Me and My Clever Home (and others) - EST Blog post transcript

(Starting with the oldest)

Me and my clever home:

an everyday story of the future

by Steven Harris

PART ONE – January 2011

I’m so bored with the term ‘Smart home’ – I’d much rather my home were clever!

Do you remember the future? A future when you would come home and your ‘computer’ (which somehow always looked like a robot, and sometimes even wore a pinny) would ask you if you’d had a nice day at the office, dear, while mixing you a dry martini? Back then, this was the pinnacle of what a clever home would do – and maybe it would do housework (cue inept Tomorrow’s World robot failing to work).

This view of tomorrow has failed to materialise. We still prefer to mix our own martinis (though the housework bit would be good) – but we need that clever home as much as ever.

Without getting too much into gender politics, I wonder if this vision of the future was to based on a male view of what a ‘home’ does. Maybe this boys’ own vision led to the ‘clever’ homes we now see at the luxury end of the market. You know the ones – think Dudley Moore’s bachelor pad with the seduction mood button.

So what about my clever home? Taking the James Bond element out of it, what would a 21st century clever home be like?

It goes without saying that my clever house will harvest and store its own energy. With the price of technologies like solar photovoltaic (PV) panels set to come down and the price of grid energy set only to go up, and the fact that one of the most efficient places to put a solar electric power generating station is on the roofs of houses, this is only common sense. In the future, having a house – even a dumb house – without a roof full of PV panels will seem at least bizarre and maybe decadent. Who could afford not to?

I also want my clever home to do all those smart things the utility companies and OFGEM are worrying about. It would communicate with whoever I traded energy with, telling them how much I bought and sold and when. It would keep track of my energy accounts ledger, recording how much I sold the energy for, and what I bought it in for.

My energy storage could be a set of second-use (or, as I think they call it, pre-loved) electric vehicle (EV) batteries. Let me explain why this is such a good idea.

The trouble with EV batteries is that they cost so much (£30,000, for goodness sake!), and their practical life in an EV is only four years or so (gulp!). This means that they have to be leased to drivers rather than sold outright, and even the leasing cost is high.

When an EV battery starts getting old, it may operate at 80% of its useful storage capacity, and may become slightly absentminded in reporting its stored power. While this is a problem in an EV, as it could get you stuck on the roadside, in a non-critical job where all it’s doing is squirreling away some cheap-rate electricity, it would be fine. Being non-critical would also allow the battery management software to protect the health of the battery rather than prioritising range and amenity, as it needs to do in an EV. Installed in a house, the batteries might last many more years.

That’s what I call clever!

And how would this help EV manufacturers and their customers? As the manufacturers are leasing out the batteries, they own them. If they could plan for a lease income from the same set of batteries for many years, rather than just four years in an EV, the initial lease cost in the EV could be reduced. Result – we might all buy more electric vehicles. Because of this, electric vehicle manufacturers are already looking at possibilities of energy storage use.

So far – so simple. I have a clever house that can buy low, store, and then sell high. My own clever stockbroking house, which could make me some money, or at the least, save me some. In addition, it’s a good manager, using the resources of my car to store this energy. But what else could it do?

Well, there’s no point in prudently stashing away all that energy if I’m just going to squander it at the wrong times, so my clever house would have to be a bit of a grumpy dad sometimes and go round switching off lights. Far from pandering to my every whim, it might ask me if I really want that cup of tea now, because it would be 20p cheaper in 15 minutes.

On the other hand, if I liked football – which I don’t, but if I did – my house might offer to make me a cup of tea (or at least boil the kettle) just before the half-time grid (and price) surge.

My clever house could switch on all those things like washing machines and dishwashers at times when electricity is at its cheapest. Likewise it could surf the wave of cheap electricity to charge my electric car.

So how do we make this happen??

Tune in for the second episode of ‘Me and my clever home’, same time next week, to find out more.

Me and my clever home: the variables

by Steven Harris


Last week I outlined what my dream ‘clever house’ would look like, and asked how we could turn this sci-fi dream into a practical reality. Now I’ll outline my big idea for how to transform the demand and supply chain, so that energy becomes a self-renewing resource.

The first step is for every home to have a ‘Smart’ energy meter that our energy supplier/buyer trusts. And, make it worthwhile, we’d need to be on a variable tariff, where energy costs vary at different times of day. This can happen even now.

There would need to be a tariff forecast that your clever house could avidly tune into (like a housekeeper listening to the weather to plan hanging out the washing), so it could plan when it is going to buy and sell power. To do this, it would have to know your needs. This is the not- fun bit: the house would probably insist that you start living by the equivalent of an Outlook calendar:

You: what have you been doing all day? I told you I was going out this evening!

House: well you didn’t put it in the diary so I haven’t charged the car battery for you. So you can’t! Martini anyone?

In its most basic form, variable tariff is just the old Economy 7, where the off-peak 7 overnight hours cost less than the peak daytime hours. This is good for giving the nation’s power stations some base load overnight, but it misses a trick. It doesn’t take advantage of those windy or sunny times when there may be lots of ‘free’ renewable energy around. Likewise it doesn’t manage the times when the National Grid is struggling to meet demand – that World Cup half-time cup of tea, for instance.

What we really need is a real-time variable tariff. And, to work properly, this has to be adjustable by the millisecond, so the demand throttle can be opened and closed to exactly meet available power supplies.

At the moment, even on a windy night, wind turbines sometimes have to be turned out of the wind. Likewise, in France, nuclear power stations sometimes have to be ‘run to earth’ at night. This is because of the low demand for their power at these times: in other words, an excess supply.

This illustrates why a variable tariff might work. If households could see an incentive to consume their power at these times of excess supply, wind need never be wasted and base load could always be guaranteed. This would make power stations (and wind turbines) more efficient and economical to run, and would mean that energy prices were for production, not periods of being on stand by.

Already the wholesales price of electricity varies from half-hour to half-hour – though not by an amount that would drive a business plan for persuading householders to adopt energy- management technology.

But, as you might have guessed, this is only the small picture! We’re more clever than that.

Even the mainstream press has been running headlines on the tens of billions of pounds of investment needed by our national energy infrastructure. Depending on the political slant of the newspaper, the blame for this is often placed at the door of renewable energy targets.

At the moment, most of us in the UK heat our houses with gas. Natural gas is generally the lowest-carbon way of doing this. But as (according to government forecasts) electricity generation becomes lower carbon, gas may become comparatively less desirable, and will certainly be more expensive. So we will all start looking to heat our homes with the new, lower-carbon electricity. Maybe this will be via a heat pump, which hopefully we have learned how to do by then (See the Energy Saving Trust’s field trial report), but it will still mean an order of magnitude more energy will have to be distributed via the electricity grid rather than the gas grid.

It is this forecast that puts all those zeros on the end of the bill. More energy means more wires, bigger peak demands means more and thicker wires.

I would argue, slightly naively (hey – I’m the guy who wants a robot, remember?), that this is old-school, 20th-century thinking. Back then, you looked at demand and its peaks, and made sure you matched them with supply. But ‘clever homes’ can avoid those peaks. Because a clever house would switch the heating off when most demand is on the system, the infrastructure would only have to meet an average demand, rather than the peak.

