By Steven Shackell
In October 2019, wildfires in Northern California prompted a multi-day precautionary main-grid power shutoff in Humboldt Country, California. Unfortunately, there were several Humboldt residents whose lives depended on medical equipment that ran on electricity. Luckily, the nearby Blue Lake Rancheria microgrid welcomed those electricity-dependent residents and quite literally saved their lives.
Microgrids are transforming the way we generate, distribute and consume electricity. This article explores the fundamentals of a microgrid and the advantages of decentralized energy harvesting and distribution.
What is a microgrid?
A microgrid is a small, localized energy system that can operate independently or in conjunction with the primary energy grid. Given the broad nature of its definition, a microgrid can vary greatly in size, ranging from a single residential home to an entire municipality with tens of thousands of buildings.
The defining feature of a microgrid is its ability to operate autonomously and quickly disconnect from the primary power grid in the event of a natural disaster, grid failure, or planned outage. Microgrids’ resiliency is invaluable to critical facilities like hospitals, emergency services, defense outposts, data centers and manufacturing plants.
Moreover, microgrids can independently produce their own electricity. In most but not all cases, microgrid energy production utilizes highly efficient and environmentally friendly energy sources. These sources work together to generate, store and distribute electricity within the microgrid’s service region. For example, the University of Colorado Boulder campus operates as a microgrid relative to Boulder County, servicing dozens of buildings, research facilities and dormitories to increase energy resilience on campus and reduce carbon impact.
The role of energy harvesting in microgrids
Since the Industrial Revolution, fossil fuels have been a primary means of generating electricity. However, coal and natural gas-powered facilities are large, expensive and rely on a centralized energy production model.
Decentralized energy harvesting is a critical component of a microgrid system and involves capturing and storing sustainably produced energy from the surrounding environment. There are several common technologies used for energy harvesting in a microgrid.
Solar energy harvesting
Solar panels are extraordinarily scalable, with systems ranging from single board-level microgrids to megawatt solar farms. Solar energy harvesting, paired with battery technology, is directly enabling smart grids and microgrids worldwide. This abundant, clean energy can generate electricity during the day, store energy in batteries for nighttime and days without sunshine and provide fully independent energy resilience at a variety of scales. Switching battery charger technology, such as BQ255 from TI, makes switching between direct solar and battery power seamless and near instant.
Wind energy harvesting
Generally used in municipality-sized microgrids, wind energy harvesting technology utilizes wind turbines that capture the kinetic energy of wind. Wind energy harvesting is particularly useful for microgrids in regions with consistent wind patterns and is most often used as an intermittent supplemental energy source. Wind turbines can vary in size, with the largest wind turbine producing enough electricity for 80,000 residents year-round.
Thermal energy harvesting
Thermal energy harvesting systems are more regionally restricted than wind power, as they can only exist in regions with high geothermal activity. However, in areas where this activity is present, thermal energy harvesting can generate constant, dependable electricity for microgrids. For example, Iceland generates over 20% of its electricity and nearly all its heat from geothermal activity. Its capital city of Reykjavik operates on a microgrid, with 95% of its heating and 25% of its electricity coming from geothermal energy harvesting.
Microgrids – the power of the future
Microgrids are at the forefront of transitioning to a sustainable and dependable energy infrastructure. The necessity for centralized mega-power plants is eliminated with the advent of sustainable energy harvesting and storage, which now play a vital role in enabling microgrid, decentralized energy systems around the world. As society continues to evolve amidst the challenges of climate change and the diverse energy landscape, microgrids offer a promising, scalable and sustainable solution without negatively impacting energy availability.
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