SECTION 1 – MICROGRID BASICS
What is a microgrid?
Let’s start off by defining what a microgrid is. A microgrid is a collection of distributed energy resources (DER) that provide power to a connected set of loads, such as those of a community. A microgrid can be connected to the main grid or operate self-sufficiently in “island mode”. Getting approval to connect with the main grid is typically complicated and requires the approval of the local utility. Due to its versatility and ability to boost energy system resilience, microgrids are a topic of research and development and are even being set up within rural and remote regions. Although rural is a straightforward term, what does it mean to be remote? If your community is not connected to a utility substation which receives energy over transmission lines, you are not connected to a centralized grid and are therefore a remote situation.
It is common for a rural or remote community to operate on fossil fuel-based microgrids. Clean or renewable microgrids are known to provide “reliable, affordable, and resilient energy” during times of climate uncertaintyii. Due to recent economic market developments, renewable energy resources are becoming more financially affordable and can provide communities with energy without negative impacts such as localized air pollution and fuel supply chain disruptions.
The microgrid will be expected to manage energy supply and demand. Energy supply is produced by the DERs, and a microgrid can be composed of one or more of them. These resources address the load which is the electric demand that the microgrid must meet and is caused by energy needed for day-to-day activities such as lighting, heating and cooling.
On the controls side, the system controller monitors the state of the microgrid while considering changes in energy generation. The system controller is important for ensuring the smooth functioning of the microgrid while accounting for any issues such as increased demand or decreased energy production.
What Microgrid DERs are available?
There are a variety of Distributed Energy Resources (DERs) that can be used for a microgrid. DERs include renewable energy technologies, energy storage and combined heat and power (CHP). DERs not only provide energy generation but can also provide energy savings, cost savings and resilience.iii Energy and cost savings can be found when operating the DERs is more efficient and lower cost than getting power from the utility or existing power generation equipment.
Listed in the figures below are some of DERs that can be utilized in a microgrid system with their respective descriptions, including the pros and cons for each. Note that the values listed for cost are estimates and can vary widely depending on several factors such as location and project size. The Estimated Cost values are based on other estimates from an industry-recognized energy modeling software, Xendee. These values are subject to change and may be different in the future due to economic factors such as inflation and technological advancements.
Figure 2: Available DERs. *Note that price ranges are estimates based on pricing for residential and small commercial equipment and may not reflect actual values depending on location. References includeiv, v,vi,vii, viii, ix, x,xi, xii
Microgrids offer numerous benefits, particularly in terms of reliability, environmental impact, economic growth, flexibility, equitable energy transitions, sovereignty, and community wellbeing. They enhance reliability by providing power during natural disasters and grid outages, ensuring critical systems remain operational. Environmentally, microgrids reduce reliance on carbon-based energy, lower greenhouse gas emissions, and decrease noise pollution. Economically, they lower utility costs, reduce maintenance needs, create job opportunities, and can increase property values. They also support the growth of industries that require reliable power, such as medical and educational sectors.
Reliability: Microgrids provide power during natural disasters and grid outages, ensuring critical systems, like medical and other emergency equipment, remain operational.
Example: Blue Lake Rancheria in California was subjected to a wildfire event in the area, which required the utility to de-energize the grid. The microgrid enabled the local community to retain power while the broader area lost power.xiii
Environmental Impact: DERs such as solar and wind reduce reliance on carbon-based energy generators, lower greenhouse gas emissions, and even decrease noise pollution. Offsetting emissions from fossil fuel sources reduces the production of ground-level ozone which damages crops, trees and other vegetation. Fossil fuel emissions also create acid rain, which affects soil, lakes and streams and enters the human food chain via water, produce, meat and fish.
Example: Soboba Band of Luiseño Indians has 1.5 MW of rooftop solar and a 6 MWh energy storage system, which saves 20,000+ tons of CO2 in emissions.
Economic Growth: Microgrids can lower utility or fossil fuel costs, reduce maintenance needs, create job opportunities, and can increase property values. Less expenses on fuels increases the economic wealth of the customer, increasing buying power.
Example: Kodiak island in AK has a hydro plant that saves 70% in operation costs from the diesel plant, which costs about $100k/day. The island is sourced from >99% renewables with the wind turbines in full operation.
Example: Blue Lake Rancheria sees about $150,000 in annual electricity savings to about 10,000 people.
Public Health: Renewables improve air quality and reduce health issues like carbon monoxide poisoning by offsetting/decreasing the emissions from dirty polluting technologies.
Example: The Environmental Protection Agency states diesel exhaust can lead to serious health conditions like asthma and respiratory illnesses, and can worsen existing heart and lung disease, especially in children and the elderly. Renewables emit no pollutants.
Sovereignty: Microgrids support local ownership and governance, giving communities control over their resources.
Example: California Resolution # 23-0302-09 recognizes the importance of sovereignty, especially after tribal experiences of historical violence, exploitation, dispossession and the attempted destruction of tribal communities within the state. The support towards energy sovereignty is supported by consultations, improved protections, increased access to funding, and increased workforce development for clean energy initiatives.
Equitable Access: Microgrids provide modernized energy solutions to more people, ensuring equitable access to reliable and sustainable energy. In some cases, this can help reduce disproportionate poverty.
Example: Navajo and Hopi Nations are electrifying 300 individual homes with 2.5 kW off-grid solar and battery storage systems.
Example: San Xavier District of the Tohono O’odham Nation was rewarded with a 50/50 price match with DOE resulting in $434,534.38 system costs savings.
Several rural and remote communities are currently operating with microgrids. High-level overviews of these communities are provided on the next couple pages. Each community has unique characteristics that necessitate specific microgrid configurations based on their ambient environment and can offer a way to relate the size of the system to the outcomes they produce. The examples show unique examples of successful deployments and operations.
