All sources of energy have to find their way, through transmission, to an end user, whether it is a home, a car or an industrial plant.
Utilities and their transmission structure are undergoing significant transformation, driven by an aging power grid and a growing shift from fossil fuels to renewable sources of energy, such as solar and wind.
Sources often have different transmission challenges as they provide energy, either directly (i.e. gasoline to a car) or secondarily (i.e. through electricity).
RENEWABLES
Solar energy is transmitted to the electrical grid when inverters convert the direct current (DC) produced by solar panels into grid-compatible alternating current (AC), which then travels through transformers and transmission lines to connect with the existing electricity grid.
Wind energy is converted by wind turbines into electricity, which is then sent via cables to an offshore or onshore substation. There, a step-up transformer increases the voltage to reduce energy loss during long-distance transport. Finally, high-voltage transmission lines carry the electricity to an electrical grid, which then distributes it to communities and businesses.
Hydropower uses the force of moving water to create electricity by spinning a turbine connected to a generator which is then fed into the electrical grid to power homes and businesses.
Geothermal either uses a closed-loop of buried pipes to circulate water from under the ground into a building to heat or cool it OR naturally occurring hot water or steam is pumped from deep wells which is subsequently reinjected. Geothermal uses electricity to move the heat into the building or to extract heat from the building.
FOSSIL FUELS
Crude oil can be moved through a pipeline to refineries and from refineries through a pipeline to large storage terminals from which they are loaded onto tanker trucks and delivered to gasoline stations.
Natural gas travels from its underground source through a pipeline to processing plants to remove impurities and valuable byproducts. From there it is transmitted to smaller local distribution centers from which it is trucked to homes, businesses, industrial facilities, and power plants.
While generally safe, aging pipelines can pose environmental and safety risks, including methane leaks.
Coal moves from mines to markets, primarily to power plants, with railroads handling the majority of the coal movement, supplemented by barges, ships and trucks to power plants. After extraction, coal is transported to consumers, which include the electric power sector (the largest consumer of coal in the U.S.) and industrial users (cement production, iron smelting, & the manufacturing of chemicals and fertilizers).
THE GRID
The U.S. electric grid is a complex network of power plants, transmission lines, and distribution systems. The system is separated into three major interconnections that operate largely independently: the Eastern Interconnection, the Western Interconnection, and the Texas Interconnected system (ERCOT).
Key challenges facing the grid include:
- Aging infrastructure: Many transmission lines and components are decades old and have surpassed their intended lifespan, leading to reliability issues and vulnerability to severe weather which, as we have seen in the past years, is accelerating in intensity.
- Decentralized planning: The fragmented and compartmentalized nature of the grid, managed by various entities, has historically hindered the coordinated, large-scale upgrades needed for the clean energy transition.
- Integrating renewables: Renewable energy sources like wind and solar are often located far from population centers, requiring new, long-distance transmission lines to deliver power where it's needed.
- Increased demand: Growing energy demand from data centers (particularly AI), electric vehicles, and other electrification efforts is putting immense strain on the grid, with projections indicating the grid may need to double in size by 2050.
FUTURE OUTLOOK
The U.S. utility and transmission landscape is set to undergo major changes in the coming years.
- Record investment: The industry is seeing record capital expenditures for grid modernization, with utilities shifting toward more resilient, sustainable technologies.
- Renewable integration: The shift to clean energy sources like wind and solar is driving the need for significant transmission expansion, especially for long-distance lines.
- Technological advancements: Innovations such as battery storage, advanced conductors, and small modular nuclear reactors (SMRs) are helping utilities manage rising demand and increase grid reliability.
- Policy and funding: Federal policies like the Infrastructure Investment and Jobs Act (IIJA) and the Inflation Reduction Act (IRA) have provided substantial funding to support these investments.
BATTERY STORAGE
Utilities are using battery storage systems in several strategic ways to enhance grid reliability, especially as they integrate more intermittent renewable energy sources like solar and wind. By acting as flexible, fast-response buffers between electricity generation and consumption, batteries help manage a complex and dynamic power grid more effectively.
One of the primary uses of battery storage is to manage the variability of renewable energy sources.
- Solar shifting: Batteries charge from solar panels during the day when electricity is abundant and cheap, then discharge that energy during peak evening hours when solar generation drops off and energy prices are high. This process, called "energy time-shift" or "arbitrage," helps balance the grid and reduces costly peak electricity purchases.
- Mitigating curtailment: When renewable generation exceeds current demand, utilities can store the excess energy in batteries instead of curtailing or wasting it. This maximizes the use of clean, low-cost power.
Managing peak demand
Utilities use battery storage to smooth out the fluctuations between low and high energy demand.
- Peak shaving: Batteries can discharge stored energy during peak periods, reducing the strain on the grid and eliminating the need to bring more expensive and often dirtier "peaker plants" online. This can lead to lower overall electricity costs for consumers.
- Replacing fossil fuel plants: In some cases, battery storage has become a more economically viable solution for meeting peak demand than building new natural gas-fired power plants.
Providing ancillary services
Batteries can respond to grid conditions in milliseconds—much faster than traditional generators—allowing them to provide critical grid stabilization services.
- Frequency regulation: To keep the grid stable, operators must maintain a consistent frequency of around 60 hertz. Batteries can absorb or inject small amounts of power almost instantly to correct any frequency fluctuations.
- Ramping and reserves: Batteries can provide immediate backup power to the grid during sudden changes in supply or demand. This allows operators to maintain stability while other generators are slowly brought online.
Enhancing grid resilience
Battery storage can improve the grid's ability to withstand and quickly recover from disturbances like severe weather events, cyberattacks, or equipment failures.
- Black start capability: Certain grid-scale batteries have the ability to re-energize a section of the grid after a complete blackout, a process known as a "black start".
- Backup power for critical infrastructure: Strategically placed batteries can ensure continuous power to essential facilities, such as hospitals and emergency shelters, during an outage.
- Transmission deferral: Deploying energy storage systems at key points on the grid can provide local energy supply and help manage power flow, thereby deferring the need for expensive and time-consuming upgrades to transmission infrastructure.
Supporting distributed energy resources (DERs)
Batteries are key to incorporating distributed, customer-sited resources into the larger grid.
- Virtual power plants (VPPs): Utilities can aggregate customer-owned battery storage and other DERs to act as a single resource, creating a "virtual power plant." This allows them to manage and dispatch these distributed systems to support the grid during periods of high demand.
- Microgrids: Batteries are a crucial component of microgrids, which can operate independently from the main grid. This allows a community or facility to "island" itself and maintain power during a major grid outage.
