Storing energy is nothing new. From the Neolithic Revolution to the present, humans have attempted to harness the latent power of nature whether it be falling water or fire. In building dams, we created an early form of storage technology. The end goal wasn’t to produce electricity but to use the force generated by water falling from a height to power machinery. In this case, the water wheel which became a common way to power mills for grinding cereal crops. Water wheels were used to power sawmills before we learned to harness electricity. The water wheel’s descendant today is the turbine which in hydroelectric facilities is used to power generators turning the energy of falling water into kilowatt-hours of electricity.
The grids that crisscross continents today are extremely complex. They have been designed for power-sharing and distribution that follows daily patterns. Energy storage currently plays a small part in ensuring power is available where needed at all times. One of the reasons it plays only a small part is because existing power generation and distribution capacity have been built to exceed peak demand.
The pattern of power requirements is a predictable cycle of daily, weekly, and seasonal demand. Matching supply to the need is one of the raison d’etres for continental power grids. The current grid has been built to ensure demand will always be met at the highest peaks unless something not predictable happens. When the unpredictable does occur in one or more utilities that feed the grid, power generation capacity from other sources can meet the emergency. This isn’t always the case leading to brownouts and occasional blackouts.
The U.S. Energy Information Administration describes how power demands change daily and throughout the year. The patterns are consistent:
A pool of water’s latent energy is a form of storage. Today, dams that provide hydroelectric power stations with energy from falling water to continuously produce electricity can take advantage of lower than peak periods to reverse the water flow. By pumping water uphill into reservoirs, they can use the increased water volume during peak demand periods to deliver added kilowatts of power to the grid.
In the United States, the first pumped storage facility opened in 1929 in Connecticut. Since then the growth of energy storage has surpassed 31.2 Gigawatts as of early 2019, a fraction of the more than one thousand Gigawatts of the country’s installed generation capacity. That amounts to 0.3% which sounds absurd considering the balancing act previously described for dealing with peak, shoulder, and low demand electricity requirements.
Globally, elsewhere energy storage for power generation plays a greater role in the mix. In 2018 total energy storage capacity exceeded 175 Gigawatts. In Europe, 10% of the continent’s power came from stored energy, while Japan’s stored energy amounted to 15% of capacity.
California has been the big player in energy storage in the United States. As of 2018, of the 300 energy storage projects there, 220 were grid-connected. The remainder were associated with distributed local energy delivery and off-grid.
The future of energy storage on the planet is likely less and less tied to traditional utilities and the grid as new energy storage materials and technologies emerge. The illustration below shows the range of energy storage technologies present and future.
Beyond pumped hydro, compressed air, different types of batteries using familiar chemistry such as lead-acid, and ones more exotic based on aluminum, sulfur, potassium, that breathe air and don’t require oxidizers, flow batteries, cryogenic storage, flywheels, magnetic energy storage, supercapacitors, and advanced fuel cell technologies, these existing and nascent technologies are ready to play a role in supporting the existing power grid. But more importantly, they are the bridge to solving the intermittency issues associated with the current forms of renewable energy on the planet today: wind, solar thermal, solar photovoltaic, geothermal, wave, and tidal power.
Their application will alter both grid and off-grid power delivery. Storage technologies give utilities greater flexibility in distribution and capacity. Storage technologies can save money and prolong the life of the power grid which has some old-age problems. If you don’t believe me, read the article I posted previously on this website about the long-term survival of the electrical grid.
Just how innovative can we get with energy storage. Carbonate fuel cells are a technology that does not just supplement the energy requirements of a powerplant burning fossil fuels, but also captures and uses the carbon emissions as the material in its fuel cell stacks. In 2016, Exxon installed a pilot project of experimental carbonate fuel cells at an existing coal and gas-fired power plant near Mobile, Alabama. So far so good. If widely adopted, this type of innovation could be a significant gamechanger for both grid and distributed power.
Recently, Tesla built a 100 Megawatt lithium-ion battery for an Australian utility. It is the world’s largest lithium-ion storage system, and one of a number of Australian-based projects slated for completion next year.
