The first four posts of the TCASE series were logically sequential — each post built on the conclusions of the previous one. Overall, I hope the TCASE will retain a sense of coherency, but at the same time, I don’t want to get too constrained in following a rigid structure. To be frank, I can’t plan the ‘storyline arc’ well enough at this stage to make that even half feasible, and besides, I want to the series to be responsive to topical debates (and keep each post to a digestible, bite-sized chunk of information).
So future offerings in TCASE will branch out to cover everything from examinations of different technologies/energy sources, case studies of actual real-world projects, evaluation of new policy decisions (such as Australia’s 2020 ERET), questions of build rates and constraints, cost/feasibility assessments, consideration of technology gaps and physical limitations, exposing spin and hype, limit analyses, thought experiments, etc. I certainly hope to continue to get ideas from the commenters on this blog, which collectively represent an enormous wealth of knowledge, experience and ideas. To me, this is a fine form of peer review and a great source of inspiration. Thanks BNC readers!
Today’s post offers a first look at ocean power — the mighty fist of Poseidon (mythologically and in reality) — harnessing the energy in waves (I’ll look at tidal energy separately). Wave power is a form of indirect solar energy — driven by fairly consistent oceanic winds, which whip up waves over hundreds or thousands of km of open ocean. This energy may be harnessed with the use of buoys, oscillating air columns, barrages and so on, with a conversion efficiency of ~30%. Waves are a linear energy resource — once you’ve tapped its energy, you need thousands more km of ocean to regenerate new waves, so the resource is measured in kW per linear metre (not metre-squared, like direct solar). Average annual wave power density range from 10-40 kW per metre in inshore regions to as much as 70 kW/m in highly energetic regions. Although it is somewhat more regular (‘available’) than wind (and with a higher power density), wave energy is not constant and will still require substantial back-up and/or energy storage. More technical documents here.
Carnegie corporation, an Australian wave power company, state that their CETO technology (which I will look at in detail in another post — it has some fascinating prospects) can generate 100 MW peak using an a 500 buoy system; so, 200 kW peak per undersea buoy. To date, however, the only commercially operating wave farm in the world is in Aguçadoura, Portugal, about a year ago — so let’s focus first on the energy potential of this technology.