The negative effects of renewable energy are the same as those for non-renewable fossil fuels. The materials used to produce wind turbines- for instance- include petroleum-based products, so oil has to be extracted from the ground and refined. The raw materials have to be transported to the manufacturing facility, which at present, requires fossil fuels. The factory itself produces pollution during the production process (carbon emissions, shavings and dust with petroleum chemicals in it, etc). The wind turbine has to be transported to its final location, again, burning fossil fuels in the process. The people who maintain the turbine use vehicles to drive to it, and they may use battery-powered equipment that derived its charge from a grid powered by coal-burning power plants. The lubricants needed to allow the wind turbine to spin are probably petroleum-based as well. The wires required to transport energy from the turbine to your home require metal, rubber and petroleum, all of which have to be extracted from nature at some point.
Every source of renewable energy has costs, especially up front. Photovoltaic cells used in solar energy production require silicon and some toxic chemicals. Nuclear requires uranium. Biodiesel requires large amounts of corn (harvested using fossil fuels). Etc.
Renewable energy is only renewable once you have the system in place, and there are always costs to the environment to maintain the system (new materials, fuel to drive to the units, etc). The goal is to have the energy produced from the unit outweigh the energy taken to manufacture/maintain it.
Every source of renewable energy has costs, especially up front. Photovoltaic cells used in solar energy production require silicon and some toxic chemicals. Nuclear requires uranium. Biodiesel requires large amounts of corn (harvested using fossil fuels). Etc.
Renewable energy is only renewable once you have the system in place, and there are always costs to the environment to maintain the system (new materials, fuel to drive to the units, etc). The goal is to have the energy produced from the unit outweigh the energy taken to manufacture/maintain it.