The Joy of Solar 3: Making Electricity

Solar Array – South Facing (Image: T. Larkum)
Solar Array – South Facing (Image: T. Larkum)

I previously described the installation and setup of the solar system on the back (south facing) roof of our house. It was installed by Greenday Renewables who I highly recommend – we have had no trouble with it and it works very well.

The most important information, however, is of course how successful it has been at generating electricity. The system is a 3.7 kWp array, consisting of 10 panels each of 185 Wp (plus an inverter in the loft), where Wp indicates ‘Watts peak’. What this means is that in an ideal (‘peak’) situation the 185 Wp panels could each produce 185 Watts of electrical power, so all ten together could generate 3.7 kilowatts. Of course, they are never used in perfect conditions so an estimate is generally provided of the likely total amount of power generated for a particular system arranged at a given angle, direction and latitude. For our system this was 3333 kWh per year, where 1 kWh of energy is a kilowatt of power provided for one hour.

The size of the system was determined by the roof space – it was the largest system that could fit. It is eligible for the government feed in tariff (FIT) which applies to any domestic system up to 4 kWp. We would have gone for the full 4 kWp if there had been the space.

The system was installed in September 2010 so we now have two full calendar years of data on electricity generation, covering 2011 and 2012. Up until the start of 2012 I recorded the meter reading virtually every day but since then I’ve been doing it once per week. The data is recorded manually and then transcribed into an Excel spread sheet (soon I hope to replace that process with an automated system, but more of that in a later post). From the spread sheet I have been able to graphically chart the data – see below (and click to enlarge).

Electricity Generated by Solar Array in 2011 and 2012 (Image: T. Larkum)
Electricity Generated by Our Solar Array in 2011 and 2012 (Image: T. Larkum)

Considered in broad terms the chart shows pretty much what you would expect – low generation in the early part of each year, building up through the summer and dropping again as winter returns. However, looking in more detail it is perhaps surprising just how much the rate of generation varies week by week as well as year by year. It is possible for one week to generate twice as much energy as another week in the same month. Similarly each year can have very different weather, so for example 2011 had generation peaks in April and May, while 2012 had peaks in May, August and September. In fact 2012 was significantly more variable than 2011.

Fortunately over a whole year the peaks and troughs average out pretty well, and the system has performed well. It generated 3650 kWh (3.65 megawatt hours) in 2011 and 3500 kWh (3.5 MWh) in 2012, and these numbers compare very favourably with the 3333 kWh that was predicted. Over these two years it was eligible for FIT payments of £3130 which is about one-fifth of its installation cost (£15750) so it is on course to pay for itself in about 10 years without even counting the cost of the electricity saved.

After it’s paid off the benefits don’t stop, of course – it is eligible to get FIT payments for a further 15 years – index linked – and after that we will have free electricity for life.

Overall it has been a great investment, so much so that we are looking to add another system on the front of the house with a view to using it to power our ZOE – more to follow on that in a future post.

[The Joy of Solar 4: A Second Installation]

[See also Grid Electricity Usage]

ZOE Wins 25 Hour Energy Saving Race

ZOE at the ‘25 Ore di Magione’ (Image:
ZOE at the ‘25 Ore di Magione’ (Image:

Last weekend the Renault ZOE took part in the Italian ‘25 Ore di Magione Energy Saving Race’ (25 Hour Magione Energy Saving Race) and won both categories in which it competed: ‘utility’ and ‘electric powered vehicle’. The race began at the Autodrome di Magione in Umbria with the first part following the road around Lake Trasimeno, while the night section took place within the autodrome.

The total distance covered was 236km, which the ZOE achieved with two uses of its fast Chameleon charger. It won on criteria that considered the vehicle weight, average speed and distance travelled per kWh, at one point achieving 193.4km on a charge at an average speed of 45km/h.


Renault ZOE Cabriolet

ZOE Cabriolet rendering (Image:
ZOE Cabriolet rendering (Image:

The Renault ZE page on Facebook has a timeline picture of a convertible version of the ZOE. It says:

“Renault ZOE cabriolet: ideal for driving in the fresh spring air! Would you like this concept made by a fan to be real?”

