Cloud forecasting could improve outlook for solar power

(Photo by Asian Development Bank via Creative Commons)

The amount of solar power on the Midwest’s electricity grid is minuscule enough that a cloudy day doesn’t cause problems for the system.

As solar makes inroads, though, utilities may eventually need new tools to make sure they can continue providing cheap, steady power when the sun goes behind a cloud.

Several efforts are currently underway to provide the industry with better sunlight forecasts, much like what grid operators currently use for wind power. Earlier this month the U.S. Department of Energy announced $8 million in funding for two projects to improve solar forecasting.

With wind power, accurate wind forecasts let grid operators make early decisions about how much electricity it will need from other, non-wind sources.

Making those calls in advance allows them to avoid running other power plants unnecessarily, and also reduces the odds of having to bid for electricity on expensive spot markets.

Sunlight forecasts could play a similar role for solar power and might help resolve some of utilities’ apprehensions about solar’s variability.

“The utilities are scared they won’t be able to manage too much solar on the grid,” says Manajit Sengupta, a senior scientist with the National Renewable Energy Laboratory in Colorado who studies solar radiation.

Challenges ahead

Managing an electric grid requires a constant balancing act, making sure the amount of electricity generated is always in line with what’s being used by customers. Variable electricity sources like wind and solar add a layer of complexity.

Solar is barely a blip today, so grid operators don’t need to react every time it clouds over. If the share of electricity coming from solar increases, though, an unexpectedly overcast day could cause problems.

“The moment we start reaching 3, 4, 5 percent, that’s huge. When you suddenly lose half of that, making that up is significant,” says Sengupta.

With solar prices falling by about 10 percent per year, that could come sooner than many expect, especially in regions with higher than average electricity prices.

Most of the interest in solar forecasting today is limited to those regional pockets, places like California and Hawaii where solar photovoltaics are already at or near grid parity.

“It’s very much an emerging market. It’s not nearly as mature as wind [forecasting], but I see it rapidly growing,” says Tom Hoff, president of Clean Power Research, a California firm that’s among the first to offer a commercial product for solar forecasting.

Keeping your head in the clouds

Clean Power Research released its SolarAnywhere product in May. The satellite-connected software gives a minute-by-minute update of approximate electricity output for a solar fleet, as well as forecasts up to seven days ahead.

“One of the beautiful things about solar is you can kind of see which way the wind is blowing the clouds,” says Hoff.

For shorter-term forecasts, up to five hours, SolarAnywhere uses satellite images of cloud movement and projects where the clouds are moving. Longer-term forecasts, from five hours to seven days, use data from weather forecasting models.

Another forecasting technique under development at the University of California-San Diego uses images from sky cameras placed on the ground at solar installations for short-term predictions.

“Ultimately solar forecasting is cloud forecasting, and clouds are very hard to forecast,” says Sengupta. A simple “partly cloudy” isn’t enough. Solar energy managers need to know variables like the cloud type, thickness, and elevation.

“A partly cloudy day at a solar plant can cause a lot of variability,” says Mark Ahlstrom, CEO of WindLogics, a subsidiary of NextEra Energy that works on renewable integration issues.

Thinking big

The promising news for solar is that when several solar plants are installed in the same region, the variation tends to smooth out more quickly than wind, says Ahlstrom. A cloud usually doesn’t shade every solar plant at once.

One of the lessons learned from wind integration is that grid operators should focus on variation in the system as a whole, rather than looking at individual wind farms or solar plants, he says. Also, variability can be better absorbed in larger balancing areas.

“I think you’ll see things move along more quickly when it comes to advancing solar integration into the grid because of what has been done with wind in the past,” says Ahlstrom.

Another big grid innovation that helped wind power integration and should do the same for solar, says Ahlstrom, is faster, near-real-time electricity markets.

Historically, almost all electricity generation decisions were made a day ahead of time. Now, many grid operators can adjust generation every five minutes in response to changes in electricity demand and wind output.

“We anticipate the need to do much shorter time frames to manage some of those grid integration challenges,” says Marie Schnitzer, who oversees the solar consulting business for AWS Truepower, which also sells forecasting services.

The demand for solar forecast data is regionalized but growing, says Schnitzer, who spoke about the need for better solar forecasting tools at the Renewable Energy World Conference in Orlando, Florida, last week.

“It’s not going to be an easy problem to solve,” says Ahlstrom, “but I think the current research is certainly on the right track.”

Originally published December 19, 2012 at 05:00AM at Midwest Energy News

Could anonymous reporting produce better wind-wildlife data?

(Photo by Graeme Maclean via Creative Commons)

A new wildlife fatality reporting tool for the wind industry aims to give researchers more data on bat and bird deaths — without publicly identifying the wind farms where they occurred.

The American Wind Wildlife Institute will start seeking voluntary submissions of wildlife monitoring reports next month. Approved researchers will have access to the collection if they agree to keep specific projects and companies anonymous.

The data repository project is an attempt to resolve developers’ fears about legal liability and negative publicity, while also making it easier for researchers to find information on bat and bird collisions at wind turbines.

