The United States could slash greenhouse gas emissions from
power production by up to 78 percent below 1990 levels within 15 years
while meeting increased demand, according to a new study by NOAA and
University of Colorado Boulder researchers.
The study used a sophisticated mathematical model to
evaluate future cost, demand, generation and transmission scenarios. It
found that with improvements in transmission infrastructure,
weather-driven renewable resources could supply most of the nation’s
electricity at costs similar to today’s. “Our research shows a transition to a reliable, low-carbon,
electrical generation and transmission system can be accomplished with
commercially available technology and within 15 years,” said Alexander
MacDonald, co-lead author and recently retired director of NOAA’s Earth System Research Laboratory (ESRL) in Boulder.
A high-resolution map based on NOAA solar irradiance data shows a snapshot of solar energy potential across the United States.
(Credit: Image by Chris Clack/CIRES)
The paper was published online in the journal Nature Climate Change.
Although improvements in wind and solar generation have
continued to ratchet down the cost of producing renewable energy, these
energy resources are inherently intermittent. As a result, utilities
have invested in surplus generation capacity to back up renewable
energy generation with natural gas-fired generators and other reserves. “In the future, they may not need to,” said co-lead author
Christopher Clack, a physicist and mathematician with the Cooperative
Institute for Research in Environmental Sciences at the University of
Colorado Boulder.
Since the sun is shining or winds are blowing somewhere
across the United States all of the time, MacDonald theorized that the
key to resolving the dilemma of intermittent renewable generation might
be to scale up the renewable energy generation system to match the
scale of weather systems.
So MacDonald, who has studied weather and worked to improve
forecasts for more than 40 years, assembled a team of four other NOAA
scientists to explore the idea. Using NOAA’s high-resolution
meteorological data, they built a model to evaluate the cost of
integrating different sources of electricity into a national energy
system. The model estimates renewable resource potential, energy
demand, emissions of carbon dioxide (CO2) and the costs of expanding and operating electricity generation and transmission systems to meet future needs.
The model allowed researchers to evaluate the affordability,
reliability, and greenhouse gas emissions of various energy mixes,
including coal. It showed that low-cost and low-emissions are not
mutually exclusive. “The model relentlessly seeks the lowest-cost energy, whatever
constraints are applied,” Clack said. “And it always installs more
renewable energy on the grid than exists today.”
Even in a scenario where renewable energy costs more than experts predict, the model produced a system that cuts CO2
emissions 33 percent below 1990 levels by 2030, and delivered
electricity at about 8.6 cents per kilowatt hour. By comparison,
electricity cost 9.4 cents per kWh in 2012. If renewable energy costs were lower and natural gas costs higher, as is expected in the future, the modeled system sliced CO2
emissions by 78 percent from 1990 levels and delivered electricity at
10 cents per kWh. The year 1990 is a standard scientific benchmark for
greenhouse gas analysis. A scenario that included coal yielded lower cost (8.5 cents per kWh), but the highest emissions.
At the recent Paris climate summit, the United States pledged
to cut greenhouse emissions from all sectors up to 28 percent below
2005 levels by 2025. The new paper suggests the United States could cut
total CO2 emissions 31 percent below 2005 levels by 2030 by
making changes only within the electric sector, even though the
electrical sector represents just 38 percent of the national CO2 budget. These changes would include rapidly expanding renewable energy generation and improving transmission infrastructure.
In identifying low-cost solutions, researchers enabled the
model to build and pay for transmission infrastructure improvements —
specifically a new, high-voltage direct-current transmission grid
(HVDC) to supplement the current electrical grid. HVDC lines, which are
in use around the world, reduce energy losses during long-distance
transmission. The model did choose to use those lines extensively, and
the study found that investing in efficient, long-distance
transmission was key to keeping costs low.
MacDonald compared the idea of a HVDC grid with the interstate
highway system which transformed the U.S. economy in the 1950s. “With
an ‘interstate for electrons’, renewable energy could be delivered
anywhere in the country while emissions plummet,” he said. “An HVDC
grid would create a national electricity market in which all types of
generation, including low-carbon sources, compete on a cost basis. The
surprise was how dominant wind and solar could be.”
The new model is drawing interest from other experts in the field.
"This study pushes the envelope,” said Stanford University’s
Mark Jacobson, who commented on the findings in an editorial he wrote
for the journal Nature Climate Change. “It shows that
intermittent renewables plus transmission can eliminate most fossil-fuel
electricity while matching power demand at lower cost than a fossil
fuel-based grid - even before storage is considered."
U.S. National Oceanic and Atmospheric Administration (NOAA) www.NOAA.gov
Press Release dated January 25, 2016
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