The image is believed to have been produced by the creator of the Spanish Facebook community page Renault Zoe. It has generated a lot of interest and discussion, but there is no suggestion that Renault has any plans to build a ZOE Cabriolet.

Forks in the Road: Last Exit to Two Degrees

Forks in the Road: Last Exit to Two Degrees (Image: J. Garrett)
Forks in the Road: Last Exit to Two Degrees (Image: J. Garrett)

The road we are on leads to a climate hotter than any humans have yet endured. Only by cutting carbon emissions can we steer toward a stable climate. Each day that we don’t choose the path of reduced carbon emissions we cut off a possible climate endpoint. And the longer we delay turning down the path carbon-free energy the sharper and more difficult the turn will be.

Skeptical Science

Car of the Year 2013: Best alternative fuel car

[Source: Diesel Car Magazine]

The past year has seen some impressive debuts on the new car scene, and Diesel Car magazine is very proud to announce the winners of its much coveted and well respected annual Car of the Year Awards 2013. Our award winning writers have put every single new car through its paces, in a stringent test programme, to decide upon the very best cars in ten different segments. From a shortlist of 26 cars, our expert judges have come up with the class winners.


Class: Best Alternative Fuel Car

Electric finalist: RENAULT ZOE

Renault is proving to be quite a champion of electric cars, and the Zoe is its fourth EV and the most convincing one yet.

It is also the most instinctively appealing battery model so far.

With its trim little supermini looks, Clio underpinnings and roomy practicality, the Renault makes a strong case for going electric, with a 130-mile range and a similar price to a diesel Clio to boot.

Any anxiety about battery life longevity is overcome by a lease plan, and Renault will replace the pack for free when efficiency drops below 75 per cent.

Good to drive and blissfully quiet, the Zoe is a peach.

Hybrid finalist: MERCEDES-BENZ E-CLASS

Driving a hybrid should not be a quirky choice, as you want it to be utterly seamless and entirely unobtrusive, and that is what is so impressive about the E300 BlueTec Hybrid…

Commended: Chevrolet Volt / Vauxhall Ampera

And the winner is…

Renault ZOE


ZOE Test Drive – 3: Driver’s Controls

ZOE Display with Selector Button, left-hand drive version (Image: TheRegister)
ZOE Display with Selector Button, left-hand drive version (Image: TheRegister)

[Part 2 is here]

During the test drive I had a chance for the first time to try out some of the driver’s controls. First of all there is a display selector, just to the left of the main dashboard TFT display screen. This cycles between three different forms of display – as I recall one that’s primarily a numeric display of speed, energy consumption, mileage and so on; one that’s like a speedometer dial going up and down as electricity is used or generated, and one that has a more artistic display showing lines of energy moving to the right, from battery to car, when accelerating or moving to the left, from car to battery, when regenerative braking.

ZOE Display, ‘speedometer’ version (Image: MyElifeNow)
ZOE Display, ‘speedometer’ version (Image: MyElifeNow)

Next I tried out the cruise control. I believe this is initiated by the button to the left of the gear lever (it was actually done by the salesman) but then I was able to operate it using buttons on the steering wheel. When switched on the vehicle will accelerate or decelerate to the currently set speed; this speed is shown top centre on the driver’s display. The set speed can be adjusted up and down by a centre-biased switch on the left side of the steering wheel – pushing the top half of the switch (marked ‘+’) increases the set speed and pushing the bottom half (marked ‘–’) decreases the set speed.

Cruise control buttons on steering wheel (Image: T. Larkum)
Cruise control buttons on steering wheel (Image: T. Larkum)

The cruise control was certainly a novelty to me, perhaps because I’ve never driven a car before that had it. It was mildly disconcerting having it speed up or slow down apparently under its own control, though I can certainly see the attraction and use of such a system, particularly on the motorway. Pressing the accelerator or brake disabled it.

