What are Microgrids?

by Anna Gretz
November 12, 2019

At this point, we're ready to do just about anything to escape California's planned blackouts.

In the past month, more than 2 million households and business lost electricity when the grid shut down to prevent the spread of wildfires in California.

People were (understandably) frustrated, and as a result... the hills were alive with the sound of dirty, diesel-powered generators. California, we can't blame you. But we also think we can do better than that.

What's wrong with generators?

Here's the [kinda loud, kinda dirty] scoop on generators:

How powerful are they? That depends on the size of generator you’re looking at. Generators are generally broken up into two groups: larger, permanent generators, and smaller, portable generators. Permanent generators are weather-resistant, outdoor installations kind of like air conditioners. These generators are connected to a non-electrical power source, like propane or natural gas. Permanent generators can be installed with an automatic transfer switch that will switch enable their power to kick in automatically when grid energy shuts off, which means they can operate even when you’re not at home to turn them on. They are quieter than the smaller, portable generator option, but still produce a substantial level of noise. Because they are bigger and more powerful, permanent generators are pretty expensive--the most simple and generic types start around $2,000, while larger more sophisticated generators can run more than $20,000.

Portable generators are the smaller, less powerful option, but are definitely easier on the budget than permanent generators. Portable generators typically provide between 2 and 4 kilowatts of power, and all portable generators require a manual start. Though they are called portable generators, they are still quite heavy and hard to move. Storing potable generators is also a big complicated, as owners need to be careful to prevent fires. Portable generators are also quite loud while they are running.

Generators are incredibly helpful for those who need power for life-giving and life-saving medical equipment, so we want to be fair. But generators are inefficient, and pretty bad for everyone's health. EPA calculations say that if every generator currently hanging out in the San Francisco Bay Area powered up (say, during a planned power outage), they would emit the same level of carbon dioxide as burning 2,000 tons of coal, all while tossing thousands of pounds of pollutants into the air.

Ok, that's rough. But what are our options here?

Well, let's talk about home batteries for a minute.


Most home batteries are constructed with lithium-ion technology. Lithium, the lightest of all metals, has the greatest electrochemical potential. This means that lithium provides the highest energy density per weight, which lends quite a bit of convenience to lithium-ion home battery customers. Home batteries are often used in conjunction with renewable energy sources like solar panels, but home batteries can also be connected to the power grid, and store grid energy.

Lithium-ion home batteries boast an impressively small carbon footprint, and a long cycle life, even in extreme climates. Home batteries can also be installed indoors or outdoors, and home batteries are generally smaller and less obtrusive than other back-up power options. Home batteries are low-maintenance, quiet, and clean, providing seamless power in the case of power outages. Many lithium-ion home batteries also have the capability to be connected and controlled by the cloud. This means a home battery can learn weather and energy trends, and focus on storing energy at ideal times, and maximizing power usage.

Most home batteries kick out between 3 to 9 kilowatts of power, and costs range from $4000 to $10,000, depending on the features you’re looking for in a home battery.

Generators vs. Batteries

Noise: Generators, specifically portable generators are quite loud, while home batteries can run with little to no sound.

Environmental Quality: Generators run on non-renewable energy sources like gas and diesel, and contribute to climate change and air pollution. Home batteries don’t generate power, but store it, often from renewable energy sources like wind and solar.

Power Supply: Generators typically kick out a lower-quality energy current that is prone to power surges and other quality issues that can damage equipment like computers. They often need to be started up manually, which means their power supply is not seamless (unless you have an automatic switch installed on a permanent generator.) Home batteries can be set to provide a seamless back-up power supply, starting up within milliseconds of a power outage. Home batteries are also less prone to surges and interruptions.

Maintenance: This is where generators really take a hit as opposed to home batteries. Generators require continuous refueling. Generators consume large quantities of non-renewable fuel, which requires storage in addition to the storage of the generator itself. Households with generators also need to store conditioning additives, all of which can be dangerous, and must be kept outdoors.

Runtime: Here, generators have an edge against home batteries, though it comes with a price. Gas generators are going to run as long as you need them to, granted you continue to fuel them up with gas and don’t have any mechanical breakdowns. Home batteries need to be recharged after their power supply is depleted, though if home batteries are storing power from renewable energy sources, this energy doesn’t cost anything.

Cost: The cost of both generators and home batteries varies a ton, depending on what you’re looking for. The least expensive, portable generators are, at this point, cheaper than the least expensive home batteries. Generators, however, have the cost of fuel, which is a frequent, repetitive investment. Home batteries require an investment in a power source as well, but in the case of renewable energy sources like solar, this is a single investment that then provides free, clean energy for years to come. There are additional costs with both generators and home batteries; it depends on the features you’re looking for.

Safety: Generators produce toxic exhaust, which is part of the reason why they need to be installed outdoors. Generators, along with their fuel, are more prone to fires if not stored properly. Home batteries have zero emissions, and though there is always a chance that an accident can happen with home battery usage, these are less common because they do not require fuel or fuel storage.

Both generators and home batteries can provide energy security for your household, but comparing them reveals just how many differences there are between them. If you don’t mind the noise, low-quality current, and non-renewable fuel of generators, then you can likely install them at a relatively low cost. Home batteries, however, can hook you up with clean, renewable energy security, and as the demand for home batteries increases, costs will continue to fall.

Home batteries have another superpower: they can create microgrids.

Microgrids use solar, wind, and batteries to create mini power grids that are much more resilient than the aging, centralized grid. Microgrids can cut ties from the central grid and run on their own, dishing out power during natural disasters, or... planned power outages.

Microgrids are a great option in areas that are susceptible to power outages, like California.

Energy security is key, especially now. As we move toward a more reliable, less centralized grid, you can take hold of your own power. Start with the installation of solar + storage on your own home, and make your house a protected energy fortress.