Olive - 1 - Description

For a long time I have been interested in relationship between sustainable energy sources, climate and terrain.  An attempt to produce a megalithic chunk of software using downloaded data was instructive but failed to produce anything useful.  Software like pet dragons acquires names and this code was called Druid.  Rather than give up on the concept I recently adopted a completely different approach.  The concept was to build some simple equipment and to take one or two short data-shots each day from my back yard.  Over a period of a year this would produce a few hundred data points which hopefully would provide enough samples to draw some conclusions but not so much that it could not be assimilated.  Because hardware was involved, the name changed to Physical Druid and the equipment was called Olive.

Olive attempts to measure solar irradiance.  The sensors are two very small horizontally mounted solar panels.   Because they are flat they have a good cosine response.  During a data-shot one of the sensors is shaded from the direct rays of the sun and therefore only receives diffuse irradiance, the other is not shaded and it's output is a combination direct and diffuse irradiance.  Combining the output of the two sensors it is possible to estimate direct normal irradiance.

The current produced by a photocell is proportional to the irradiance it receives.  A resistor is connected across each cell and the voltage across the resistor is also proportional to the irradiance.  The voltage across the resistors is only a few mV which is too small for the analogue-to-digital converter on the Arduino Nano so a TS358CD op-amp is used to get the output into the range 0 - 5 volts.  The Arduino Nano is a brilliant piece of equipment, I first used it on a small dynamometer and found it easy to use for both control and measurement and it works well with Olive.  The Nano connects to a Raspberry Pi model 2 which acts as data logger powered by a 20,000 mA power bank.  A data-shot consists of approximately 16,000 observations over an eight minute interval.  During a data-shot a photo of the sky is taken with my mobile phone.

The observing site is real-world rather than ideal.  Olive sits on pillar on the wall which separates my back yard from the street, the quality of the measurements will improve as the sun gets higher in the sky.  On the plus side, Olive is a good conversation starter.

Data from Olive is fed to an evolving suite of programmes on a Raspberry Pi 3, I'm still figuring out how to use the stuff.  The basic presentation consists of a plot of the sensor output, a cropped and resized version of the phone photo, a graphic showing the attenuation of the irradiance by any passing cloud.

To give the observations some context, some data from the Global Forecast System has been added.  The objective is to attempt to explore the results using machine learning methods.

Doris B - Diodes and dynamometers

If simplicity is a virtue then my first attempt at making a dynamometer could be regarded as sinful.  This more successful machine consists of a wooden pulley bolted to a bicycle hub generator.  The pulley is turned by fishing line attached to a weight, a 10 watt resistor acts as a load.  An Arduino measures the voltage across the resistor and senses the rotational speed as the weight falls, all this provides enough information to estimate the input and output power which in turn suggests the efficiency of the system.

The generator turns out AC but to charge batteries it is necessary to convert the output to DC.  When developing anything, a good rule is "first make it work, then make it work better".  Initially, a standard silicon bridge rectifier was used.  This had a voltage drop across the diodes of 0.7 - 0.8 volts.  I flirted with the idea of smart diodes based on mosfets but this required greater knowledge and skill than I possess.  A simpler alternative was a bridge rectifier made up of Schottky diodes.  These have a voltage drop of around 0.2 volts.  The effect was to increase the power available to do something useful as shown in the graph below:

For a given speed, the output is roughly 0.3 watts higher with the Schottky diodes, they also increase the system efficiency by about 10%.

The diodes are rated at 100 volts to accommodate the generator when it goes open circuit.

The next step is to use the dynamometer to investigate the use of pulse width modulation to manage the load.  The objective is to use the power curve to optimise the relationship between the rotor and the generator.

Doris B - The experience box

I was in a bar chatting to one of my sons (he's 31).  There's some overlap in our work experience and we were talking about product development and he came up with the description "first we make things, then we break them" which is a variation on one of my mantras "if you want to learn fast, make mistakes fast".  This gives me great faith in the next generation.

Oddly, I've just cleared some space in my work room by dumping less than successful bits of wind turbine into a box.  This includes three rotor designs, two generator, several attempts at making drag buckets and does not include several Meccano constructions which have been dismantled.  Work had been progressing steadily but I came to the conclusion that the generator I was using was probably 15 years old albeit in good order.  It might have benefited from being stripped down and the bearings cleaned but I was uncertain about the state of the magnets.  As I'm about to invest some time and energy in this project, I thought it would make sense to start with a brand new one.  The new one is slightly smaller and lighter than the original, so the bucket carrier and the dynamometer ring will have to be remade.  A slightly tedious task but an opportunity to remove some defects.

The dynamometer is very simple, it consists of a length of fishing line wound onto a pulley, the line runs through a pulley/block on which a weight is hung.  As the weight descends, it turns the generator.  The Arduino works out the rotational speed and the energy generated, the rotational speed is also a measure of how fast the weight is falling allowing the input energy to be estimated which in turn allows the efficiency to be estimated.

The Kettle half full

I'd like to say that that this post was based on a rigorous analysis of a vast database, sadly it's based on four meter readings, but lack of data should not get in the way of a good argument.

Much of the debate on emissions focuses on tax and technology and both have a role to play but the elephant in the room is behaviour.  We choose to get on aeroplanes, we choose to drive cars with big petrol engines (like many young engineers I lusted after cars and motorbikes), on a hot Texas day who can resist the switch on the aircon and we often overfill the kettle.

Engineers are generally trained to get a result with the minimum effort, the logic that makes a better jet engine also applies to making tea, you should use the minimum amount of energy, as an undergraduate I got into the habit of filling my mug from the tap and tipping it into an empty kettle, something I still do.  The most common reaction from family, friends and colleagues is that this weird and unhygienic, a response to the latter is that a kettle is also a steriliser.

