Power and spot price monitoring projects & resources

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k1wi

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#173453 24-May-2015 02:44

Given the talk about spot pricing and power management I think it's appropriate to have a thread where we can share resources and talk about projects we have. I'm thinking of websites, use cases (time shifted water heaters etc), implementations and so on.

My own story starts around 2010-2013, when I was big into Folding@Home, with a watercooled CPU and a far more powerful GPU than I needed for day-to-day. Between my trusty i7-920 and GTX 570, the overclocked parts were drawing a decent amount of energy 24x7. I had created a simple bash cron script for that monitored the CPU temperatures for spikes in temperatures, in case of pump/cooling failure etc (the 30+% overclock meant it was always operating at the limits of what was 'safe') or just from a particularly hot day. But my first foray into demand management came when I wrote another cron script that checked the wholesale spot price and started/stopped my folding clients when it increased above a particular figure and restarted them once the price dropped again. I never got around to completing them, but I was also planning on modifying it to adjust the clockspeed of the GPU (and thus marginal power consumption) in a stepped manner and another that used the reported grid frequency as a measure of under/over supply - with the intent of shutting down my load if national demand increased faster than national supply.

The motivation for this was effectively altruistic. Obviously because it was one computer shutting down when prices were high, it didn't have any impact on the market at all, and our power bill was only lowered by the amount of power I didn't use. So it did nothing for the average cost of power. But I enjoyed the process of experimenting with what demand management looks like, including the pros, cons and difficulties. Some of the difficulties I see are the speed with which decisions need to be both disseminated and applied - demand response is ineffective if the price has more or less come back down by the time you are able to shut down your load, so it needs to be as responsive as possible. Another is the cost of monitoring – trying to manually monitor the situation is a huge cost in terms of time. A further difficulty I see is what load is even able to be shed - I obviously don't want my whole computer cutting out!

I'm happy to update this post with updated lists of resources if people think that's a good idea?

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#1310664 24-May-2015 07:27

I'm interested in monitoring power prices as I've moved to Flick electric, and it makes a big different to my power bill.

The best resource I know is EM6, which shows live power prices. I have a couple of others, not as useful but maybe a good reference, I'll add them to this post later.

What I'd really like is two things:
- An Android widget telling me the current floating power price
- Some kind of standalone device telling me the power price: either a simple very expensive/expensive/average/cheap/very cheap done by a colored LED, or an LCD display that shows current price including the various margins by the line company and end user power company (Flick in my case).

k14

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#1310712 24-May-2015 11:23

Very interesting thread. Having been an electricity trader for one of the big 4 companies for the last 8 years this is of particular interest to me.

Probably the best place to get the most accurate electricity prices for your location is here http://www.electricityinfo.co.nz/comitFta/five_min_prices.main. The 5 min price is usually the definitive answer for the "spot" price. It is best at indicating a transmission constraint (a high price) occurring in real time and alerting you to reduce demand (if you are using a retail company such as Flick). Although in saying that the 5 min prices are not always the same as the final price (the price you will be charged by Flick). They are usually released the day after and can also be found on electricity info. EM6 is a great site for other information, and looking at it in a prettier format, however I wouldn't use that as the price signal for determining if you should reduce/increase your load. They don't display all nodes on there so if you are on a slightly obscure node (off the top of my head there are around 250 nodes in NZ) you could get caught out.

Your setup for reducing load under a frequency event sounds interesting. How were you getting the frequency signal into your PC? You shouldn't worry too much for matching the load/demand decreasing just due to normal events (i.e. frequency above 49.8), what you are really wanting to cater for is events that cause the frequency to go outside this band. There is a market itself that caters to this, this is called the reserve energy market. Generators and large load customers are paid to increase generation or decrease load when the frequency drops. Have a look at this https://www.systemoperator.co.nz/sites/default/files/bulk-upload/documents/Frequency-barometer.pdf. They get paid for every MW of reserve energy they have available. You can see the price if you open up the 5 min dialog on electricity info and click on the time stamp of the 5 minute price. The reserve market is per island (i.e. one in the north island and one in the south island). If you were able to scale out your system there could possibly be a commercial application for it. There is already a company in NZ (called Enernoc) that does this with medium sized factories and commercial companies by aggregating their load and selling this into the reserve market.

Let me know if you have any questions about the market. Happy to assist.

linw

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#1310719 24-May-2015 11:34

I'm thinking of switching to Flick and am interested in this thread. Thanks for starting it.

k1wi

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#1310773 24-May-2015 12:47

k14: Your setup for reducing load under a frequency event sounds interesting. How were you getting the frequency signal into your PC?

Because it was in the 'I wonder how easy this would be' category, I just scraped the data off of a publicly available website for a short period of time. I know that's not good Internet behaviour so I'm not going to name it in the thread.

Probably not hard to find and the group behind it actually look at this sort of stuff, so maybe it's good publicity for them if people find it heh. But it does raise another issue around the whole information dissemination/speed issue – how do you rapidly get data out to a large/massive number of consumers. Particularly if you start looking at personal demand forecasting – which will bring into account weather forecasts amongst other things. Such as the Nest is doing in some locations, in exchange for reduced utility rates.

