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- Taking solar panels to the next level
- Follow the sun: How dual-axis solar panels work
- How grizzly bears have learned to live with humans
Taking solar panels to the next level
In the world of solar energy, the main measure of success has always been panel efficiency. Progress over the years means the best photovoltaic (PV) systems can now turn more than 20 per cent of the sunlight hitting them into electricity.
"Solar cell efficiency is the figure of merit in the PV community, and improving efficiency is the most common research effort," Carlos Rodríguez Gallegos, a research fellow at the Solar Energy Research Institute of Singapore, told CBC via email.
"Yet the amount of energy produced by a panel – its energy yield – can also be increased by other techniques."
With that in mind, Rodríguez Gallegos and his team recently analyzed the effectiveness of two well-known techniques: bifacial modules and axis tracking.
As the name suggests, bifacial modules have PV cells on both sides of the panel, with direct sunlight absorbed from the top and reflected light absorbed from the underside.
As a result, the performance of a bifacial module "can considerably increase depending on the surface it is installed on," Rodríguez Gallegos said. For example, snow has great surface reflectivity (or albedo), resulting in more absorption. Sand? Not as good. Water? Not great.
The other technique, axis tracking, is essentially following the sun. Using motors (or even simpler, non-electronic methods), panels will tilt for maximum sun exposure.
"Single-axis trackers are commonly used to rotate the module from east to west," said Rodríguez Gallegos, "Dual-axis trackers have two axes of rotation and therefore, in principle, have the potential to rotate to any desired angle."
Dual-axis trackers come in handy during times of the year when the sun is in a different position. With that added complexity, they are more expensive than single-axis trackers. Rodríguez Gallegos's analysis suggested one particular combo was the most cost-effective.
"We found that bifacial solar panels combined with [single] axis trackers produce, on average, close to 35 per cent more energy [than standard fixed panels] and reduce the cost of electricity, on average, by 16 per cent."
This is a huge shift, considering these are tweaks to a system rather than a massive leap in material efficiency, which would undoubtedly raise the overall price.
"Solar continues to employ significant technological advancements that are improving efficiency and increasing power at reduced costs," said Geoff Atkins, an executive advisor in business development at Mississauga, Ont.-based Silfab Solar via email.
Atkins said Silfab uses a range of technology, including reflective glass coatings and optics, that "fill dead spaces between solar cells" to try to draw more yield while keeping the panels affordable.
Some of these solutions may also help Canada in particular get more from the sun.
"For latitude locations very close to the equator, the benefit of using bifacial panels is not too strong. Yet, as the latitude increases, performance also increases," said Rodríguez Gallegos.
"Canada, being a territory located at high-latitude locations, has a notorious advantage when adopting these technologies."
It's hard to throw shade at solutions that could improve Canada's solar energy output by as much as 40 to 50 per cent. In turn, that could drive up solar energy's worldwide power generation, which sits at three per cent.
— Anand Ram
Reader Lana wrote in with this thought:
"How can we get more people being co-operative, interested, committed and responsible where the environment and climate change are concerned?" she writes. "How do you get a population to believe in something and be more responsible about it in their personal habits? That's what I find missing here in Canada, and I won't even comment on the U.S. My relatives, back in Germany, were talking about and doing things about climate change and environment before it was a fully formed concept here. My frustration is, what makes too many Canadians so lax and maybe even stupid about this?"
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The Big Picture: Solar panels that follow the sun
In his piece above on innovation in solar panels, Anand Ram explained that some panels, rather than remaining stationary, are able to track the sun from east to west. Single-axis panels can move in a single line; dual-axis panels (below) are even more flexible.
Hot and bothered: Provocative ideas from around the web
It's been a bad week for pipelines. Citing regulatory uncertainty and its efforts to move toward net zero carbon, Virginia-based Dominion Energy, the second-biggest power utility in the U.S., has cancelled the Atlantic Coast Pipeline project. Meanwhile, a U.S. federal judge sided with the Standing Rock Sioux Tribe and ordered the Dakota Access Pipeline shut down for more environmental reviews. And the U.S. Supreme Court kept in place an order blocking further construction of the Keystone XL pipeline.