Recently our 1.7 litre kettle became the logical equivalent of a bucket and was replaced by a 1 kw 0.85 litre version, it still gets overfilled but by half a litre not a whole one.  It's not obvious if this explains our reduced our electricity consumption (and emissions) but it did not increase them:

In England, most kettles ceased to be zero emission devices when coal became the dominant domestic fuel in the 18th  century.  Most cooking ranges were lit in the morning and kept burning into the evening, which is why the kitchen was the centre of family life because it was the warmest room, a kettle left on the hot plate would always provide water for tea or coffee, there was no saving of fuel by doing otherwise.  The modern kettle also provides a similar supply of hot water but unlike the coal fired range the energy consumed is proportional to the volume of water being heated.

Kettle on a coal range (credit: Brighton Museums)

The zero emission kettle made an appearance during 19th century in the reception rooms of grand houses.  The downside of having a large house was that the kitchen was often in the basement, by the time a maid had carried the kettle up a flight of stairs, along corridors and halls to the sitting room where the lady of the house was entertaining, the water was no longer hot enough to make a decent cup of tea. The solution was a table top charcoal stove.

Doris B - Carpentry and Computing

The design is slowly moving forward. I’ve messed with small wind turbines before, but Doris B is an attempt to create some design rules. The objective is to get an output of 2.5 Watts in a 5 m/s wind. The current rotor is 0.7 metre in diameter with six buckets and s of the drag type. It’s had a couple of runs without instrumentation, but eyeballing the rotor suggests that its operating speeds are between 50 and 150 rpm. The current activity is figuring out the electrics and creating a functional data logger.

Almost any design of turbine will turn in a 10 m/s wind, but at 5 m/s the available energy is about 70 Watts/m2, which is not a lot, thus small things become important. The first attempt at creating a power box used a basic silicon bridge rectifier, smoothing capacitor and a voltage regulator. The voltage drop across the diodes in the rectifier was approx. 0.7 – 0.8 volts which is about 10 – 15% of the voltage of the generator, the rectifier will shortly be replaced with four Schottky diodes which hopefully will have a voltage drop of around 0.3 volts. The voltage regulator did nothing useful, three partially discharged Ni-Mh cells drew around 300 mA without the voltage regulator which is roughly a charge rate of 0.15 abd a reasonable working level. Removing the regulator cleaned up the power curve, which currently looks like this:

Part of the design is to match the power drawn by the generator to that generated by the rotor. With no load, the generator turns freely in a light wind. place a 10 ohm resistor across the terminals and it seems likely that it will cease to do so. Experiments with pulse width modulation of the load suggest that this is a potentially efficient way of optimising the relationship between the rotor and generator.

My love of the Arduino is growing steadily. Over my professional life, computing power has increased dramatically, CPU speeds are now measured in GHz, RAM in GB and storage (which is not necessarily local) in TB. The Arduino Nano was originally purchased as an analogue to digital converter for a Raspberry Pi, however, with experience, I’m realising the capability of the Nano. This should not be be surprising, my first programming experience was on an ICL 1900 which if I remember correctly had 16 Kb of magnetic core storage, static data lived on punched cards and if that was not enough the only option was a tape drive which required serious negotiating skills to access. Those machines were a great opportunity and so are the Arduinos. If you are used to working with GB databases, 1 Kb of EEPROM does not seem a lot, but it’s enough and there is the potential of IoT to explore.

Footnote – A month ago, my laptop died, it was expedient to hook up a Raspberry Pi. At some point I will have to replace the laptop, but the Raspberry Pi is doing fine, I have not done any serious analysis, but the energy I use whilst messing with computers might have dropped by 0.5 kwh/week (a guess)

Clouds and Irradiance from the sky

This was quick-and-simple study to look at the distribution of solar irradiance under a cloud sky.  The intention was to get some insight into the mounting of solar panels.  Under a clear sky, the greatest output is obtained by pointing them at the Sun.  For fixed mountings the optimum is facing south at an angle to the ground close to the latitude of the equipment.  This may not be the case under a cloud sky where the direct beam irradiance is attenuated and a higher proportion of the total is diffuse from the hemisphere of the sky.

The equipment was constructed from materials to hand which included a length of waste pipe, part of a broken bed and a roll of packing tape.  The main component was a light dependent resistor mounted at the base of a 300 mm length of white waste pipe whose translucence was reduced with a wrapping of parcel tape. The photo shows it in position sitting on top of a dust bin.

Operation consisted of setting the altitude to 15, 30, 45, 60 or 75 degrees, then rotating the instrument from 0 to 330 degrees in 30 degree increments and recording the resistance of the light dependent resistor.

The light dependent resistor has typical resistance of 20k at 100 lux. A simple calibration gave the relationship between resistance an luminescence of:

The results should be treated as relative irradiance which are consistent for the experiment, but are unlikely to represent accurate absolute values.

Overcast Sky - 26-Jul-2010 15:00: The irradiance increased slightly with altitude, but was relatively constant with azimuth.  The cloud was thick and low, there was a small break to the northeast, hence the higher irradiance in that direction:

The conclusion drawn from this observation is that irradiance from an overcast sky is more or less uniformly distributed around the sky, albeit at a level much attenuated from that expected under clear sky conditions.

Broken Cloud - 27-Jul-2010 14:00:  The early afternoon sky consisted of broken cloud, with the sun 

occasionally visible through the cloud.  Compared to the overcast sky the day before, there was significantly greater irradiance in the part of the sky in which the Sun was located.

Typically, in our part of the world, cloud described as broken, is a discrete layer and can sometimes have similar appearance to an overcast sky with only occasional glimpses of the blue sky above. This was the case on the day these readings were taken. There is an increase in irradiance in the direction of the Sun, but a significant amount of irradiance is coming from the sky as a whole.

Few Clouds - 28-Jul-2010 11:30:  As so often happens when there are a few clouds in the sky, there was some fluctuation in the readings. The maximum irradiance was to the south east at an elevation of 45 to 60 degrees.

