*Solar panel - snow. Snow is hard on solar
panels. It is hard to remove, panels are often in awkward places and
many areas have snow cover for many months. When snow it is not
directly on the panels it makes a good reflector.
*Bio-diesel -
cold. Cold weather in most of the temperate zone will solidify
bio-diesel. Not helpful to be running a vehicle on bio-
diesel in cold
weather.
*Wind power - storage. Wind power is an off and on again
power source in most of the geographies that haven't already been
developed for wind power. Off and on again means storage and storage
remains a problem for any volatile power source.
*Tidal power -
maintenance. The biggest drawback for ocean tides is that seawater is
terribly corrosive of every known human tool, attracts underwater
mollusks and is usually hard to retrieve from underwater.
*Economies
of scale - transmission. Many ecological power sources can benefit from
economies of scale such as solar power in a desert, wind power in a
canyon and tidal power at entrances to bays. However, transmission of
electric power is subject to dramatic and costly losses of power.