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17 december 2012

Early bird catches the worm – a solar-powered conundrum

Location, location, location not only applies to accommodation. It's important for PV-cells too. And south-facing high roofs that catch the morning sun would be just the ticket, if Sustainable Ålidhem's PV-cells could speak for themselves.

Mats Andersson at Energibanken in Jättendal has evaluated the different photovoltaic plants on behalf of Sustainable Ålidhem and come to some unexpected conclusions. For example, he noticed that the new installation on Geografigränd produced significantly more electricity in the morning than in the afternoon.

"It was a little surprising; it's angled to the south, so it should give out as much electricity during the hours before midday as during the rest of the day," Mats Andersson explains.

"The answer lies in the coastal climate of Umeå, where it is less cloudy in the morning than it is later in the day, when clouds have had a chance to form. Over the summer, 15-20 per cent more electricity is produced in the morning than in the afternoon, and in October the morning production is almost double that of the afternoon."

The new installation gives more

It was also clear just how important the position of a photovoltaic plant is. The new installation on Geografigränd produces almost a third more electricity per installed kilowatt than the PV-cells on the pilot building, which were the first to be installed in Ålidhem.

There are a number of explanations for this. For one, the panels are south-facing, which means a higher production than those installed on the pilot building can be expected; the latter are west-facing. Another factor is that the PV-cells on Geografigränd are positioned higher up and on a roof with a somewhat steeper angle. This means that less snow is accumulated there, and the snow that settles also melts off quicker in spring.

Valuable experience

The experience gained is now used in the next stage of Sustainable Ålidhem. On Matematikgränd 23, the project will also see the installation of east-facing PV-cells in order to make the best possible use of the morning sunlight.

"If just a year ago someone had suggested we put up east-facing PV-cells, I would have said they were crazy. But now I can see they're worth testing," says Fredrik Westerlund, Bostaden's Project Manager for the redevelopment of Sustainable Ålidhem.

"It's incredibly exciting! We're learning a lot about how solar power can be produced in the conditions we have up here in Umeå and Västerbotten. Now we're hard at work developing a package solution to help the households that want to produce their own solar power," explains Lena Ahlgren, Umeå Energi's Project Manager for the solar power investment for Sustainable Ålidhem.

The Sustainable Ålidhem project is a collaboration between Bostaden, Umeå Energi and Umeå municipality. Its focus: to make a safer, more pleasant and more energy-efficient suburb.

For further information:

Mats Andersson
Energibanken i Jättendal
Tel: 070-418 27 88
E-mail:mats@energibanken.se