I hadn’t heard of the “smart grid” until I arrived in Oregon. Our department is pushing for a sustainability research collaboration initiative, SENERGI, and so it wasn’t long before I heard our former director, Terri Fiez, talking about the smart grid. Now, at INFORMS in San Diego, I’m listening to a keynote on the smart grid by Richard O’Neill, the Chief Economic Advisor to the Federal Energy Regulatory Commission
For the unenlightened, the smart grid is the idea of changing the price structure of electricity as well as the appliances that use electricity to manage congestion. As we move toward more electricity use (i.e. from gas-powered cars, to electricity-powered cars) and electricity generated from renewable and time-constrained resources, congestion could cause more frequent brown-outs than we’ve seen. Some concrete examples of “smart” include:
- Appliances equipped to decide when it is best to run: refrigerators that turn off and on to minimize draw on the grid during high-demand hours, dishwashers that wait for low demand hours to run.
- Batteries equipped to charge by use time: if you arrive home from work in your car (which I’ve been told is possible, but have yet to experience), and plug your electric powered car in along with everyone else who works 9-5, but you don’t need your car again until 6 AM, then the battery will decide to not charge until the middle of the night, perhaps according to some neighbourhood schedule.
- Batteries used as storage devices on the grid: if you don’t use your car during the week because you do walk or bike or bus to work (congratulations), then the grid could use the battery as a storage device on the grid, charging during low-demand hours and discharging during high-demand. (Of course, if you don’t need a car during the week, consider not owning a car. Renting a car almost every weekend is often cheaper than owning a car.)
Of course, for such a system to work, there are significant engineering (after all, even my dishwasher’s simple “delay-start” timer doesn’t work), design and optimization challenges. The market will become much more complex – will every appliance be considered a player on the market? Sheesh! Currently for the (much simpler, I imagine) pricing problems, the cost functions are linearized, which apparently isn’t a great approximation – essentially treating AC current as DC current. In a system that is worth $10^12/year, a 1% savings is huge news.
I worry though … what if my laptop tells me I can’t write an email at 2AM because I woke up in the middle of the night wracked with algorithmic thoughts because my battery has been discharged so my neighbour can run their washing machine.
essentially treating AC current as DC current Are you referring to the issues of apparent power versus real power? If not, what are you referring to?
Yes, I think I am. It wasn’t explained in depth. O’Neill essentially said “we approximate this linearly because we use LP-solvers, but it isn’t the right thing to do”.
It seems doubtful that everything will go “smart grid” overnight. But I think a practical plan to start with would be to:
1. Group electricty-using technologies into “traditional” and “smart grid” groups.
2. Let “traditional” technologies (computers, heaters, etc) stay on the standard way energy is used.
3. Let “smart grid” technologies (electric car, etc) leverage lulls in electricity usage.
This way, people can 1) get used to the change that comes from these new fangled devices and 2) the brain trust that introduces this stuff can learn about the effects these things have on the consumer and come up with a better way to charge the devices.
Don’t worry about your laptop being discharged to run your neighbor’s refrigerator. Firstly they’re probably too small to bother with. Secondly you would probably choose to keep your laptop out of smart grid programs to avoid incidents like you describe. Finally laptop batteries are too expensive to be economical for storing grid electricity. Let’s suppose your laptop battery has 300 watt-hours of capacity and lasts for 1000 charge/discharge cycles. That’s a potential of 300 kWh of electricity your battery can move from one part of the day to another. If moving electricity is worth 5 cents per kWh that’s only $15 worth of electricity storage at the cost of wearing out a laptop battery that costs far more than that.
My guess is that the vast majority of smart grid energy storage and demand management will be done by carefully timing activities such as battery charging, refrigerator operation, and air conditioning that be done eventually smart grid or no. Unless battery durability improves dramatically I don’t expect consumer devices to be discharged to feed the grid on a regular basis. Using consumer devices for peaking during the 5 hours of the year with highest demand makes sense, but using them every day does not as far as I know.
Warren: for the record, I was exaggerating.
Your blog is certainly kindling lot of thoughts in me. Very interesting and quite informative. But to be honest, lot of stuffs are very high for me to understand (e.g., your algorithms class at OSU ;-)). But I follow your blog, to improve my reading abilities and try to learn how the information is communicated in a concise manner.
I browsed the term “Smart Grid” in Wiki only after I went through your post. I was so fortunate to have read about this as I was thinking of a similar project for the recreation center at OSU as a part of curriculum. Need to look into it more deeply.
By the way, do you think algorithms play a role in Smart Grid? 😉