“The ultimate goal is to build a comprehensive wind-wildlife database,” says Taber Allison, director of research and evaluation for the American Wind Wildlife Institute.

The institute is an independent nonprofit organization whose board of directors is split evenly between representatives of the wind industry and conservation groups (including members of RE-AMP, which publishes Midwest Energy News.)

Making data accessible

The initial focus will be on gathering data on post-construction fatality monitoring — wildlife surveys conducted after a wind farm is built and in operation. State agencies are requesting post-construction monitoring more frequently in recent years as a condition for granting permits.

Even though the studies are becoming more common, they’ve been largely inaccessible to wildlife researchers. Many reports are never made public. Others are hard to find or don’t provide enough detail about analysis and assumptions to be used in broader studies.

The American Wind Wildlife Institute has been developing its Research Information System for about a year and a half. It just completed a successful test run for technical issues, and now it’s ready to start soliciting its first submissions after the holidays.

Wind farm operators who conduct post-construction monitoring studies will be able to upload their data and literature to the system, which will convert it to a common, searchable format that can be queried by approved researchers.

After gathering enough studies, the institute will likely hand-pick an analyst who would be given controlled access to the information and be asked to produce a peer-reviewed, published research report using the data.

Allison says he eventually sees opening up the database to outside research proposals, but first they need to establish trust with wind developers and prove they can protect participants’ privacy.

There’s still plenty researchers could learn without publicly identifying the wind farms involved, he says. They could compare fatalities by region or turbine type, or look at how different wildlife survey techniques produce different results.

Allison says they’ve had a “generally favorable” reception from wind developers. Several have already provided the institute with sample data for use in the test run. The American Wind Energy Association passed a resolution of support in February 2011.

Study barriers

One reason the wind industry is on board with the project is that it seeks to address some of developers’ top concerns about collecting and sharing wildlife fatality monitoring data.

A new survey of wind industry officials in the Great Lakes region found that fears about legal liability and negative publicity were developers’ top reasons for not wanting to share post-construction wildlife fatality data.

The survey, by Minneapolis environmental research firm Dovetail Partners, interviewed 46 stakeholders, including 19 developers or consultants and 17 employees of state or federal agencies.

As wind developments have moved closer to more populated areas, several projects have run into resistance from local activists. Companies don’t want to publicly share data that’s going to be misinterpreted and spun against them by opponents.

They also don’t want to be in the position of building a criminal case against themselves. Most birds are protected by federal law, and wind developers don’t have any guarantee they won’t be prosecuted for unintentional kills.

On top of that, the studies are expensive, ranging most often between $50,000 to $250,000 per year, says Rob Bouta, a senior environmental scientist with Westwood Professional Services, which consults for energy and land developers.

“It’s time consuming. It’s labor intensive. It requires a certain amount of statistical analysis,” says Bouta. “You wouldn’t want to do that kind of study, and as a result put your project more at risk.”

Finding common ground

Post-construction wildlife monitoring is becoming more common, but that’s only because more government agencies are asking for the studies as part of permitting agreements.

Over the last eight years, Bouta has worked on around 70 wind projects, mostly doing pre-construction wildlife studies. He’s currently working on his first post-construction study, which he believes is the first in Minnesota in more than a decade.

Can he say which wind farm he’s studying? “I would prefer not to,” says Bouta, citing the same privacy sensitivities identified in the Dovetail survey.

Wind developers and agency officials both identified cost as the top barrier to collecting post-construction wildlife data, but they gave different responses when asked why more data isn’t shared with government agencies.

Agency representatives said developers don’t share wildlife data with them because they’re afraid of being told to change or curtail their operations, which developers actually cited as their fourth highest concern.

Dr. Sarah Stai, an associate ecologist and author of the Dovetail report, says she hopes the survey can help agencies and developers find common ground by better understanding each others’ perspectives.

“That’s really important to overcoming the barriers, that everyone’s on the same page,” says Stai. “We don’t have a huge sample size, but it does appear they’re not on the same page.”

Stai says the reporting system by the American Wind Wildlife Institute is a promising step toward solving some of developers’ concerns about sharing data.

“The idea is everybody benefits from learning what happens [after construction] so that we can make better predictions in the future.”

Originally published December 11, 2012 at 05:00AM at Midwest Energy News

After changing light bulbs, utilities look to change behavior

(Photo by Chris Campbell via Creative Commons)

New federal light bulb standards are about to dim the amount of energy savings utilities can take credit for.

And as utilities look for ways to make up for those lost savings in their state-mandated energy efficiency portfolios, there’s growing interest in programs that essentially use peer pressure to encourage homeowners to save energy.

Most utilities in the Midwest are required to help customers achieve a certain level of energy savings each year. Lighting programs have been by far the most popular means of meeting those targets, which are mandatory in Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin.

Behavior change programs, rather than helping to replace appliances or light bulbs, seek to get people to use them more efficiently, often by providing more detailed data about a customer’s energy use.

