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.

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.

The early days of electricity - Diverse decsions and technologies

Public electricity supplies started to evolve in the UK during the 1880s.  Today electricity is a utility accessible by a high proportion of the population, but in its early days it was part of the luxury goods industry, a unit might cost between 4d and 1s 3d (2p to 6p) which is around £1 in today's money.  Its attraction was that it was convenient and clean and therefore perceived as being healthier than the gas lamps that it was to displace over the next half century.  Arc lamps improved the lighting of streets and public spaces and this gave local authorities an interest in the industry.  The industry grew using both public and private capital, and some local authorities proved to be adept in managing the evolution of a new technology.  Street lighting was often managed by the gas committee, because that was how the streets were lit, so decisions about borrowing substantial sums against the rates were being made by men who were often involved in decisions about the lighting of urinals

The caption on this cartoon was Electricity for the Ballroom

Electricity works, especially those supplying DC had to be close to the consumer because of the limitation of the early distribution systems.  This resulted in generating plant being located in unlikely places like London's Carnaby Street: its contribution to the swinging sixties is well remembered but its power station is long forgotten. The search for early power stations often takes one to the posher parts of town.

Most of the early dynamos and alternators were turned by reciprocating steam engines.  The early engines were relatively small and built by companies also known for their traction engines and road rollers such as Robey or Fowler.  Until the development of high speed engines such as those of Willans which facilitated direct coupling, the generators were connected to the engine by a belt drive.  Belts would sometime break, in 1882,  the Mansion House was provided with electricity from a generator installed in the basement, where the belt was driven by a gas engine.  During a dinner the belt broke giving the diners the impression they were being attacked by gunfire.  In 1888, the first turbine driven alternator was installed at the Forth Bank power station, close to the centre of Newcastle.

Large generators were steam driven because steam engines could be built to supply hundreds of horsepower and it was a mature technology. At this time steam engines were almost as common as electric motors are today, they powered mills, railways, ships, sawmills, pumps and anything big which needed turning.  Smaller plant in urban areas often used gas engines.  By 1880, most urban and some rural areas had a gas supply and whilst this was mainly used for lighting, it could also used as fuel for engines such as those made by Crossley.  The attraction of gas engines was that there was no need for a boiler and most could be hand cranked into life when needed.  Judging by the number of adverts for fractional horsepower gas engines in pre-1900 magazines, many modest homes may have generated their own electricity from gas.  Such a system is described in a biography of Magnus Volk, the house in which it was installed is comfortable, but not grand.  Many micro systems incorporated a bank of lead acid accumulators making it unnecessary to run the gas engine continuously.

During 1880s and 90s AC and DC systems competed for supremacy.  The AC system would eventually win because it facilitated transmission over long distances allowing big power stations to be sited away from city centres.  However, DC did have the advantage of being able to use lead acid accumulators for storage.  Then as now, the demand for electricity peaked in the early morning and early evening and if only a few hundred homes were being supplied overnight demand could be met from the accumulators allowing the steam plant to be shut down or the boilers banked up.  Accumulators also provided some back-up in the event of plant problems, for this reason, some consumers perceived DC systems as being more reliable.

In the early days, the demand for electricity was measured in kW rather than MW making it possible to supply rural communities using small plant connected to consumers by wires hung from wooden poles. Some of these used water power, Godalming claims the distinction of having the first public electricity supply, this was from a generator turned by a water wheel in a mill. Reeth in Yorkshire had a similar arrangement.

Initially, electricity was an urban industry relying on clusters of high income households, some smaller communities were still not connected to a central generating station until well into the interwar period.  It was during this time that many small electric companies were formed, examples include the Steyning Electric Light Company and the Peacehaven Electric Light and Power company.  I've seen photo's of these companies' plant, both show belt driven generators, in both cases it looks like the motive power is coming from an industrial internal combustion engine, but it is not clear if the fuel was oil or gas.  One of the more interesting of these companies is the High Salvington Electric Light Company, this served a small development of houses on the Downs to the north of Worthing. The generator was turned by a wind mill/turbine similar in design to those of West Texas -the electricity was used to charge up accumulators which in turn supplied the consumers.  There was an oil engine back-up for days when the wind did not blow.  Now that utility scale storage, like Tesla's installation in Adelaide is becoming available, High Salvington can claim to be pioneer in the field of sustainable energy.

A Random History of Energy Economics (1) - Gas Engines in the Home

Over the past year I've been acquiring a few copies of the "The Model Engineer and Amateur Electrician" at car boot sales.  I now have about 15 examples dating from 1899 to 1919.  Models make up a large part of the content, but there is also an informed debate on technology as it was evolving.  At the bottom of one page is a note that a Frenchman has observed that a platinum wire is heated with an electric current and then placed in a jar of methane continued glow.  I'm guessing that this curiosity was an early version of the catalytic converter found on most modern cars.  There are notes on telephones and wireless telegraphy and a discussion of the ideal way of storing energy to power motor vehicles, electricity is was thought to have potential and compressed air to be a bad idea.  Electric shock treatment must have been fashionable as some advertisers claimed it was better to be shocked by their apparatus than that of a rival company.  With hindsight X-Rays were not something the citizen scientist should be encouraged to mess with.  The classified ads can be intriguing, there is a suggestion that a vicar had a model gunboat to sell and why would someone expect to exchange an accordion for a lathe?

In the diversity of items advertised, three occur frequently, these are gas engines, dynamos and accumulators.

