Solar Energy To Get Boost From Cutting-Edge Clouds Forecasts

A new research initiative is designed to lead to unprecedented 36-hour forecasts of incoming energy from the Sun, thereby helping utilities obtain energy more efficiently from solar energy power plants. Credit: NCAR.

National Center for Atmospheric Research News Release

BOULDER—Applying its atmospheric expertise to solar energy, the National Center for Atmospheric Research (NCAR) is spearheading a three-year, nationwide project to create unprecedented, 36-hour forecasts of incoming energy from the Sun for solar energy power plants.

The research team is designing a prototype system to forecast sunlight and resulting power every 15 minutes over specific solar facilities, thereby enabling utilities to continuously anticipate the amount of available solar energy. The work, funded primarily with a $4.1 million U.S. Department of Energy grant, will draw on cutting-edge research techniques at leading government labs and universities across the country, in partnership with utilities, other energy companies, and commercial forecast providers.

Much of the focus will be on generating detailed predictions of clouds and atmospheric particles that can reduce incoming energy from the Sun.

“It’s critical for utility managers to know how much sunlight will be reaching solar energy plants in order to have confidence that they can supply sufficient power when their customers need it,” says Sue Ellen Haupt, director of NCAR’s Weather Systems and Assessment Program and the lead researcher on the solar energy project. “These detailed cloud and irradiance forecasts are a vital step in using more energy from the Sun.”

The project takes aim at one of the greatest challenges in meteorology: accurately predicting cloud cover over specific areas. In addition to helping utilities tap solar energy more effectively, detailed cloud predictions can also improve the accuracy of shorter-term weather forecasts.

The project expands NCAR’s focus on renewable energy. NCAR designed a highly detailed wind energy forecasting system with Xcel Energy that saved Xcel ratepayers an estimated $6 million in a single year. The center is also creating advanced prediction capabilities to enable wind farm developers to anticipate wind energy potential anywhere in the world.

“Improving forecasts for renewable energy from the Sun produces a major return on investment for society,” says Thomas Bogdan, president of the University Corporation for Atmospheric Research, which manages NCAR on behalf of the National Science Foundation. “By helping utilities produce energy more efficiently from the Sun, we can make this market more cost competitive.”

Clouded forecasts

More than half of all states in the U.S. have mandated that utilities increase their use of renewable energy as a way to reduce dependence on fossil fuels such as coal, oil, and natural gas, which affect air quality and release greenhouse gases associated with climate change. But the shift to energy sources such as solar or wind means relying on resources that are difficult to predict.

Because large amounts of electricity cannot be stored in a cost-effective manner, power generated by a solar panel or any other source must be promptly consumed. If an electric utility powers down a coal- or natural gas-fired facility in anticipation of solar energy, those plants may not be able to power up fast enough if clouds roll in. The only option in such a scenario is to buy energy on the spot market, which can be very costly.

Conversely, if more sunshine reaches a solar farm than expected, the extra energy can go to waste.

But predicting clouds, which form out of microscopic droplets of water or ice, is also notoriously difficult. Clouds are affected by a myriad of factors, including winds, humidity, sunlight, surface heat, and tiny airborne particles, as well as chemicals and gases in the atmosphere.

Solar energy output is affected not just by when and where clouds form, but also by the types of clouds present. The thickness and elevation of clouds have greatly differing effects on the amount of sunlight reaching the ground. Wispy cirrus clouds several miles above the surface, for example, block far less sunlight than thick, low-lying stratus clouds.

To design a system that can generate such detailed forecasts, NCAR and its partners will marshal an array of observing instruments, including lidars (which use laser-based technology to take measurements in the atmosphere); specialized computer models; and mathematical and artificial intelligence techniques. Central to the effort will be three total sky imagers in each of several locations, which will observe the entire sky, triangulate the height and depth of clouds, and trace their paths across the sky.

The team will test these advanced capabilities during different seasons in several geographically diverse U.S. locations: the Northeast, Florida, Colorado/New Mexico, and California. The goal is to ensure that the system works year round in different types of weather patterns.

Not just for solar energy

Once the system is tested, the techniques will be widely disseminated for use by the energy industry and meteorologists.

“This will raise the bar for providing timely forecasts for solar power, ” Haupt says. “It also represents a great opportunity for providing far more detail about clouds in the everyday weather forecasts that we all rely on.”

One application for such detailed forecasts could be short-term predictions of pavement temperatures. Such information would be useful to airport managers, road crews, and professional race car drivers.

“Pavement temperatures make quite a bit of difference in how tires grip the surface,” says Sheldon Drobot, deputy director of NCAR’s Weather Systems and Assessment Program. “This has substantial safety implications.”

NCAR is launching the solar project with numerous partners in the public and private sectors. These include:

Government labs: National Renewable Energy Laboratory, Brookhaven National Laboratory, the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory and other NOAA facilities;

Universities: The Pennsylvania State University, Colorado State University, University of Hawaii, and University of Washington;

Utilities: Long Island Power Authority, New York Power Authority, Public Service Company of Colorado, Sacramento Municipal Utility District (SMUD), Southern California Edison, and the Hawaiian Electric Company;

Independent system operators: New York ISO, Xcel Energy, SMUD, California ISO, and Hawaiian Electric; and

Commercial forecast providers: Schneider Electric, Atmospheric and Environmental Research, Global Weather Corporation, and MDA Information Systems.

