{"id":9608,"date":"2022-08-11T10:00:00","date_gmt":"2022-08-11T14:00:00","guid":{"rendered":"https:\/\/www.plugpower.com\/?p=9608"},"modified":"2024-07-24T13:20:46","modified_gmt":"2024-07-24T17:20:46","slug":"water-electrolysis-powering-the-world-with-green-hydrogen","status":"publish","type":"post","link":"https:\/\/www.plugpower.com\/blog\/water-electrolysis-powering-the-world-with-green-hydrogen\/","title":{"rendered":"Electrolyzers & Water: Powering the World with Green Hydrogen"},"content":{"rendered":"\n

Green hydrogen production isn’t just carbon-free, it can be independent of the grid.<\/em><\/p>\n\n\n\n

by Dr. Thomas I. Valdez, Principal Engineer for Office of the Chief Technology Officer <\/p>\n\n\n\n

Energy which does not emit carbon, and is independent of the electrical grid seems far-fetched. This is possible with hydrogen. However, some people question if hydrogen production is an effective use of our water, particularly in drought-stricken parts of the world.<\/p>\n\n\n\n

If we want to help the world combat climate change, hydrogen production is an effective use of water. Water is life; as such, making sure communities have access to water for drinking and living is paramount. Water is used by many different industries \u2013 to grow food, to produce gasoline, to make steel, and to manufacture other products. The process we use to make hydrogen, called electrolysis, occurs in an electrolyzer, and does use water.  However, electrolyzers do not add to our water usage, they displace other technologies which may use more water in the long run.<\/p>\n\n\n\n

\"Renewable<\/figure>\n\n\n\n

What is an Electrolyzer and How Does it Work?<\/h2>\n\n\n\n

An electrolyzer is an electrochemical device, which converts water into hydrogen and oxygen gas. Water and electricity are fed to an electrolyzer, and depending on the type of electrolyzer used, water is then converted to protons, hydroxide ions or oxygen ions through electrochemical reactions. As the protons, hydroxide ions, or oxygen ions, complete their respective electrochemical reactions, they liberate hydrogen and oxygen gas from water. Water electrolysis uses no chemicals, only water and electricity. When using renewable power, no carbon dioxide or particulate matter is emitted to produce hydrogen and oxygen gas through electrolysis.<\/p>\n\n\n\n

As shown in Figure 1, hydrogen is captured, transported, and stored for use by any industry looking to decrease their carbon footprint. The oxygen produced is released into the air. It is projected electrolyzers will soon supply giga-tons of green hydrogen as we transition from fossil to renewable fuels.<\/p>\n\n\n\n

\"PEM
Figure 1: Plug\u2019s Green Hydrogen Ecosystem<\/figcaption><\/figure>\n\n\n\n

Where Does the Water Come From?<\/h2>\n\n\n\n

The electrolysis process can use different water sources to produce hydrogen. Industrial water, which can include municipal water or groundwater, is the most common source of water used in electrolysis. Different from drinking water, industrial water is used in many different industries including smelting facilities, petroleum refineries, and industries producing food, paper, and chemicals, according to the U.S. Geological Survey<\/a>.<\/p>\n\n\n\n

Prior to being used in the electrolysis process, the industrial water goes through several phases of filtration to ensure maximum purity. Imagine a Brita\u00ae water filter you may use at home to clean your tap water. The water filtration process is like a complex Brita\u00ae water filter where the water is purified in several stages \u2014 removing ions such as calcium, magnesium and other minerals that cannot be used during electrolysis. A schematic for such a water filter is shown in Figure 2.<\/p>\n\n\n\n

\"Electrolyzer
Figure 2: Electrolyzer water purification system.<\/figcaption><\/figure>\n\n\n\n

“The water we use to produce hydrogen needs to be as pure as possible,\u201d said Tim Cortes, Chief Technology Officer for Plug. \u201cAfter hydrogen is produced, any excess water is then recycled to be used for other needs \u2014 ensuring the electrolysis process consumes the least amount of water as possible.\u201d<\/p>\n\n\n\n

Following the Water<\/h2>\n\n\n\n

Every nine liters (2.4 gallons) of water contains one kilogram of hydrogen and eight kilograms of oxygen. When you include purifying the water and some water vapor lost with oxygen release, the actual amount is about 12 liters (3 gallons) of water for every kilogram of hydrogen generated through electrolysis.<\/p>\n\n\n\n

Water Usage in an Electrolysis Plant<\/h3>\n\n\n\n

Plug\u2019s Woodbine, Georgia Green Hydrogen Production Plant produces approximately 15,000 kilograms of hydrogen per day. It uses about 240,000 liters (63,400 gallons) of water to produce this amount of hydrogen. On the hottest days of the year, the electrolysis process also uses water for cooling. A hydrogen production plant such as the one in Georgia will use an average of 43,000 extra liters (11,000 gallons) of water per day on the hottest days of the year. Thus, the maximum daily water usage at Plug\u2019s Woodbine, Georgia Plant would be 283,000 liters (74,300 gallons). This is about half the water a large dairy farm could use, and much less than other agricultural uses such as alfalfa and almond production. Typical industrial water usage is shown in Figure 3.<\/p>\n\n\n\n

\"Typical

Figure 3: Typical industrial water usage.<\/figcaption><\/figure>\n\n\n\n

Water Usage in Power Plants<\/h3>\n\n\n\n

Compared to other power plants, a hydrogen-fed power plant uses less water. A nuclear power plant, for instance, uses 4.2 liters (1.1 gallons) of water for every kilowatt hour of energy produced. <\/a>Similarly, a coal power plant would use 3.8 liters (1 gallon) of water for every kilowatt hour of energy produced. A hydrogen-fed power plant, however, would use 0.97 liters (0.225 gallons) to provide the same energy, according to the Monarch Partnership<\/a>, an energy consultancy firm. See Figure 4 below to compare the water usage at various power plants.<\/p>\n\n\n\n

\"Power
Figure 4: Power plant water consumption<\/figcaption><\/figure>\n\n\n\n

Water Usage in Consumer Vehicles<\/h3>\n\n\n\n

Water is also used by the oil and gas industry to refine petroleum products.\u00a0 To refine three billion liters (800 million gallons) of petroleum products every day in the United States, we use 3.8 to 7.6 billion liters (1 to 2 billion gallons) of water<\/a>, as estimated by the Lawrence Berkeley National Laboratory<\/a>. Petroleum products such as gasoline can take up to 22.7 L (6 gallons) of water to produce 3.8 liters (1 gallon) of fuel. Best case, 3.8 liters (1 gallon) of water would be required to produce sufficient gasoline to allow you to drive:<\/p>\n\n\n\n