When you look at appliances such as the Nest, or the cloud-backed energy monitors it is something they can take and push out to their own 'community', but my own preference is a collection of open source projects that allows the user to retain their information, pull in data and then apply their own model based on their situation & preferences. Like the solar hot water configuration I saw on here that diverts into their water heater the solar power that would otherwise flow back into the grid.

Perhaps there is a common ground. A cloud based service that pushes data to the client, with the client taking that information and then applying the analysis & implementation...

timmmay

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#1311384 25-May-2015 15:41

Here's a practical question... power seems to get more expensive in the evening, though I'm not sure by how much. This evening will probably be more significant because of the cold weather.

Does it make sense to have heat pumps come on 3pm (or 4pm/5pm) to preheat given I want the house warm for 6pm? I figure it uses the majority of the power to heat, then less when it's running in efficient mode to keep up to temperature.

k14

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#1311401 25-May-2015 16:15

timmmay: Here's a practical question... power seems to get more expensive in the evening, though I'm not sure by how much. This evening will probably be more significant because of the cold weather.

Does it make sense to have heat pumps come on 3pm (or 4pm/5pm) to preheat given I want the house warm for 6pm? I figure it uses the majority of the power to heat, then less when it's running in efficient mode to keep up to temperature.

Yes, you are right, power does get more expensive in the evening. Referred to usually as the evening peak, currently the maximum power consumption occurs around 1800 give or take 10 mins. I am unsure on the specifics of how a heat pump works but that could possibly reduce the peak. Although currently there is no reason for the average consumer to do anything because the cost of power is flat at all times of the day.

Theoretically, as the introduction of smart meters become more prevalent there should be power plans that give consumers a financial incentive to shift consumption away from the peak and into the troughs. However I am not holding my breath. The power industry is very slow at moving and contrary to popular belief, the majority of people don't actually care as much about price as you are led to believe. In some parts of NZ the majority of users are with the most expensive customer and have been since the market was introduced (late 90's). The proportion of people that are willing to switch is in the 20-30% range. This is slowly changing as more computer/internet literate people come into the market but it is more a 10 year than 1-2 year process. In saying this, I believe the auto load controlling systems that are mentioned in this thread will become more and more mainstream for those pro active consumers that understand the system better and there could be some interesting products that come out to take advantage of this.

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timmmay

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#1311412 25-May-2015 16:42

k14:
timmmay: Here's a practical question... power seems to get more expensive in the evening, though I'm not sure by how much. This evening will probably be more significant because of the cold weather.

Does it make sense to have heat pumps come on 3pm (or 4pm/5pm) to preheat given I want the house warm for 6pm? I figure it uses the majority of the power to heat, then less when it's running in efficient mode to keep up to temperature.

Yes, you are right, power does get more expensive in the evening. Referred to usually as the evening peak, currently the maximum power consumption occurs around 1800 give or take 10 mins. I am unsure on the specifics of how a heat pump works but that could possibly reduce the peak. Although currently there is no reason for the average consumer to do anything because the cost of power is flat at all times of the day.

Theoretically, as the introduction of smart meters become more prevalent there should be power plans that give consumers a financial incentive to shift consumption away from the peak and into the troughs. However I am not holding my breath. The power industry is very slow at moving and contrary to popular belief, the majority of people don't actually care as much about price as you are led to believe. In some parts of NZ the majority of users are with the most expensive customer and have been since the market was introduced (late 90's). The proportion of people that are willing to switch is in the 20-30% range. This is slowly changing as more computer/internet literate people come into the market but it is more a 10 year than 1-2 year process. In saying this, I believe the auto load controlling systems that are mentioned in this thread will become more and more mainstream for those pro active consumers that understand the system better and there could be some interesting products that come out to take advantage of this.

Flick Electric customers pay the national spot rate, plus a fixed margin for transmission, not a fixed rate. That's mostly why this thread exists. During the morning and evening peaks I pay more for power ($65/MWh), at 3am it's around $25 - $35/MWh. On top of that the distribution rate drops between 11pm and 7am, so I try to schedule dishwasher, clothes drier, and in a few months most of my water heating in that period.

Heat pumps are effectively efficient heaters.

I pay around $52/MHw for power at 3-5pm, I'm guessing it will hit $65/MHw during the peak. That's not really much difference, not sure if it's worth preheating or not.

k14

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#1311460 25-May-2015 17:26

timmmay:
Flick Electric customers pay the national spot rate, plus a fixed margin for transmission, not a fixed rate. That's mostly why this thread exists. During the morning and evening peaks I pay more for power ($65/MWh), at 3am it's around $25 - $35/MWh. On top of that the distribution rate drops between 11pm and 7am, so I try to schedule dishwasher, clothes drier, and in a few months most of my water heating in that period.

Heat pumps are effectively efficient heaters.

I pay around $52/MHw for power at 3-5pm, I'm guessing it will hit $65/MHw during the peak. That's not really much difference, not sure if it's worth preheating or not.

