Large-scale green energy systems can affordably replace fossil fuel as the world's primary source of electricity within 20 years, new research from the United States weather office suggests.
Critics in the U.S., notably those with links to electricity producers who rely on coaland natural gas-fired generation, argue that the uneven production of power from wind turbines yields only nominal reductions in greenhouse gas emissions compared to fossil fuels.
The differences in emissions are too small to justify the higher costs associated with wind - and solar - production, the argument goes.
However, a director with the U.S. National Oceanic and Atmospheric Administration (NOAA) said Friday in Vancouver that wind and solar could supply 70 per cent of electricity demand in the lower 48 states, with fossil fuel and hydro/nuclear renewables each accounting for just 15 per cent by 2030.
Sandy MacDonald, director of the earth system research lab at NOAA, presented the research at a symposium of the American Association for the Advancement of Science's annual convention, which is taking place in Canada for only the second time since the inception of the AAAS in 1848.
NOAA assumed an average price for natural gas-fired power of nine cents per kilowatt hour, which is slightly below the current range for wind power costs, and substantially below solar electricity costs at present - although the cost for both those sources continues to fall, the symposium was told.
NOAA embarked on the renewables project three years ago, collating 16 billion pieces of weather data derived from satellite observations and airplane observations and weather station reports.
Then it designed a program to filter the information to remove unlikely venues for wind or solar power arrays - such as national parks and urban areas - and came up with a map showing robust wind resources in the middle of the continent and decent ones in the northeast Atlantic states, as well as strong solar production areas in the desert southwest.
Those findings confirmed common-sense expectations about the location of optimal resources, MacDonald noted.
But NOAA took the research a step further and considered how best to balance potential power production with electricity demand. For example, U.S. power demand peaks in August during air-conditioning season. That would coordinate well with large-scale solar electricity production in California, but that's when solar production falls off in the desert state of Arizona due to seasonal cloudy weather.
Similarly, about half of the mid-continent wind resource is at its peak at night when demand is at an ebb. The bigger the grid, the more effective it can be at transitioning to green energy, MacDonald said. An optimal system would encompass coordinated energy generation and transmission over an area of five million square kilometres. "There's a lot of people looking for a flat place with a lot of wind and saying, 'boy, that must be where to put a wind turbine, and I will make a lot of money'," MacDonald said.
"But that isn't necessarily so, especially if you recognize that if we are going to optimize over larger areas, it matters what the load is over larger areas."