The US media is full of stories about our decrepit electrical grid. Power companies and politicians respond by saying we need more high voltage transmission lines.
Are they right? I would argue that they are not. When a particular technology requires a major overhaul and large amounts of new capital investment, you don’t pour all that new investment into the obsolete technology. Back in 2006, AEP came up with a power line pipedream that it had created for the US Dept. of Energy. The AEP plan was to build a brand new 765 kV transmission system in the US at a cost AEP estimated at $100 billion. $100 billion was probably a wildly low estimate. If you had $200 billion to invest in our electrical system, why would you invest it in what amounts to a 50 year old technology?
The centralized grid depends not only on bulk transmission lines, but on huge generating plants far from electric load in population centers. For the last 20 years, electric generation plants in the US have been getting smaller and closer to load, not bigger and more distant. Larger coal fired and nuclear plants have been cancelled one after the other, as investors have shied away from the uncertainty and risk involved with this technology. So if we build AEP’s pipedream, there may not be any mammoth generating plants to connect to it in 30 years.
Here is an excellent description of how new microgrid technology offers a way out of our obsolete centralized grid.
This story starts out the way most other stories on the grid begin:
Most Americans don’t have to think much about energy reliability. We plug in a computer and it powers up; we flip a switch and the lights come on.
While very reliable today, the U.S. electricity grid is old and has gone at least five decades without a significant technological upgrade.
But instead of advocating more of the same, the article goes on:
A microgrid is a smaller power grid that can operate either by itself or connected to a larger utility grid. Microgrids can serve areas as small as a few houses, all the way up to large military installations.
“If your home was part of a microgrid, you could continue to receive power even when the utility power goes out,” NREL Electrical Engineer Mariko Shirazi said. “It gives you the ability to ride through any disturbances or outages by seamlessly switching over to locally generated power.”
It’s important to note that a backup power system — like a diesel generator — is not the same as a microgrid. Backup generators supply power to local loads in the event of an outage, but there is usually a delay or blip when you lose power and disconnect from the utility grid before the backup kicks in. In addition, a backup system is never meant to run continuously, nor to put power into the grid. However, the reverse is true — a microgrid can serve as a backup power supply.
A microgrid senses the quality of the power flowing through the grid. In the event of an outage, it can disconnect from the grid at a moment’s notice. It can also leverage solar, wind, or stored energy to supplement a dip in the current power supply. If things are running smoothly with the regional grid, a microgrid generating electricity from renewable sources can export that clean energy to the grid for everyone’s use.
Just Connect and Go?
The major components of a microgrid include a source of power generation, local loads, and electrical switching gear. It might also include inverters and energy storage — all of which sounds easy enough to just connect up to get started, right?
“These technologies are in different stages of maturity; the challenge is to get them all to operate together in a stable, concerted way to accomplish the goals of efficiency, security, and energy reliability — all of which are required from a microgrid,” NREL Electrical Engineer Greg Martin said.
Meeting this challenge of bringing microgrid technology to the average electrical consumer is the real investment in the future of our grid, not a more brittle centralized grid based on 50 year old technology.
And by the way, the description of a microgrid is essentially a description of the photovoltaic system we have on our farm — power company connection, hybrid inverter that controls switching, solar panel independent generation and a battery storage system. A micro-microgrid. It would not be difficult to scale up this individual microgrid to serve a neighborhood or even a city.