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Google's Wind, Solar Power Investments Top $1B
Lucas123 writes "Google just announced it is investing another $80 million in six new solar power plants in California and Arizona, bringing its total investment in renewable energy to more than $1 billion. The new plants are expected to generate 160MW of electricity, enough to power 17,000 typical U.S. homes. They are expected to be operational by early 2014. With the new plants, Google's renewable power facilities will be able to generate a total of 2 billion watts (gigawatts) of energy, enough to power 500,000 homes or all of the public elementary schools in New York, Oregon, and Wyoming for one year, it said. Currently, Google gets about 20% of its power from renewable energy, but it has set a goal of achieving 100% renewable energy."
While many states offer subsidies for solar, Arizona is starting to tax solar installations
God spoke to me
Peak capacity is used throughout the electrical industry, from the generators to the nameplates of the devices in your house. The reason is the peak determines the size of the wires - in your walls or for transmission lines - to carry the load safely. For power sources, the other number you care about is "capacity factor", the percentage of peak capacity you can supply on average. It may be 90+% for nuclear (they still shut down for refueling, and sometimes for unplanned maintenance), and lower for other sources. Even hydroelectric has a limit if the water supply is less than peak turbine capacity. Photovoltaic can be as low as 15% in poor locations, while solar-thermal with storage can be much higher.
Less than 100% capacity factor is OK, because no power plant routinely operates at 100% capacity. For one thing, customer demand has daily and seasonal variations. For another, every plant stops for maintenance sometimes. Lastly, each power source has a different marginal operating cost. Hydroelectric, wind, and solar don't burn a fuel, so are relatively cheap per kWh when they run. Coal and natural gas consume fuel, thus have higher marginal cost when they run. A utility operator wants the cheapest mix to satisfy demand at any given time. Since natural gas prices can fluctuate dramatically over the life of a plant, one thing solar does is stabilize their costs. You know for sure that a solar plant will still not be burning fuel at the end of it's life. You have no idea what natural gas will cost in 40 years.
As far as photovoltaic peak production only being part of the day, that is well matched to the US southwest, where the peak air-conditioning demand happens exactly when solar has maximum power. Something like nuclear is better suited to baseload power, the part of demand that is always there. A nuclear reactor is a bitch to turn on and off, so they would rather keep it running all the time between refuelings.
If you are going to discuss power grids, you need to stop using just one performance parameter. That's not how real grids operate.