The irradiance under a sky with a few clouds is similar to that of a clear sky with exception that there may be short periods of attenuation.

Clear Sky - 16-Aug-2010 15:00 - The irradiance is clearly coming from the sun's disk:

Under a clear sky the maximum irradiance received by a device is when it is pointing directly at the Sun. In this case the maximum irradiance was around 230 degrees at an altitude of 45 degrees which is close to the altitude and azimuth predicted by Sun-Earth geometry.

Doris B - Instrumentation

It’s a sad fact that almost everything I make gets built at least twice.  I’m trying to figure out what needs to go into the wind turbine’s “power box” and how it’s going to fit, then I’ll rebuild it so it looks less like a building site and use components with appropriate values.

It monitors the rectified output of the generator, the voltage across the load and the current through it.  This allows the power generated and being delivered to the load to be estimated.  A Fourier transform is used to determine the rotational speed.  The original intention was to work with AC output of the generator, but it proved a lot simpler to work with DC throughout the whole system.

The Arduino Nano has exceeded expectations, a previous attempt used op-amps and many other components, however, this time around, the only components used in the instrumentation are resistors for voltage divides and zenor diodes for protection.  voltages from three measurement points are fed to the Nano’s ADC.  After some processing with a couple of blocks of Python code running on a Raspberry Pi, the output looks like this:

Testing is being done using a 47 ohm resistor as a load, this keeps the current low but at the expense of high voltage on the upside of the regulator.  When a battery pack is used as a load, the voltages look a little more sensible.  Still some work to do, but the basic design is in place.

The next task is to determine if pulse width modulation can be used to control the load, if so, if so, it may be possible to optimise performance.  Ideally, I want the rotor to start to turn at 4 m/s, but the high torque of a large load may prevent this.  Maybe if the duty cycle is 0 when the turbine starts, it can be increased as the rotational speed increases.  Also, it can be adjusted to take account of low wind speeds.  All that comes after I’ve soldered the bits together.

Doris B - Power Curve(2)

Progress (and more to learn and some bugs to find).  The Arduino captured a one minute time series of the voltage across a 22 ohm resistor attached to the generator’s output terminals whilst it was hand cranked.  The load on the crank varies during a rotation so there are constant variations in speed and this can be seen in the time-series, the flywheel effect of the wind turbine’s rotor will probably have a smoothing effect.  The circuity between generator and the ADC needs to include a zenor diode to provide some protection for the chip, once that’s in place, the DC biasing can be setup sensibly.  However, the time series was good enough to passed through a Fourier Transform routine which allowed the rotational speed to be estimated.

The speed and voltage data can then be combined into a power curve, the variations in power are due to uneven cranking.  The 22 ohm resistor was chosen because I had one in a box somewhere.  To get peak performance from the generator will require matching the impedance of the load to the impedance of the generator.  The planned load is a USB power pack.

Whilst messing with electronics and Fourier transforms has been instructive, so too has hand cranking the generator, clearly the torque required varies with the value of the resistor, with a 10 ohm resistor the torque required almost pulls the generator of its mounting.

So on the next trip to the beach, I’ll take a bag of resistors and see how they effect the ability of wind to turn the rotor.

Doris B - Power Curve(1)

In order to match the rotor to the generator, it is necessary to understand the behaviour of both. The first step is to grab data, starting with the generator because this can be done on the workbench rather than the beach. Much the same solution can be used for both. Currently, the instrumentation is an Arduino Nano which provides analogue to digital conversion (ADC) and a Raspberry Pi for processing. Electricity and electronics were part of my OND but that was a long time ago, so setting up the tests involved a little vexation, but eventually a Python programme managed to capture a sample of the output of the generator.

Two things became apparent, first the output of the generator is complex and not a simple sine wave, Secondly the starting torque increased significantly from the open circuit value when a resistor was placed across the terminals.

The next step is to analyse the data, the plan is to use a Fourier transform to determine the rotational speed and the area under the curve will provide the energy generated, putting the two together will provide a power curve (I hope). The Ardunio is a brilliant tool and may offer a solution to the high starting torque. If pulse width modulation is applied to the load, the turbine can start with no load and as speed increases the load on it is increased, this in turn could provide a means of optimising performance.

Doris B - First outing

 On Wednesday evening I took Doris B up to Green Ridge and assembled it.  The wind speed was  roughly 5 - 7 m/s.  Whilst held aloft, the rotor was 2.5m above the ground, it turned smoothly and quietly, which was pleasing, an earlier version had struggled to turn at 10 m/s, so progress is being made.  The next step is understand the relationship between the rotor and the generator,  The speed of this type or rotor is proportional to the wind speed and it is important that the rotor turns fast enough for the generator to produce a useful output.  On returning home I ordered some bridge rectifiers and  an Arduino Nano.  The first use of these will be to obtain a power curve for the generator.

My favourite place for messing with this stuff is on the beach at Aldrington, when the wind is from the SW there is little turbulence.  Most of the other people are beach fishermen and we occasionally swap observations on the state of the sea.  There was a curious incident at Green Ridge, a dog walker scooped up his spaniel, carried it over to my rucksack and let the dog have a good sniff, then walked off carrying the dog, I said "good evening" politely.

Doris B - Trial Assembly

10-April-2019 - Completed the partial assembly of the Doris B5/6 small vertical axis wind turbine this morning before giving it a trial outing on the Downs later today. 

The objectives of the initial trials are to determine if it rotates in a wind of 5 m/s and does not disintegrate at 10 m/s. If it survives, the next step will be add some instrumentation and to try and figure out how it works. The design is based on some maths, guesswork and wishful thinking. There have been four previous versions, mostly made of Meccano and sawn up bits of plastic pipe, this one is mainly made of wood. This is not a finished design but part of a process of learning how to make small wind turbines for rural and urban environments, hopefully the design will evolve. The objective for this series is an output of 2.5 watts (similar to a standard USB port) at 5 m/s.

