Energy Innovation Brief
Issue 28 | February 23, 2023
In Western Canada and around the world, the energy sector is rapidly transforming to one that promises to be cleaner, greener and more efficient. Each month, the Canada West Foundation’s Energy Innovation Brief brings you stories about technology innovations happening across the industry – in oil and gas, renewables, energy storage and transmission. If you have an idea for a story, email us at:
Energy storage solutions explained
This month’s issue of the EIB is focused on energy storage. Compared to some of the shiny new energy production technologies featured in the EIB (Nuclear fusion! Solar space lasers! Algae-produced biofuels!), energy storage can appear sort of boring. But while energy storage may be more akin to a supporting actor than the star of the show, it plays a significant role in the operation of our electrical grids.
We need energy storage to fill gaps between supply and demand, to aid in system recovery after blackouts, and to enable the increased integration of intermittent renewable energy sources like wind and solar. It really is critically important—there’s no successful energy transition without it.
While batteries are often the first thing that come to mind when thinking of energy storage, there are a lot of different ways to store energy—each designed to offer different solutions to different circumstances. In this month’s issue, we take a look at various ways to store energy and provide a few cutting-edge examples.
01| Thermal storage
02| Gravity storage
03| Kinetic storage
04| Electrochemical storage
05| Chemical storage
You can heat things up or cool them down, and retrieve the energy when you allow them to return to “normal” temperatures. There are lots of materials that can be heated or cooled in this way, and many of them—like rock, sand and salt—are inert and pose little to no environmental risk. It sounds like it might be hard to keep the energy from dissipating too quickly, but some thermal storage mediums can hang onto the energy for up to 20 years. These qualities make thermal storage especially useful for application at remote sites.
- Researchers in Finland have developed the world’s first working sand battery. The battery stores thermal energy by using cheap wind and solar electricity to heat 100 tonnes of sand to around 500°C. Due to sand’s low heat-transfer coefficient, researchers believe the battery could maintain these temperatures for several months, enabling it to provide heat for homes and offices throughout the winter when electricity is more expensive.
- Thanks to solar water heaters and underground thermal storage, the Drake Landing Solar Community in Okotoks, Alberta can supply 90 per cent of space heating and 60 per cent of hot water needs year-round using solar energy alone. The community’s Borehole Thermal Energy Storage (BTES) system consists of an array of 144 boreholes drilled to 35 meters deep and filled with a high thermal conductivity grouting mixture. When excess hot water is produced by each home’s solar collectors, it is used to charge the BTES by pumping it underground to store the thermal energy. Then, when space heating is needed, cooler water can be pumped through the system to pick up the residual heat and transfer it back to the homes. After three years of charging, the BTES can maintain temperatures of 80°C for nearly the entire heating season.
By raising an object from a lower elevation to a higher one, energy can be stored as gravitational potential. When the object is released, its downward return can be used to turn a turbine to generate electricity.
In practice, gravity batteries can take many forms—raising and lowering concrete blocks or other heavy objects using cranes or winches, moving loaded rail cars uphill and allowing them to run back down, or pumping water to an upper reservoir and using it to generate hydroelectricity (pumped hydro). This flexibility in storage methods is an advantage, as is the fact that the potential energy (usually) stays put and does not deplete over time. And unlike traditional batteries, the energy potential does not diminish no matter how many times the system is “cycled.”
- Renewell Energy, a U.S. energy storage start-up, has developed what it calls “gravity well” technology to convert abandoned oil and gas wells into low-cost energy storage opportunities. The gravity well uses a high-efficiency electric motor to raise and lower a large cylindrical weight, consisting of used oilfield tubing and high-density filling, within the borehole. It’s a smart use of abandoned oil wells and results in minimal environmental impacts. And because the average well is nearly 2 km deep, the system can store a great deal of energy for every kg of cylinder weight.
While the company’s pilot projects are U.S.-based, Western Canada has no shortage of inactive well sites—the AER estimates Alberta alone has over 170,000 abandoned wells. These could provide an excellent storage opportunity for the province.
- Two proposed pumped-hydro projects—TC Energy’s Canyon Creek Pumped Storage project and Montem Resources’ Tent Mountain Pumped Hydro Energy Storage project—will bring nearly 7,600 MWh of energy storage to Alberta in the next five years. The Canyon Creek project consists of two man-made reservoirs separated by 500 m in elevation and connected by seven kilometres of pipe. Tent Mountain will use two existing reservoirs left over from coal mining operations in the area and is part of a larger project by Montem that will include a 100 MW Offsite Green Hydrogen Electrolyser and 100 MW Wind Farm.