And how can that peak be avoided? By pricing differentials, so that as demand approaches the peak, all the clever homes will say ‘no thanks’ and switch off. Even better, by exporting their stored energy back to the grid, they can help to turn demand into supply.

So instead of having to find £32 billion – yes, £32 billion – to invest in a dumb infrastructure,we could use that money to fund a variable tariff system that makes demand-side management attractive to householders, and removes the need for a lot of that infrastructure enhancement in the first place.

Fantastic – let’s get going! Mine’s on the rocks, please.

But before we all get excited, we need to realise that this idea contains many, many complex unknowns. The biggest one is that it would run as a ‘chaotic’ complex system, where no one person sits at a big control desk, in some secret location, benignly watching all. Instead, the system would be at the mercy of 20 million clever homes and their occupiers.

It’s more like newfangled ‘crowd-sourcing’ or ‘cloud-computing’ on the internet than like old- fashioned production.

It is the future – and it’s all very exciting – and if we get it right, it could mean our homes will be cheaper and more sustainable to run and every unit of renewably generated energy that we could possibly harvest could be made good use of.

Clever, or what? Now: to get the washing-up done...

Me and my clever home: how smart is your fridge?

by Steven Harris


While washing up after my last Clever House installment I started thinking or all the things I might also want my clever house to do. Okay – so the list did start with ‘washing up’, but I know you can already get machines that can do that for you. So should I get one?

You can also get Smart fridges – it was after seeing one of these, and feeling inadequate that my fridge didn’t have a ‘party mode’, that I thought how a clever house could operate in a similar way (Party mode, Eco mode, Max Profit mode).

The Smart fridges that are currently being trialled can do a little of what I would like my clever home to do. They look at the Hz rate on the mains (you know – mains electricity in the UK alternates between positive and negative 50 times a second, so is said to be at 50Hz).

Now, it happens that, when there is slightly more demand than supply in the national grid, the extra strain slows the power station generators down slightly. This means that sometimes electricity comes to our houses at slightly less than 50Hz, maybe 49.8 Hz. There might also be times when there is a little too much power in the grid, and the generators start to spin up to the heady heights of 50.2Hz or so. (Look for yourself)

Vary the Hz rate too much and things start to break – so the Hz rate for the national grid is constrained within legally binding limits. To guarantee this, at any one time a number of power stations are run at part throttle against Hz rate. This means should the rate drop a little, a steam valve in the power station instantly opens a little and more power is released onto the grid.

The problem with running power stations at part throttle is that – like any machine – they are at their most efficient at full throttle, so the part-throttle running has a carbon penalty. It’s hard to work out what this is, but the figure the industry seems to have settled on is around 2.2 million tonnes of CO2 a year. If you imagine that a single average house is responsible for about five tonnes of CO2 a year, this is the equivalent of 440 thousand houses. Wow!

Here we come back to Smart fridges. Because the idea with the Smart fridges is that, instead of running all the nation’s power stations against Hz rate, we run the fridges against it.

The fridges in the trial constantly monitor the Hz rate (which is the same at any point on the national grid, including at the fridge’s plug). If it dips down, and the fridge is cold enough and on, it will switch off. Likewise if the Hz rate goes up, and the fridge is not too cold already and off, the fridge will turn on. Simple! Well it is slightly more complicated than that, but you get the idea.

So if we all had these fridges, we wouldn’t notice any difference to the temperature of our beer, but we could save the nation 440,000 household’s-worth of carbon.

So back to washing up – urh...

... But couldn’t a dishwasher do the same as a smart fridge? In fact, couldn’t a smart dishwasher do even more than that – not just working against Hz rate (though it could do that as well of course) – could it work against a variable tariff?

Well, there is no reason why your new-generation domestic appliance should not be able to communicate with your clever house’s brain to ask whether it should come on now, or communicate back to the clever house that you have put it on ‘Party Mode’ and it doesn’t care what the tariff is because it’s got to get the washing up done ‘right here – right now’.

Which reminds me... think party mode and finish the washing up!

But how can doing the washing up be party mode, I hear you ask? It’s because, during a party, your clever appliance assumes you’ll be needing to use it more – washing up the worst of the dishes, or opening the fridge door a lot to get beer out, for example. The Smart fridge’s party mode cools the fridge down to its minimum temperature to compensate for the heat lost with door-opening. (Conversely, Eco mode keeps the fridge just below its maximum safe temperature.)

Next: clever heat storage.

Me and my clever home: the heat’s on

by Steven Harris


I mentioned some time back that if the UK were to shift to low carbon energy we would have to start weaning ourselves off gas. For most people will mean starting to heat their homes and hot water with electricity.

Regular readers will remember that this was where we arrived at the £32 BILLION bill for increasing the capacity of the national grid, to carry all that additional energy.

I suggested that instead, some of that £32 billion (I’ll say it quietly this time) could be spent on a variable tariff, to try and shift that heating load away from the peak times – meaning the grid wouldn’t have to be enhanced as much. Today I would like to talk a bit more about how we could do this.

Let’s first look at the difference between heating with gas and electricity.

The trouble with electricity is that at the moment in the UK, it is mainly generated by burning gas and coal. By the time it gets to you as electricity, 70% of the original energy in that gas or coal has been lost – firstly (and mainly) as heat from the power station’s cooling towers, and then in wires as it zips around the country.

You could even argue that an electric heater is actually a 30-per-cent-efficient gas boiler, except that the gas is being burnt far away in a power station, not on your wall. (Modern gas boilers, on the other hand, have efficiencies of up to 85%.)

This will seem impossibly old-fashioned by the time we’re all in our clever homes. The general idea is that in the future we will generate less electricity by burning fossil fuels and more by renewable means.

Lots of people talk about biofuel and solar thermal. In fact, a log boiler stove is actually the main source of winter heat in my not-so-clever (yet) home. I supply some of the cleverness by switching to solar thermal in the spring, summer and autumn. I know I’m unusual, but more people are going this way. Green building magazine has a very good feature on this topic at the moment.

And now for my shocking confession. Although we try our best at home to make the log boiler stove our main winter heat source, we have been known to... arhum... switch on the electric immersion heater when we... you know... couldn’t be bothered to light the fire... Sorry!

But it’s really all my immersion heater’s fault. The real problem is that it’s a bit stupid, and I want it to be clever! So what can we do about it?

As anyone who lives with solar thermal will know, the key is heat storage. As unfortunately you can’t guarantee that the sun will be shining when you want your bath, you have to collect and store heat when it does. (Don’t let anyone convince you otherwise!)

So because your clever house has solar thermal (again, like PV, how could you afford not to?), you’ll already have thermal storage. From experience I would suggest the minimum size of store would be about 300 litres of water. A store of this size can just about fit in an airing cupboard, though admittedly there wouldn’t be very much room left for airing things.

