Desalination and Energy Consumption
- January 20, 2017
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Fresh water is a necessity in everyday life, and is vital for the survival of human beings. The ability to get fresh water in dry areas, or in times of shortage, comes from the process of desalination, where the salt in seawater is displaced and it becomes drinkable water.
Desalination plants consume a lot of energy, though, and aren’t as green as they could be. Here are the facts you need to know about desalination plants and how they can conserve energy for a greener future.
Modern-day facilities that desalinate seawater use the process of reverse osmosis through high-pressure treatment systems. If high-pressure doesn’t ring any bells, think of how high your water bill is when you take a 30-minute shower every day. Simply put, it takes energy to move something that wants to stay still.
Not only does the environment suffer from the energy expenditures of desalination plants, but so does the economy. Just one plant in California cost 1 billion dollars and provides about 7% of drinking water to the city of San Diego. California has plans for more plants, which means more money has to be accounted-for from the state.
Unlike California, other areas and governments are hesitant to build desalination plants because of the cost. However, due to the amount of fresh water it brings to areas surrounded by seawater, such as islands, they may be forced to build a plant anyway.
Of the 71% of water on earth, only 4% is drinkable, so areas with water shortages might consider desalination plants, even if the cost and energy consumption of desalination plants make people hesitant. Some notable desalination pioneers, however, have been improving on the fundamentals of this technology since WWII, which means we might be getting closer to a version that doesn’t tax the natural world quite as highly.
The Energy Consumed
Energy consumption is one of the biggest hurdles desalination faces. Although it’s been around for hundreds of years, desalination still consumes too much energy for the environment’s sake. The amount of energy consumed from a desalination plant, which supplies water to 300,000, is the equivalent to one jumbo jet’s power.
SWRO stands for Salt Water Reverse Osmosis — the ability to turn salt water into freshwater, also known as desalination. The high-pressure system used to desalinate salt water requires a high amount of energy to do. Billions of gallons of water are forced through the pressure treatments, consuming an average of 10-13 kilowatt hours (kwh) per every thousand gallons.
Researchers think there are better ways to reduce the footprint of desalination plants. One way to do this is simply by making more water, with the same amount of energy they’re using now. By increasing the membrane to graphene, which separates salt from the water, they can produce more water without needing to use more energy.
Ultimately, scientists need to figure out the best way to pump water through the pressure treatment systems without requiring so much energy.
The Environmental Impact
Desalination is a fast way to get drinkable water to consumers, but it has a major impact on the environment. Desalination is viewed as one of many factors contributing to climate change and global warming. Areas where fresh water was once plentiful are now dry and desert-like.
As the global temperature rises, sea ice melts, which causes the sea levels to rise. The more greenhouse gases are emitted and the more energy that’s consumed, the worse global warming gets. Sea levels will continue to rise.
The ocean is home to many creatures, and desalination poses a threat to ocean biodiversity and marine habitats. Coral reefs require marine organisms to flourish. But as desalination takes place, numerous organisms, plankton and fish larvae are vacuumed up in the salt water that goes to the plant.
This is a factor that plays a role in the death of coral reefs, and it decreases the bottom of the marine food chain. When there’s a disruption to the food chain, the entire biodiversity of the ocean is at risk.
The Green Possibilities
To reduce the amount of carbon emitted into the atmosphere, desalination plants can make environmentally friendly choices.
One plant sets the bar high with its solar-powered desalination. This plant, located just outside of Santa Monica, California, uses sustainable energy for the process of electromagnetic desalination. It was even given a nickname — “The Pipe” — due to its architectural design.
Any desalination plant has the possibility to use sustainable energy. Solar power is a great source of energy, for example. Although desalination plants are already extremely costly, solar panels are becoming more and more affordable.
Offshore wind power plants provide clean energy, and should be considered a viable power source for desalination plants. The best way for desalination plants to minimize their energy consumption is by using renewable energy to power the facility.
Although it carries a huge cost, desalination benefits people by providing them with fresh water. High-speed electrical pumps on desalination plants consume more energy than is needed. If desalination plants focused on sustainably using renewable energy, it would be a major step toward a greener environment.
Photo Credit: Tony Hisgett via Flickr