A group known as Climate Power 2020 — which includes Gerald Butts, the former principal secretary to Prime Minister Justin Trudeau, as well as prominent U.S. Democrats like Stacey Abrams and Tom Steyer — has been pressing executives at Facebook to take steps to rein in "lies and misinformation" about the environment on its platform.
- In a development that has bewitched and bewildered researchers, white-throated sparrows have changed the tune they sing to attract females and broadcast their turf. Over the last two decades, white-throated sparrows fromB.C. tocentral Ontariochanged the three-note ending to their song to two notes — and scientists have no idea why.
How grizzly bears have learned to live with humans
In areas where bears and humans coexist, there are often policies in place to protect bear populations while safe-guarding people's lives. But it turns out the bears are also helping their own cause.
A team of researchers from B.C. and Alberta pooled data on the movements, habitat use and mortality rates of 2,669 grizzly bears over 41 years to examine how they survived when living in or near human-dominated areas.
The researchers found that even as humans encroached further into the animals' habitats, the bears didn't necessarily shy away from people. Instead, they gradually shifted their behaviour to become more active at night, when they would be less likely to come into contact with them.
The data was compiled from an area of 378,191 square kilometres predominantly in B.C., which has an estimated 15,000 grizzlies — more than half of Canada's grizzly bear population. The research was published earlier this week in Proceedings of the National Academy of Sciences.
Typically, bears in the wilderness spend about half their time in daylight and half under cover of darkness, said study co-author Clayton T. Lamb, who is affiliated with the University of Alberta, the University of British Columbia and the University of Montana.
But by increasing their "nocturnality" by two to three per cent each year, bears living in "coexistence landscapes" — in proximity to people — also increased their survival rate by two to three per cent per year. This led the researchers to conclude that the shift to more nighttime activity was induced by humans.
The older the bears got, the more nocturnal they became, starting from the age of three onward, to the point where the bears observed in the study reached at least 60 per cent nocturnality, and most of them 70 per cent or more.
Younger bears and those that didn't adopt the behaviour didn't do as well. "A lot of bears don't switch fast enough and they end up dying," Lamb said in an interview.
Grizzlies are "integral" to maintaining a healthy ecosystem, the B.C. government says. But their survival is at risk, according to both the provincial Conservation Data Centre and the federal committee on the status of endangered wildlife in Canada. The biggest threat to bears? People.
This shift to nocturnal behaviour is not only better for the bears, but it's also better for humans because it reduced the number of conflicts between the species, the study said.
Looking at the records of conflicts with 45 individual bears that were fitted with GPS collars, the researchers found there was about a 71 per cent lower chance of conflict with one of them at least once a year if the bears were more active at night than during the day.
"There's more conflict where there's more people, obviously," Lamb said. "Bears are helping to shape that landscape to benefit themselves."
Nonetheless, bears are still on the losing side of the equation. Even though a majority of adult female bears in the area have become more nocturnal and are breeding successfully, they are dying in numbers too high to maintain their population.
For every bear that becomes a successful "coexister," 29 die prematurely, the research found. They have to rely on "immigrant" bears from nearby wilderness areas to keep thriving.
This isn't the first time animals have been observed shifting their schedules. A 2018 analysis of dozens of studies covering 62 species, including brown and black bears, found animals increased their nocturnality "in response to human disturbance."
But Lamb said the four decades of research on bears brings the whole picture into focus: the extent of the risk they face from living near people, the adaptation that helps them survive and the need for "demographic rescue" via bear immigration to sustain their numbers.
"The next steps in all this research is really the applied aspect — what can we do with this information to make the landscape work better for people and carnivores," Lamb said.
— Sherry Noik
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