P.E.I. sees 'exponential growth' in solar energy production

At the beginning of 2024, most solar energy production on P.E.I. came from the rooftops of people's homes, but that has changed dramatically.

Two large-scale solar farms, Summerside's Sunbank and the Slemon Park Microgrid, have come fully online since then, and P.E.I. is suddenly producing producing more than twice as much solar energy as it was.

"With SunBank and Slemon Park coming online and all the rooftop installs it's really an exponential growth," said Spencer Long, engineering project manager for the P.E.I. Energy Corporation.

The corporation runs the microgrid, which can push up to 10 megawatts of power into the Maritime Electric system. Sunbank, owned by the City of Summerside and supplying Summerside Electric, is a 21.6 MW facility.

Both facilities came online at about the same time at the beginning of the year. As a result, monthly production that previously came largely from residential rooftop solar jumped from about 1,475 megawatt hours a month in 2023 to more than 6,000 by April.

"January, February and March we were still dealing with some operational issues," said Long about the ramp up to full power.

"Really got things nailed down and looking good in April."

The Sunbank farm followed a similar trajectory, generating small amounts of power in the late winter and hitting its stride in April.

Rooftop solar has also been growing.

Rooftop generation in 2023 was 39 MW, about four times what it was two years earlier.

While the rated output of rooftop solar is higher than the two wind farms, actual output is expected to be lower because the placement of the panels is not ideal. They may be off the ideal orientation, at the wrong angle, or partially shaded.

Actual output of those panels is also an estimate, because what Maritime Electric measures is the net metering amount. That doesn't include the electricity used on site, which never makes it into the grid.

That is estimated to come to about 30 per cent of what the panels produce.

A good mix

The larger farm at Sunbank builds on a renewable energy tradition in Summerside, which already produces a significant amount of electricity from wind.

"Both solar and wind are at the mercy of the weather, but by diversifying the system and having a combination of both types of renewable energy we believe it makes our system stronger," said Sam Arsenault, renewable energy production supervisor for the City of Summerside.

Both Long and Arsenault point out there are seasonal advantages to having a mix of the two.

Generally speaking, there is less wind in the summer when long daylight hours are putting solar production at its maximum. Windier winters balance out lower solar production in the darker time of the year.

But power generated by the winter sun is not insignificant, Arsenault said, and fears about long stretches of time of zero production due to snow-covered panels have proven to be groundless.

Summerside has been running a smaller solar farm at Credit Union Place for five winters. The experience there is the dark-coloured solar panels warm up enough in the sun to melt the snow where it contacts them. Then, because the panels are tilted, it slides off.

"There's really only been one occurrence in five years where the panels stayed covered in snow for any more than about two days," said Arsenault.

Production ramps up quickly in the spring.

On April 10, for the first time ever, Summerside was 100 per cent powered by solar energy.

Power after the sun's gone down

The two solar farms also come with a new innovation for P.E.I. — batteries that can store a significant amount of energy.

"The good thing about the battery system is if during peak sunshine hours we have some spare solar in excess of what our customers use, we can use that energy to charge into the battery," Arsenault said.

"We can then use that energy from the batteries at nighttime, after the sun's gone down."

The storage system at Sunbank can also be used to capture excess wind power generated by the city.

With wind and solar both being intermittent, storage is key, said Long.

These two new facilities will allow the province to explore the most cost-effective ways of using storage for weather-dependent systems.

Limits of solar

Wind has been the go-to source of renewable electricity for P.E.I., and despite the recent growth of solar, still produces almost 10 times as much energy.

While the mix is desirable, Long notes the Island is limited by its size.

"Solar is challenging from a land-use perspective just because of the acreage it consumes," he said.

The Slemon Park Microgrid occupies 40 hectares, and Sunbank 32. That's a lot of land on a small island where farming, housing, and nature preservation are already competing for space.

The Slemon Park farm was able to take advantage of space on a former airbase, and Sunbank sits on Summerside's wellfield, which is limited in the kinds of development that could be allowed to preserve the water underneath.

But there are only so many spaces on the Island like this, and these farms are still small by some standards. The 465-MW Travers Solar Project in Alberta covers more than 1,300 hectares.

Rethinking electricity generation

There are still lessons, however, to be taken from the sun farm experience, Long said.

"The answer is not [an] all-eggs-in-one-basket kind of approach. I think a variety of [electricity] generation, distributed as well," he said.

At the turn of the century, virtually all of P.E.I.'s electricity came from one source, an electrical cable connecting the Island to the mainland. Then, in 2001, the P.E.I. Energy Corporation built the province's first commercial wind farm at North Cape.

More wind farms followed. In 2023, 30 per cent of P.E.I.'s electricity was locally generated by wind.

It was the beginning of a more distributed system of electricity generation. The bulk of the Island's power still comes from the mainland, but solar is now adding more small-scale generation.

Long sees that trend continuing.

"A shift to more distributed systems inside communities at lower voltages is going to be an interesting approach that we'll be looking at in the future," he said.

How much further this approach can take P.E.I. toward energy independence remains to be seen.