Rhubarb battery from Harvard
By Tina Casey, Originally published on Clean Technica 13 Feb 2017
A research team from Harvard University’s John A. Paulson School of Engineering and Applied Sciences has come up with a new, low cost “mega” scale energy storage system that could function effectively for ten or more years with minimal need for maintenance and repair. In commercial operation, the new battery would open up the door for more wind and solar energy in the grid, and slam the door on coal.
Aside from hastening the demise of coal for power generation, the new battery also poses a threat to the current gold standard for energy storage, lithium-ion. In addition to large arrays for grid use, the Harvard technology is easily scalable for home use, where it could store energy from rooftop solar panels.
New Energy Storage System From Harvard: #ThanksObama!
The US Department of Energy has not updated its news page since Inauguration Day, but advanced energy programs that flourished under the Obama Administration are still bearing new fruit.
The Harvard University energy storage project has been supported by the Energy Department’s Office of Electricity Delivery and Energy Reliability, and by its Advanced Research Projects Agency-Energy funding division for breakthrough technologies. ARPA-E was launched under the Bush Administration but did not kick into gear with funding until Obama took office.
The Harvard project caught the eye of ARPA-E because it promises low cost, grid-scale energy storage. ARPA-E began funding the Harvard energy storage research back in 2012 under its OPEN funding program. The program was “designed to catalyze transformational breakthroughs across the entire spectrum of energy technologies.” OPEN focused on “game-changing” projects that would cement America’s history of global technological leadership in energy related fields. To make the cut, applicants had to meet three main goals:
- Security: Increased access to and use of domestically produced sources of energy would help reduce U.S. dependence on foreign oil and increase our nation’s energy security.
- Environment: Developing new and renewable sources of energy would reduce our reliance on fossil fuels that create harmful greenhouse gas emissions and contribute to global warming.
- Economy: Inexpensive sources of energy would help the millions of American consumers and small business owners who can’t afford the energy they need to live and work.
Revving Up The Next Generation Of Flow Batteries
The Harvard device is a flow battery. Loosely speaking, this type of energy storage system is based on the electrical charge that occurs when two specialized liquids flow adjacent to each other, typically separated by a thin membrane. The liquids are stored in separate tanks until they are needed, so flow batteries are easy to maintain and can sit idle for long periods of time without losing efficiency.
On the down side, conventional flow batteries are large, clunky affairs. They rely on expensive metals and require regular maintenance in order to maintain capacity.
The Harvard project demonstrates how quickly flow battery technology has improved in recent years. In 2014, the Harvard team reported that it had successfully replaced the metal-based liquid in flow batteries with organic molecules called quinones. If you had to look quinones up, so did we. Here’s an explainer from a paper published in the US National Library of Medicine: Quinones are ubiquitous in nature and constitute an important class of naturally occurring compounds found in plants, fungi and bacteria. Human exposure to quinones therefore occurs via the diet, but also clinically or via airborne pollutants.
The Harvard team was interested in quinones because they are cheap and abundant. They exist in crude oil as well as plants, for example. However, quinone exposure can provoke toxic reactions in humans, so supply chain issues are going to be one challenge for commercializing the technology.
Setting that aside, once the team began focusing on quinones, the question was which quinones would function most effectively in a flow battery. The 2014 research involved identifying the properties of more than 10,000 different quinone molecules in search of the best candidates for a flow battery. In a win for bio-based alternatives to petroleum, the first iteration of the new flow battery used a quinone that was practically the same as a quinone from rhubarb.
More And Better Energy Storage
The 2014 report covered a flow battery that maintained efficiency over 100 charge-discharge cycles. That’s not much, so one critical task of the team was to improve the discharge rate. It looks like they did that. The new research was just published in the journal ACS Energy Letters under the title, “A Neutral pH Aqueous Organic/Organometallic Redox Flow Battery with Extremely High Capacity Retention,” which has all the details.
For those of you on the go, the bottom line is that the Harvard team boosted the performance of their flow battery up to a loss of just one percent capacity every 1,000 cycles. The key breakthrough was to find molecules that don’t degrade as quickly in neutral solutions. The use of a neutral solution is important from a cost control perspective, because it helps keep the cost of the membrane down: …Most flow batteries today use expensive polymers that can withstand the aggressive chemistry inside the battery. They can account for up to one-third of the total cost of the device. With essentially salt water on both sides of the membrane, expensive polymers can be replaced by cheap hydrocarbons.
Though the primary target is grid scale energy storage, the new iteration of the Harvard flow batteries requires minimal maintenance and would be as safe for home use as any other large appliance. Here’s the rundown from Harvard:
Because we were able to dissolve the electrolytes in neutral water, this is a long-lasting battery that you could put in your basement…If it spilled on the floor, it wouldn’t eat the concrete and since the medium is noncorrosive, you can use cheaper materials to build the components of the batteries, like the tanks and pumps.
What About Lithium-Ion Batteries?
The Harvard team focused on flow batteries in order to meet a two-day energy storage standard for integrating wind and solar energy into the grid. According to the team’s 2014 research, lithium-ion does not fit the bill: To store 50 hours of energy from a 1-megawatt power capacity wind turbine (50 megawatt-hours), for example, a possible solution would be to buy traditional batteries with 50 megawatt-hours of energy storage, but they’d come with 50 megawatts of power capacity. Paying for 50 megawatts of power capacity when only 1 megawatt is necessary makes little economic sense.
In contrast, flow batteries offer a more stable discharge platform:
…in solid-electrode batteries, such as those commonly found in cars and mobile devices, the power conversion hardware and energy capacity are packaged together in one unit and cannot be decoupled. Consequently they can maintain peak discharge power for less than an hour before being drained, and are therefore ill suited to store intermittent renewables.
