Swiss taxpayers have been footing the bill – amounting to more than SFr1 million – to house the Solar Impulse project at its base at Dubendorf military airfield near Zurich since 2007. Now the government wants the project to pay up.
Swiss public radio revealed on Tuesday that the Federal Audit Office had established there was no “legal basis” for Solar Impulse not to have paid rent for the use of the hangars at Dübendorf or Payerne in canton Vaud.
SFr700,000 worth of modifications made to the Dübendorf hangar in order for it to house the giant solar plane were also picked up by the government.
Sponsored by Deutsche Bank and Omega, the Solar Impulse project aims to fly the first fully solar-powered airplane around the world in 2014 to promote the use of clean energy.
A spokeswoman for the defense ministry, which operates the Dübendorf airfield, said although it had requested rent from Solar Impulse in February last year, “Solar Impulse has not yet signed the lease”.
The defense ministry has also asked Solar Impulse to pay rent to cover costs from 2014.
A spokeswoman for Solar Impulse said the matter was being discussed with all government departments concerned.
Seven years of work, calculations, simulations and tests were needed by the 70-person team to complete the aircraft.
The plane has the wingspan of a Boeing 747-400 and the weight of an average family car at 1,600kg.
It has 12,000 solar cells mounted onto the wing, which will supply energy to the four electric motors with a maximum power of 10 HP each.
During the day they will also charge the polymer lithium batteries (400kg), which will allow the aircraft to fly at night.
A second plane – which will be undertake the round-the-world flight in 2014 – is currently under construction.
The ten-year project is expected to cost around SFr120 million ($133.6 million).