Yes, I am fully aware of flick. I was trying to work out how I could use an arduino or the like (maybe even a cheap PLC) to take the spot price and use logic to control relays that are in my switchboard (although gave up after finding they aren't likely to be near me anytime soon). The savings can be quite decent if you are sure that you won't be burnt by a massive price spike. Its just a pity that the complexities of the NZ market mean that flick will most likely never have an offering for me at my location. It is a great idea and I hope they force the big companies to be a bit more innovative in their retail offerings.

Although in saying that, there is something to be said for having some sureity for the price of your power bill. I liken it to taking out insurance for your house, you don't want to risk loosing the $$ if it burns down, similar to taking a fixed price from your power company. They wear the risk if the $hit hits the fan.

timmmay

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#1311463 25-May-2015 17:30

Rather than using embedded stuff an app on a smart phone that most people own maybe easier.

Spikes are apparently rare - like this last weekend it was high because of a transmission cable out. Given the significant savings just with a little care I think it's worth the risk. Flick should notify customers if prices really spike, and I'm on an email notification service - which for example told me today power was $50,000/MHw, 1000x more than usual - hoping it's an anomaly! If it happens too badly too often I'll move providers.

linw

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#1311646 25-May-2015 21:46

Youch, $50K/KWh!! Hope that didn't last long. Blackout time in Tim's house!

k1wi

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#1311711 26-May-2015 00:12

Pre-heating only makes sense for the consumer if the addition heat lost (heating the house a little warmer for a little longer) is outweighed by the lower cost of power. Unfortunately, that that is largely dependent on the characteristics of your house. If your house is poorly indulated, you might expect a substantial amount of the pre-heating to go straight out the walls, if it is well insulated, you may find that pre-heating by two or three degrees or more doesn't actually lead to that much in the way of heat-loss at all and saves some coin.

The reason it works for the Nest is that the power supplier provides an incentive for the consumer to use it, like the old night store, as they can control it and shift enough demand to avoid turning on that last expensive peaking power station.

The ideal 'ramp' or pre-stage is going to be dependent on your home, the change in cost of power and on the weather outside (with major interaction effects and endogeneity). So it requires some serious algorithms to be optimal. One thing also to consider (and we all should) is can you turn your heat off (or down) a little bit earlier before you go to bed. So also see how quickly the house cools down after you turn off/down the heater.

If you preheated using the middle of the day 'trough', you would probably also get a bonus of your heat pump operating more efficiently in the warmer outside temperatures. How that balances out though I don't know.

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timmmay

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#1311780 26-May-2015 08:11

Yeah, those are all factors I'm considering. Also on super cold days everyone will turn heating on when they get home from work, which where I live can occasionally lead to blackouts, so heating before that happens is good.

We turn the heating off when we go to bed, in the middle of winter if it's 21 degrees when we go to bed it's usually around 17 when we get up, so the house insulation is probably pretty reasonable especially given it's 100+ years old. The evening price is not really that much higher than the afternoon price, but with it being a bit warmer outside like you say that might help too.

Looking at the five minute prices the average price midnight to 6pm is around $40/MWh, with occasional periods that are cheaper and more expensive. I get a cheaper line rate 11pm - 7am too. It climbs to around $60/MWh in the morning peak (update - just hit around $80). I saw it at $140/MWh on the weekend when one SI -> NI cable was out, and it spiked to that once yesterday evening, but didn't sit around there. All in all it's not varying all that much throughout the night, but peak times it's definitely more expensive.

But as for turning heating on mid to late afternoon, I still don't really know if it helps or not. I may do some tests, looking at power and costs, once Flick starts showing my usage online (it can take two weeks after the meter is installed).

timmmay

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#1313712 28-May-2015 20:51

Power pricing seems to be fluctuating a lot tonight. This is the half hourly pricing info for my node. $50 up to $200, down to $80, back up to $200. Seem a bit odd. I know these aren't final prices, but I have no access to final prices because it can take two weeks to get the meter ID to Flick after it's been installed. You can see it here too - large swings (live link will show other data if viewed another day).

k14

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#1316571 3-Jun-2015 09:02

timmmay: Power pricing seems to be fluctuating a lot tonight. This is the half hourly pricing info for my node. $50 up to $200, down to $80, back up to $200. Seem a bit odd. I know these aren't final prices, but I have no access to final prices because it can take two weeks to get the meter ID to Flick after it's been installed. You can see it here too - large swings (live link will show other data if viewed another day).

That price pattern is a reasonably common one for this time of year. The first price spike was pretty standard due to the evening peak, peak load occurs around the start of TP37 which runs from 1800 to 1830. The second price spike is when all the networks turn everyone's hot water back on after turning it off (usually referred to as ripple control) after the evening peak (around 2000 usually) and this in turn creates a second smaller evening peak. Sounds odd I know but that is the best way to try and smooth out the peak with the current technology. I'll see if I can find the load profile from that night and post a screenshot.

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#1317163 4-Jun-2015 08:27

Yea... 6 to 6:30. Everyone comes homes, cranks the heaters, cranks the oven, cranks the kettle, cranks the TV, cranks the lights, has a shower... etc.

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