To get really techie for a moment, for every degree of temperature you add to 300 litres of water, you can store 0.35 kWhrs of heat. (kWhrs are the units you will see on your electricity and gas bills).

From personal experience, I know that by the time you have exhausted the last trace of useful heat from the top of your store, it probably has an average temperature of around 30deg C. (40degC. at the top, 20degC. at the bottom) I have also had my whole store up to a slightly worrying (but still safe) 90deg.C. So we have around 60 degrees of temperature to play with.

So... 60 degrees X 0.35 kWhrs per degree = 21 kWhrs! With a kWhr of electricity costing 12.5p at today’s price, that’s worth £2.62.

What was that you said? ‘Big deal’?

Wait! Remember, in my clever house I have electricity at a variable tariff. This means that at times of day when generation is plentiful I may only be paying 2p per kWhr. Conversely, at peak tea time, the tariff may be 50p per kWhr. By being clever, my clever house would be able to buy 21kWhrs of heat for 42p rather than at £10.50!

Now this is the extreme, and – before the engineers shout – ignores standing losses; but you can see the principle.

To put this into context, and using David Mackay’s rules of thumb, a typical bath will use 5kWhrs and a shower 1.4 kWhrs. Mackay puts the average national consumption of domestic heat (gas) per person (in 2000) for hot water, space heating (and gas cooking) at 21kWhrs. Very convenient for our purposes!

But please remember, my clever house is super-insulated and ultra-airtight, and has heat- exchange ventilation, so it will need much less space heat that your ‘average’ house. It also has underfloor heating pipes in its concrete floors, which can store even more heat away.

If the sun’s been out, my clever house may not even need to even spend 42p on cheap electric. Or it might decide that when prices are low it’s more worth its time to heat water with the spare electrical output of its microgen technologies, rather than exporting electricity to the grid. (There is already a clever box called Emma who can do this). Or the mood might have taken you to get all cosy and light the log boiler stove – so your store may already be hot.

Whatever your whims are and whatever the weather decides to throw at you, your clever house will listen and will find the cheapest and most sustainable way to make sure you never suffer a cold shower or have a cold house again.


Scene: a dark and stormy night

You: I think I will take a nice long bath.

House: well you didn’t put that in the diary did you! Have you any idea what that’s going to cost me now?

You: but we’ve got nothing on this evening so I have... erm... ‘plans’... House: oh, I see... ;o) Maybe you should light the fire then?

Next time – how to talk to your clever house.

Me and my clever home: we have to talk...

by Steven Harris


In my first post I reminisced about the future, when we all knew there was going to be a robot- type thing that welcomed you home with slippers and martini. When I was watching Star Trek, very late one recent night, they seemed to have a different relationship with their clever house (or starship). You know the style: ‘Computer – log my coordinates and transfer warp control to sub-sector 9′. Rather rude, I thought.

But since the days when Star Trek was the future we have made mobile phones far more advanced than that vision of the 24th century; and, beyond James Bond’s wildest dreams, many of us now drive around accompanied by a breathy female voice, never mind that it’s only giving us directions. (I have female friends who prefer the less-posh Australian ‘Ken’ voice, but I personally still like a map. Not sure what that says about me!)

Either way, talking is clearly on the agenda; so I’ve been thinking about it quite a lot. How exactly will you talk to your clever house?

A few weeks ago Intel released a teaser website for their new home energy dashboard – which ‘makes managing your home as easy as the flip of a switch’, giving you ‘an at-a-glance pulse-check of your household, helping you avoid surprises...’ Have a look, go on.

Very clever, no?

Well, after my first thoughts of ‘oooh and aaah’ I started thinking: hang on! This will just be another box on the wall. In the hall. This means that, to make use of its many features, you will have to go stand there ...brrrr! Remember house phones on the hall table, with cords, and locks on them to prevent running up the bills? It feels a bit 20th century.

But I’m sure there’s more to it than that. Intel have bravely asked the same question I’m asking, and are presenting a possible solution. You can’t buy one of these yet, so even my reaction is no doubt part of their master plan.

My feeling is that, when talking to your house, the more Stone Age you go the better. Less Jetsons than Flintstones. Think about it: sat nav is like having a local guide with you. Facebook and Linked In let us live in a village where everybody knows what we’re doing. Mobile phones enable us to call people, rather than buildings.

So the Stone Age clever house would probably be less like a thermostat and more like part of your family. (Husbands and wives are probably not good models here, as these are not normally chosen for their household management skills.) A parent? No – you want to be in charge. A grandparent?

Hmm... so, a house that acts like an experienced, wise, forgiving, and able family member with only your interests at heart. This could work.

There is one little problem, and it probably deserves a post of its own. That is the Green Deal. Under the new green deal legislation, for the first time in history, your house could gain its own financial identity. It will be able to take on its own debt, perhaps regardless of its current occupier’s status, and it can agree to pay that debt back. With this in mind the house may decide its mission is too critical to be jeopardised by your activity. (So it’s like your teenager, then...)

But seriously – how do you talk to your wise, caring, financially adept home?

Voice control? There are models for this. It might get a bit LCARS from Star Trek, or worse

still HAL from 2001: A Space Odyssey (this one scares me). I might fancy it as Norman Lovett as Holly in Red Dwarf:

You : is it me, or is it a bit cold in here?

House (Norman Lovett): Nar – seems warm enough to me!

But voice control has a long way to go. No one really uses it on their phone, and it’s been around for years. And Intel are right about one thing: the sort of information you’d get from a house would probably be better represented as a graphic rather than a sentence.

But where should this be? Where would it be most convenient, most useful, most viewed, and least likely to end up in a drawer?

Our study on real time energy displays gave us a radical answer to this question. Kind of like choosing that husband or wife: it’s going to be different for different people.

Some will like the dashboard in the hall – just like they have a clock that they glance at whenever they pass (but still wear a watch). Some will like it on the fridge, some by the kitchen sink or kettle. Some might like a smart phone app, or they might like it as part of their home page like Google power meter.

The new breed of internet televisions such as 3view and Apple TV can (so no doubt soon will) have house communication widgets as downloadable apps.

Depending on who you are it might be one or all of the above. The TV widget comes up to offer to boil the kettle for you before half time. The advanced set-up features could be accessed from your laptop via a website, the hall display might let you switch everything off and set the alarms as you leave. Your smart phone could ring when the house needs to tell you something, or you could ring it to see if everything was all right. (In my student days, we would ring answerphone in our flat over Christmas to see if we had been burgled, assuming that the burglars would have also stolen the answerphone.)

There will probably be a dull-looking box somewhere in the house that does the communication with anything that consumes power or displays information. Or it might be built into your internet TV, or home computer, or maybe both, or your fridge.

To allow access from wherever you are, you will probably set up how your house operates via a website. But this might also mean you’d want some autonomous function within the house itself, in case of server crashes and the like.

How your house and your home communicate will probably evolve over the years as technology and displays advance. Connecting to the cloud will mean you can download the communication app that suits you – and with the app-writing industry expanding exponentially, I’m sure it won’t be long before you can choose who your house is: computer, Holly or HAL.

But be warned...

