Hallquist and the grid
Christine Hallquist, CEO of Vermont Electric Cooperative, presented the third class in my course: The Grid: What Your Electricity Bill Won't Tell You.
On May 3, 2016 at my class on grid issues, Hallquist described the grid from the perspective of a rural electric cooperative in Vermont. She heads Vermont Electric Cooperative (VEC). This utility was one of the rural Cooperatives of the Rural Electrification movement: it was founded in 1938 to bring electricity to rural Vermont. It is now the largest locally-owned electric distribution utility in Vermont. VEC is dwarfed by Green Mountain Power, a utility with a very Vermont-y name. However, Green Mountain Power is actually a wholly-owned subsidiary of Gaz Metro of Quebec.
In my opinion, Vermont Electric Cooperative is the quintessential Vermont utility. It started in the Rural Electrification movement of the 30s, and and it is a cooperative in which the owners and the consumers are the same people.
Update 2018: The videos still exist, but their URLs have changed. Here's the link to this video.
https://www.youtube.com/watch?v=4zN0D_CAkKE
As CEO of VEC, Hallquist is concerned with the cost shifts involved in net metering, since VEC's service area includes low income areas of Vermont. When your owners are your customers, you pay sincere attention to the economic issues.
Late in the talk, Hallquist also discusses grid stability. Intermittent power tends to be destabilizing: the grid was set up for rotating electric machinery. Rotating machinery has a healthy inertia which helps keep the grid stable. Starting at about 1:20 (1 hour 20 minutes into the talk), Hallquist shows the jagged effects of wind and solar, and the almost un-analyzable harmonics of the intermittents on the grid. Few utilities collect this type of data.
I am very grateful to Christine Hallquist for sharing her information and her wisdom with our class.
It happens first in a village
Agatha Christie's Miss Marple is able to solve crimes because she has carefully analyzed many (supposedly) smaller issues in a small village.
To a large extent, Vermont Electric Cooperative is a "village" for the growth of renewables. The owner/customers are not rich, and they need to keep electricity costs low. While places like Germany can boast of their renewables while simultaneously building lignite-fired plants, VEC is actually adding renewables and dealing directly with the costs and stability issues that renewables present.
For example, the owner/customers have made decisions, very recently, on how to keep wind energy from being curtailed on their grid. They are making decisions, right now, on how much net metering the customers can afford.
VEC is hopeful about advances in energy storage and weather forecasting and so forth. (See Hallquist's last slide on "What are we doing about it.") But right now, there are very real limits for renewables on a small grid, and VEC is reaching those limits.
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Previous sessions
The first session was The Grid: Power and Policy Introduction, and Howard Shaffer on the Physical Grid. The second session was Payments on the Grid: What Every Citizen Should Know. This post is the third session. The fourth session was a field trip to ISO-NE, the grid operator headquarters.
I'm not so sure that all that rotating mass keeps things rock-solid. Wind turbines set up resonances throughout the grid as discussed in this video of an informal talk with Andrew Dodson http://tinyurl.com/h3towok Also this presentation by Andrew points out the complexities that arise http://tinyurl.com/hhh4qbp
ReplyDeleteA 19th century analogy can be made to the challenge of combining the output of a bunch of steam engines via leather belts. All those engines would have to be providing power in lock-step, increasing pulley speed to match the other steam engines otherwise the belts feed the power difference back to lagging generators, setting up resonances in the belts. That is exactly what happens in electrical grids which are equivalent to the olden day belts connecting the power generator, the steam engine, now an electrical generator to the load, in the olden day a threshing machine or wool mill, now any number of resistive and reactive loads.