And speaking of distributed energy storage, in a recent Navigant Research study entitled “Country Forecasts for Distributed Energy Storage,” it cites the increase in solar and wind power as key to a projected 20 times increase in distributed storage systems by 2028. Research analyst for Navigant, Ricardo F. Rodriguez, sees the growth of distributed energy storage as a panacea for dealing with peak capacity requirements with or off-grid. And unlike reserve gas-fired powerplants that need to be brought online in periods of peak demand, storage systems can release electricity instantaneously with no downtime or ramping up, a distinct advantage over older paradigms.
]]>In the latest Navigant Research study entitled “Country Forecasts for Distributed Energy Storage,” it cites solar and wind power as the primary growth drivers for DESS indicating a twentyfold increase in usage in 26 countries by 2028. Ricardo F. Rodriguez, one of Navigant’s research analysts argues that DESS represents flexibility in energy generation infrastructure deployment and “limits the need for peak capacity resources.”
Generating continuous electricity to match demand requirements has always been the most significant detractor for the use of intermittent renewable energy resources. Particularly, in countries where the bulk of electricity is distributed over a ubiquitous grid, utility companies to ensure predictable, continuous power build to exceed peak demand requirements. Whether the power comes from thermal power plants burning coal, or natural gas, or from solar and wind farms, exceeding peak demand is an industry sacred cow. That surplus power generation, produced in off-peak periods can find a home in DESS.
You are probably thinking that DESS comes in the form of large batteries that can discharge stored energy when needed. But energy storage comes in many different forms, not just chemical batteries. For example, surplus power can pump water uphill into reservoirs where it can be released as needed or can create compressed air storage which when released can drive turbines connected to generators.
The real strength of DESS is in its ability to help energy companies transition from traditional thermal-power generation to renewables. DESS smooths out the supply of electricity from intermittent energy sources of which the sun and wind are two. And DESS can discharge power quickly unlike reserve fossil-fuel burning thermal power stations which require a considerably longer ramp-up. DESS also works best in remote areas away from a ubiquitous transmission grid where power disruptions are more frequent. In these more isolated regions, a microgrid distribution system with DESS backup can prove to be an ideal solution.
The Union of Concerned Scientists, in a 2015 publication, noted that the United States had 23 Gigawatts of storage capacity equal to 38 typical coal-fired power plants. At that time pumped hydroelectric storage represented 96% of total capacity. But growth in DESS is likely not to come from hydroelectric pumped storage but rather from alternative solutions such as large-scale chemical battery vaults like the ones seen to the right in the illustration below.
Examples of DESS in practice are growing. There is the Tesla-installed 100 Megawatt lithium-ion battery system recently installed in Hornsdale, South Australia. Billed as the world’s largest lithium-ion storage system, it is one of a number of projects slated for completion in Australia by 2021 and includes a 900-Megawatt battery from Neoen SA, a 270-Megawatt installation built by Total Eren SA, and a 140-Megawatt battery from EPS Energy.
Flow batteries are among the mix in energy storage solutions. These giant storage tanks of liquid electrolytes can provide a lower-cost solution than lithium-ion stacked battery technologies such as the system Tesla installed at Hornsdale.
More recently I have written about modular cryogenic energy storage systems such as the CRYOBattery providing power to 200,000 homes in the United Kingdom. And even funkier is kinetic storage devices like flywheels which, deployed in a farm of these devices, is currently providing 20-Megawatts of power at the Stephentown Flywheel Energy Storage Plant in New York State.
The biggest impediment to wholesale DESS deployment will be the reluctance of energy providers to adopt the technology with a pre-existing infrastructure of sunken costs into fossil-fuel-based electricity production. Mitigating climate change, however, will be the driving force for DESS growth with governments around the world seeing the value of storage associated with intermittent renewable energy as the new paradigm for power generation.
Energy storage will not come cheap. The necessity, however, to address carbon emissions, and the limitations on hydroelectric renewable power capacity with fewer sites available, are among the factors behind Navigant’s forecast of a 2,000% growth.
A reader of this blog posting, Bob Meinetz, suggested that Navigant’s forecast is, in his words, “far too conservative.” He refers to Lazard, and Deutsche Bank forecasts of anywhere from 12,000 to 20,000%, and GreenTech Media reporting an increase of more than 70,000%.
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