Distributed Renewable Energy Generation and Storage

Continuing our series on climate change and the next generation electric energy system, this week we discuss the necessity of distributed renewable energy generation and storage. The technology required to both produce and store electric energy throughout the grid exists today. Within the next decade, distributed renewables such as rooftop solar panels will contribute significant energy to the power grid and to replenishing energy storage modules.

Several changes to the status quo must occur before renewables can become commonplace. A grant system must be created for renewables to become more affordable for all, including low income households, public schools, and small businesses. To provide continuous, reliable electric energy at all times, energy storage modules must be built in strategic locations throughout the current power grid. Furthermore, new energy storage methods must be developed to enhance the energy storage strategies of today.

Let’s explore how each of these advancements will make the transition to distributed renewable energy generation and storage more approachable for all.

Renewable Energy at Homes, Schools, and Businesses

Distributed renewable energy sources, usually in the form of a rooftop photovoltaic (PV) system, are already more affordable than they were 10 years ago. Within the next decade, rooftop solar will be so cost effective, and will require so little space, that it can be installed almost anywhere. This will be a necessary step to address the climate crisis while continuing to supply reliable electric energy to consumers.

Developers will build small, solar energy production facilities on rooftops at schools, warehouses, industrial and business parks, as well as in open spaces near industrial parks and along highways. Electric utilities should expect that more than 50% of single family homes and multifamily residential buildings will install rooftop solar panels within the next decade. To prepare for this future, electric utilities must update their billing and rate structure.

Grants Make Renewables More Affordable

Today, consumers with disposable income are installing rooftop solar panels because federal and state tax rebates offset installation costs. Within the next decade, tax rebates should be replaced by federal and state grants for solar system installation, awarded on an income-based sliding scale. For example, a resident with an annual income of $100,000 could apply for a $10,000 grant; a resident with an annual income of $50,000 could apply for a $20,000 grant.

In this system, grants will be used rather than tax rebates because only about 30% of US taxpayers earn more than $100,000 per year - the threshold at which tax rebates offset installation costs. Installation of rooftop solar panels on homes owned by lower income households should be subsidized to reach the point that renewable energy provides 100% of the electric energy needed during April, May, September, and October, the months when peak load usually does not occur.

Grants could also be implemented for schools and universities, small businesses, and more. With a grant system in place, locally owned grocery stores could install solar panels to support the energy usage necessary to power refrigerators and freezers. Elementary schools could add solar panels to their rooftops, and use the panels as an opportunity for students to learn about energy production and usage.

Distribute Energy Storage for Increased Reliability

Also necessary to address climate change and maintain reliable electric energy is increased distributed energy storage. A concern often associated with renewables, especially rooftop solar, is that energy may not be produced when it is needed, such as after dark. A large amount of energy storage will be needed to address this concern.

Storing energy close to consumers will increase efficiency and reliability. Electric utilities will need to install energy storage facilities at strategic locations along distribution lines to ensure continuous reliability.

Storage locations must be able to accommodate energy storage modules: shipping containers that are 8 feet high, 8 feet wide, and 20 feet long, in which energy storage equipment will be housed. Locations may include substations, parking lots, or parking garages located near energy usage points.

As our reliance on distributed renewables grows, more energy storage facilities will be needed than substations. This will require more land than is dedicated to the current electric energy system.

A typical, enclosed substation with three 50 MVA transformers can be located on less than one half acre of land. Each transformer can provide 1,200 MWH of energy each day. As a point of comparison, the Big Battery at Hornsdale Power Reserve in South Australia, rated at 193 MWH, occupies 1.5 acres, can only supply 22 MW for 8 hours before discharging.

To store the electric energy required to power large areas for multiple hours, energy storage modules must be located at every substation and other available space along a distribution line.

Develop New Energy Storage Methods

To continue to enhance energy storage strategies, new energy storage and recovery methods must be developed. Liquid hydrogen can be used as an energy storage technology, as the process of transforming the hydrogen back into its gaseous form produces electric energy. The source of hydrogen in this scenario is simple: H2O.

The chemical reactions associated with water, hydrogen, and oxygen are:

Splitting one liter of water into hydrogen and oxygen requires about 4.4 KWH, about the amount of energy produced by two typical rooftop solar panels in one day. Liquid hydrogen produces about 2.36 KWH per liter. A 100 liter tank of hydrogen can produce about 236 KWH.

Liquid hydrogen can be easily stored and transported. Electric utilities could refuel hydrogen energy systems so that a 1000 KWH system could provide energy for days, weeks, or months, offering essential grid support when distributed renewables are not producing energy or while substation transformers, transmission lines, and distribution lines are being repaired after a climate change-related severe weather event.

Renewable Energy: Accessible for All

Although Thomas Edison left us almost 100 years ago, we need to continually embrace his mother’s words of wisdom: “Never stop learning.” As we continue to learn about the severity of the climate crisis, electric utilities must strive to develop new techniques and technologies to mitigate the worst impacts by removing all fossil fuels from their systems, and making renewables accessible for all.

Check out our next generation or climate change blog collections to learn more about Prescient’s recommended updates to the 4Ge electric energy system. Contact us with any questions.

This article was written in collaboration with Prescient's Lead Editor Alyssa Sleva-Horine.

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