Former Reddit CEO Crashes Bill Gates’ AMA To Correct Him On Solar Desalination

Bill Gates opened himself to Reddit users Friday in his ninth Ask Me Anything, and while he answered everything from his alleged conspiratorial activities to his advice for job interviews, he focused mostly on climate change.
Gates just published a book on climate solutions, “How To Avoid A Climate Disaster,” but one particular Redditor found lacking Gates’ answer to a question about seawater desalination.
Another user, Sahil Raza, had asked Gates: “Hey Bill! How do you think Seawater Desalination will impact the issue of global water shortage in the coming years?”
“We have lots of water,,” replied Gates. “The problem is that it is expensive to desalinate it and move it to where it is needed. This is all about the cost of energy. The cost is prohibitive for agricultural use of water. New seeds can reduce water use, but some areas won’t be able to farm as much.”
That’s when former Reddit CEO Yishan Wong stepped in, declaring that freshwater scarcity is “a problem that will likely be completely resolved in the next 10-20 years” thanks to the falling price of solar energy.
“This is no longer as big a problem as it used to be, due to ongoing declines in the price of solar,” Wong wrote in a 538-word comment.
Wong is now the CEO of Terraformation, a Hawaii-based company he started in 2017 to promote native forest restoration. The company recently built the world’s largest off-grid solar-powered desalination system, according to its website, “to alleviate water shortages that hinder arid ecosystem restoration.”
The main cost of transporting water, Wong clarified, derives from the energy needed to lift it, but solar-powered pumps can move water uphill when the sun is shining and store it in tanks, avoiding any solar intermittency issues, until it’s needed. Then it will flow effortlessly downhill with no energy cost.
Other than cost, desalination has been hobbled by the waste brine it produces. Terraformation’s system draws water from a brackish well near the ocean—not directly from the ocean—so it begins with water that’s about 25 percent as salty as seawater. It produces two streams—1) clean water devoid of salt and 2) water that’s about 50 percent as salty as seawater. The saltier product is used to irrigate salt-tolerant plants.