The Solar Microgrid: A Clean, Decentralized Solution

The Solar Microgrid: A Clean, Decentralized Solution

In a recent blog series, GoSun has been following the October 2019 power outage in California, suggesting alternative ways to keep running your refrigeration and lighting without electricity, namely using solar-powered accessories that don't rely on grid energy.

In this post, we will look at the meta-idea behind these inventions, namely that most of the problems that come from modern refrigeration, cooking, and lighting come from reliance on our electrical grid. All of these problems can be solved by the same solution: switching over to the microgrid.

What is a microgrid? It is a small, localized group of electricity sources and sinks that usually operates with the centralized grid (mostly to charge batteries) but can disconnect and operate anonymously when necessary.

Here's an example. Let's say you use the GoSun Chill, a solar cooler that doesn't need ice. The Chill includes a Powerbank battery that you can charge with the grid. When the power goes out, so does your bridge, but the Chill keeps going for 14 hours. Once your lithium battery runs out, you can attach a solar panel that keeps your fridge running until the power comes back on until the Sun burns out (note: we hope the power outage does not continue for 5 billion years).

UC Berkley engineering professor Alexandra von Meier recently spoke about the solutions that solar-powered microgrid technology can offer. Here are excerpts from that interview. I

Can people use existing solar panels to power their homes during a shut-off?
A big problem right now is that we have a whole lot of solar photovoltaics installed on people’s rooftops, but in an outage situation like this, almost all of them are useless because they can’t be safely energized. That’s because, by rule, by the interconnection agreement, when the power in your neighborhood is out, your solar inverter also has to be shut off, unless you invested in a whole separate system where you have a battery at your house, and you disconnect from the grid. And that’s something that mostly only wealthier people can afford.
But what I think is going to be more and more interesting going forward, and maybe this event is going to spark a little motivation on that, is to better connect existing solar and additional solar that’s going to come online, in a way that it can operate safely locally, either on PG&E’s distribution network or independently.
One of the research projects that we’re working on at the California Institute for Energy and the Environment and Berkeley is called the Ecoblock project, which is actually looking at a multi-customer microgrid for exactly this kind of scenario, where you can share the solar resources and share energy storage among multiple households on a city block.
Could you tell me a little bit more about what a multi-customer microgrid would look like and how it would work?
So, there are actually a lot of different designs for microgrids and different combinations of resources. What’s unique about the Ecoblock is that we intend to aggregate multiple residential customers, say a dozen or so properties, that didn’t previously have that much to do with each other, and connect them on a microgrid separate from PG&E where they would be sharing the same storage resource. That makes it more economical than for everyone to have, for example, a battery in their garage.
Do you think transitioning to locally-sourced power might be a more likely scenario than going out and beefing up these old grids that we are currently living with?
Well, in terms of beefing up the grids, or making the grids safer with respect to fires, the main thing that would be helpful is to make them smarter, to recognize problems immediately as they happen, because the fire hazard is pretty much inherent, even if you work hard to manage the vegetation. The other option that really would address the fire hazard is putting lines underground, and that is a whole different order of price tag, especially if you are looking at Northern California, where you have thousands of miles of transmission lines.
And then you would still have vulnerabilities other than fire. Underground lines are much more reliable than overhead lines because they are impervious to falling trees and that kind of thing, but there are some other risks that still exist, such as cybersecurity risks. If you imagine a possible cyberattack against the electric grid, in that case having a physically more secure transmission line doesn’t help you at all. Whereas, having the ability for communities to be locally resilient and sustainable makes a big difference.

Many challenges remain to update our old grid-reliant system to a truly robust solar-powered microgrid. But with companies like GoSun leading the charge, the future is closer than many of us realized.

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