With Renewables, It’s Location, Location, Location

By Catherine
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By Catherine Bolgar

As renewable energy projects multiply, and with momentum expected to accelerate thanks to the Paris Agreement on climate change, advances in modeling and simulation are improving site selection in order to maximize the return on investment.

A flood of new, mostly small entrants are providing simulations using meteorological parameters to compile detailed information about solar irradiation and wind conditions. “It’s relatively new. It’s disrupting the market,” says Nicolas Fichaux, senior program officer at the International Renewable Energy Agency (IRENA), the global intergovernmental organization for renewable energy, based in Abu Dhabi. “If you’re on a remote island in the Pacific, you can contact a private company and, for a couple of thousand dollars or euros, buy data about how much solar or wind power you have in a specific location. It will give you a good overview on the site quality. If you move ahead, you will combine it with local measurements to develop a bankable project.”

IRENA helps governments looking for the best sites for renewable energy projects. Considerations include not only the amount of sun or wind, but also topography, environmental factors and the distance to grid connections and population centers.

“We can help a government to select the combination of technology and area where energy will be the most cost effective,” Dr. Fichaux says. “We can say, ‘If you develop this cluster, this is the price of electricity you could expect, depending on the cost of capital.’ We can also test policies—for a given tariff, we can assess whether the returns will be fair. We can do this for every square kilometer on the globe. Three years ago, nobody could do that.”

The models use decades of public data from satellites, as well as other information, such as aircraft data and detailed mapping.

“We take the initial conditions—the larger-scale portrait of the atmosphere—and we improve the resolution and have more details of the flow characteristics,” says Gil Lizcano, Brussels-based director of research and development at Vortex, a cloud-based wind-modeling company headquartered in Barcelona. “We make meteorological models with very high resolutions of 100 square meters. You need to compute with high resolution to distinguish areas within a wind-farm domain.”

Clients may be project developers, manufacturers, governments or other entities. Locations may be greenfields—for example, a government wants to know the best places in a country for wind farms—or microsites, where the locations have already been chosen and the question is how to distribute the turbines for maximum effect, including their spacing and height. Technical advances have increased turbine capacity, blade length and tower height.

“Now modern turbines are 80 to 120 meters, even higher,” Mr. Lizcano says. “This 40 meters can make a lot of difference. Wind increases with height, and we need to know how much.”

Turbulence is another factor, reducing machine performance and lifespan; stronger machines are available but more expensive, and the client needs to know whether they’re necessary and worth the investment, he says.

Similarly for solar irradiation, the SoDa service combines a database of images taken every 15 minutes for 12 years by the Meteosat satellites with geographic data, such as altitude and land cover, to show where solar irradiation is high or low, with a resolution of a square kilometer. “On the scale of a country, this is very precise,” says Etienne Wey, general manager of Transvalor Innovation, which operates SoDa and is part of Transvalor SA, a Mougins, France, company that works closely on research with the Mines ParisTech engineering school.

Steep slopes, forests, swamps and farms aren’t ideal for solar plants; neither are places that might be very sunny but are far from population centers. “We use techniques of exclusion to filter the area with other data, then rank the site based not only on solar irradiation but also on, say, the distance to an electrical sourcepoint, because it has to plug into the network, or availability of water for cleaning mirrors if it’s concentrated solar power. Then we make a map with the ranking,” Dr. Wey says.

“What we have added are tools where you click on a point on a map and we will give the amount of photovoltaic production you can have at any place. Also, how much hot water you can create if you put in so many square meters of solar hot-water collectors,” he says. “We are trying to polish our crystal ball.”

For a successful integration of renewables in the electrical network, a key element will be the ESS – Energy Storage Systems. Such systems – commonly called batteries – will ensure a minimum level of energy availability as well as a good level of energy quality. Whereas only around 2 GW is installed today, IRENA estimates that the world needs 150 GW of battery storage to meet the desired target of 45% of power generated from renewable sources by 2030.

Once sites are narrowed down, customers need to complement the satellite data with measurements taken on the ground. “The amount of radiation over a year could have an error of 3%-5%,” Dr. Wey says. “On a global scale it’s not much, but as competitive bids for solar plants are more precise and cheaper, missing a prediction by 2%-3% could mean losing money. The ground measurements correct any bias in the satellite data.”

Other companies are creating prediction software to forecast the output of a photovoltaic farm or wind farm over the next three, six or nine hours, so the operators can bid on electricity markets and maximize revenues, Dr. Fichaux of IRENA says.

