Although, we can anticipate some of the switching to electricity, the greatest long-term need is to replace the direct burning fossil fuels to provide primary heat or power. Generally, the main renewables which are capable of meeting this need are biomass and burning waste. These would need to be deployed on a vast scale to replace our current use of fossil fuels. Consequently, to get an equivalent amount of renewable electricity produced to, say, a 1000MW power station needs a large number of separate installations, for example a very large area of wind generators. The most familiar example is large hydroelectric dams, which change the character of the local visual environment, interfere with water courses, wildlife habitats, and sediment and mineral deposition patterns downstream.
Tidal power has similar problems.
Depending on location, dam failure can also present a safety and environmental risk - like a nuclear accident, rare, but with devastating consequences. Wind power needs installations in exposed areas which, by their nature, are often areas associated with beauty. Impacts that are small at the level of a single unit, unlike the noise of a wind turbine or risk of blades shearing off, can assume significant proportions when you multiply the number of installations to, say, thousands of units. Offshore wind or wave power carry the risk associated with major offshore installations. Broadly speaking, the less energy you have bound up in a resource, the less its impact, but also the less is its usefulness.