“Several companies, mostly from the IT [industry], realized that utilities have a lot of data on their customers, but often can’t put it all together in a way to affect consumer change,” says Jay Wrobel, executive director of the Midwest Energy Efficiency Alliance, a nonprofit that promotes energy conservation.

The highest-profile service so far is Opower, which partners with utilities to give customers periodic reports on how their energy use compares to neighbors and similar households. On average, customers who receive the mailings wind up reducing their energy consumption by about 2 percent.

Opower now offers its service through 75 utilities, including 20 in the Midwest. Minnesota has the most utilities signed up, with 10, although the Midwest’s largest Opower programs are at American Electric Power in Ohio and Ameren and ComEd in Illinois.

“The Midwest has a number of the features that [make our program] attractive for utilities,” says Arkadi Gerney, Opower’s senior director of policy. Those include mandatory energy efficiency targets in most states and well-designed compensation to utilities for lost revenue, he says.

Decreasing emphasis on lighting

Many utilities will have a vacuum to fill in their efficiency portfolios as new federal lighting rules are phased in. By January 2014, all light bulbs will have to meet new efficiency standards, raising the baseline for how much utilities can take credit for in their own conservation programs.

Opower recently reviewed the efficiency portfolio plans for three dozen utilities, including both current and prospective customers, says Gerney. In 2012, lighting accounted for about 40 percent of residential portfolios. By 2015, that share is projected to fall to just 10 percent.

“We’ve already seen utility efficiency planning that’s accepted that lighting, which has been the backbone of their residential portfolios, is probably going to be a declining portion,” says Gerney. “I think that’s one of the reasons that utilities have been attracted to Opower, as one of a number of choices they have for picking up that slack.”

Wrobel says behavior change programs such as Opower’s have proven to be among the most cost-effective options for residential efficiency. Utilities generally want a broad suite of programs to make sure they hit their targets, which are fairly aggressive in the Midwest.

Lee Gabler, director of demand-side management for Xcel Energy, says the lighting standards are “absolutely” part of the reason Xcel is interested in Opower. The utility is expanding its Opower pilot program in Minnesota from 50,000 customers to 150,000 in 2013.

“We’re looking at all different areas right now to fill that void that will occur when those baselines change,” says Gabler. “I think behavioral is going to be a small piece of it. We don’t see it as a silver bullet. I don’t know if we know of any silver bullet. It’s going to be a lot of silver buckshot.”

‘Every gigawatt hour helps’

Minnesota requires utilities to achieve annual energy savings equal to 1.5 percent of sales. Xcel Energy recently filed its efficiency plan for 2013 through 2015, during which it plans to help customers conserve 436 gigawatt hours, of which only 8.5 will come from the Opower program.

“It’s a small program, yet every gigawatt hour helps as we try to achieve the 1.5 percent,” says Gabler.

Gabler says he would consider the Opower program very successful if it ever grows to 5 percent of the utility’s efficiency portfolio. Gerney says the program can go higher. In Massachusetts, for example, Opower accounts for 24 percent of residential efficiency programs.

Gerney says behavior change programs are a good successor to CFL giveaways and lighting rebates for another reason, too: there’s opportunity for anyone to participate.

Other residential programs such as insulation rebates or refrigerator recycling are cost-effective, but participation is generally limited to homeowners with the means to make those investments.

“Most of the other programs, everybody pays through their rates but only a small number of people, often concentrated in the higher-income categories, are the ones who are able to directly participate in the programs each year,” says Gerney. “With Opower, everybody pays but an enormous proportion of people are able to benefit.”

Originally published December 07, 2012 at 05:00AM at Midwest Energy News

Could wood biomass help clean up coal-fired power plants?

Could wood biomass help clean up coal-fired power plants?(Midwest Energy News, December 5, 2012)—Cheap natural gas and flat electricity demand has left the prospects for wood-chip and wood-pellet fuels barely smoldering in recent years.

But wood biomass could soon have a new role in energy production: cleaning up coal-fired power plant emissions.

A year-old company called Biogenic Reagents recently completed construction of a $30 million, commercial-scale production facility in Marquette, Michigan, where it’s cooking sustainably harvested wood into a product that can pull mercury out of power plant emissions.

The technology could enable coal plants to comply with forthcoming EPA mercury rules at a relatively low cost.

The process involves a technique called pyrolysis, in which wood is heated in an oxygen-deprived container. Without oxygen, wood can’t burn. After a sequence of chemical reactions to remove volatile organic compounds, what’s left is a pure material known as activated carbon.

Activated carbon, sometimes called activated charcoal, is a porous material that’s good at absorbing or bonding with other materials. Its most common use is in water filtration, everywhere from municipal water treatment plants to the water pitcher in your refrigerator.

The use of activated carbon at power plants is a relatively new one. A mercury emissions control program at the U.S. Department of Energy’s National Energy Technology Laboratory in Pittsburgh funded activated carbon research for about a decade ending in 2008, when it decided federal support was no longer needed.

“What’s compelling about it is it’s an inexpensive retrofit technology,” says Tom Feeley, a senior technical advisor who managed the DOE mercury control program. Continue reading “Could wood biomass help clean up coal-fired power plants?”