The cruise control can be engaged or disengaged by pressing the centre-biased switch on the right side of the steering wheel – pushing the bottom half of the switch (marked ‘O’) turns it off and pressing the top half (marked ‘R’) re-engages it.

The other button on the right of the steering wheel is to turn on voice-activated commands. I didn’t get a chance to experiment with it beyond pressing it and having the R-Link respond ‘Say voice command’ or something similar.

I certainly had the impression from my test drive that the ZOE is loaded with technology and clever controls, and look forward to experimenting with mine when it arrives.

ZOE Test Drive – 2: Driving Notes

ZOE Zen demonstrator (Image: T. Larkum)
ZOE Zen demonstrator (Image: T. Larkum)

[Part 1 is here]

For my test drive I had the opportunity to take a long drive out of the town and through the local countryside and so I was able to try out the ZOE in a variety of conditions. The experience of starting up is disconcerting, as is often said when someone used to a combustion engine tries an electric vehicle. You put your foot on the brake and then press the Start/Stop button on the dashboard. At that point the dashboard lights up but of course there is no engine noise – to someone used to a combustion engine it lacks the obvious feedback of a revving engine, though I imagine one could get used to it quickly enough.

To move you engage the gear lever (marked P R N D) from park to reverse or drive. Having always driven cars with manual gearboxes I really don’t like this lever. It seems to be to be a simple sop to those used to driving with an automatic gearbox. Since the ZOE has no gearbox I believe it would be far preferable to dispense with a gear lever altogether and have simple selector buttons on the centre console, or even a simple selector lever on the steering wheel like a sports or racing car. Similarly, as soon as you release the brake pedal there is ‘creep’ and the car starts to move – this makes no sense in an electric car and again, I believe, just panders to those used to automatics.

When starting off and moving at slow speeds it would be fair to describe the travel as ‘silent’. While technically not actually silent the quietness is eerie. There is no detectible sound from the electric motor, and the noise from the tyres is little more than you would get from someone walking past.

At slow speeds the brakes are noticeably ‘grabby’ – this was commented on by each driver. This is presumably because at low speed the friction brakes are being used exclusively. This may have been particularly noticeable on our demonstrator vehicle as it had such a low mileage and the friction brakes may not have been bedded in – it’s possible we would have noticed the same effect on a brand new Clio. At highway speeds the brakes are mostly using regeneration and felt fine – very smooth. When decelerating to a stop there is a point at which the brakes necessarily transition from regenerative to friction, but I don’t notice this changeover particularly.

Leaving the dealership and starting on the test drive I found the ZOE very straightforward to drive and I had to agree with my colleagues’ comments – on the whole it is very much like driving a conventional car. In fact, given the wide range of performance and behaviour of cars, it is fair to say that the ZOE sits comfortably within that range and doesn’t stand out in terms of handling, acceleration, steering, braking, etc. for being electric.

ZOE Zen demonstrator (Image: T. Larkum)
ZOE Zen demonstrator (Image: T. Larkum)

I initially found the acceleration acceptable but not remarkable. However I realised fairly quickly that the ZOE was in ‘Eco’ mode (there’s an indicator at the bottom of the driver’s display) and switched this off (the button is to the left of the gear lever). After that I found the acceleration to be satisfyingly lively at low speeds and still perfectly acceptable at higher speeds.

The ride is good but erring towards firm – the ZOE certainly doesn’t glide over potholes or broken road surfaces (of which there seem to be a lot on British roads at the moment) but nor is it excessively jolting. Overall it gave me the impression of having suspension similar to a ‘hot hatch’ of which I’ve driven a few – a sacrifice of a soft ride to provide good handling. And the handling is good, with the ZOE comfortably managing curving and sharp corners at a range of speeds. Only a couple of times did I have the impression that the car was not responding quite as fast to steering inputs as I expected – the feeling that it was ‘heavier than it looks’. That is a largely unavoidable consequence of carrying a heavy battery pack, only partially compensated for by carrying it low and largely under the centre of the vehicle.

