Monday, November 4, 2019

demand side power management

This is a thought experiment on how a local community might utilize electricity on a completely solar powered resource.

The obvious changes and limitations from our current arrangement are radically less energy available, and much restriction on when the power is even available.

But let's say that we want to ( or simply must) power our village, town, or neighborhood with only solar power. Till now, it seems all focus is on how solar could replace fossil energy as we are currently used to using it. That ain't going to happen.

Rather than figuring out matching power output to demand, what if we matched demand to supply? Individual off gridders already do this, and seem to get by fine, though with different habits and patterns than the rest of us. What if a neighborhood or small town did this collectively?

It might look like this.

The power grid gets divided up into many microgrids, with optional connections to the wider grid.

All homes have solar panels if homes are situated correctly.

Some shared solar farms could also be part of the generation mix.

All energy users have smart meters, as well as smart disconnects, meaning a central coordinating function controls where and when available energy is routed if needed.

Someone(s) in the collective could manage and maintain the system. There doesn't have to be help from some distant on call utility office. This will be a big step toward self reliance.

Some sort of equitable allotment scheme would be created, and then schedules and rules would be followed which basically gave each household a turn at the power so the generation does not get overloaded by demand.

This really goes against the normal individualistic mind set and culture of America, but when the end of easy energy looms, compromise and collaboration may well be forced on us as the alternatives would likely be even less palatable.

The thought experiment gets interesting when you try to imagine what the fair rules and scheduling might be. How to share cost, how to allocate power- by size of family? Strictly by ability to pay? Some mix? What about medical needs? How might time slot trading work? What about time of use pricing, or peak use pricing?  Lots of questions come to mind.

How would you rearrange your life to use electricity only for certain stretches, and in only partly predictable patterns. Maybe  a collective choice to spend on more storage would improve flexibility and access, but would it be worth the ongoing cost? Each microgrid might decide for themselves.

I guess the first thing I personally would do is ruthlessly eliminate waste and inessential loads. Find new ways to do things without electricity, or don't do them at all.

Another big one for each house would be water use. In rural areas, everyone is on a well here in the midwest, with an electrical pump at the bottom of it. Increase or create aboveground storage? Have an extra large pressure tank and even a cistern? What about homes in an urban neighborhood on city water? How will local utilities power themselves and still provide sufficient water? I can see water bills going up. Less and very quick showers would become the norm.

Home heating is a whole other can of worms I won't go in to right  now.

Next would be learning how to time shift, and how to get household chores arranged so they are prepped and ready to go as soon as a sunny day occurs. Lots to think about.

Electricity will become very expensive, and thus husbanded like the unique resource it is. Could this concept even be affordable?

But at least we'd still have it for a while.


  1. Good post. I think a big thing is that, in a 100% renewables grid, power prices will fluctuate more -- but the fluctuations will be more predictable (currently, prices fluctuate wildly when a big, centralised generator or connector fails, which is inherently unpredictable).

    Hence, in a 100% renewable grid, we can make good estimates 24 hours out of what electricity will cost. This allows simple embedded computers to make decisions about when to draw power.

    eg. You dishwasher knows you want the dishes done by 5pm, and chooses the time where it estimates power will be cheapest.

    Cheers, Angus

  2. Hi Steve,

    I tend to agree with Angus and such a system would be practical and make the most of renewable resources. However, it would be very expensive.

    Most people aren't home when the sun is shining enough to produce moderate amounts of electricity - and it is a bit of a problem. People also want to use electricity at night, and that too requires storage of some sort and such things are by their nature expensive and tend to only last between one and two decades (most industrial sized generators last only a few more decades than that).

    After a decade I have a good feel as to what is possible to do with the electricity harvested and stored, and that takes a bit of learning. Hey, I have only ever washed clothes in cold water and the other day tested the hot water cycle, and was really gobsmacked at the electricity used by the washing machine when it was heating the water. Bonkers and next to the microwave oven it wins the coveted award for energy hog.

    I don't know about well water, but lifting water 66ft here takes about 1KW of electricity. The higher the water has to be lifted, the more electricity required.