Don’t hold your breath for that, but as of 2014 Harvard’s partner in the project, Sustainable Innovations, was looking forward to building a demo model that would fit into a horse trailer.
And What About Coal?
The combined one-two punch of energy storage with renewable energy is a dire threat to the market for coal in power generation, but that’s still off in the future. For the here and now, industry analysts widely concur that a glut of cheap natural gas has been the main driver pushing coal out of the market.
President Trump ran his campaign on a promise to bring coal jobs back to the US, but three weeks into his presidency he seems much more preoccupied with supporting his daughter’s fashion business while Republicans in Congress aim to cut coal miners out of their new ACA benefits for black lung disease. Trump also worked hard to get longtime ExxonMobil CEO Rex Tillerson on board as US Secretary of State. With that status Tillerson is in a good position to continue his company’s business model, which in recent years has included pushing coal out of the global power generating market in favor of natural gas. Just sayin’.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.
This new battery runs on seawater!
There have been so many new approaches to batteries lately that it’s hard to keep track of them all, but most of them have one thing in common: they are all cheaper and safer than lithium-ion batteries.
Listen, lithium-ion batteries are the best we’ve got on the market right now. They can store a lot of energy in a small, lightweight package — that’s why they’re in basically everything we own — but they also have some drawbacks. The materials needed to make them aren’t earth-abundant, which makes them more expensive, especially as you scale up in size. They are a fire risk and they also have a fairly short life span.
For years, researchers have been looking to more abundant, safer materials to create a better battery. Engineers at South Korea’s Ulsan National Institute of Science and Technology (UNIST) are just the latest. They have developed a seawater battery that runs on water and salt, which they say could soon rival the lithium-ion battery in performance.
Sodium is the sixth most abundant element on earth, making this battery far cheaper to manufacture and using seawater specifically greatly reduces any chance of fire. The researchers believe that in the future, seawater could be the key to the large-scale energy storage that’s needed as the world shifts to more renewable energy. The batteries could also be used as emergency back-up energy for homes, businesses and ships.
The seawater battery works much like a lithium-ion battery as the structure is the same, swapping out lithium for sodium. The university explains:
The battery extracts sodium ions from the seawater when it is charged with electrical energy and stores them within the cathode compartment. Upon electrochemical discharge, sodium is released from the anode and reacts with water and oxygen from the seawater cathode to form sodium hydroxide. This process provide energy to power, for instance, an electric vehicle.
The salt water is not just acting as an electrolyte; according to the American Chemical Society newsletter it is actually a “catholyte — an electrolyte and cathode combined. In batteries, the electrolyte is the component that allows an electrical charge to flow between the cathode and anode. A constant flow of seawater into and out of the battery provides the sodium ions and water responsible for producing a charge.”
Currently, the seawater batteries have a lower electrical output than lithium-ion batteries, but the researchers are working on building the batteries in various sizes and shapes to increase the charge rate. They will soon start mass producing the seawater batteries in a testing facility and join cells together in battery packs. The goal is to produce a battery pack by the end of next year that is capable of providing the home energy needs of a family of four.
Danish Company ready to store renewable energy in large scale water basins: ‘GigaStorage’ could solve one of the biggest problems in the green transition; i.e., how to you store green energy from renewable energy sources?
By adding green energy from wind turbines or solar cells to water basins with a depth of 20 metres, the future’s energy system could look considerably different.
The Danish company European Energy is trying to patent a new method called GigaStorage, which could solve one of the biggest problems in the green transition away from coal, oil and gas: How to you store green energy from renewable energy sources?
Since 2004, the company has developed or built wind farms and solar parks in twelve European countries for almost EUR 1 billion, informs the CEO Knud-Erik Andersen.
– In this endeavour, the perspective is be able to reduce fossil fuels quickly – fossil fuel that we still use to a large extent. The same goes for our large import of biomass such as wood chips and other materials, says Knud-Erik Andersen.
The solution consists in sending electricity from wind turbines and solar cells through heat pumps or kettles. The electricity will heat water in the deep basins when the price of electricity is low. Then several months later, the water will be utilised for district heating.
Maximum 20 percent heat loss
During the season, the level of heat loss is low, a maximum of 20 percent. As two thirds of the population is connected to the district heating system, in time the majority of Danish consumers will be able to access cheap and CO2-neutral district heating.
– There is no limit to the size of the facility we could build. We now have the possibility for regulation that Denmark has been asking for, says Knud-Erik Andersen.
At plant in Esbjerg will be the first to apply GigaStorage on a larger scale in two to three years’ time. It has already been partly tested on a smaller scale in projects conducted in Vojens and Gram.
Together with the Technical University of Denmark (DTU), European Energy has sought funding from the EU Framework Programme for Research and Innovation “Horizon 2020” for a demonstration plant in Esbjerg.
In Esbjerg the hope is to house GigaStorage, says the first Deputy Mayor of Esbjerg and Director at Din Forsyning Jesper Frost Rasmussen.
Din Forsyning will be in charge of supplying water and heat as well as managing water waste and waste from 100.000 citizens in the municipalities of Esbjerg and Varde.
GigaStorage could redress our situation, says Jesper Frost Rasmussen:
– This seems to be a possible ‘game changer’ in energy policy as systems would really become interconnected. It is truly interesting for us living in Esbjerg and it will definitely also be interesting for the country and for the rest of the world.
At present, Esbjerg has so much surplus heat from its incineration plant, that they occasionally have to send it directly out into the Danish Wadden Sea. GigaStorage could change that.
– We would be able to replace coal and replace it with 100 percent green energy. That would also contribute to a cheaper heating bill, states Jesper Frost Rasmussen.