As touched on previously the ZOE is not silent at highway speeds – in fact it almost seemed quite noisy even in the absence of the combustion engine, though of course it’s likely that without engine noise all other noises become relatively more obvious. As well as the road noise there is also noticeable sound from the electric motor. It is much less than that of an engine but it is there. Most of the time it is just a background whirr, but under hard acceleration it produces a distinctive whine which can’t be ignored though – one could argue – it does give back to the driver some of the visceral feedback that you get from a hard-revving petrol engine. Most of the time, though, the motor just produces a background noise that is much less invasive than a combustion engine.

At one point while driving through a pedestrianised area I became aware of another sound that I couldn’t place – a bit like a low frequency rumble as though we were passing a busy factory. The salesman pointed it out as being the ZE Voice becoming activated at our slow speed. I wound down the window to listen to it. I can’t comment on its effectiveness at warning pedestrians of our approach, but as a driver I didn’t like it. I can see me turning it off, or at least choosing my own ‘ringtone’ for it (assuming I can do that) – something like a futuristic Stars Wars-style spaceship sound perhaps. Or just a music track, if that’s possible, such as Ride of the Valkyries.

[Part 3 is here]

ZOE Test Drive – 1

ZOE Zen demonstrator (Image: T. Larkum)
ZOE Zen demonstrator (Image: T. Larkum)

Yesterday, more than a year after pre-ordering my ZOE, I finally had the opportunity to take a test drive in a ZOE. The vehicle had been the showroom model but a new ZOE was on its way, with a higher specification (I imagine it will have the 17” alloy wheels and so on), so this vehicle – a standard Zen – was now the demonstrator. It had less than 300 miles on the clock.

I went with two colleagues from work to our local Renault dealer, Marshall in Milton Keynes. They had a drive each first and were both very positive about the experience. It was interesting that as passengers they commented on how much it was just like a conventional car and I would have to agree – as a passenger it was very difficult to tell it was electric.

A comment was made about how much of the noise in a car while driving is road noise – and this was an interesting point that I would have to agree with. Even though you remove engine noise, as you largely do in the ZOE, the drive is not silent because of road noise – and I think that’s particularly true in Britain at the moment due to the poor state of road surfaces. It’s great not to hear an engine, but it would not be true to say the drive is silent; it is quiet but with road noise evident at most speeds, and presumably there would also be wind noise at high speeds (though we didn’t have the opportunity to try that).

As a passenger in the back I would say that it was comfortable enough, but certainly not roomy. My colleague, at a little under six foot tall, appeared to be sitting slightly sideways to provide enough space for his knees behind the front seat passenger. Similarly, although there was a proper three-point seat belt for the middle seat, it would appear to only really be useable when there are three children sitting in the back – adults would be quite tightly packed.

Marshall Renault, Bletchley, MK with charge posts (Image: T. Larkum)
Marshall Renault, Bletchley, MK with charge posts (Image: T. Larkum)

After their drives finished my colleagues returned to work and I stayed for a longer drive. I asked to see how the ZOE was charged. It was very straightforward: a button inside releases the cover over the charging point, inside this there is a dust cover that you open by hand. The cable connector is inserted – at this point it appeared to become locked into position. Once the charge station is activated (in this case by an electronic card) the charging starts. On completion it is necessary to release the charging connector using a button inside the car – this is presumably to prevent other people (either passers-by or other EV drivers) from disconnecting you while you’re charging at a charge point in a public area.

[Part 2 is here]

Renault signs with Spark Racing Technology and Formula E Holding as Technical Partner in the FIA Formula E Championship

Renault signs with Spark Racing Technology and Formula E Holding as Technical Partner in the FIA Formula E Championship (Image: Renault)
Renault signs with Spark Racing Technology and Formula E Holding as Technical Partner in the FIA Formula E Championship (Image: Renault)

Renault SAS, leader of Electric Vehicle and expert in motorsport, has signed on as official Technical Partner of Spark Racing Technology to supply the Formula E cars to be entered in the FIA Formula E Championship.

