However, these are expensive to run and require a lot of input energy compared with a relatively low output. (sciencedaily.com)
The output energy, however, was similar in the two systems, indicating much lower ratio of output energy to input energy in the organic system, suggesting greater energy use efficiency. (fao.org)
In your second example the oceans get an extra 5 watts of input energy. (joannenova.com.au)