“There is a global understanding that there is a lot to be done on renewable energy,” he says. “We’re ready to move, but we need to estimate how big it will be, how much it will cost and how it will take place. It’s creating a boom in detailed modeling.”

 

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe, now working as a freelance writer and editor with WSJ. Custom Studios in EMEA. For more from Catherine Bolgar, along with other industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock

Better Batteries Stabilize the Electric Grid

By Catherine
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By Catherine Bolgar

Energy storage for the electric grid is taking off as the technology improves and battery prices fall. The global capacity of storage connected to the grid is expected to grow to 15-fold to 21 gigawatt hours this year, compared with 2015.

Energy storage can take many forms: freezing ice, then using a fan to blow over it and cool a building, replacing air conditioning; melting salt, then splashing water on it to create steam that powers a turbine; compressing air or other substances; pumping water up a hill behind a hydroelectric dam; flywheels; rechargeable flow batteries that use liquids; and solid-state batteries.

“There are so many ways to store energy. All are viable in their own way. All have applications and scale that they are suited for,” says Matt Roberts, executive director of the Energy Storage Association, a Washington, D.C.-based industry group. “The lion’s share being installed today is lithium-ion batteries.”

Industrial sites may use energy storage, often in the form of batteries, in order to reduce their peak power demand and cut their electricity bill by two-thirds to three-quarters, he says.

Most storage, though, is for controlling the frequency on the grid—60 Hertz in North America and 50 Hz elsewhere, which is achieved when supply and demand for electricity are in sync. If there is too much supply, substation transformers may be damaged; too much demand can cause brownouts.

Traditionally, the fluctuations in supply and demand have been smoothed out by peaking power plants, often fueled by natural gas. However, they may take three to five minutes to react, Mr. Roberts says. “In that time, the entire thing could swing in the other direction. Using a natural-gas plant for frequency control is like using a club for a surgical procedure.”

By contrast, battery storage can react in 100 milliseconds or less, says Andreas Ulbig, research associate at the Power Systems Lab of the Swiss Federal Institute of Technology Zurich (ETHZ) and co-founder of Adaptricity, a Zurich start-up that simulates active distribution grids. “Batteries are able to fill the gap with rapid response for balancing out renewables or reacting to any change in grid operations.”

In Europe, ancillary services—regulating frequency—from conventional sources and batteries get paid the same, he says. But in the U.S., the PJM Interconnection, which coordinates wholesale electricity in 13 Midwestern and mid-Atlantic states, pays battery owners a bonus for providing frequency control because they are so much faster, and therefore higher quality.

Under the PJM system, “a gas-powered plant chasing the grid signal can run at 99.9% efficiency 100% of the time,” Mr. Roberts says. “It means more profits, a better emissions profile, and less wasted energy on the grid.”

Energy storage is key to making smart grids and super grids work by balancing fluctuations over wider areas, using automation and modeling.

However, “most modeling systems are based on outdated asset class systems”—electricity generators such as power plants and photovoltaic arrays—Mr. Roberts says. “An energy storage system doesn’t generate electricity, but when it pushes energy onto the grid it looks like a provider. But it can also look like it’s absorbing energy. Current simulation systems aren’t sophisticated enough. They still model for the power plant spoke-and-hub model of the 1970s.

Models and simulations are improving. ETHZ and Adaptricity have created algorithms that allow battery owners to provide ancillary services that use less battery energy capacity while providing the same control services, Dr. Ulbig says. “It shows that smaller batteries can provide the same ancillary services as those with higher energy capacity.” Energy capacity is the biggest factor in the cost of batteries, so being able to get the same results with smaller batteries can cut costs significantly.

The importance of energy storage is set to grow as renewables make up a bigger share of the energy mix. The way that conventional power plants generate electricity, with gigantic rotating masses, creates slower deviations in frequency. With more renewables on the grid, “changes in grid frequency may happen faster. So it will be particularly useful to have faster frequency control,” Dr. Ulbig says.

Energy storage is set to grow, because it can “create a grid that integrates renewables, is flexible and resilient,” Mr. Roberts says. “It’s more cost effective and valuable.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe, now working as a freelance writer and editor with WSJ. Custom Studios in EMEA. For more from Catherine Bolgar, along with other industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock

 

 

 

 

Storage is the key to next generation energy

By Catherine
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Written by Catherine Bolgar*

Batteries

The linchpin in making sustainable energy mainstream is power storage.

Renewable energy sources can’t overtake carbon-based energy without good storage of energy for when the sun isn’t shining or the wind isn’t blowing. Electric vehicles won’t outsell gas vehicles until they have more autonomy and faster charging.

