Electricity Purchase and Production Going beyond energy consumption also the electricity purchase respects ecological criteria. Moreover, the roof of the 2014 built teaching pavilion has been equipped with a photovoltaic system. Electricity Purchase100% hydropower is purchased for the main buildings on the HSG campus. The “St. Gallen Eco Electricity” mix has been used in a minor part of the rental buildings for many years. This electricity mix consists of 70% percent hydropower, 22% waste incineration, 6% wind energy and 2% solar energy. It does not contain any nuclear energy. Solar Plant The idea of building a solar plant on the roof of the new teaching pavilion to produce electricity was realised with the support of a private leasing partner, the Swiss Photovoltaik GmbH. Swiss Photovoltaik took over the installation and operation of the plant, which was cost-free for the HSG. In return, the HSG and the owner of the building, the canton of St. Gallen, provided the roof free of charge. The produced electricity is fed into the grid. Its revenue from the sold electricity allows Swiss Photovoltaik to refinance the construction and operation of the solar plant. The new building will serve as a temporary classroom facility until the planned campus expansion has been completed. Thereafter, the building will be removed and the solar plant will be deconstructed.Swiss Photovoltaik will be in charge of the deconstruction and ensure that the materials are re-used in another facility. Until this point is reached, the solar plant will annually generates 55,000 kWh of electricity. An average household consumesbetween 4,000 and 5,500 kWh of electricity, the solar plant thus generates electricity for 10–11 households. On the existing campus, there is no other space available to build a solar plant; this lack of space is partly due to monument protection. However, the HSG supports the idea of installing more solar plants in future and the use of solar power is included in the new campus plans.