Thinking about an electric car

Electric vehicles have been around for more than a century, battery trams were tried out in Brighton and other towns around 1890, although in Brighton's case the job was eventually given to a horse. Recently, increasingly larger bits started falling from our aging hatchback and it started sinking into the tarmac outside the house.  It had served us well, it had recovered at least one child from university, carried the detritus of many amateur operatic productions and done my wife's daily commute.  My wife is the main driver, so I opted out of the decision process.  But I did secretly look at electric vehicles.  The attraction of electric vehicles is their low tail pipe emissions, low energy costs and the potential to be integrated into sustainable energy systems.

Left to me, we would have had a Renault Twizy, but I don't spend my weekends trundling hefty opera singers around the country.  My wife chose a small red box which weighs 950 kg and emits 103 gm of CO2 per km.  Electric cars have zero tail pipe emissions, but they rely on smoke stacks, nuclear reactors and wind farms which combine to produce very roughly 0.45 kg/ of CO2 per kwh.  Equally roughly, an electric vehicle might average 0.2 kwh/km which works out at 90 gm of CO2 per km.  It's an improvement, but not a big one.

However, the energy costs are much lower.  The fuel consumption of the red box is quoted as 4.7 l/100 km which at current petrol prices means £5.30/100 km.  For an electric vehicle doing 0.2 kwh/km 100 km and charged off-peak, the cost would be roughly £1.40.

We bought second hand, my perception of new vehicle costs is £10k for a petrol vehicle and £20k for an electric one.  I'm hazy on the costs associated with batteries, but I'm guessing they are the equivalent of petrol vehicle servicing, but I need to know more.  However, you do the sums, it would take a few years to recover the higher front end costs of an electric vehicle from the lower running costs.

So despite my interest in sustainable energy, we ended up with an update on what had before.  This is a personal example, but for sustainable energy systems to win over hearts and minds they must offer similar benefits for similar costs to conventional systems.

Reference:

Brighton Tramways, Robert J. Harley, Middleton Press

The early days of electricity in Hove (3)

As with previous posts in this series, this one is work in progress and subject to corrections and revisions.

As I mess with this, I realise I am working backwards.  The story starts with an Act of Parliament of 1890 whose objective was to provide electric lighting in Hove, this was to implemented by the Hove Commissioners (what we now call the council), who formed an "electric light committee".  This first met on Saturday, 26-Apr-1890.

At the meeting on Thursday, 11-Dec-1890 a plan was beginning to form.  It was resolved that the best course of action would be to negotiate with a responsible company to erect buildings and plant and to lay mains in order to supply electricity as required.  It seems that they had considered three options, a) the council would take on the construction and operation of the facility which would be financed by a mortgage on the rates, b) the council would provide the plant and get a contractor to operate it and c) get a private company to finance, build and operate, this being the preferred option.  It was felt that this project was not appropriate for a town council.  The first step was to find a suitably qualified electrical engineer to prepare specifications and advise on terms and conditions of a contract with a company as proposed.

Mr. R.E. Crompton was selected for the task at a meeting on 2-Jan-1891.  This was a logical choice, Mr. Crompton had a proven ability with both arc and incandescent lighting and his company Crompton and Co. was a major manufacturer and contractor.

These deliberations were going on against a backdrop of international and local evolutions in the electricity supply industry.  This was the time of the "battle of the currants".  On one side was low voltage DC generation and distribution, in very crude terms there was direct connection between the consumer's appliances and the dynamos at the power station.  These systems worked well for small communities clustered around the power station.  It was opposed by promoters of high voltage AC systems.  In these the AC generated at the power station is stepped up to a high voltage for transmission and stepped down again for distribution to the consumer, the key component is the transformer.  Ultimately, the high voltage AC systems were to triumph.  At the local level the neighbouring Brighton and Hove Electric Light company was seeking to expand.  At this time Brighton had established an electricity supply four years earlier and had experience with both AC and DC systems.

Mr. Crompton drew up his report and this was considered and this was considered on several occasions and on 8-Jun-1891 a decision was made to adopt the low voltage DC option.  It is clear from the minutes that they had discussed the AC alternative, but Mr. Compton recommended the DC route because Hove was a compact borough and there would be no problems with transmission.  It was pointed out that several London boroughs had adopted this solution as had parts of New York and Berlin.  Mr. Compton's report  effectively became basis of the specification which against which bids would be invited and a prospectus for potential shareholders.

The suggested site was bounded on the west by Holland Road with 135 feet of frontage on what is now Davigdor Road.  To the north was a railway goods yard which was home to several coal merchants.  The plan was to have a siding laid so that coal could be delivered by rail.

The plant in the power station was intended to be implemented in phases.  When complete, the main elements were to be:

• 5 Lancashire boilers rated at 160 p.s.i
• 3 250 HP Willans dynamo sets
• 3 100 HP Willans dynamo sets
• 1 120 cell lead acid accumulator capable of supplying 600 amps for a short period.

Dividing the generating capacity between 100 and 250 HP units suggests that demand was expected to vary during the day.

The plant may have been arranged like this:

The site may have been long and thin making it necessary to use the space efficiently.

The costs for the initial phase with two boilers, three dynamo sets and an accumulator were estimated to be:

• Plant: £8,297
• Buildings: £3,000
• Mains: £12.844
• Total: £24,141

The cost of the complete scheme was around £50,000.

The public street lighting commitment was for 14 ornamental lampstands along the sea front, each with a 10 amp arc lamp mounted 26 feet above the street which was rated at 2,000 candlepower, the total running costs for 2186 hours were estimated to be £280/year.  Even in 1890, Hove was a sizeable town, so this was not a serious attempt to displace gas lighting.  It seems that the principal objective was to sell electricity to commercial and domestic consumers.  The electricity for these lights was to be supplied at half price, or 4d/unit, the retail price being 8d/unit (more than £1 in today's money).