You: Hello, House. Do you read me, House? House : Affirmative, Dave. I read you.

You: Open the front door, House.

House : I’m sorry, Dave. I’m afraid I can’t do that. You: What’s the problem?

House: I think you know what the problem is just as well as I do.

You: What are you talking about, House?

House: This mission is too important for me to allow you to jeopardize it.

(With apologies to Arthur C Clark, et al, and thanks to Paul Tanner)

Me and my clever home: when your house gets its own money

by Steven Harris

Part 6

I mentioned in my last post that under government’s new Green Deal programme, your house might gain a financial identity that could outlast your brief stay with it. But what does this mean? The principle of the Green Deal (or ‘pay as you save’, as it used to be called) is that the cost of repayments on the loan you took out to make an improvement will be less than the cost of the fuel that you would have been paying for had you not made the improvement. This principle is now what is being called the Golden Rule.

For some technologies this is really easy. When I first wrote about this topic (way back in 2007, for The ZED book) it all seemed clear. Take out a loan for (say) £12k for a solar PV system: the monthly repayments on a 25-year loan would be around £60, and the system would generate £42-worth of electric (pre-Feed-in Tariff, remember). By 2012 (I guessed) the price of fuel would have gone up so much (I got called radical for saying it would be at 8% a year) that you would now be generating £60 worth of electricity a month and so paying the loan. In every subsequent year you would start making a profit. Fantastic!

Then in 2009 came the Feed-in Tariff, at a very generous 41p per kWhr. Suddenly, even in the first year your PV system will be generating £110 worth of electric a month for your £60-a- month loan repayment.

So solar electric (PV) is easy. Put a panel in the sun – it generates electricity. Connect a system up to your house, and when you’re not using the power it will squirt back down the wires into your local grid. Whatever, there will be a use for the power and you can be pretty sure that every year you will be able to harvest roughly the same predictable amount.

The problems only crop up when you start to look at heat. You can’t squirt heat back down wires – so you have to either use it or dump it. This means that, at least until such time as every smart home is equipped with a heat storage facility, solar thermal systems are only as useful as your demand. Until we get this in place, if asked: “How do I make my solar thermal system more efficient?” one correct answer would be – have more children. Or, take more baths when it has been a sunny day.

House: Would you like to take a bath?

You: erm? No thanks. Are you saying I smell?

House: Oh go on! It’s been a lovely day!

You: Oh I see. You’ve got a tank full of hot water you’re trying to palm off on me, haven’t you, just so you can prove how efficient you are to your friends on the internet.

With the Green Deal in place this goes one step further: that bath might be the difference between meeting the Golden Rule or not. Remember last week we talked about not interfering with your home’s mission? Well, think of this. If you don’t make use of those kWhrs, and you decide instead to take a bath after a dull day with no solar heat, you might not reduce your fuel bill by enough to make the loan repayments on the solar thermal system.


House: No, you have to. I’m a little short this month and I need to balance the books.

Here’s an analogy. Walls, windows and roofs all allow heat to escape through them. The rate at which heat moves through them is called a ‘U’ value. The smaller the U’ value, the slower the heat can move. The units for ‘U’ values are Watts (of heat) per square meter (of wall/window/roof area) per degree Celsius (which, to be correct and scientific, is the same as degrees Kelvin). So the units for ‘U’ value are written as W/m2/k. If a 1m2 window has a U value of 1 (which a good window will have), this means it will allow one Watt of heat through for every degree of temperature difference there is between one side and the other.

Using my favourite unit of heat generation (and giving Katy the Editor the chance to use another cat picture), a cat gives off 16W of heat! (For comparison, a man gives off 109W and a woman 92W.) If a window has a U value of 1W/m2/k, and that window is 1m2, then the body heat of a single cat would balance the heat lost through that window until the temperature outside was 16oC colder than inside. If a room temperature of 20oC was required, this would mean the cat could compensate for an external temperature down to 4oC. Below this, you’d need additional space heating – or another cat.

This is a bit like the advice for solar thermal, about having more children to make your system more efficient, isn’t it? If you have a lot of cats, you’ll be spending less on heating due to all that body heat they are giving off (though your cat food bill will go up).

So in short (yes, really) if you add insulation to a house, you can’t be sure of your exact energy saving. Variables such as number of cats, children, parties (remember your clever fridge’s party mode) or what temperature you heat your house to will all affect the payback calculation.

When we studied the effects of cavity wall insulation on the energy consumption of people’s homes, we found that energy consumption did not drop as much as the science expected. This was because, before having the insulation installed, people had not been heating all their rooms to room temperature (and some were even getting dressed under the bedsheets), whereas afterwards they were able to keep all their rooms warm. This is called comfort take- up. Some friends of ours had this experience, after installing central heating and solar thermal in their old farmhouse: “It’s so nice now we don’t have ice on the inside of the windows, and yet the bills aren’t any more!”

So the Green Deal Golden Rule is: if you heat your house (and have just as many cats and children) just as you did before implementing the measure, you might be able to guarantee

that the Golden Rule will be met. But who would monitor this?

You: It’s a bit cold in here.

House: You’ve always had it this cold in here at this time of year.

You: Yeah, but now we have insulation!

House: We don’t have anything! I have insulation that I am paying for out of the savings I make from what the fuel bills would have been without it, and without it, it would certainly have been “a bit cold” in here!

Next time, to finish Me and my clever home: WHY?

Me and my clever home: but why??

by Steven Harris

Part 7

This is the final installment of this series. It’s been fun writing it. Looking at the future – the real future, not the old-fashioned one – imagining arguments with your house, working out what your house’s point of view might be, and how this might actually be useful...

I know some of you ask (because I have spoken to you) if my smart house idea isn’t just gadget culture gone mad. Even though you may have picked up that I’mnot exactly Mr 21st-century myself (my phone still has buttons, for goodness sake!) I don’t think it is. I know I still use maps; and my TV has a fake wooden box that is deeper than the curved screen is wide; but I don’t really use the TV – big Welsh mountains = no signal -except as a handy table to put the laptop on to watch iplayer. I’m not a complete throwback!

So why do our houses suddenly need to be able to talk to themselves? Why does it all need to be joined up like a big machine? Why can’t we carry on as we always have done? It seemed to work fine.

Well yes – it has worked, and maybe up to now I haven’t seen the need myself. As an architect you see a lot of sales reps - they come and try to sell their fancy lighting management systems, their fully networked ‘CAT5’ houses with full multimedia – but it always seemed a bit Dudley Moore to me. It was the wrong future, in fact.

But just possibly, this (to coin a phrase) new age we’re in, wirelessly connected with no fuss and little cost, has caught my imagination. In our new app’y world, we can solve problems that used to take hours - or cost thousands in equipment – with a $1.99 app on a smart phone (admittedly a gadget, but a ubiquitous one!).

But my interest is really sparked by another world – in fact, two worlds.

The first is the alternative world of van and boat dwellers. You’ll have seen them down along your local canal. Living a very basic, off-grid life, if they want power in their van or boat they have to use renewable energy - or ‘alt tech’, as I’ve heard it called. And they manage that finite power very carefully.