The agreement was signed by Patrice Ratti, Renault Sport Technologies Managing Director and as a Renault SAS representative, Alejandro Agag, CEO of Formula E Holdings and Frédéric Vasseur, President of Spark Racing Technologies.

Renault has demonstrated a unique commitment to zero-emission mobility, with a range of 4 cars available for sale. Renault in Europe, and the Renault-Nissan Alliance worldwide, have gained a position of EV sales leader. Formula E is an exciting opportunity to demonstrate the excellence and the reliability of our EV solutions” said Philippe Klein, Executive Vice President, Corporate Planning, Product Planning & Programs  of Renault Group.

We believe that motorsport is an efficient manner to promote the efficiency of new technologies, and we’re eager to use that single-seater in FIA Formula E championship to show our technology is the best.”

Renault’s ongoing involvement in motor racing’s series provides it with a unique technological laboratory, giving it an edge not only in the world of production vehicles but also on the race track. Renault’s technological excellence extends not only in F1 but also in all Z.E. range.

“Renault and Formula E both share the same commitment to innovative technology and sustainable motoring and we’re delighted to welcome them to the Championship as a Founding Partner,” said Alejandro Agag, CEO of Championship promoter Formula E Holdings.
Not only is Renault one of the world’s leading car manufacturers, with a very successful motorsport pedigree, it is also a pioneer for electric vehicles being the first full-range car manufacturer to market zero-emission vehicles. To have a manufacturer of this calibre onboard is a great testament to the growing appeal of the FIA Formula E Championship.”

Spark Racing Technology sided toward this technological expertise to optimize the electric and electronic layout.  The 42 Formula E single-seaters built for the beginning of the first season will be named “Spark-Renault”.

Spark Racing Technology is extremely proud to have a new major quality player in motorsport, Renault” said Frédéric Vasseur, CEO of Spark Racing Technology.

Their record and involvement in high level motorsport speaks for the brand. In addition, Renault has always been at the forefront of innovation and having their expertise and know-how is invaluable at such a key moment in the creation of the FIA Formula E World Championship. This partnership with Renault is a new corner stone in a building harmoniously taking shape at all levels.”

Renault Sport Technologies  is the only car manufacturer to design, develop and market a comprehensive range of sporting cars and vehicles made for motorsport within the same entity.

It was an evidence for Renault to ask to his subsidiary to work on this project and to put on evidence all the engineers’ expertise on motorsport vehicles.

Renault’s expertise in electric powertrain design and integration acquired both in production E.V. and in Formula 1 makes Renault Sport a natural partner for Spark in this exciting Formula E project” said Patrice Ratti, Managing Director of Renault Sport Technologies.
Engineers from Renault Sport F1 and Renault Sport Technologies will collaborate with Spark Racing Technology team to optimize the electric and electronic layout and performance of the powertrain. Our experience will be particularly valuable to ensure the safety and reliability of the car

About Renault SAS
Renault has since 1995 been committed to a strong environmental policy that takes account of the environmental impact of all its activities at each phase in the vehicle life cycle. From 2007, the Renault eco² signature represented Renault’s commitment in this area in the eyes of customers and the general public. Through a number of innovations, including the electric vehicle and new internal-combustion technology, the emissions of Renault range vehicles in Europe should fall from 137g at the end of 2010 to less than 120g in 2013, and less than 100g / km in 2016 with electric vehicles.

About FIA Formula E Championship
Formula E is a new FIA (Fédération Internationale de l’Automobile) championship featuring racing cars powered exclusively by electric energy. It represents a vision for the future of the motor industry over the coming decades. The races will be held in the heart of the world’s leading cities, around their main landmarks. Demonstrations of the first cars will commence in 2013, followed by the first official electric car race in 2014. The plan is for a grid of 10 teams and 20 drivers in 2014. The FIA has expressed its delight with the sport’s shared values of clean energy and sustainability. Formula E hopes to promote general awareness around sustainability. It also intends to serve as a framework for R&D around the electric vehicle and accelerate general interest in these cars for personal use.

News and comment on the Renault ZOE electric car – quiet, lively, and non-polluting for £300 per month including fuel.