DC Desalination - The monetization

The goal would be to convince one of these tech companies to build a DC in one of these water poor regions; DC Desal would then pay the tech company for their waste heat. For an idea how how much this might be worth, lets take a look at Los Angeles. In the dry season, the cost of water is basically $4 per hundred cubic feet or $1.40 per cubic meter. Using electricity for an MED plant, it’s possible to achieve $0.70 per cubic meter of desalinated water, or half of what LA citizens are paying. It’s worth noting that the water cost they are paying is likely heavily subsidized or politically negotiated with other parts of the state. Now, if the company running the DC is paid $0.40 for the heat required to desalinate a cubic meter of water and the water was sold to the city at the current rate, that would be a dollar of profit per cubic meter.

The electricity cost in LA is about $0.20 per kilowatt hour. It takes roughly 3.5 kWh to make a cubic meter of water using MED. Let’s say that the DC that would be built would have an average load of 40 megawatts and 35 of those would turn into heat used for desalination. That means that 240,000 cubic meters (or 63 million gallons) of drinking water could be produced per day. The per capita daily usage of water in LA is 123 gallons, so this could be enough water for about half a million people or an eighth of the city’s population. If revenue from the water is $1 per cubic meter, that would be $88 billion a year. The cost of building the MED would be several hundred million to half a billion dollars, which could be paid for within two days of desalination revenue.

Another, smaller, source of revenue would be the sea salt from the brackish water that comes out of the MED. Ocean water has 35 ppt salt or 35 kilograms per cubic meter of water. The brackish water wouldn’t be pure salt water, but that’s good enough for this approximation. Per day that would be 8,400 kg of sea salt. I think the salt would be worth about $2 per kg. Over a year there would be about $6 million for salt. Clearly the salt isn’t nearly as valuable as the clean water.