At Mære, three solar cell systems have been installed on the roof; the suckling pen, the dormitory house and the stable. The system on the suckling pen is a roof-integrated system. The solar cells form an integrated part of the roof itself. On the dormitory house, the solar cells are placed on top of the existing roof. The system on the dormitory house is designed to provide an annual electricity production of 55,000 kWh. In 2019, the system provided just over 50,000 kWh. An overview of the production throughout the year varied from 11.5 kWh in January, to the best month in April with a production of 9,000 kWh. The system on the suckling pen is designed to provide an annual production of 34,500 kWh. In 2019, the system provided 24,680 kWh. The variation throughout the year varied from 6.22 kWh in January to 4,250 kWh in April, which was also the month with the highest production.
A solar cell system has been installed on the stable with an estimated annual production of 31,600 kWh. There are also plans to install systems on the roof of the new milking barn. This is estimated to provide an annual production of 29,000 kWh. In total for all the systems, this will provide an annual potential production of 150,000 kWh.
Most of the electricity produced in the two plants is used directly at the school. What is not consumed goes into the transmission grid. It is most profitable to use the electricity yourself locally. Storage in batteries or, for example, in hot water during periods of surplus may become more relevant over time.
The total cost of installing solar cells on a roof varies greatly depending on which solution is chosen and whether additional roofing work is required.
The payback period for such an investment will often extend up to ten to fifteen years, and in some cases even longer. The lifespan of a solar cell system is from 30-40 years. The efficiency will decrease somewhat over time. The production of electrical energy in a solar cell system is greatest on sunny days. Energy production is not dependent on warm days - it is relatively greater on cold days with a lot of solar radiation (March-April).
The facility at the suckling cow barn at Mære Agricultural School
Solar cells convert solar energy directly into electrical energy. The energy can be used directly in electrical appliances, stored in batteries, or transported to consumers via the transmission grid. Local production of electrical energy has become more interesting as energy demand increases and the transmission grid is not developed to handle the energy peaks that will come. Domestic production of electrical energy can also be too low in relation to consumption at times. At times, a large amount of electricity is already imported to Norway. Local production of electrical energy from the sun is a good climate measure rather than importing electricity that may be produced in coal-fired or oil-fired power plants abroad.
NTE and the Norwegian Agricultural Advisory Board joined us for an online meeting about solar cells and solar energy in June 2020. At this online meeting you can learn more about what you should consider when using barn roofs for solar energy production. You will also learn more about how the thermal storage at Mære works.
Facts about the facility in the dormitory building:
Installed power: 58.3 KW
Expected annual production: 55,000 KWh
Solar panel: Solitek Standard p60-270W
Facts about the nursing barn facility:
Roof-integrated plant with “Power optimizers”, which optimizes production and raises the safety level of the plant
The system is connected to a fire alarm and SD system.
Number of panels: 120
Total output: 34.8 kW
Area: 192 m2
Expected annual energy production: 34500 kWh