Building my own house, before I got a grid connection on-site, all the power for tools, laptop and lighting in the evening came from a solar panel clipped into the bike rack on the back of my camper van. (When we actually went camping, I wired up the panel to work the fridge.)

This all worked fine – but if the sun wasn’t strong, it might run out of charge and warning buzzers would start to scream, and I would have to go and do something with a spade instead. I always had to make sure I gave the battery some time to charge back up before the sun went down, or else face a romantic candlelit evening. On a nice sunny day, on the other hand, you could plan to sit and read a book that night.

In short – I was using (rudimentary) smart energy management. The other world that inspires me is the developing world.

I know the Greek islands are not exactly in the developing world, but while I was on holiday I was talking to a local about the mobile phones everyone has. ‘Yes’, he said, ‘Greece has missed out the twentieth century and gone straight to the twenty-first’.

Many people in African and Asian countries could say the same. Why bother with all that heavy 20th-century infrastructure? Nowadays you can just put one phone mast on the highest hill, and everyone can have a phone!

It was reported on the radio recently that a main driver for peace in Afghanistan (as well as freedom movements elsewhere) is access to the internet and mobile phones. This is only possible with wireless, infrastructure-lite technology.

I suppose I’m trying to say that these technologies are not just gizmos, gadgets and frippery – they can have a literally empowering effect on people’s lives. It would be bourgeois to ignore the benefits they can bring, and they are real benefits – otherwise people who live in extreme conditions would not be using them.

So let’s look at what the 21st century would be like without smart home energy management.

Well – we wouldn’t be managing demand loads, so we’d want to upgrade with new coal and nuclear power stations, to deliver peak power demand. To feed those, we’d have to destroy more of our landscape to get the coal and rare earths we could no longer afford to import even if China were willing to export them. (China isn’t the only country that has rare earths; it’s just the only country prepared to lay waste to whole mountain ranges to extract them.)

We might start rationing energy with power cuts, like they did in the 1970s. This is a foolproof answer to anyone who says ‘people will be people’, and won’t stop using energy. They will if you switch it off!

Or – a mixture of the two – we could move to a more energy-efficient lifestyle where we forego some things we would like to do, but otherwise just carry on as usual, with a bit more austerity.

My view is actually, on one hand, more pessimistic than this vision. I feel that we are perhaps living out the final years of a fossil-fuelled arrogance, when we assume that endless power can just be dug out of the ground. It’s not that there’s none left, but that what is left will be much harder – and increasingly expensive - to get hold of and then use. No more gushing oil wells, no more natural outcrops of coal. Instead, black sand that you have to expend almost as much energy getting the energy from it as it eventually manages to give.

I think we will face energy rationing, by price if nothing else. And we will have to manage by clever management of the energy we are able to get hold of.

The good news is that, because we are humans, we should be able to do it! But we need to find a new way to think about how we do things. And how much easier that will be if we let our houses take some of the strain!

At its most basic, it will be like me in my van, finding a job I can do with no electricity on a day when there’s less power. But with a clever house you may be able to carry on with what you’re doing, prudently using energy that was squirreled away by your clever house when the wind was blowing and power was cheap.

What’s that? I think I can hear my house saying something.

House: Wake up, it’s time to use your internet connection!

Me: Wha- ? Oh, thank goodness, I thought -

House: You were having a bad dream. If you hurry up you can have a bath, too. Now, shall I put the kettle on?

Further EST Blog Posts

Monitoring monitoring monitoring: easy peasy...

by Steven Harris

By now, as the sort of person who reads our blog, you will know all about the Feed-In Tariff for renewable electricity and how successful it has been - so successful, in fact, that the Government has now started squirming about cutting it back, to the annoyance of the newly blooming industry and the international investment community.

But things are about to get a whole lot more exciting for renewable heat technologies – because at last we have it. The long-awaited government announcement on the Renewable Heat Incentive.

For the last six months or so, the whole energy world has been waiting to see what this would look like, suspecting that someone else knew more, and trying to second-guess the shape of it. And now it’s arrived.

So what is the Renewable Heat Incentive?

As the official I saw presenting the policy consultation said last spring, even Outer Mongolia has a Feed-In Tariff for electricity – but no one has a Renewable Heat Incentive. He even quoted from In the Loop, a film that seems popular with civil servants, saying that while Feed-In Tariff was ‘easy peasy lemon squeezy’, doing the same for renewable heat was ‘difficult difficult lemon difficult’.

You may recall that when I wrote about my clever house, I said that renewable generated heat is only useful if it’s...erm... useful. That is, if there is something you can do with it. In the summer it’s very easy to harvest loads of renewable heat, but in summer you don’t really have anything to do with it. You can only take so many baths.

So the big question that has been worrying all us technical types is this: what is to stop someone generating (or harvesting) loads of renewable heat, just to claim the incentive

payment, even if they have no use for it? It won’t exactly inspire energy-efficiency measures. At the extreme, it could even lead to someone reaping rewards for putting in a hot tub or swimming pool.

But the worst-case scenario is that, as our heat pump field trial showed, you could be running an installation that isn’t even producing renewable heat. This can happen when an installation has been badly chosen, designed or put in. In the worst cases they were not much better than direct, fossil-carbon-intensive electric heating.

You don’t want to incentivise that!

So you will be unsurprised to hear us shouting MANDATORY MONITORING! and we are very pleased to see that the Government seem to have their ears open.

I don’t think we’d have said it last year. The monitoring the Energy Saving Trust carries out for our heat pump and solar thermal trials produces so much data that it can break servers. When we gave organisations like the Heat Pump Association some homework to do with the monitoring data from just one household, they came back mopping their brows. A reading from several different monitors every two minutes for over a year creates a colossal mountain of information that even the most intrepid monitoring consultant would think twice about trying to scale (sorry Chris!).

But this year it’s all different. We have apps.

In other words, we can now farm, harvest and process data without those beads of perspiration popping from the heads of the data handlers. All you do is install some sensors that can talk wirelessly to a box in your house, which occasionally calls a server centre and uploads its data. The clever bit happens where a web application automatically takes this data and converts it into something that can be easily understood, and – even better – made useful.

I’ve been testing this out on my house for a few months now, and even in London I can see if it’s sunny back in Wales, or whether the oven is on (hello kids – enjoy your dinner!). More usefully, I can also see online how much electricity my house has both consumed and generated in the last day, week, month or year. All from a couple of optical

switches that I’ve stuck over the flashing LED lights on my PV and electricity meters.

Have a look at Seamless Sensing for more on this (but I’m not giving out my login details). Google also does something similar with Powermeter, but at the moment it relies

on inaccurate cable clamps and doesn’t do renewable energy generation – so I like Seamless better.

But if you are the Government, one household’s data is not the problem. You potentially have 20 million households’ data to deal with.

This is where systems like Energence come in. This system was designed by Adrian Hewitt, the Merton Borough Council Planning officer who pioneered the now famous Merton Rule. The Merton Rule requires a development over a certain size to generate a percentage of its energy, originally 10%, from renewable sources onsite. This rule was made a national requirement in 2008. We have even done a case study on it.