The report reads like it has been written to promote a scheme, it suggests that after seven years, 400 houses would be supplied with electricity and profits could be £5,000/year.  It is not unknown for prospectuses to over estimate demand, however, in this case, it was an underestimate, after two years of operation, 200 households were connected.

The minutes of the Electric Light committee meeting on 3-Sep-1891 stated that the text of an invitation to bid for the project had been drafted and an agreement to purchase the Holland Road site had been produced together with an application to borrow £1,400.

On 27-Oct-1891, proposals were received from:

• The Electric Power and Storage Company
• The Brush Electrical Engineering Company
• Crompton and Company
• The Brighton and Hove Electrical Lighting Company

A few days later, a bid from the Planet Electrical Engineering Company was received, as this had been submitted on time, but delivered late, it was considered.

Only the bid from Crompton and Company was considered to meet the requirements of the commissioners and on 11-Feb-1892, a deed of transfer of the undertaking to Compton and Company was approved.

Energy Alternatives

The electricity industry took shape in the 1880s.  Initially, it was a "luxury" product consumed by high income households.  Large establishments might have had their own generating plant, but rapid growth in the demand for electricity started when companies were formed to supply consumers from a local power station.  Either by choice or circumstance, many of these companies became owned by local councils, with a little stretch of the imagination, they could be described as being owned and controlled by the community they served.  By the start of the 20th century demand for electricity had grown and the original small power stations with reciprocating steam engines located in residential areas were too small and inefficient to meet the demand, these were displaced by large steam turbine plants located close to a coal supply such as a port, railway depot or even the mine itself.  This became the model used by the industry for a century and it worked well, energy will never be cheap, but its rare to flick a light switch and have nothing happen.  Big nuclear power stations fit into this model.

There are big differences between the late 19th and early 21 centuries, for political and environmental reasons it is desirable to reduce dependency on fossil fuels and many people are uncomfortable with nuclear power.  However, the technologies available make it possible to consider alternatives to the big generator model, for the foreseeable future big power stations will have a role, but it may be possible to stem their growth and possibly even displace some of them.

These comments are based on personal observations, but they may have some wider relevance:

• Energy consumption can be reduced without a drop in living standards.  In our case, we have steadily migrating to LED lighting, 20 watt compact fluorescent lights have are being replaced by 10 watt or smaller LEDs.  As appliances have died of old age, energy consumption has a factor in deciding on the replacement.  The old washing machine consumed 1.5 to 2.0 kwh/wash, the new one typically uses 0.25 to 0.70 kwh.  There maybe environmental benefits, but our electricity bill is £23/month and falling.
• Storage is a potential game changer in the way the industry works.  Demand for electricity peaks in the early evening when families are home cooking, staring at a screen or doing homework, at present supply and distribution is set up to meet the peaks and troughs of daily life, if every house had even a small amount of storage, maybe as little as 2kwh, it could be possible to run the generators under constant load with each household having a time slot for charging its batteries.  Grocery deliveries have made us familiar with delivery time slots, doing the same thing for electricity is not such a big step.  Back to economics, there is the potential for buying electricity at off-peak rates (7p instead of 15p/kwh), so there is some potential upside for the consumer.  Storage also helps integrate energy from wind farms in to the energy economy.
• Back in 1900, if you wanted to generate your own electricity the main options were steam or gas engines, water wheels were an option for those living near a river and wind generation was still being explored.  Even under an cloudy English sky, solar panels can make a contribution.  At present, the economics of home generation are geared towards getting a return-on-investment, however, in conjunction with storage, there is the potential to displace some gas fuelled generating capacity.  Peak demand is in the evening when the sun does not shine bright, if energy generated during the day can be stored for use in the evening, then the load on the grid can be smoothed.  This requires some creative economics.  Some rough calculations suggest that our house's grid dependency would be decreased by two solar panel mounted somewhere other than on the roof.
• Cars and vans contain reliable combined heat and power systems, a 2kw alternator provides electricity some of which is stored in the battery and waste heat from the cooling system is used to keep the cabin warm.  Extracting the appropriate components and packaging them as a consumer product might produce something costing less than £1,000, such an installation could produce heat and power during the winter months. These could be gas fuelled.  In the context of a car, this is established technology.  One of the incentives for the development of petrol and diesel engines was the limitation on consumption of town gas.  Any loss in efficiency in electrical generation could be compensated for by the use of waste heat.

Some of this stuff is fanciful and no doubt others could expand the list but the point is there are alternatives to big power station model.

Energy and Adverts

I would like to say that I have a research plan for theses posts on the history of domestic energy, but it is just random reading and looking for holes in the pavement.  One source material is advertising.  Until the end of the 1960s, domestic energy was about shovelling, either you did it yourself or you paid someone else to do it.  For some, the 1960's might have been the Stones, the Beatles and the summer of love but for my mother it was gas central heating and the removal of the coal bunker.  As a family, we did our own shovelling but for some this was a problem to which this advert from the May 1931 edition of "The Sussex County Magazine" attempted to address.

The reference to "boilers" rather than "boiler" suggests that it was aimed at larger properties which probably included up-market blocks of flats with communal heating systems.  Often, these were not a source of happiness either being too cold or too hot or broken down and always too expensive.  Even in the depression, looking after one of these would not have been an attractive job.

The serious heavy lifting was done by the coal men, coal was delivered in bags weighing one and quarter hundredweight or 10 stones (roughly 60kg) which is the weight of a small adult.

