Throughout our recent series on electric vehicles (EVs), readers have commented with concerns about how electric utilities will provide enough clean energy to power a future with considerably more EVs. This concern is especially relevant given the recent Intergovernmental Panel on Climate Change (IPCC) report, which calls for the world to rapidly move away from burning fossil fuels, the number one cause of climate change.
Renewable energy sources, including solar, wind, and hydropower, are a good start along the path to 100% clean energy. However, the key to powering an all-electric future with lots of EVs is to invest in upgraded energy storage technology. This will likely be in the form of both large-scale batteries that provide short term energy storage, and green hydrogen and ethanol fired power plants that provide long term energy storage.
Energy storage technology already exists and is in use, although improvements will be necessary before it can be implemented as a replacement for fossil fuel power plants. In this article, we explore a few methods of improving the application of energy storage technologies by repurposing existing grid infrastructure and changing battery housing designs. But first, let’s take a brief look at existing renewable energy sources and associated concerns.
Solar, Wind, Hydro: A Brief Overview of Renewable Energy Sources
Ideal locations for solar panels are places where the sun shines frequently, as solar panels only produce electric energy from sunrise to sunset. In Florida, solar panels produce electric energy for 12 to 14 hours on sunny days. In Alaska, solar panel energy production time can be as little as 6 hours a day in December, and as much as 18 hours a day in July. Both states can provide ideal locations for solar panels, with the understanding that their energy production will be variable.
The best places for wind turbines are locations where the annual average wind speed is at least 13 mph. At coastal locations, wind can blow toward land during the day and toward the sea at night. Maximum wind speed may occur every afternoon. At ridge-crest locations, maximum wind speed may occur at night with daytime minimums. A good starting point for electrical engineers who wish to gain a better understanding of wind energy is Google and a large pot of coffee.
Hydropower is ideally produced by dams that are taller than 100 feet with water flows exceeding ten thousand cubic feet per second. Waterpower variations are seasonal, with high flows during the rainy season and reduced flows during the dry season. Some dams have restrictions based on endangered species, water rights, saltwater incursion, and recreational activities.
Variable Renewables: Concerns and Solutions
All these renewable energy sources are extremely variable, accessible only if the sun is shining, wind is blowing, or water is flowing. This is why many people express concern about moving to a fully renewable energy powered grid. How will variable energy sources provide power when the sources themselves are not available?
One solution is improved battery storage technology for short term energy storage. A 100 MWH battery can supply 12.5 MW for 8 hours. Other solutions, including green hydrogen, nuclear energy, and plant-based ethanol, will be needed for long term energy storage. These storage methods can store energy for several months.
Utilizing all these solutions will be vital if the world is to shift away from fossil fuels in time to avert a climate catastrophe. However, improvements to battery storage technology are essential before it can be a reliable part of the climate solution.
The Energy Storage Conundrum
Recharging batteries with renewable energy to provide power when renewables are offline will be effective during mild weather conditions, typically in the spring and autumn. However, during cold winter months and hot summer months, all the energy that renewables produce will be necessary to meet load demands, and little to no energy will be left over to recharge batteries. This is when green hydrogen or ethanol based storage will be needed to support renewables when they go offline.
A 100 MW ethanol fired power production facility can supply 100 MW per hour, when ethanol is available. To maintain ethanol availability for up to 30 days, four 25,000 barrel ethanol storage tanks will need to be onsite. Ethanol can be stored until an anticipated energy shortfall necessitates its use. Similarly, green hydrogen can be stored for months until it is needed to support renewables.
Repurpose Existing Energy Infrastructure to Support Batteries
The existing electric energy grid has been designed to transport energy from production facilities to load centers, such as cities. When considering implementing new renewable energy sources and energy storage facilities, it would be wise to repurpose existing infrastructure rather than build from the ground up.
For example, coal-powered generating facilities need to be shut down to move away from fossil fuels. The still-functioning Jim Bridger power plant, located west of Cheyenne, Wyoming, has the capacity to produce 2,400 MW and the grid infrastructure to transport this energy to load centers. As one of the largest coal-fired power plants in the Western US, Jim Bridger produces about 58,000 MWH of electric energy daily.
Rather than shuttering this facility for good, it could be converted to an energy storage facility. This power plant sits on about 1,000 acres, 700 times larger than the amount of land occupied by the Hornsdale Power Reserve, South Australia’s big battery. By storing energy at Jim Bridger or any other coal-fired power plant across the US, energy could be easily transmitted across existing powerlines and employment opportunities could continue for those who work at the site.
There are over 200 coal-fired power plants across the US that could be similarly repurposed. Hundreds of miles of high voltage transmission lines are in use to transmit energy from these power plants and could easily be repurposed for renewable energy transmission from batteries.
Additionally, transmission lines in coastal areas were built to transport energy from inland locations to beach communities. It would be prudent to locate offshore wind farms near spots with electric energy infrastructure already in existence. The flow of energy could be reversed so that energy produced by offshore wind can reach inland areas without building new transmission lines to coastal areas.
By repurposing existing energy production locations and grid infrastructure, the monetary cost of renewable energy projects could be significantly reduced. The environmental costs associated with large scale construction would also be lessened considerably.
Reshape Battery Storage Technology
Another key to improving battery storage technology is to reduce the areal footprint of energy storage facilities. This will increase the number of batteries and therefore the amount of energy stored in any given location. To do this, batteries can be housed in 20-foot-tall containers rather than the 12-foot-tall containers in use today.
These “high-top” containers will be effective when they can be shipped by rail. To allow these large containers to pass, communication cables, low voltage power lines and medium voltage distribution lines will need to be temporarily raised if containers are shipped via roadways. Of course, the cost of transportation is a tradeoff for the smaller footprint of high-top battery storage containers. However, the benefit of increased energy storage outweighs the high transportation cost.
Improve Grid Reliability with Energy Storage
By repurposing existing energy production facilities and grid infrastructure, and improving the design of large-scale batteries, energy storage technology can become a workhorse of the clean energy future. Improved battery storage technology will increase grid reliability by allowing renewable energy to be accessed even when the energy sources are not available. Implementing green hydrogen or ethanol based storage will support renewables when power demand exceeds supply.
Want to learn more about Prescient’s ideas for the next generation electric power grid and vital steps to mitigate the worst impacts of climate change? Contact us today!
This article was written in collaboration with Prescient's Lead Editor Alyssa Sleva-Horine.