Tag Archives: energy

Go, Octopus, Go!

One of the surprising things about Octopus, the UK company from whom we purchase our gas and electricity, is that, despite growing to the point where they handle about a quarter of UK households, they continue to innovate.

For a long time, we’ve been on the ‘Octopus Go’ tariff, which means that for the four hours starting from 00:30 each night, we get electricity at less than one-third of the cost of the rest of the day. We make good use of this, charging our home batteries to the point where, combined with our solar, we very seldom use any normal (i.e. peak-rate) power.

We also charge our car during this time, meaning that our ‘fuel’ costs are about 2p per mile, and one of my favourite statistics is that, since it cost me about £600 to replace our car tyres recently after 30,000 miles, we pay almost exactly the same per mile for fuel as we do for tyre rubber.

All of this may sound very impressive, green and economical… just don’t ask me how much I’ve spent to get to this point! Still, I find it very satisfying.

One of the purposes of this post, by the way, is to remind anyone else also on Octopus Go that, from today, the cheap period has been extended to five hours: from 00:30-05:30. So go and reprogram your cars, car chargers, home batteries or whatever now, before you forget! For those of us who have a standard 7kW home charger, that means 35kWh of cheap-rate power per day, which probably translates into about 100-150 miles, depending on your car.

But Octopus also have some interesting features aimed at balancing the load on the grid during times of peak supply or demand. They’ve tried a few variants, and the availability of any particular one will be rather dependent on your postcode, but here we do quite well, as a result, I think, of generating vast amounts of wind power off the East Anglian coast and not yet having all the cabling that’s needed to distribute it effectively to other parts of the country!

One of these schemes is called ‘Saving Sessions‘, where, at times of peak demand, you can get paid surprisingly high rates per kWh for using less than your normal amount of electricity. At first, I ignored this because we use so little daytime grid power anyway that I thought it would be pointless, until a friend pointed out that even if your usage is normally zero, you can be paid for negative usage; in other words, for exporting to the grid.

“Oh ho!”, thought I, “I can do that!” And so, after a bit of programming, my home automation system notices whenever a Saving Session is active and starts discharging my house battery (and any excess solar) to the grid. These sessions only happen in the winter, and not very frequently, but we still managed to export 40kWh between November and March, earning us about £100. Yes, they really do pay as much as £2.50/kWh for energy we might have bought the night before for 9p. On rare occasions even more.

And finally, there are Octopus Power-Ups. When they think supply is going to exceed demand, they need to absorb it, and so they will let you consume as much as you want for free. Since this is primarily down to the weather forecast predicting strong winds, or lots of sunshine, or both, you don’t get very much notice: typically an email the day before or even on the same day. I just plug the times into my system, and when the moment comes, my car starts charging, my batteries start charging, my hot water starts heating, and so on. It costs me nothing, Octopus probably make more money the more I use, and everyone is happy. (Except my envious friends who don’t live in one of the blessed postcodes!) The main challenge was that I had expended so much effort over many months trying to configure the house to draw as little as possible from the grid, and I now had to set all of the components to do precisely the opposite for a short time and then revert! Still, that’s what home automation is for!

Octopus is a large company now, and like all organisations on such a scale, does have plenty of problems too. They suddenly realised at one point in the past, for example, that they had been billing me for gas but not electricity for nearly a year, and I got a very large bill that month. Also, I had smart meters installed for both gas and electricity, and the gas one has never worked, so I still have to go and read it manually. To be fair, this is a technical problem suffered at a lot of UK households by most providers, who didn’t realise that providing the electricity meter with connectivity and assuming that the gas meter could relay its reports through it using Zigbee wasn’t going to work when, as is often the case, the meters are on opposite side of a brick or stone house filled with competing 2.4GHz signals!)

But, in general, I’m a happy customer, and I hope they continue to explore new and interesting ways to optimise supply and demand. Further innovations will, of course, require me to keep tweaking my code, but, hey, everyone needs a hobby!

My thanks to my pal Gareth Marlow, who has a similar set-up and whose Home Assistant configuration helped me make mine much better! Gareth has also done some great YouTube videos analysing the costs and savings resulting from his home solar/battery system; perhaps the best I’ve seen on that topic for UK enthusiasts. Recommended.

The Christmas Lights Fallacy

Just twenty years ago, there was a popular factoid doing the rounds:

Half of the world’s population have never used a telephone.