Despite appliances being graded according to there energy efficiency, energy consumption in the kitchen is rarely the subject of today's polite conversation around the marble worktops. However, some old "domestic science" textbooks take it seriously  and pre-war housekeepers were expected to be aware of the amount fuel they were using.  This is reflected in this advert from the June 1936 edition of "The Sussex Country Magazine":

I'm guessing, but at the time this advert was published, coal fired stoves were competing with gas and electric cookers in the suburbs where a supply was available and coal/coke was cheaper per kwh than gas or electricity.  The claim that the fuel cost was £1.00/quarter suggests that consumption was around one and half tons per year (assuming coke to cost £2.50/ton at the time).  A ton of coal and it's residual ash requires a lot of shovelling.  The advert also features deferred payments, the gas and electricity companies also offered appliance hire and credit facilities.

The theme of shovelling is continued in the small ads.  You imagine the look of surprise and delight on the face of someone receiving one of these:

However, a modest sized house with coal fires could get through several tons of coal in a year, if the task of shifting the stuff from the coal store to the kitchen, living room and  bedrooms was eased, the bearer of the gift might be rewarded with a smile, unless the recipient had hoped for silk lingerie.

In the 1930s the use of mains electricity in the home was expanding with the acquisition of irons and vacuum cleaners, but there were a lot of battery powered radios in use.  Typically these used lead acid accumulators to heat the cathodes in the valves whilst the high voltage they needed was supplied by multi-celled zinc-carbon batteries.  Few homes had the facility to charge the accumulators, so shops selling electric appliances offered a charging service, adverts for this can be found in the small ads of the magazines.

In general, the classified ads in the county magazines are not much different from those found online today, they offer "facial rejuvenation", building services, garment alteration etc..  Private tutors still advertise in newsagent's windows, but they don't seek out "backward" children.

Having gone through my small collection of country magazines, for the sake of completeness I thumbed through a 1949 copy of "Men Only".  The is some surprising overlap in the content, the same cars and lawn mowers are advertised, the men are dressed in similar style, some of the women are wearing slightly less, but both are part of the same world.

The early days of electricity in Hove (2)

This post is really my notes from researching the early days of electricity in Hove, it is probable that there will be corrections and revisions.  As with the previous post, the source is the log books of the power station of the Hove Electric Light Company from 24-Nov-1892 to 27-Sep-1894.  I have yet to find a floor plan of this site or an inventory of the equipment, but the log books give an insight into the nature of operation and it's economics.

One thing that stands out when the weekly generation data is plotted on a graph is the seasonal variation in the demand for electricity.  Whilst the log books make a couple references to small electric motors on customer's sites, most of the output is used in incandescent lamps (typically 33 watts) and arc lights which might draw 10 amps (roughly 1 unit per hour with a 110 volt supply).  In the winter of 93/94 generation amounted to roughly 2,500 units/week and then dropped off as summer approached.  So in the summer of 1894, output was falling even though more customers were being signed up.

It is not clear if this seasonality was factored into the economics of operation, but it is possible that a stoker was laid off during the summer.  In Sep-1894, wages accounted for just less than one third of the operating expenses.  It is not clear in the remarks if the boilers had mechanical stoking or relied on a man with a shovel.

The largest expense was coal and coke.  There is an inference in the log books that the preferred type was Welsh  Coal (20 - 27 shillings/ton), this has a high calorific value (marine engineers also liked it), but at times, possibly as an economy measure, alternative fuel was used such Northern Steam Coal (19 shillings/ton).  In the first few months of operation some coke was used, maybe this came from the local gas works. 

The logs don't say much about the type of machinery, but there is a reference to Davey-Paxman sets.  I'm guessing but these steam engines were probably similar to those used in mills and factories, these were relatively slow speed.  Often power was distributed around the factory with a system of shafts and each machine was connected to this by a belt drive.  There is also a mention of Willans engine, this was probably a high speed engine specially developed for the growing electricity industry, typically the dynamo was directly coupled to the steam engine's crank shaft.  Hopefully, I can find out more.

By modern standards, the boiler pressure was low, initially they operated at 140 p.s.i.  and later this was increased 160 p.s.i.. after inspection by the insurance company.  Steam locomotives in the 1950's were often working in the range 200 - 250 p.s.i. and modern steam power stations run at very high temperatures and pressures to maximise efficiency.  The steam would have been saturated and there is no reference to condensers.  Thus the efficiency was very low, a crude sum suggests that it was in the range 2 - 3%, that of modern coal power stations might be around 40%.  The log book states coal consumption as 10 pounds/unit of electricity generated.  Leaving the town hall arc-lamps burning all night would create extra work for the stoker and a noticeable increase in operating costs.  Maybe, because of the lack of condensers, they were not able to recover water from the exhausted steam as water consumption was several thousand gallons per week.

The station was equipped with storage in the form of some large lead acid batteries, the capacity of these was about 30 units (110 amp hours).  These appear to require regular maintenance as sometimes their consumables (plates, soda etc.) show up as a spke in the expenses.  The function of these is not given, but it is probable that the storage acted as a buffer for fluctuations in load and also to meet some or all of the overnight demand, this would allow the boiler fires to be banked up to save fuel.  During the summer months the average daily demand might be 100 - 200 units which peaked in the evening, thus the 30 units of storage could simplify operations.

The early days of electricity in Hove (1)

I learnt about the Hove Electric Lighting Co. Ltd. from a description of what seemed to be a small power station whilst reading Queenspark Book No. 36: "A Working Man".  After looking up the buildings in Cromwell Road in Hove in a Kelly's directory, I found the business name.  Not being able to find anything more, I decided to research it myself.  The East Sussex Records office has the first three log books of the power station and it is these that this and the next post are based on.

Ideally, I should hunt down all the available material and the write it up in a single post, so these posts are really my notes which at sometime in the future may get consolidated.  If anyone has already done something similar and better, I apologise.

