Pure Water
Pure Water From OTEC
The process of desalinization to provide drinkable water for Small Island Developing States (SIDS)
It uses only warm seawater as its fuel, and some sunlight as its supplementary energy source. It not only doesn’t consume any of the Earth’s depleting natural resources, it puts back more into storage than it took out. And, it breathes new life into the atmosphere, helps to provide financial opportunity for its neighbours and always has a free drink awaiting everyone who needs it. Sounds like the perfect friend, the ideal environmentalist. And it is. It is OTEC.
Although ocean thermal energy conversion has been around since 1881, it has been used commercially only a handful of times, and never to its maximum capacity. It has been treated more as a novelty than an opportunity. Aside from its significant capital cost, OTEC has been viewed with some scepticism and suspicion, largely because it seems too good to be true. It is – too good, but also too true.
OTEC generates electricity by drawing up cold water from the ocean’s depths, passing it by warm water from the ocean’s tropical surface water, and, through the heat exchange method, creating electricity. But it creates more. In addition to raw hydrogen and oxygen, OTEC creates fresh, desalinated water; enough drinking water to provide over 1,200,000 liters along with each megawatt of energy generated. Some estimates place the total production potential at 2.8 million liters per megawatt per day.
It is a cruel twist for small island developing states (SIDS) that, living along a huge ocean of water with massive energy potential, the two essentials to which they are most often denied access are clean drinking water and cheap energy. But OTEC’ s potential to supply both means that these SIDS will see a huge window of opportunity open both for improved health and improved economic opportunity.
The concept of desalination is so simple that it can be replicated in one’s garage. As the warm water effluents from an OTEC generation unit is passed through a flash evaporator and surface condenser, the sea salt is precipitated out of the seawater, leaving clean, drinkable water. That flash evaporation involves nothing more than submitting the warm (20-25 degree) surface ocean water to a turbine pressurization process that creates steam (leaving behind the salts & minerals) or by using a refrigerant like ammonia, exposing it to the cold ocean water from the depths of the sea, which condenses it back into liquid once again.
Compare this virtually cost-free process to multistage flash desalination at a cost of $1 per 1,000 liters, or reverse osmosis costing about $0.50 per 1,000 liters. What a welcome neighbour an OTEC plant could be! Free drinks, a chance to put cash in its neighbour’s pockets, and the alter-ego to the stereotypical leeching friend. OTEC- the environment’s (and SIDS’) best buddy.
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