The cost of different renewable sources is mentioned in this chart. The variation in cost of a source compared to 2002 and 2030 is expected to decrease in most cases.
According to graph, the cost of production of both wind onshore and wind offshore energy is likely to be decreased in 2030.
But the costs of hydro, geothermal and biomass energies are projected to be remained the same. However, the cost of energy through solar(heat), tidal/wave, solar planes are predicted to be dropped down significantly.