The energy required to change the length of the year is very large. Solar tides could transfer some energy from the Earth's rotation to the Earth's revolution, but even tapping all that energy (leaving the Earth tidally locked to the Sun) would not change the year length very much,
It is basically defined by distance to the sun since it has ~99.8 of all mass of the solar system, so the change of Jupiters orbit would have a large effect (edit: for Jupiter).