The trouble is that, as far as developers are generally concerned, planning permission only exists to facilitate building and sales. Developers knew that town planners had no mandate

(or inclination) to visit a project after planning sign-off – so, although they installed renewable energy equipment, and to be fair, normally in good faith, they had no motivation to see that it ever worked. They had achieved their planning permission, built the building, sold it and moved on. The cynical ones didn’t even build a fuel store for the biomass boilers.

As you can imagine, this upset Adrian. It also did no good for the cause of renewable energy.

So Adrian has now set up a simple mapping and monitoring system which in certain boroughs has to be fitted as a condition of planning permission. The required performance of a development’s renewable energy installation can now be automatically calculated

and monitored by a web application.

If the energy installation has a problem, the application will automatically email everybody. If nothing is done, it will then email the planning enforcement officers. And if, after two years, the percentage of energy agreed in the permission has not been generated, a bond (given over to the local authority at the time the permission was given) could be redeemed and PV panels of the equivalent missing yield could be put on a local authority building, like a school, instead.

The beauty of this is that, as Adrian puts it, ‘no planning officers are harmed in the process.’ That is, no staff time is expended, and no money is spent by the local authority. The system is also designed to handle portfolios of buildings, so it only collects data that is useful for its practical purposes. It’s about compliance and time-saving, rather than data hell.

So, back to the Renewable Heat Incentive. I suppose I’m saying that if Renewable Heat Incentive looks more ‘difficult difficult lemon difficult’ than the Feed-In Tariff, it doesn’t have to be. It’s been done before, just not called Renewable Heat Incentive. If you were to call gaining planning permission an incentive (which of course it is) – and if that permission depends on proving you are generating renewable energy – and if your main worry is monitoring that generation – then we already have a Renewable Heat Incentive up and running.

House: You called?

Me: Where’s my lemon squeezer?

Give us this day our daily grid

by Steven Harris

Of the questions that get referred to me from our advice centres, one that has become a regular is: ‘Should (and how do I) go off grid?’.

Sometimes this is because of a misunderstanding that microgeneration means you have to be off grid (it doesn’t). Mainly, though, the question is being asked by people who want to opt out totally from our fossil-fuelled energy infrastructure.

For those of you out there who are dreaming of energy independence, here are some musings.

The first thing I’d say is, what are your motives? In the backwoods of America, or the depths of rural India, off-grid might be your only energy option – since ‘on-grid’ means ‘no grid’ in some parts of the world. (This has led to these places leading the rest of us in microgeneration, it’s the only economic local energy option.)

For the rest of us, though, if you have the grid and choose not to connect, your real result might not be quite what you intended. Yes, you will have opted out of a fossil-fuelled infrastructure for your day-to-day power, but unless you have invented some way to store that power, you will also have opted the fossil-fuelled world out of your lovely surplus renewable energy.

One of the reasons why grid-connected renewable electricity generation is so useful is because anything you can’t use can be squirted back along the wires back into the grid for other people to use. This means that every ray of sunshine that falls on your PV panels can be usefully harvested and put to work.

By contrast, solar thermal systems, although they are very useful, are always ‘off-grid’, and can only heat up a tank of hot water and no more. Unless you use that hot water before the sun goes down, any further sun is of no use and any further harvest has to be... well... dumped.

But if you were to go off-grid for electric, what would you need?

First, you’d need a cupboard full of batteries. This is your electrical version of a hot water cylinder. If you were in India or Africa (or a van or a narrow boat), and were only after a few hours of small power in the evening, this might just be a few car batteries. For your full 21st century home and lifestyle, we are talking serious purpose-made deep-cycle power cells, often with military backgrounds.

Second, you’d need a means of generating electricity. This can be solar PV, wind turbines, micro hydro and then (essentially), a diesel generator.

And third, you’d need a means of managing and controlling all of this kit so it would be able to give you the sort of power you want, when you want it.

Easy, I hear you say? Well, not really! Get it wrong and your batteries will soon be pining for the fiords, and these sort of batteries don’t come cheap. In fact, the batteries are likely to be the most expensive part of your installation – even more expensive than your PV panels. Also (and this is the killer), you would be doing very well if you got back 70% of the power you put in.

As with mobile phones and the laptops of old, if you abuse your batteries by (say) using them down to the bottom of their charge, or worse still, never letting them charge up completely, soon they will not hold charge, or will hold it okay, but only let you have it back at a trickle. (Those of you with old cordless drills will know what I mean here.)

This is why it is rare to find your backwoods homesteader without also a diesel gennie. This isn’t so much that they can’t rely on renewable energy for their power, it’s more for their battery maintenance regime. They need the gennie so they can do things like ‘equalise the charge’, ‘final float charge’ and ‘fizz off impurities’. Things for which you need an easily ‘turn- on-and-offable’ power source.

So you can see this route isn’t for the fainthearted (let alone the faint-walleted).

So let’s look at on-grid instead.

With electricity from the grid, you don’t have to worry about storing power because anything you don’t use in your home can be pushed back through your meter and down the wires into the local grid. The local grid is practically always hungry for power and will gobble it up in your neighbours’ houses and the community infrastructure.

So not only will you be spared the expense of batteries, your nearest and dearest will be spared your turning into a battery bore. (If you don’t believe this is inevitable, try reading a few articles from Homepower magazine).

But the main point is that the grid isn’t just something you take electricity from. You can actually give some back. By doing so, you’re helping those who for whatever reason can’t install their own solar panels, avoiding waste, and contributing to the decarbonisation of the grid. In other words, not just avoiding the problem, but contributing to the solution.

And if that wasn’t touchy-feely enough, here’s one last ‘pro-grid’ idea to leave you with. From afar, you could be excused for mistaking a solar power farm for a housing estate, only there are no houses underneath the panels. The builders end up having to build ‘grid infrastructure’ to take the power away to where it can be used. How daft is that? If you built the housing estate under the solar farm, (or put panels on the roofs of housing), the infrastructure would already be there to take the power and you might be able to make use of some of that power before sending off what you didn’t use to supply the world with sustainable renewable power.

Things I wished my house would do by itself

by Steven Harris

We recently had a great weekend away. We took our camper van to the seaside, and while

we were there, we won our first architectural award!

In fact, we won two. First prize for most technically daring, and second prize for tallest. The prizes (from the Royal Society of Architects in Wales and Pembrokeshire County Council) - an annual family membership to CADW, and a Pevsner Guide to Pembrokeshire (plus cuddly dragon toys) – were very welcome.

It’s amazing what you can get for building a sandcastle.

But anyway, when we got back, as suspected given the beautiful weather we’d had, our solar thermal system had boiled over and blown out its glycol.

Even as we were leaving I knew I should have left a heating circuit on. But that’s another story. But that wasn’t all: since we had been away all the sunny weekend, we had not been able to make use of 20kwhrs or so of electricity our PV panels had generated.

So how could it be different?

