Gas consumption 2007-2011

I've finally gotten round to plotting our gas consumption on a graph. I'm not expecting a measurable drop in our consumption yet. We finished insulating our living room in July 2011 and I'm only just getting round to insulating our bedrooms (Feb 2012). We installed a new condensing gas boiler and solar thermal in July 2011. But we also had a baby in August 2011 so we've had the heating on far more than normal for the last quarter of 2011!

Temperature data from the Heathrow MetOffice weather station

What does this data tell us? And why did it take a fair amount of effort to plot our gas consumption?

Smart Meter Disaggregation

This blog entry is part of a series of posts introducing the topic of smart meter disaggregation.  In previous posts we've looked at the wider reasons for wanting to reduce energy consumption and we've taken a brief look at smart meters.  In the following blog post, I want to introduce the concept of smart meter disaggregation, also known as "non-intrusive load monitoring" or NILM for short1.  The main aim of smart meter disaggregation is to infer two things from a smart meter signal: 1) which appliances are active in the signal and 2) how much energy has each device consumed.  This blog post will summarise the arguments for disaggregation and we'll look at some of the main challenges.

Dimmable LED down lights

Our kitchen is currently lit with 10 × 50 watt tungsten lamps. Yes: that's a total of 500 watts. Which is utterly obscene and I feel distinctly uncomfortable just thinking about it. We want to replace these tungstens with LEDs, hence reducing the power required to light the kitchen by a factor of 10 or so. We have several requirements:

  • Must be dimmable down to 5% or 1% (some LEDs only dim to 60%)
  • Must produce enough light to fill the kitchen
  • Must produce a warm, cosy light
  • Must produce a light with a high enough colour rendering index to mean that skin looks like skin and not like pale plastic

This post is basically a collection of notes recording my research into dimmable LEDs.

Getting the Linux 1-wire file system owfs to work

I followed the installation instructions on the Ubuntu wiki but got stuck on the line where we try to get owfs to talk to the 1-wire network.  This worked for me:

sudo /opt/owfs/bin/owfs u -m /var/lib/1wire

I have a Dallas Semiconductor DS1490F 2-in-1 Fob, 1-Wire adapter.  Also, after installing, I found that the Navitron forum has a discussion on owfs.

All I want to be able to do is log temperature data to a text file.  I think I'll write a simple C++ app to log the temperature data to a text file and then use gnuplot to plot graphs.

Why bother to reduce energy consumption

This blog entry is part of a series of posts introducing the topic of smart meter disaggregation.  This specific post looks at the wider reasons for reducing energy consumption.  In other words, this post explains some of the reasons which keep me up at night when I'm not distracted by work! The reasons for reducing energy consumption typically fall into one of two categories: financial and environmental.  We'll focus mostly on the consumption of electricity but the arguments are mostly applicable to the consumption of all sorts of energy.

Financial reasons

There's been a lot of coverage in the press recently about high energy prices.  In January 2012, for example, the Citizens' Advice Bureau stated that 43% of people are worried that they can't afford their next fuel bill.  The following plot shows average annual domestic electricity prices in the UK from 1994 to 2011 (data from DECC, 2011).

Average annual domestic electricity prices in the UK.Average annual domestic electricity prices in the UK.

Electricity prices have risen from 2004 to today; but, when compared to data from the 1990s, today's prices are not quite as earth-shatteringly high as some news papers would have us believe.

What has caused the 35% price rise (in real terms) from 2003 to 2011?  I'm no expert but let's discuss two datasets which shed some light on what's going on.

Planning to insulate bedrooms this weekend

This weekend my wife and 5-month old daughter are going up North so I'm going to take the opportunity to insulate our two bedrooms. In this post I describe in detail my plans for insulating the walls of our bedrooms and also attempt to calculate how much carbon and cash the insulation will save us.

What is a smart meter?

This blog entry is part of a series of posts introducing the topic of smart meter disaggregation.

Your existing electricity meter probably looks something like this:

Attribution: Kristoferb at en.wikipedia

(image taken by Kristoferb at en.wikipedia)

By 2019, the UK government have mandated every electricity meter in homes and businesses will be replaced by a "smart meter" (that's a grand total of 53 million meters).  A smart meter is simply a digital meter with some basic communications functions.  It will be paid for and installed by the utility company.  It will talk to the utility company over a GPRS data connection; and it will also be able to talk to the "home area network" to provide data to in-house energy displays.

The draft spec for smart meters in the UK was published by the Smart Metering Design Group in August 2011.  The specification states that the meter must be able to supply meter readings to the home area network at a rate of one reading every five seconds.  The meter will measure voltage, real power and reactive power (in both directions).  Some utility companies have already started to install smart meters; British Gas plan to have 2 million smart meters installed by the end of 2012 (Centrica, 2010). 

If you can't wait for a smart meter to be installed then you could buy and install a "home energy monitor". These are available for around £40; although some utility companies give them away for free.  Home energy monitors are user-installable.  I used a Current Cost home energy monitor for my MSc project on disaggregation.  It recorded a sample of apparent power once every six seconds.

This is a reading produced by my Current Cost home energy monitor:


The value of sample at time t is the sum of the power being consumed by every appliance active at time t​.

Existing central heating control systems

A little while ago I wrote some notes describing my "ideal" central heating control system, which I was planning to build myself.  Time is short so it looks like this system won't be built for a while so I need something which I can buy off-the-shelf which will satisfy as many of my requirements as possible and also leave the door open to DIY tinkering in the future.  This blog post is a collection of notes about off-the-shelf central heating control systems.

Insulating our Victorian living room part 2

We live in an end-of-terrace Victorian house, built around 1905.  I've spent the last few years insulating our living room.  This blog post is the second in a two-part story.  By the end of the first part of the story, our living room looked like this:


I'm pleased to say that our living room now looks like this:


One big design change since my last blog is that we decided to install wet underfloor heating ourselves.

So, let's start the story...

LSE Podcast: State of the World Economy in 2012

The London School of Economics produce an excellent series of podcasts.  Last night I listened to "State of the World Economy in 2012".  Packed with lots of juicy economics facts and analysis.  One point which stuck in my mind was the suggestion that, in previous global economic slumps, a natural ballancing force has been the reduction of commodity prices.  Yet, this time around, commodity prices are not reducing; far from it: most commodity prices are at or near their peak values despite very low growth in many developed countries.


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