Computing time will be provided by the New York State Department of Economic Development’s Division of Science, Technology and Innovation on an IBM Blue Gene supercomputer at Brookhaven National Laboratory.

— NCAR News Release

15 Responses to Solar Energy To Get Boost From Cutting-Edge Clouds Forecasts

  1. Paul Magnus says:

    I wonder how large solar farms will affect the weather….

  2. Paul Klinkman says:

    That’s a reasonable question.

    Current dark PV collectors absorb heat. In large arrays they create microclimates, raising everybody else’s air conditioning costs and incidentally reducing solar power production due to higher temperatures.

    If a certain type of solar collector only needs one particular wavelength of light, a surface similar to Low-E film, a product available for window treatment at your local hardware big box store, would bounce 50% to 90% of solar rays back out into space, driving the microclimate the other way.

    Solar thermal plants have both a high temperature problem and possibly a higher humidity issue due to their producing quantities of waste steam. Coal plants also produce lots of waste heat. My patent pending solar thermal electricity system manages to get around this problem.

  3. Paul Klinkman says:

    When the country starts facing up to the fact that we always need power supply to meet power demand, clouds or not, these forecasts will help us to save up impounded water behind dams for those occasions and to conserve on marginal energy uses — that extra streetlight will have to go dark at 2:00 a.m. We’ll still be burning storable fuel (biodiesel, cellulose) on those few days when demand peaks and supply fails.

  4. Paul Klinkman says:

    I encourage these people to mix detrendent correspondence analysis into their modeling. Local weather features react consistently, and in curious ways. For example, in New England, the rain/snow storms consistently dry up long before a predicted changeover to snow. We’re used to the forecasters being wrong, and the good local weather forecasters adjust their rip and read forecasts accordingly.

  5. Joan Savage says:

    It’s odd that the other purposes listed for a 36-hour insolation forecast included NASCAR tires, but not forecasts for either human health risks or agricultural crop watering.

  6. Gingerbaker says:

    You don’t put up wind towers where it is only marginally windy, do you? You don’t build hydro-electric dams on small streams, you use large rivers, right?

    Why not just put all the solar installations where there are no clouds, the sun shines all the time, the days are long, and the sunshine is intensely strong?

    You know – in the American southwest, where a single large-scale PV installation could provide 100% of the electricity the nation needs. Where we could build such a facility in 5 years, and actually solve the AGW problem in time.

  7. Joe Romm says:

    Short answer: Rooftops!

  8. Bart Flaster says:

    The question that comes to mind is:

    How is Germany handling this?

  9. Daniel Coffey says:

    Joe: We will not get a second chance to deal with global warming. Half-measures will not get it done.

    Not to engage in gratuitous argument, but a “rooftops” response demands a bit more detail. How many rooftops? How dispersed? Who will own them? Who will maintain them? How will the energy be dispatched to match demand? How will high production be managed on clear days with low demand transmitted across small wire distribution?

    The simple answer “rooftops” is not altogether an unqualified answer, nor is it one which can be rapidly deployed, or which can be used across large demands such as pumping water for water or sewage. Rooftops are fine at rather low penetration, but it really messes up the distribution system – upon which consumers are dependent when solar does not provide electricity – when deployed beyond a relatively small level.

    It would be very useful to have a candid discussion of the real limits, logistical time to deploy, and important ancillary effects on the electricity system when solar-on-rooftop is used.

    Note also that the Germans did a lot of post-deployment retrofitting.

  10. Daniel Coffey says:

    It is my view that the time to deploy for large scale solar is very short, with actual construction times in months, not years, even for very large multi-megawatt (50 to 100 or more) facilities. Large scale solar PV, when linked into proper transmission can do a great deal more that people think. It also produces electricity at about 1/3 the price of solar-on-rooftop (SOR).

    My predominant concern is that we are slow-walking our responses to global warming and not acting rapidly enough with respect to transforming our electricity production by decarbonizing it, and not doing enough to provide adequate substitute power to facilitate electrification of transportation. We can do all of these things, but people need a real substitute, not expensive and impractical options.

    I recently wrote two pieces about large scale solar and transferring solar power into vehicles using grid-connected solar PV. We have the technology, but it appears that philosophy is locking us into a slow-walk strategy which will prevent adequate deployment of the technology in ways which will make it readily available and competitive with coal, natural gas and oil.

  11. Daniel Coffey says:

    Super good question. The German experience is much more complicated than people tend to realize, and the requirement to retrofit post-deployment, especially with better inverters, is a lesson we need to learn from and anticipate.

    Inverters is a huge topic almost never discussed, but one which has an enormous effect on how solar can be beneficially deployed.

  12. Mulga Mumblebrain says:

    Priorities, Joan, priorities.

  13. Joan Savage says:

    Do the Germans have a hybrid coal-solar parabolic plant in the works?

    That’s what Xcel Energy, the main partner in this DOE project wants to do.

  14. Joe Romm says:

    Don’t follow you. I assume you’ve read my proposed solution. You need to do everything.

  15. Joan Savage says:

    From the perspective of the Xcel Energy project, this R&D could also be announced as “Coal use efficiency to get a boost from cloud forecasts.”

    The NCAR piece doesn’t indicate if the plans for regional implementation are all for similar partnerships between coal fired plants and supplemental solar installations.