As reported by Green Wombat's Todd Woody, Arizona Public Service, the state's largest utility, plans on paying around $4b over the next 30 years to power 70,000 homes. Wired Science's Alexis Madrigal calculates that the plant's kilowatt hour rate should therefore correspond to about 20 cents per kWh - taking into account the consumer markup - or roughly twice the kilowatt hour rate of coal-based alternatives.Regardless of the exact figures, such large-scale installations will help lower the kilowatt hour rate over time and bring them in line with conventional energy sources, as Woody explains:
"That cost disparity is likely to evaporate when the United States moves to price carbon — either through a carbon tax (unlikely) or a cap-and-trade system that requires fossil-fuel power plants to pay if they exceed limits on CO2 emissions. And the cost of financing carbon-spewing power plants will grow in coming years as Wall Street shies way from projects that carry climate change risks. And as solar power plant components and systems go from being one-off prototypes to mass-produced commodities, the cost of solar electricity is expected to drop even further."
Abengoa Solar will use a so-called "solar trough design" for the plant - which consists of rows upon rows of parabolic mirrors that focus the sun's rays on water-filled tubes to heat them and produce steam to power electricity-generating turbines (i.e. a solar thermal system). In case the sun's not out, the plant can release heat stored in molten salt silos to drive the turbines.
Image courtesy of Business Wire