In 1905, electricity was still a luxury product costing may be 4d - 6d per kwh (roughly 50p in today's money) and many urban areas did not have a supplier and remote households had to generate their own electricity if they wanted it.  Gas, however was a mature technology, many gas companies had been established between 1820 and 1850 and most urban areas had a gas works.   In some coastal towns, the coal was supplied by brigs from Newcastle running themselves aground on the beach  and being re-floated after their cargo had been hauled away by horse and cart. The cost of gas might be something like 2s 6d and 3s per 1,000 cubic feet, depending on the nature of the gas this would be roughly 10p/kwh today.

At the turn of the century gas was increasingly being used for heating and cooking, but the principal application was lighting. Whilst gas lighting was better than candles, it could make the air in a room foul, the products of combustion being carbon dioxide, carbon monoxide and water vaoiur plus anything else the gas company could not get rid of.  Gas mantles required cleaning  and lighting, whilst electric lamps were clean and available at the flick of a switch.  Doctors wrote letters extolling the benefit to health of electric lighting.  It's not easy to make a like for like comparison with the cost of gas and electric lighting but it seems that electricity was perceived as being 5 - 10 times more expensive.

Fractional horsepower gas engine/dynamo sets provided a source of electricity where a public supply was not available and possibly a means of getting a supply at a lower cost.  At the time of writing, I'm still attempting to identify a property which had such an installation.  At a guess, a common configuration would be to have the machinery in a shed where it was used to charge accumulators which were in turn connected to the lighting circuits in the main house.  Voltages seem to have been in the range 4 - 12 volts and accumulators could be relative large, say more than 50 AH.

After 1900, the public electricity supply expanded rapidly, but in most places this was AC, whilst the use of DC in the home decreased, cars and motorbikes created a new demand and low voltage dynamos were used to charge automotive batteries.  Early radio sets also needed a DC supply.

The magazine has several references to water engines, for owners of landscapes which were suitable for the construction of small dams and there a few mentions of "hot air" engines, I take this to mean "Stirling" engines, but so far no description of the workings of these devices.

Art and Energy

The Brighton Museum is staging an exhibition of the work of John Constable which he produced whilst living in the town from 1824 to 1828.  I went because it's a form and period of painting I'm attracted to.  The space is quite low key and does not shout "great art" making it possible to appreciate the pictures for what they are, sensitive and imaginative depictions of Brighton and the surrounding countryside at the start of it's period of expansion.

What I did not expect was an insight into the energy economy of the town before the arrival of the railways.  There are several pictures of beached collier brigs.  After 1840 most Brighton and Hove's coal supply was came from the harbour at Shoreham by rail, but before that a lot of it was landed on the beach and taken to buyers in the town by horse and cart.

The collier brigs were two masted vessels of 100 - 300 tons with a length of between 70 and 90 feet and a small crew, maybe 6 - 10 men.  They mostly worked out of the Tyne taking a cargo of coal outward and returning home in ballast.  Some vessels also carried passengers between the North and London, before the railways this might have been preferable to several days in a coach travelling along rutted roads, at least in fine weather.  Navigational equipment was probably the master's experience and a compass.

At coastal towns like Brighton and Hove which did not have port facilities, the brig was run on to the beach and the cargo unloaded into horse drawn carts using local labour.  When the vessel was empty she was re-floated on the rising tide.  The price realised for the cargo would have depended on the season, the weather and before 1815 the trade could be disrupted by French privateers, this threat may have been used to hike the price.

Coal landed on the beach within the parish boundaries was subject to coal tax.  This explains the location of the Brighton Gas works (1819) just beyond the eastern parish boundary at Black Rock and the Hove Gas works (1825) which is at the extreme west of the town.  These works were located to avoid the coal tax.  Coal tax was abolished around 1870 and was not a factor in the location of electricity generating plant.  From 1820 to 1880 gas was used for street lighting and in  the posher town houses.  After the establishment of electric light companies in Brighton and Hove, gas lighting was displaced, initially by arc lamps, then by incandescent bulbs.

At the turn of the century the demand for coal in Brighton and Hove had greatly expanded.  In 1928 there were four railway goods yards, each of which acted as a base for coal merchants, some of these operated nationally, others were local family businesses.  Going west to east, the goods yards were located at Sackville/New Town Road (Hove), Holland Road (Hove), Cheapside (Brighton) and Kemp Town (Brighton).  With the exception of Cheapside which is close to the main Brighton station, these yards are now industrial estates doing amongst other things, serving the local building trade.

By the 1880s, the railway's coal distribution network was evolving at the same time as the market for coal for electricity generation emerging.  Brighton's first power stations were close to North Road and supplied from the Cheapside yard.  Hove's was at Holland road where it may have had it's own siding for coal deliveries.  At the end of the 19th century, the demand for electricity was growing and city centre locations for industrial plant was neither desirable or practical.    Brighton built a new power station at Shoreham harbour, close to the gas works which had already located, both the gas and electricity works were now supplied directly from the sea by steam engined colliers.

Industry attracts fewer artists and poets than traditional landscapes, seascapes and portraits, but there is one reference in John Masefield's "Cargoes" which is relevant.  I suspect generations of English teachers have hoped to inspire a love of words and rhythm with this, the last verse is:

    Dirty British coaster with a salt-caked smoke stack,
    Butting through the Channel in the mad March days,
    With a cargo of Tyne coal,
    Road-rails, pig-lead,
    Firewood, iron-ware, and cheap tin trays.

I've always been troubled by the "salt caked smoke stack", maybe I'm too literal, but the verse does invoke the rhythm of a reciprocating steam engine.

Footnote

I wrote this quickly from memory without checking the facts, please feel free to offer corrections.

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.

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.