Page 76 - North American Clean Energy January February 2018 Issue

energy storage
Hydrogen Electrolysis
A viable solution for large-scale renewable energy storage
by Everett B. Anderson
e global demand for power is increasing. is has caused power grids, energy resources, and the environment to face a variety of challenges that often result in high levels of pollution, greenhouse gas emissions, and elevated indirect costs on society. Renewable energy is a viable option to meet the world’s ever-increasing demands for energy while combatting greenhouse gas emissions. However, employing solar and wind to generate clean energy on a utility scale doesn’t come without caveats.
Potential investors in renewable energy assets look for two things: capital cost, and return on investment (ROI). From a nancing perspective, dealing with renewables can prove di cult due to their natural variability; a uctuating income stream can make it di cult to predict the ROI. For example, if energy demand is high but there
is a lack of wind at a wind farm, or cloudy weather that hinders photovoltaic panels from generating energy, local supply su ers. ese inconsistencies can be intimidating to stakeholders. Conversely, renewable energy may be wasted if the highest output
is produced during lowest periods of demand. Whichever the case, it is critical that stakeholders identify the proper tools to leverage the full potential of renewable assets. Having a scalable, cost-e ective solution to storing power will help yield higher returns for renewable energy producers. Many stakeholders are turning to one reliable method for both generating and storing energy - hydrogen.
Why Hydrogen?
Hydrogen generated from renewable assets is referred to as “green hydrogen.” Green hydrogen can be generated and stored in times of low demand, and utilized in periods of peak demand. is exibility yields predictable and consistent energy gures for stakeholders, essentially acting to ll gaps, meet supply and demand mismatch,
and balance the grid. Hydrogen can be stored in high or low-pressure tanks, in large volumes, inde nitely and without any energy “leakage”, as compared to a battery. Hydrogen energy storage infrastructure is extremely scalable; it can utilize the existing natural gas grid, or even natural underground caverns. Hydrogen’s ability to store large amounts of energy for long periods of time enables seasonal energy storage, which gives it a signi cant advantage over battery storage. Furthermore, green hydrogen is becoming increasingly valued in the marketplace, as corporation’s search for broader solutions to meet their sustainability goals and automotive OEM’s embrace the transition to low/no carbon fuels.
It’s also important to note that hydrogen energy storage costs more than 50 percent less, compared to battery storage systems - primarily due to the limited life expectancy of batteries. Additionally, batteries that cannot be recycled create other cost and pollution issues.
Three Ingredients for Hydrogen Energy Storage
Advances in hydrogen generation technology have made it possible to store renewable energy produced by wind, solar, or hydroelectric power, in the form of pressurized gas.
1. Proton Exchange Membrane (PEM) electrolysis is the enabler that makes this possible. PEM electrolyzers utilize
an advanced membrane technology and electricity to split water into hydrogen and oxygen. PEM electrolysis has the capability to closely match the variability of wind and solar assets. PEM electrolysis o ers a wide dynamic operating range, e ciently generating hydrogen gas over a broad capacity range, ensuring that available energy is not wasted. PEM electrolyzers can also rapidly start up and shutdown operation, which allows renewable energy assets to generate hydrogen e ciently in periods of either peak electric generation or low demand. In addition, the battery-like
rapid response of the PEM electrolyzer makes it capable of providing grid ancillary services, such as voltage or frequency regulation. ese services can provide additional value streams for the investor, further improving the project ROI.
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