Storage is the key to next generation energy

By Catherine
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Written by Catherine Bolgar*


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.

Energy planning for a world turned on its head

By Catherine
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By Catherine Bolgar*

Data centers guzzle it. The coming Internet of Things, with the gadgets and appliances in our homes and workplaces interconnected, depends on it. A shift in our automobiles away from petroleum fuels will vastly multiply our need for it.

Solar Power Panels

Our future is powered by electricity. Demand for electricity by 2050 will increase 127% from 2011 levels, the International Energy Agency predicts, with demand in developing countries booming fourfold.

We love electricity because it’s so nonpolluting at the point of consumption. We don’t have nasty fumes coming from our refrigerators or our computers. But electricity isn’t carbon-free. Emissions from electricity generation rose 75% between 1990 and 2011, the IEA says. Increasing electricity generation to meet future demand requires a 90% cut in emissions in order to limit the rise in global temperature to two degrees Celsius.

That means not only relying more on renewables but also rethinking the entire electricity industry, from generation to distribution.

There is a big revolution occurring in the power industry,” says Martin Green, professor at the Australian Centre for Advanced Photovoltaics at the University of New South Wales in Sydney. “The whole business model has collapsed in a few years.”

Peak prices for electricity, whether in Europe or Australia, used to occur during summer afternoons. In Europe, where nuclear energy is widely used, plants had to trim output just as demand was peaking, because they weren’t allowed to dump the hot water they create into rivers, Dr. Green explains. That exaggerated the gap between supply and demand, and created even higher prices.

In Australia, many utilities were able to make their profits for the whole year thanks to summer peaks, he says, adding, “Everyone was bidding up their prices.”

However, the huge surge in solar panel installations—cumulative installed global capacity rose about 44-fold from 2010 to 2011 , the IEA says—has changed that equation, by producing the most electricity exactly at the times of peak demand: summer afternoons.

Utilities need to find a way to make money from solar. For the unadventurous ones, solar is really bad news. It’s taking away from demand for electricity,” Dr. Green says.

Renewables pose two big challenges for the power industry: They are intermittent and thus require storage or a backup, and they require a different kind of grid.

To ensure that when the wind is calm or the sky is cloudy there’s still enough electricity for peak demand, the system needs extra capacity. Average power demand in Germany, for example, is 80,000 megawatts, and peak demand is 130,000 megawatts, says Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany. If 80% of the energy mix is renewables, as Germany intends by 2050, such a system would need 200,000 megawatts of wind power and 200,000 megawatts of solar power—overcapacity is necessary to compensate for the times when it’s calm or dark.

So at off-peak times and on sunny, windy days, Germany would have far more electricity than it needs. “The future will be characterized by times where we have excess electricity,” he says.

One way to take advantage of the surplus is storage. Better storage, in the form of batteries or other means, is advancing. For example, electric cars that charge while parked during the day would be one way to store some solar power. Another way is to use the solar energy to split apart water molecules, releasing the oxygen and keeping the hydrogen for use as fuel.

As for backup power, “natural gas is the absolute complement for renewables,” says Oliver Inderwildi, senior policy fellow at the Smith School of Enterprise and Environment at Oxford University in the U.K. “Gas can be shut off or turned on quickly and can operate at various levels. If it gets cloudy, you can fire up a couple of turbines to make up the shortfall from solar. You can’t do that for coal or nuclear.”

The boom in cheap shale gas in the U.S. is crowding coal out of the energy mix there, he says. Building a gas-fired plant is much faster and cheaper than for coal or nuclear as well. A gas-fired plant can be built in 18 to 36 months, versus about six years for a coal plant.

In much of the world, however, gas is more expensive than coal. India and China are building coal plants to meet electricity needs, but they are locking themselves into a high-carbon infrastructure over the long term, Dr. Inderwildi says. The catch, he adds, is “CO2 is a global problem. It doesn’t matter where it’s emitted.”

The other challenge with renewable energy is distribution. The dispersed nature of renewable sources, such as rooftop solar panels, makes planning difficult.

The grid network is moving away from centralized plants to more distributed generation: wind, solar, biomass and other options,” says Dr. Green. “Some costs and benefits arise from that. You don’t have to have power lines carrying the same density of power. You used to have electricity flowing out from power plants in one direction. Now a lot of electricity is flowing the other way. The grid needs upgrading.”

Solar panels in front of wind turbines and mountains

And since the cost of maintaining and upgrading the grid’s assets is typically bundled into the cost of electricity consumption, people who generate renewable energy – through rooftop solar, say – are using the grid infrastructure for storing their extra solar energy without paying for the grid, which is an unsustainable utility model.

Smart grids use technology to communicate between energy suppliers and users to make the system far more efficient, for example, by allowing consumers to choose to reduce energy use at peak times.

“Smart grids are definitely happening,” he says. “It won’t be overnight, but they are incrementally being implemented.”

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

#IFWE Challenge prizewinner to pitch at GreenBiz #VERGECon

By Aurelien
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Milos Milisavljevic

Milos Milisavljevic, co-founder and CEO of Strawberry Energy, and prizewinner of the #IFWE Challenge will be pitching today at VERGE Conference in San Francisco, an international event “where tech meets sustainability” organised by our partner GreenBiz.

Indeed, not only Milos will be attending the conference (as part of his perks for winning the 2nd prize of the #IFWE Challenge), but he has been selected among tens of other candidates to pitch about his projects in front of a large audience of sustainability professionals, media, and investors.

See his application pitch below:

As a matter of fact, Milos is already used to such exercise as he brilliantly spoke at the New Cities Summit 2014 event (organized by our partner New Cities Foundation). Watch his presentation below: YouTube Preview Image But for now, let’s wish best of luck to Milos’ pitch today, between 10:05 and 10:30 (San Francisco time)! If you’re not physically attending VERGE Conference, you can still attend VERGE Virtual Event by registering for free.

Strawberry Energy

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