By Emily Douglas
It’s been pouring rain here in the Bay Area this week, Nature’s way of celebrating World Water Day. I grew up in the rainy Northwest, but even I have been complaining about the rain this week. When our highways are flooding and our hills are falling down, it’s too easy to forget that millions of people lack access to clean water, and things are expected to get worse. By 2030, analysts predict that available water supplies will satisfy only 60% of demand. By 2025 China will build 221 cities with a million or more people and fifteen mega cities with populations of over 10 million. Today China has approximately 300 million people with no access to water.
Even as water becomes increasingly scarce, energy gets more attention and investment. In 2010, the Cleantech Group reports that 24% of all venture capital went into solar companies, and water didn’t even register on the list. In recognition of World Water Day this week, Dow Water and Process Solutions (client) issued a paper (PDF) about the intersection of water and energy. Making electricity uses water, and making clean water uses electricity. In many regions of the country, Americans use as much water turning on the lights and running electric appliances as we use in taking showers and watering lawns. USA Today posted earlier this week on what you can do to reduce your own consumption and get involved.
Four percent of all electricity used in the United States is used to treat or move our water. Three-quarters of the cost of making clean water goes to paying the power bill. In particularly parched areas like the Middle East, desalinating seawater can be the most practical option to supply drinking water. Current methods require anywhere from 8 to 20 kilowatt-hours of energy to produce 1,000 gallons of desalinated seawater through reverse osmosis. Using a thinner membrane and a more complex pressure-recycling flow, the Ashkelon Seawater reverse osmosis plant in Israel dramatically lowers the electricity use, which lowers overall costs as well.
Solving the water-energy equation from the other direction, power plant developers have to consider water use before picking the right technology. Some solar plants in California have been challenged for their environmental impact and water use. Solar thermal power plants, which emit no pollution, use a whopping 1,060 gallons of water for every megawatt hour of electricity produced. As we’ve learned from the painful news out of Japan this week, nuclear power plants depend heavily on clean water for cooling, using an average of 720 gallons of water to make the same megawatt-hour of power. By contrast, a photovoltaic solar power plant would use just 30 gallons of water.
The rising cost of oil has driven cleantech innovation in energy, but it’s hard to picture how the same dynamics will drive water innovation. Because water is essential for life, developed-world governments resist letting the market set a price. Without rising prices, how do you think we can encourage clean water innovation? How can we reward innovation without driving up the cost to poor communities and countries? I can’t wait for developing-world projects to surprise us with new solutions and new approaches.