Pumped hydro is the most widely used form of energy storage globally; however, despite Canada’s vast hydro resources only one pumped hydro facility is in operation nationally. The development of these two projects will make Alberta the leading province in pumped storage and will aid in the integration of more wind and solar resources on the provincial grid.
If you think back to your high school physics class, kinetic energy is exhibited by an object in motion. Gravity storage is one example of how kinetic energy can be stored and released, but there are also other examples. Of particular note is compressed air.
- Hydrostor, a Toronto-based compressed air storage company, is in the midst of developing its record-breaking Willow Rock Energy Storage Center in Kern County, California. Once complete, the facility will be the world’s largest underground energy storage facility with 4,000 MWh of storage capacity. The company’s 500 MW Advanced Compressed Air Energy Storage (or A-CAES) system will consist of several underground chambers with a combined volume of nearly 500,000 cubic meters—enabling eight hours of storage at max power. To “charge” the system, excess wind and solar electricity from the High Desert area will be used to compress and inject air into the underground chambers where it can be held at high pressure for long durations. During periods of high demand, the pressurized air will be used to return electricity to the grid, effectively converting the intermittent resources into a flexible and dispatchable energy source. The first-of-its-kind facility is not expected to come online until 2028, but has already secured a $775 million contract with local governments for long-term purchase agreements.
Electrochemical batteries—like the ones that power phones, laptops and tv remotes—can also be used for large-scale grid storage. Regardless of size, these batteries all store and release electrical energy by transferring electrons between a positive (cathode) and negative (anode) terminal.
Lithium-ion chemistry (using nickel, manganese and cobalt) is widely known as the front-runner for large-scale energy storage and is currently found in both EVs batteries and the batteries used to complement solar and wind. However, it has drawbacks including cost, negative environmental impacts associated with the production and disposal of minerals such as lithium and cobalt, and flammability.
An enormous variety of alternative battery chemistries are being investigated or developed in the hope of finding something that relies on materials that are more abundant, safer, have lower environmental impacts, charge faster or last longer. Here are a few interesting examples:
- Iron air – non-toxic and uses some of the most widely available materials on earth—iron, water and oxygen. Set to be deployed at two U.S. coal power plants due for retirement.
- Aluminum sulphur – uses aluminum, the world’s second most abundant metal, and sulfur, which is often a waste product from industrial processes.
- Sodium sulphur – a type of molten salt that can be processed from sea water.
- Sodium ion – as noted above, sodium is abundant and a fraction of the cost of lithium.
- Fluoride-ion – may be up to ten times more energy dense than lithium ion batteries.
- Zinc-manganese oxide – a promising candidate for grid-scale energy storage due to low cost, high energy density and relative safety.
- Niobium – excels at extremely fast charging and discharging and the temperature remains fairly cool.
- Vanadium flow – long lifespan (up to 25 years) with no degradation in performance over time
- Zinc-iron redox flow – high energy efficiency and long cycle life.
- Solid state ceramics – replaces liquid electrolyte with ceramics or glass.
Energy can also be stored and released by altering chemical bonds. This is exactly how we get energy out of hydrocarbons when they are combusted. From an energy storage perspective, the biggest opportunity is for the production of hydrogen using excess solar and wind capacity, and then using that hydrogen to balance out demand when the sun goes down and the wind drops off. Hydrogen’s advantages include its ability to be stored for long periods of time, providing reliable, dispatchable electricity, and being more portable than many other energy storage solutions.
- EverWind Fuels Co., a Halifax-based hydrogen producer, has just received environmental approval for North America’s first industrial-scale green hydrogen project. Construction of the $6 billion dollar Nova Scotia facility is slated to begin in the first half of this year. The project will be developed in two phases, with phase one expected to produce 200,000 tonnes of green hydrogen annually by 2025. Phase two will include the development of a 2 GW wind farm enabling the facility to expand to 1 million tonnes per year.
The facility will play a major role in Canada’s recently announced plans to provide Germany with green hydrogen. Hydrogen from the facility will be converted to ammonia for tanker transport. Once in Germany, the ammonia can be used directly as a fuel or converted back to hydrogen.
Our list isn’t exhaustive and companies have gotten extremely creative in developing energy storage solutions. This is good, as each method comes with trade-offs and benefits, both in terms of utility and secondary environmental impact. Exploring innovative options and striving for continuous improvement is key to ensuring that energy storage is available to support increasing electrification.
The Energy Innovation Brief is compiled by Brendan Cooke and Marla Orenstein. This month’s edition features contributions by Brendan Cooke and Marla Orenstein. If you like what you see, subscribe to our mailing list and share with a friend. If you have any interesting stories for future editions, please send them to .