Batteries have become longer-lived, lighter, cheaper and safer, thanks largely to the boom in mobile electronics; new materials, nanotechnology and new understanding of electrochemistry are leading to more advances.

Batteries are an old technology, but people are really focusing on research and development now. I have no doubt that 10 years from now we will see some amazing batteries,” says Charles Barnhart, assistant professor of Environmental Sciences at Western Washington University.

Batteries remain a black box on a molecular scale. “There’s a tremendous effort internationally to understand in detail the processes during charging and discharging lithium-ion batteries,” says Olaf Wollersheim, project manager of the Competence E program at the Karlsruhe Institute of Technology (KIT), in Eggenstein-Leopoldshafen, Germany. “It’s really complex, because they are multimaterial systems.”

Lithium-ion, or li-ion, batteries have been adopted by the car industry because they are 98% to 99% efficient. However, they can burn “if they’re not treated with respect,” he says, adding that the auto industry has learned to use them safely.

Dr. Wollersheim recently inaugurated Germany’s largest solar power storage park at KIT, consisting of 102 smaller systems of 10 kilowatts each, with different orientations, module brands and inverter brands. The project aims to find the best combination for storage.

Energy plantOne avenue for improvement is software to control batteries. “A battery by itself is a stupid thing,” Dr. Wollersheim says. “It stores energy and gives it back. To do that optimally, you need an energy manager—a masterpiece of software. It has to take into account all the specifics of the electrochemistry of the cells. KIT has software with 10,000 lines of code just to control the storage system.”

Such controls can increase the battery’s lifetime and the return on investment. If the battery charges while the sun is still rising, it might be full and waiting for discharge at midday. That isn’t good for making the battery last. A control system might “charge the battery a little bit slower, in order to have shorter times of full charge,” he says.

Research also is looking at how stored energy interacts with the grid. Dr. Barnhart compared five kinds of batteries—lead-acid, li-ion, sodium-sulfur, vanadium-redox and zinc-bromine—to calculate how much energy it takes to store the electricity, including building the devices, and the amount of carbon they emit during manufacture and operation. He paired the different battery types with wind-generated and photovoltaic electricity, and matched them up against the power grid average to find the optimum combination.

Lead-acid batteries have a low cradle-to-grave energy cost, because lead is abundant and the technology is well established. However, they last only 200 to 400 charging/discharging cycles.

By contrast, Dr. Barnhart said, li-ion batteries have higher cradle-to-grave costs but last 3,000 to 5,000 cycles, making them the winner among batteries when paired with both solar and wind sources.

The cheapest, cleanest way to store power, Dr. Barnhart notes, isn’t a battery but pumped hydro—pumping water up a hill while the sun is shining or the wind is blowing, and then releasing the water to turn turbines and generate electricity when the renewable source isn’t working. A similar technology pumps compressed air into an underground cavern to spin a turbine later.hydro storage

Pumped hydro is 99% of the storage on the grid today” in the U.S., says Dr. Barnhart. “These are simple technologies that last a long time and aren’t subject to complex chemistries.”

However, geography limits the easy options for pumped hydro. In Germany, “there is strong public opposition to converting nice valleys into storage systems,” Dr. Wollersheim says.

The demand for electricity rose to 1,626 million tonnes of oil equivalent (Mtoe) in 2012 from 400 Mtoe in 1973, according to the International Energy Agency. The IEA forecasts electricity demand to grow by more than two-thirds between 2011 and 2035, and for renewables to account for 31% of power generation by 2035, up from 20% in 2011.

A big shift toward electric vehicles would add a large load to the electricity network, says Suleiman Sharkh, professor of  power electronics machines and drives at the University of Southampton in the U.K. “We and others say this would also be an opportunity to reinforce the grid, because those batteries on the electric vehicles are available when the vehicles aren’t being driven around. If we connect them to the grid, they could store energy from wind power or solar panels.”

Such a system would require the system to know in advance the driving needs for the vehicle, to make sure it’s charged enough, as well as information about electricity demand on the grid, he says. Costs would have to be calculated—perhaps car owners could charge for free or be paid for allowing their batteries to be used for grid storage, and for the extra wear and tear on the batteries.

With so much territory uncharted, the first applications of vehicles for power storage are likely to be municipal fleets, especially in China, where pollution concerns are accelerating a shift toward electric-powered transport, Dr. Sharkh says.

“It’s something we think is going to be a good option in the future,” he says.

*For more from Catherine, contributors from the Economist Intelligence Unit along with industry experts, join The Future Realities discussion.