42 Technical design of energy generating installations, in particular photovoltaic and solar installations, hydroelectric power stations, wind energy installations, wind farms, biomass power plants and geothermal power station; technical consultancy with regard to the use of photovoltaic and solar installations and of power stations; development of solar cells and solar modules, and of energy generating installations, in particular photovoltaic and solar installations, hydroelectric power stations, wind energy installations, wind farms, biomass power plants and geothermal power station; development of assembly and rack systems for photovoltaic and solar installations; technical expertise and consultancy in the field of renewable energy, namely, in the field of solar power, hydroelectric power, wind energy, biomass and geothermal power; geological calculations for the extraction of natural resources for the production of energy and energy products; technical reporting and project management and product development within the power and energy sectors; research and measurement evaluations for improving the environment within the power and energy sectors; development of technical material and industrial installations, in particular in the energy sector; development of energy saving concepts and products, for others;development solar installations, hydroelectric power stations, wind energy installations, wind farms, biomass power plants and geothermal power stations in the field of renewable energy, for others