It is no secret that cities use up a large bulk of the energy budget. Thus sourcing for more renewable and reliable sources of energy is always important.
Ocean Thermal Energy Conversion (abbreviated OTEC), interestingly generates energy through the temperature difference between surface and deep sea waters (1).
(2)
The idea is very similar to coal-fired power plants, where heat is used to excite a fluid, in this case it is ammonia (1), and the excited fluid moves and turns a turbine that produces energy. I have a few personal thoughts on this, and by any means I may be wrong.
It is definitely a very interesting idea. Although it is stated that hot & cold waters are respectively drawn out from the shallow and deep waters, and consequently the mixed, thermally averaged water is released back, the energy used to turn the turbines have to come from somewhere. Therefore the ocean ‘system’ actually loses energy as a whole. As there is a net loss of energy from the ocean to turn the turbines, I wonder whether, on a large scale, it is viable to possibly also conveniently mitigate the onset of rising sea temperatures & its subsequent ramifications on wildlife and habitat?
However I also question its effectiveness to produce energy. Comparing it to current coal plants, where coals is fired to produce steam, the temperature of coal can go up to almost 2000°C (3). The maximum difference in temperature between the coldest and warmest waters would be merely ~20°C. How effective will this technology be in displacing conventional fossil fuels?
In a city like Singapore, if this technology would be proven effective, I would think that this would be pretty viable for us, as we are situated right smack in the tropics, possibly having one of the highest surface sea temperatures.
So many ideas, yet so unattainable.
References
- What is OTEC –. OTEC news. Retrieved 28 October 2016, from http://www.otecnews.org/what-is-otec/
- Ocean Thermal Energy Conversion | Makai Ocean Engineering. Makai.com. Retrieved 28 October 2016, from http://www.makai.com/ocean-thermal-energy-conversion/
- Coal and Charcoal. Anvilfire.com. Retrieved 30 October 2016, from http://www.anvilfire.com/FAQs/coal.php
Hi Mak, this seems like such an interesting idea, especially in the context of Singapore! Do you think there is any potential for this idea to improve to be more efficient at generating electricity to the point where it becomes economically and electrically viable? This is only possible if money is invested into more research and development of this idea. If so, should Singapore play a part in investing in this idea, potentially expediting its improvement? Or should it wait for other investors to make this idea viable first, before employing this technology here?
I feel, as we heard from Prof Peter Ng, Singapore almost never takes the lead in anything, i paraphrase. Singapore does not have much of a buffer or fall back option if our economy suffers, thus from a perspective of a Singaporean I would too discourage Singapore testing the waters with both feet. However as someone who knows the consequences of unsustainable energy use, of course I would prefer if more investments were to be made in these areas. Always a conundrum.
As for the first part of your question, I do not know the specificities, and am unable to give you a satisfactory answer. However I believe that there is never too many green solutions to anything, and hopefully it does become viable and widespread some day.