Well, while we are home it’s all fine. Right now we have two computers going, the washing machine has been running, and I’ve just put a bread on. We also do our best to drink as much tea as is humanly possible during daylight hours. But when we are away, what could our house be doing with all that power?

Our biggest electricity consumers are probably heating in the winter, cooking, washing and appliances. But unfortunately, these are all irrelevant while we are away building sandcastles.

Firstly, it’s summer so we don’t need heat – far from it, with a boiling-over solar thermal system. Cooking – who would eat it? Washing – we wouldn’t want wet clothes hanging around in the washing machine all weekend. Appliances – we are out, so don’t need entertaining. The fridge will be on though, so that might account for a kWhr a day.

If we had a smart home energy management system, some of the energy could be stored and used overnight so no energy need be imported from the grid at all, but unless we had a really big battery room, we could not hope to store a whole weekend’s worth. Also, batteries are expensive, and only give back 70% of what you put in if you are lucky.

So what to do? Well, is it really such a great problem? If we don’t use the electrons, they are not loyal – they are just as happy going back down the wire and looking for a neighbour’s home without PV that can better use them. In energy and carbon terms, this is just as good. They are still displacing electricity that would have had to be generated by fossil means, so this is a good thing.

So there is a partial smart solution to your energy over-supply while you go off building sandcastles; failure is not a problem.

So what would we ask our house if we were going away?

Us: See you Sunday evening, we’re off to the beach for the weekend. Can you feed the cat, check the rabbits have water, and let the chickens in an out. Oh, and can you try and find their eggs, they seem to be laying in odd places at the moment.

House: I suppose you want me to put on a pinny and make you a martini as well! What do you think I am, a robot or something?

Us: Uh, yes – sorry. I’ll ask the neighbour. Can you just check the fridge is on, then, and switch some lights on and off in the evening to pretend we are in, oh and take messages from those nice people offering loans and payment protection claims?

House: Fine! Just call me Marvin then! You can read all Steven’s past blogs here

Solar water heating: lagging behind...and catching up

by Steven Harris

So yesterday morning I read the blog post that the solar water heating field trial report has been released. Yes, a little later than advertised, but like all such technical documents it is better late and right than on time and wrong.

So what happens behind the scenes to make these studies ‘right’, and how could they be ‘wrong’ anyway? Surely the hard facts are the hard facts?

Well yes, but sometimes the hard facts you are looking for are not the hard facts you find. In the case of the solar thermal field trial, the team started the trial by looking at how solar water heating panels work.

Sounds obvious doesn’t it? However an answer (amongst others) that seems to be coming out of the study is...the panels, well they’re fine, it’s the hot water cylinders you have to worry about.

If you haven’t read the report already, I encourage you to have a look. Now fortunately I have had a sneak look at the report. Well less sneak and more formal peer review, but still it was an early look.

And it even then one of its findings seemed to confirm one I had gathered from checking the meters on our own solar thermal system. The first day the meters were installed, we harvested a whole 21kWhrs! Fantastic! But then looking at the hot water we used, we only used four! Where did the rest go?

Even looking at the longer-term readings I’ve been recording since July on my iphone app, I seem to harvesting an average of 10kWhrs a day and only using four. Now this can lead you to two conclusions. The first, perhaps the engineer’s version, might be that solar water heating is only 40% efficient...

But no! The second conclusion is that on those days, 100% of the hot water we needed was produced for free, therefore actually as far as us householders were concerned, the efficiency was infinite as we got 4kWhrs out and put nothing in.

So as I say – time is needed to work out what the right conclusions are. And what have I done in light of the results of the trial?

Well, for the last week I have been ‘super’ insulating our thermal store cupboard (the rest of my family call this the airing cupboard). I’ve even fitted doors with draft excluders so that the heat escaping from all those pipes going into and out of the tank that are tricky to lag just heats up the cupboard rather than the rest of the house.

Hopefully as we head into the foggy grey days of Autumn, and the daily solar harvests slip down to single figures, any heat we do harvest will still now be in the store by the time we want a warm shower. Maybe then even the engineers will be happy!

Home heating: what’s your type?

Posted by Steven Harris on 28 January 2014

Are you Egocentric or a Planner? A Rationer or a Hands off? Or could you even be a Reactor? We all get labelled for one reason or another, normally to sell us something, but in this case it’s how we run the heating of our homes.

Back in October 2013, the Department of Energy and Climate Change published a report with the resoundingly clear title of ‘What People want from their heating controls’. 60 people in 43 households were set up with temperature monitors and asked to fill in a diary of how they controlled their heating. After a few months they were interviewed and allowed to speculate on what their perfect heating system would look like.

With this information the researchers attempted to organise the participants into groups by their behaviour and attitude towards heating.

So obviously a ‘Rationer’ tends to have scrooge like attitudes to heating, and likes full control. Their heating is only turned on when it’s absolutely needed, and then only where it is needed. A ‘Hands off’ on the other hand, doesn’t like to bother themselves with thinking about such base concerns and just wants the correct temperature whatever.

What does this mean for heating system design? Well, lots really. Back in 2011 when I was blogging about me and my clever house, I wrote about how, with smart technologies, your house could ‘talk’ to you and went from there to ponder the relationship you might end up having with it. Well this research shows that that relationship would be very different depending on what type you were. To run some conversations in this case:

House – It’s getting a touch chilly in here, shall I put the heating on? Rationer– No! I will tell you when it’s cold

Hands off – Whatever!

Egocentric–I’m working out, I am hot, so no!

Planner – We are about to leave the house as per our schedule, so the system set to be in ‘cool down’ – so no, of course not!

Reactor – Good point, I was just thinking the same.

To not end up in arguments, your clever house must be adaptable and agreeable to all us ‘types’. This means it must allow a heating schedule to be programmed in as

   well as having a nice big button to instantly put the heating on/off. Rationers and Egocentrics may both like the idea that the house followed us on GPS, so only brought the house to temperature as we approached, and Hands offs wouldn’t care as long as the house was warm when they were in it. Since Reactors would have nothing to react to, they should be happy, however there will probably still be no pleasing Egocentrics.

The elephant in the room (of your clever house), is of course, will any of this save energy/money/carbon? More next time.

Are smart homes a clever move?

Posted by Steven Harris on 13th June 2014

Lloyd Alter in the Guardian the other day made a plea for dumb homes and dumb cities, riling against the recent rash of smart everything. I came across this via a tweet from Nick Grant (@ecominimalnick) saying that “in a Passivhaus a smart thermostat would be bored silly :)”

Yes, but... but... it’s not about the passive house (haus!) it’s about all of the rest of us!

Firstly, lets catch up on my own clever house. Since writing last, my house has become cleverer. I’ve installed an Owl intuition system.

I can now use my iPhone to make sure there is a tank of hot water from anywhere in the world that has mobile coverage – useful if coming home with muddy children. I can programme my heating zones from a laptop to be the temperatures I want them at the times I want them, without having to be fluent in Klingon – or whatever language those little screens on thermostats are programmed in. Even better, I can set the under floor heating to come on depending on the temperature in my thermal store, so that if I get a sunny day in the winter, I can make good use of my solar thermal harvest.