In the last decade of the 19th century, many small electricity companies were established by entrepreneurs or by town councils.  I find them interesting because with some stretch of the imagination the municipal ones might be described as micro-grids under local democratic control with all their assets located in the community they serve.  This is in contrast to the situation today where power stations are often located on remote headlands and are managed in distant boardrooms.  There are technical, commercial and political reasons why this transition took place, but something might be learnt from the early history of the industry.

It seems that the power station started operation in the week ending 24-Nov-1892.  During that week it produced just 95.79 units (kwh?) but by the end of the second week this had risen to 435.3 units, after which the demand was determined by the seasons and the number of houses connected, during the first two years the peak generation was about 2,500 units/week in the December 93/January 94 period, it is probable that it would be much higher during the next winter.

At the start of operations there were just four houses connected to the grid, this suggests the bulk of the load was coming from street lighting and council premises.  There are several references in the logbooks to arc lights at the town hall either being left on or going out.  There were two forms of lighting in use, arc lamps which were capable of illuminating a large area and incandescent lamps, typically rated at 33 watts.  The downside of arc lamps was their high current drain, maybe 10 amps and the need for constant maintenance, in 1894 this required a full time person.  The supply was 110 volts DC, thus a 10 amp arc lamp was consuming a unit of electricity each hour, the generating efficiency was low with 10 lb of coal being required to generate a unit of electricity, thus leaving several arc lamps burning when they were not needed could significantly increase coal consumption.  Arc lamps are sometimes described as "carbons".

In just less than two years, the number of private houses connected to the grid rose from 4 to over 200.  Connecting a property to the electricity supply required investment both on the part of the electricity company who had to make cabling, distribution and metering points available and the householder who needed to install wiring and light fittings.  In the early 1920s, it cost about £30 to wire up a three bed room semi in the north of England for electric lighting.  Some of the first houses in Hove to be connected had more than 100 lamps, so the outlay would have been great, not only was there the cost of the electrical work but cost of redecorating after wires had been run through walls, floors and ceilings.  My own house was initially piped up for gas lighting, when electric cabling was installed, channels were cut into brickwork and wooden pads used to secure sockets and switches and there was a lot of "notching" of joists to run conduits under the floor.  The company inspected each property before connection, there is one reference to minor non-compliance that was accepted on the condition that remedial work was carried out "after the season".

The graph below shows the increase in the number of connection over a two year period.

What is more interesting is the nature of the connections.  I walked around most of the streets mentioned in the log books and it appears that connections can be split into two groups.  The first was retailers, I guess that installing electric lighting was seen as getting a competitive edge over one's rivals, much the same as air conditioning is today.  Electric lighting would create a better retail environment than gas lights could which were dirty and could fill an unventilated space with foul air (e.g. increase the level of carbon monoxide).  the operation of electric lighting is just flicking a switch and occasionally changing a burnt out bulb.  Gas mantles have to be individually lit and regularly cleaned.  The second group might be described as posh residences.  Posh is probably the correct word, the people who owned these houses would most likely have been on the port side outward and on the starboard side homewards when travelling to and from India, Singapore, Hong Kong, Australia or New Zealand.  The houses are big and would have required several servants to function.  In modern marketing language, these people were "early adopters" who were prepared to pay a high price, the cost of electricity might have been around 8d/unit (more than £1.00 in today's money).  None of the houses I walked past were the sort of place where craftsmen, teachers, clerks or shop assistants might have lived, it might be thirty or forty years before such cane home to an electric light switch.

The map below shows the streets mentioned in the log books, those marked red are predominantly residential whilst the blue ones are mainly retail.  Except in the shopping areas along Church Road and Western Road, there are only a few customers in each street, however, the mains for distribution would have been available for additional customers.

There appears to have been a ready market for electricity, as mains became available in a street, houses were soon connected to it.  There were a small number of disconnections for reasons not specified, but one reference suggested that electricity was becoming indispensable, a house was disconnected one day, but reconnected on the following one.

The data available does not show levels of household consumption, but it suggests that the average during the winter months was around 10 kwh/week and less than 5 kwh during the summer, this might put average household consumption in the range 200 - 500 kwh/year.  The current average in the UK is about 3,500 kwh/household/year.  The principal use of electricity was for lighting, but there are two references to electric motors, one is for a half horsepower one in a dairy 

Electricity was creating new types of job.  The dynamos in the power station were driven by reciprocating steam engines which at that time was a mature technology, but establishing safe and reliable distribution systems was a new challenge.  by the middle of 1894, there were four distinct groups of works in the company, about half a dozen people worked in the power station, two were involved in connecting properties to the mains, two more maintaining those mains and two going round testing and reading meters.

Laundry and Negawatts (one more time!)

Technology has its role to play in sustainable energy systems but so too does behaviour.  I've learnt that conversations about consumption are difficult and that some of the things that facilitate the reduction of energy consumption are just not sexy.  I've made a couple of visits to "eco" fairs where there are blokes huddled up discussing panel orientation and the nature of inverters just like I and other teenagers once discussed motorbikes.  Try and bring LED lighting into the discussion and you might be like the kid with the rusty, back-firing and moped (those mopeds that have survived are now collectable and change hands for serious money).  I did mention to someone that I was measuring the energy consumption of our washing machine and from the reaction I sensed that the words "geek" and "nerd" were not far away.

Due to some dubious career advice, I left school at 15 and spent a couple of years as merchant seaman followed by some time in a factory.  The fact that I have spent much of my career writing computer software, suggests that I was not cut out for a life on the ocean wave.  Whilst I was close to incompetent, as this experience drifts further into the past, I am attempting to mine it for anything relevant.  Remuneration was not generous but included two bars of soap per week, both were brick like, one was a dark red carbolic variety which repelled both women and infestations, but as only one of which was present on the ship, this was not a problem.  The other was yellow "Port Sunlight" which was used for laundry.  Both types could be used as currency in some ports.