I was working on technology for the developing world at the time, and this came up occasionally at conferences and other discussions. It was repeated by Kofi Annan, Al Gore, Belinda Gates, Newt Gingrich…. It was one of those facts that was shocking enough to be interesting, but believable enough to make you think of the implications. You may think you’re in the midst of the dot-com boom, but remember that half the world has never even made a phone call…

But, as I blogged at the time, Clay Shirky went and did some research, and found that, actually, the statistic was first used in 1994, and, even if it had been true then, it certainly wasn’t by the time everyone was quoting it in the early 2000s. Seven years, it turned out, was a very long time in technology.

I was thinking of this today as I read Charles Arthur’s nice analysis of another recent assertion: that Bitcoin may use a lot of energy, but not as much as everybody’s Christmas lights! It’s a fun fact to surprise your friends with at the pub, perhaps, but, as Charles found out, it’s not quite grounded in reality. Take a look.

Sometimes it’s very good to have proper journalists around.

Watt’s the cost?

A few years ago, I came across a really useful rule-of-thumb for calculating electricity cost:

A 1-watt device costs £1/year, if it’s running 24×7.

At the time, this was almost exactly right for most people in the UK, and it made it very easy to estimate the impact of, say, using that old 200W PC as a server for the next three years rather than getting a more modern low-power one.

Sadly, for most of us, energy costs are going up a lot at the moment, and the above is probably rather optimistic now, so you might want to do the calculation for yourself. For example, I currently have a big Synology NAS server here at home storing lots of my data and backups. Once you’ve bought such a device, how do the running costs compare with storing your data in the cloud?

So here’s my exciting new highly-sophisticated web application, which is designed to answer this simple question:

Watt’s The Cost?

Hot at the top

This is a lovely idea – the Mixergy hot water tank.

A standard UK hot water tank heats the water from the bottom, either using electricity or water heated by a gas boiler. This means that when you want to heat up your water, you need to heat the whole thing.

Mixergy, instead, put the heating at the top, so you can warm up smaller amounts of water, and then make intelligent use of pumps to circulate it as required if you need to heat larger amounts of water. Not only is this more energy-efficient, but it means you get hot water again more quickly after you’ve used it up.

There’s a more detailed discussion on a recent episode of Fully Charged.

Change the world with your DVD drive?

Researchers at UCLA produced graphene supercapacitors — an amazingly efficient electricity-storage medium — using a standard DVD burner.

“The process is straightforward, cost-effective and can be done at home,” El-Kady said. “One only needs a DVD burner and graphite oxide dispersion in water, which is commercially available at a moderate cost.”

More info here.

Smart Energy – now it’s personal

PilgrimMy pal Pilgrim Beart gave a splendid talk at the IET last week, about smart energy monitoring.

Click here to watch the webcast.

45 mins of talk, 45 mins of questions. Well worth the time.

All I want is a room somewhere, far away from the cold night air…

The very pretty Nest thermostat has justifiably attracted a certain amount of attention recently. But it has a few failings, too:

  • It’s expensive – someone quipped that the Apple-inspired design comes with Apple-inspired prices
  • It’s a single point of temperature measurement, and what most houses need is multiple thermostats, or at least sensors
  • It isn’t available in the UK and wouldn’t work with most UK heating systems anyway,

So, it’s not for me. But I am keen to upgrade my heating controls: we have pretty substantial fuel bills even for our small and fairly well-insulated house.

So I’m after recommendations. Here’s my ideal system:

  • You could set the temperature you want in each room, and control the times of day at which you want it. Or, even better, it would learn the pattern for each room. (And not get too confused by daylight savings time changes)
  • We have radiators in each room, so it would need to manage the radiator valves. (i.e. replace the TRVs)
  • The temperature sensors would not necessarily be on the radiator valves, but could be elsewhere in the room.
  • The timing of the boiler ignition would be based on the combined needs of the house, and not on the temperature of a particular thermostat in the hall, or of the time programmed into a separate heating controller.
  • Ideally, it could be programmed through a wife-friendly app or web interface.

Anyone know of anything that satisfies a significant number of these?  I don’t expect to get them all. But I also don’t want to spend a lot of money and time on a system which does some of them, only to discover that another would have been a better choice.
 
Oh, and I’d rather not have to do any major plumbing…

Any suggestions welcome!

© Copyright Quentin Stafford-Fraser