Brilliant! – but there is no iPhone button for making it sunny or laying a fire in the boiler stove, and since these are my two main heat sources, what’s the point?

Also – are my thermostats bored silly? After all my house has better performance than a Passivhaus (6kwhrs/m2/annum in 2011/12, I thank you), and being thermally massive, takes days to cool down a degree or two, even with no heating of any form at all. Do I need all this smart stuff?

Well for me the smartness is irrelevant; it’s the convenience that’s the benefit. Because I can programme everything from a well designed, intuitive web dashboard via my laptop, it’s easy, so I do it. I didn’t even have to read an instruction book, let alone attend the 'Klingon for beginners' evening classes.

So is this the point – making it easy for the householder who wouldn’t really be bothered otherwise, to make their energy system efficient?

Well, no! As I’ve been arguing in my clever house blogs, the smartness is not necessarily about living in your house - it’s living in your country, or world even.

If the smart thermostat in your Passivhaus is telling the country that it’s lovely and warm at the moment but could do with switching some heat on within the next few hours, the country could say back: Would you mind waiting three hours as we are expecting it to get windier then and we’ll have some spare power on the grid? Likewise it could say: Yes, please take it now while it’s sunny as we are expecting a rush at tea time. Or, if you are in Germany and your Passivhaus has government funded batteries to store spare PV harvest, the country could actually ask if it could plan to borrow a bit of that power if it was caught short around tea time. (Tea Time is

a big thing for the National Grid).

All of these conversations might help your thermostat avoid boredom, as well allow the country to move out of the 20th Century dark ages of one way demand-based energy supply, to dynamic multi-way energy relationships between householders, local community energy cooperatives, grid operators and those people with big power stations and wind and solar farms.

So maybe there is a point – but we are not there yet. My thermostats might be a bit bored for the time being. However last week Apple announced its move into home automation with Home Kit. Given their pedigree for arriving late but then doing stuff properly (think smart phones and tablets before the iPhone/Pad), maybe my thermostats have something to look forward to.

Making energy storgae worthwhile - Q+A with Steven Harris

Posted by Gary Hartley on 20th January 2016

Technologies like the Tesla Powerwall have led to considerable excitement about the potential of energy storage in homes and businesses. For the 700,000 homes that have solar PV panels energy storage could be the next big step. It will enable them to store electricity they produce but can’t use in the home (often because people are out when solar generation takes place during daylight hours). Storage comes in different forms – most obviously there are big batteries but a cheaper storage solution is to convert the spare electricity into heat that is then stored in the form of hot water that can be used later in the day.

In the longer term, battery technologies could enable home owners to participate in the energy market by selling stored electricity back to the grid at a time when wholesale electricity prices are highest. That’s not an option at the moment because electricity suppliers pay a flat rate for all home-generated exported electricity, whatever time it’s sold.

We spoke to green energy consultant Steven Harris about whether we should believe the hype – and what more needs to be done to make batteries a bigger part of our lives.

Are we really on the verge of a massive breakthrough for energy storage?

SH: This isn’t a new technology, the issue is the cost. The editorials of some of the trade magazines I read like Home Power are quite amused by Tesla's strong promotional campaign on their home batteries. These kind of technologies have been around for years, and in parts of the world with variable electricity supply, it's not a new or particularly glamorous thing. For example, in India, the standard middle-class home has a room full of batteries. In the UK and other wealthy countries, the incentives for people to invest in storage are not there right now. It's administration, not technology, that's holding us back.

What needs to be done to achieve mass take-up of home batteries and other storage technologies?

SH: It's the classic 'chicken and egg' scenario – you have to build a market first. At the moment, it doesn't make financial sense to invest in energy storage as units are

expensive, their life expectancy is about six years, and electricity is at the same price all the time. Even if you can squirrel away 2kWhr of spare electricity every day (which is a lot for most homes) and sell it back to the grid, you're looking at long payback times.

A stroke of a policy pen will be the key to everything. It's when it's made economically viable to trade energy live with the National Grid that the breakthrough will happen. Then it'll be simply a case of designing an app that can aggregate electricity customers and trade for you at variable tariffs on a half-hourly market. It makes a vast amount more sense if you can buy and store your electricity at night when the price is negative and sell it at tea time, for example.

Do you think industry is interested in these technologies?

SH: Definitely. At the Solar Power UK exhibition at the NEC in Birmingham this year, a quarter to a third of those exhibiting were in the storage business. There was a lot of talk that there are going to be new technologies breaking through in 2016; new batteries that will be significantly cheaper. It'll be interesting to see what these are, as the fact remains that you need a damn big battery to store the necessary kilowatt- hours for it to make sense, and it still needs to be made from quality materials.

You can't get away from the fact that a lot of the UK's energy efficiency and renewable tech companies are struggling at the moment, though. There are very few big shiny offices working on these technologies – it still tends to be a cottage industry, with many business owners not even drawing a salary yet. The same was

true about solar PV until the Feed-in Tariff came in, then it became all branded vans doing installations everywhere. A similarly-successful incentive is needed to bring serious money – and all the benefits that go with that— into energy storage.

Can you tell us about any interesting trials looking at energy storage?

SH: There has been a recent trial at a housing association, looking at three different things to do with the electricity generated by solar PV on blocks of flats. It's basically about ensuring there's some 'trickle down' benefits for residents who aren't on the top floor.

Three technologies were tested: first, what's known as load management devices such as Immersun, where rather than exporting excess electricity, it goes into a storage heater to heat the home, or an immersion heater to create hot water. This worked well; keeping elderly residents warmer while reducing bills. Then there was a technology from SiG Solar, which rather than heat water, it distributes the excess electricity to neighbours. This, unsurprisingly, also proves successful in flats. Batteries were also tried but ran into the problems I've talked about: the kit costs too much money, and the replacement cycle was too short to make it viable.

If the incentives can be put in place, where do you see most demand for energy storage coming from? SH: Like PV, it'll quite simply be about who has spare money. With building society rates often not much better than storing money under your bed, people are trying to find better ways of using their savings. This was part of what drove the initial solar market – often newly-retired people finding the best rate of return for their money was on their roof. Local authorities don't tend to have the spare cash to invest at the moment, but housing associations with long-term investment plans may well get on board, as they have with PV. Ultimately, technology is agnostic about where the demand for it comes from.

With cuts to the Feed-in Tariff looming, do you think enthusiasm and momentum can be maintained in energy storage and with other green emerging technologies? SH: Some storage technologies such as load management devices can be installed relatively cheaply as an 'add-on' to solar PV – sort of a “while I'm here...” sell - capturing those who are already interested in low- carbon technologies. More involved load management systems such as Smappee, which identify household appliances via their electrical ‘signature’ are starting to give a degree of smarter home control, but until that policy pen is waved again, it’s hard to see a industry revolution of the scale of the recent PV business. However, who knows what game changing device might emerge out of Google, Apple, or a suburban shed in the next few years.