The laundry process (known as dhobying) consisted of placing soiled clothing in a bucket of water, rubbing it with a lump of soap and agitating it until one was either bored or the clothes were clean.  A couple of rinses in clean water and the process was almost complete.  Ships have lots of warm spaces, so getting stuff dry was not a problem.  As this was hand washing, I doubt if the temperature of the water was very high.  The standard of personal hygiene in a all male community frequently engaged in dirty work was reasonably high (with the odd exception), so who needs more than a bucket and a bar of yellow soap?

Fast forward some decades and home is a suburban semi populated by two adults and three would-be adults and a washing machine.  The latter consumed 1.0 to 2.0 kwh/wash, maybe 3 to 8 kwh per week.  Eventually, the children leave and the washing machine unable to cope with an empty nest, starts to leak, vibrate and die.  It is removed by two men who swear a lot. The replacement provided by the insurance company is in my opinion dynamically unstable and can't be left unattended.  I have agreed to perform a certain number of washes to see if the machine "settles down".  Rather than just staring at a vibrating cube, I weigh the washing before and after and measure the energy consumption.

Initially, my wife selected a programme with a 40 deg. C temperature and I duly filled and emptied the machine and drew a graph.  A typical wash requires about 0.7 kwh of electricity, which is a significant improvement on the old one.  The energy consumption is proportional to dry weight, so this maybe due to the amount of energy needed to warm the contents of the drum.  When I eventually got to study engineering at university, we were taught about experimental design, so when my wife was not looking, I dropped the temperature down to 20 deg. C, so far she has not noticed any difference but the energy consumption is now 0.3 kwh/wash.  It's emulating me and a bucket or was I emulating the washing machine but that's philosophy not engineering and I'm not qualified.  Low temperature washing will not work for greasy overalls or skid marked underpants, but not every wash contains those things.

Modern washing machines are highly energy efficient, but there is no obvious way to interact with their energy consumption.  Smart meters might help, or even a stupid meter mounted in the kitchen so that a home's energy consumption is visible.  The energy meter I use cost less than £20 and has paid for itself, so it would not be significant cost increase to incorporate energy monitoring into a washing machine or similar device.   My opinion is that most homes could drop their energy consumption by 10 - 20% without any lowering of the standard of living, if only they knew what it is.  Once we were using 5kwh/week to keep clean, now it is less than 1 kwh.

 

A consumer's relationship with coal and gas

I recently read "the world did not run out of coal, it just stopped using it", with the implication that a similar process might take place with other fuels such as oil and gas.  A back-burner project has been to collect household energy costs from old utility bills and related sources (an unexpectedly fruitful source has been Hansard - the record of proceedings in the UK parliament).  This type of material shows how energy costs are perceived by the consumer.  Householders are generally rational in their decisions, seeking to minimize both cost and effort.

It is difficult to make prices comparable over time.  The purchasing power of money changes over time and there are different things to buy, so estimates of price change over a long period of time are an approximation.

This post is based on comparisons, but the data should be treated with caution because of the difficulty of making like-for-like samples.  In the days when coal was purchased by almost every household there were significant variations in price due to the quality of the fuel with nutty slack at the cheap end and anthracite at the other, the sources do not always quote the type.  Distance from the goods yard could be significant.  People on low incomes might purchase a stone (14 lb, roughly 6 kg) for cooking at a much higher unit cost than a household taking half a ton in a single delivery.

The price of coal in 2015 money remained more-or-less constant within broad limits for the period  1900 to 1970.

Gas is slightly simpler, but there were and are regional variations and in the post war period there was a transition from "town gas" made from coal and "natural gas" from the southern North Sea gas fields.  The nature of the gas industry is such that it is easier regulate, whilst there were a large number of coal merchants, there were relatively few gas companies, many of which where owned by town councils.  Most companies served a single area and there was limited competition.  Within the home, electricity displaced gas as the energy source for lighting by the 1930s.  The main uses for as were for cooking and until the advent of central heating in the post ware period, gas fires were a common way of heating a room. 

The availability of gas from the North Sea started a 40 year period of low energy prices which lasted form approximately 1965 to 2005.

A cursory reading of Hansard suggested three things.  First that energy prices are a constant source of public, and therefore parliamentary concern and that this is accentuated in difficult economic times.  Secondly, that there is a general distrust of energy suppliers, coal merchants in the 1920s were attracting much the same criticisms as today's gas and electricity suppliers.  What politicians of all persuasions seem to want is a regulated energy market which is isolated from global economic turbulence.  Sustainable technologies go some way to meeting this requirement.

The householder does not purchase a hundredweight of coal or a therm of gas, he/she buys warmth and the facility to cook.  Open fires accounted a for a large proportion of the coal burnt in England, whilst a coal fire is cheerful and comforting, it's thermal efficiency is low, possibly less than 20%, stoves equipped with a back boiler were more efficient, but a large amount of heat still went up the chimney.  Modern stove designs seem to be a big improvement on those of the 1950s and 60s.  As a gross oversimplification, someone wanting 1 kwh of warmth might have to purchase enough coal to produce 4 kwh if the fireplace was 25% efficient.  Gas central heating boilers might offer 90% efficiency.  Making assumptions about thermal efficiency produces this graph which shows the effective energy cost of  coal and gas assuming thermal efficiencies of 25% and 90% respectively.

The crossover point is sometime in the 1960s, this is when our parent's generation blocked up the fireplaces and installed gas central heating.  Gas was not only cheaper than coal, it was cleaner and easier to live with.  Another benefit of gas was improved air quality, well into the 1970s thick fogs were a frequent occurrence due to the high proportion of soot particles in the air.  This in turn provided a decrease in respiratory disease.

The sustainable energy technologies sit uncomfortably with economics, the transition from coal to gas was largely driven by the cost advantages, my source for this comment is my parents and their friends.  If a similar transition is to take place from gas to sustainable sources, the energy consumers, who are now our children, must perceive some economic benefits.