Heat stored beneath the Earth’s surface holds 50,000 times the energy of all the oil and gas in the world combined. If it could be harnessed, it would be an ideal source of base-load power: Geothermal is cleaner than fossil fuels, and more reliable than alternative sources like tidal, wind, wave and solar. Today, geothermal plants in the United States generate nearly 3000 megawatts of electricity—enough to power South Dakota. Almost all of it comes from reservoirs that are at least 300 F.While most renewable energy projects are focused on wind or solar, geothermal also has vast potential. With expensive electricity to compete with (30¢ a kWh), Alaska is an ideal location to start implementing projects like this. The more projects completed, the more knowledge is acquired and the lower the prices to provide electricity become. Once the prices get low enough, projects will become cost competitive in the continental US, well at least where geothermal potential exists.
The water rising through a fracture in the granite pluton under Chena is only 165 F. Experts didn’t think it was hot enough to produce serious power. But with the nearest electrical grid 32 miles away and generators burning through $1000 worth of diesel fuel daily, Chena had the incentive to prove the experts wrong. Now, its tepid water not only generates electricity, it heats the resort’s buildings, maintains a greenhouse and keeps an ice museum frozen year-round. There are thousands of such low- to moderate-temperature geothermal systems scattered throughout Alaska and the rest of the country. Power plants like the one at Chena could tap them to produce tens of thousands of megawatts of electricity.
Chena’s two 200-kilowatt modules provide more than enough power for the entire resort and have reduced the cost of electricity from 30 cents a kwh to only 5 cents. With a capital cost of $2.2 million, including exploration and drilling, the project is expected to pay for itself in four to five years.
via Popular Mechanics