A Cooperative investing in solar panels on school roofs, can be seen as a district social enterprise, with its members as shareholders. At this page, the example of solar panels on the Kubus roof is elaborated.
Example: Solar panels on the Kubus roof
For most participants, the social aspects are most important to participate. The financial benefits are on the second place. Nevertheless, it is nice to make money.
The solar system built on the Kubus costs 23 thousand Euros including VAT. This amount is raised by 30 members. The budget is sufficient to install the solar panels, including a reservation for replacing the inverter after 10 to 15 years. Members provide a loan, which is paid off in annual installments. These installments depends on three parameters:
- The generated energy. The system has a peak power of 15 kW. The expected annual yield is over 12 thousand kWh.
- The financial value of this energy. Each year, about 19,000 kWh is used in the building. The first 10,000 kWh is subject to a high energy tax rate. The other 9,000 kWh to a lower rate. The solar panels first generate the cheap energy, then the expensive. Based on the year 2012, the average power tariff for the annual settlement to the cooperation will be 14 cents.
- The reservation for management and maintenance of the system, which is paid by the Cooperative.
Taking into account various factors, such as a slight increase of the energy tariff, a decrease of efficiency and the expected overhead costs, the system is paid off in 17 years. The terms of the remaining six years (the contract has a term of 23 years) is the profit (return on investment).
Is this business interesting for your school?
For a school, it can be interesting to utilize a sunny roof for solar panels, without any costs for the school. Whether your school is of interest to this approach, is dependent on several issues. Small schools with low energy consumption, with an unshaded roof at south orientation offer the most interesting business.
For each school, the following aspects should be considered:
- Roof orientation. Solar panels provide optimal yield at tilt angle of about 20-40° to the south (in the Netherlands). At another orientation, you have a loss of irradiation, as the figure shows. Indicative, a sloping roof with an orientation between the south-east and the south-west is fine for a project. In case of a flat roof, the solar panels are mounted on a construction or consoles with optimal orientation.
- Shadow effect: Does the roof bother from trees, buildings or obstacles? Shade is a killer of your power yield. An open sky is optimal. Illustrative is the composition of solar panels on our example project the Kubus. Note that there is a chimney on it (the black bar). The solar panels are placed in such a way that they are not affected by the shadow. The left panels (western) bother from trees from late afternoon, which gives a small loss of the year performance.
- Energy consumption. The first 10 thousand kWh are the most expensive for the school, because of the high energy tax rate. The next 40 thousand kWh are in a lower energy tax scale, and all used kWh more than 50 thousand are cheaper once more. The lower the energy consumption of the school, the better for the business. In that case, the portion expensive energy generated is higher. You should have to be careful the solar panels don't generate more energy the school needs. This "surplus" is taken at a very low rate by the energy company.