• One watt is about equal to the energy of one burning candle; a watt-hour is that candle burning for an hour.

• One kilowatt is equal to 1,000 watts; a kilowatt-hour is 1,000 candles burning for one hour.

• One megawatt is equal to one million watts; one megawatt-hour is one million candles burning for one hour.

At its peak, the upper Androscoggin facility could generate 1,700 kilowatt-hours, equal to 1.7 million candles burning for one hour. Today, the facility puts out 380 kilowatt-hours; 380,000 candles.

Nextera Energy (a subsidiary of Florida Power and Light) manages five hydroelectric facilities on the Androscoggin River:

• Gulf Island generates 23 megawatt-hours;

• Deer Rips and Androscoggin 3 generate 9.9 megawatt-hours;

• Monty Hydroelectric generates 28 megawatt-hours;

• Brunswick/Topsham generates 20.2 megawatt-hours.

Combined, Nextera Energy’s facilities on the Androscoggin River generate 81.1 megawatts, 81.1 million candles burning for an hour – 213 times the power generated by Lewiston’s Upper Androscoggin Facility.

“We get our electricity from Central Maine Power, just like everyone else,” said Caron, the electrical superintendent for the city and the man in charge of keeping the generators turning.

Lewiston was founded because of its water power; first the churning tumult of the Great Falls and later the mannerly flow through its canals. Canal water powered the city’s mills, turning the looms and spinning wheels that made the city a fabric-making capital.

By 1909, a series of electrical generators went up along the canal and the water was used to make electricity for the mills and some of the surrounding dwellings.

They’ve since gone quiet, replaced by the far more efficient Monty Hydro-Electric Station at the head of the canal.

The city’s strategic plan rekindled interest in the canal last month, re-imagining the three-quarter-mile channel as a community park sometime in the future.

At one time, four mills housed 18 electrical generators. The Bates Mill had three generators, the Hill Mill had six, the Continental Mill had six and the Androscoggin Mill had three. Since 1877, the canal’s water power was owned by Union Water Power Co., which was owned by the city’s mills. Central Maine Power Co. purchased UWP, the canals and the generation facilities in 1948.

The city had its own generator at the head of the canal, in its water-pumping station. All told, canal water provided some 5,750 kilowatt-hours of electricity.

“The problem with this facility and the ones like it, is that they are so small and the big ones, like the Monty Station, are so efficient,” said Dick Metivier, Lewiston’s finance director. “It makes more sense to send the water through the bigger ones. Of course, when they designed them and the mills, the focus was different. They needed power for the mills and the canal was it. But it changed.”

Beginning in 1979, CMP began calling for a combined facility at the head of the canal, able to generate 15 megawatt-hours of electricity.

Both Lewiston and Auburn had the same idea, and the three entities promoted competing water-generation plans until 1984 when the state brought them all to the table.

As part of that agreement, CMP was allowed to start building the Monty Hydroelectric Facility in 1987, replacing the Lewiston plant at the head of the canal. CMP agreed to provide 3.2 million kilowatt-hour credits to the city for streetlights and water pumping and would pay property taxes on the facility – $897,387 in the current fiscal year. Auburn was given a 17.5 percent share of those taxes, which amounted to $157,043 this year. The cities also took control of the Upper Androscoggin Facility and its three generators.

The Monty station came online in 1990.

CMP began shutting down the other canal generators one by one, but agreed to keep supplying the bare minimum of water through the canal for the city generator – at least 150 cubic feet per second.

The city had a good deal back before 1999, when federal rules deregulated the industry and Florida Power and Light bought all of CMP’s energy generation plants. As part of the 1987 Monty Hydro agreement, CMP agreed to buy the city’s electricity for 10 to 12 cents per kilowatt hour, as much as three times the going rate.

That deal ended in 1999.

“It was making money until federal deregulation came through,” Metivier said. “Then the price went from the negotiated rate to what they call avoided rates, and that’s whatever the market will pay.”

Today, the city usually gets between 3 and 4 cents per kilowatt hour on the national electrical grid, where it’s sold to the highest bidder – most recently Pennsylvania Power and Light.

“We get the best rates that we can,” he said. “It’s not really a lot of money.”

The city doesn’t keep the generators running because of the money, according to Metivier. The city makes about $182,000 from the sale of electricity, but spends about $219,000 to maintain and operate the Upper Androscoggin Facility building and its generators.

Generators are massive, heavy pieces of equipment, and work is expensive. Caron estimates that a basic overhaul costs about $25,000.

“Keep in mind, it’s 1910, 1920s vintage equipment,” Caron said. “It’s good, but you need to keep an eye on it.”

The biggest generator broke down in 1994 and was never repaired. The two smaller generators keep going, one at a time.

“Besides, we don’t have the water power to run the big one,” Caron said. Capable of making more than 700 kilowatt hours of electricity, the biggest generator required three times as much water as flows through the canal today.

“Even when it was working and the water was flowing, we only kept it going for 30 to 45 days per year,” Caron said. “So it just wasn’t worth it, to spend thousands to fix it if it wasn’t going to get used.”

Caron and his staff swap out the two remaining generators, running each a week or two at a time. Both are due for their 15-year maintenance work, which would cost a minimum of $25,000.

“But it’s not going to happen for either one,” Caron said. Daily maintenance includes checking up on the generators, making sure the moving parts are well lubricated and the shaft bearings stay cool.

“Plus, we have to heat the building and pay maintenance for the canal itself,” Metivier said. But without the little generator at the canal’s end, there’s really no reason for there to be any water in the canal at all.

“The Monty station is so much more efficient, I’m sure it would be better to send all of the water through it, and not divert any into the canal,” Metivier said.

Basically, the city keeps the water flowing just to make sure the last two generators keep turning, he said.

“Back in the 1980s, there was a big concern that all of the water would be taken out from the canals, just leaving them dry,” Metivier said. “If there’s no water, the worry was the canals would just be abandoned. So we keep them operating.”

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