Historic Windmill Sites

When I first became interested in sustainable energy it seemed that it was a data-rich industry, whilst good quality meteorological data is available in long time series, a lot of it comes from aerodromes which are flat, unobstructed spaces.  Solar devices are relatively independent of terrain, however, the output of wind turbines is determined by terrain.  Within a few kilometers of where I live, the wind speed can vary between 0 and 10 m/s according to location, where the terrain ranges from seafront, urban areas, exposed ridges and sheltered valleys.  Whilst industrial scale wind turbines for electricity generation are a relatively recent development, the wind was a significant source of energy in the 19th Century for milling and pumping applications.  There were approximately 20 windmill sites within what is now the Brighton and Hove city limits with several more within a few kilometers.  It is interesting to look at the location of these mills in the context of terrain.

The graphic below was mainly compiled from two sources:

• Timothy Carder's excellent "The Encyclopedia of Brighton" which was published in 1990 by East Sussex County Libraries.
• SRTM 1 arc second elevation data.  The 1 arc second data became available in 2014, prior to that only 3 arc second data was available for areas outside the US.  I very much appreciate this data being available.

The shading is relative and based on one of the ColorBrewer schemes with linear interpolation between the intervals, this is a convenient way of working with continuous data.

The graphic clearly shows that the favored location for windmills was either on the coast or along the chalk ridges that extend southwards from the Downs, only one appears to be located in a sheltered location.  Siting a windmill or turbine requires access to land, thus available locations may not always by the optimum ones.  The Google Earth screenshot below illustrates the competing uses for land.  In this case, the contours were generated using the SRTM 3 arc second data set.

Post mills are relatively portable, the machinery is mounted in a wooden structure which rotates around a post, a picture in a local museum shows one being moved on a sled drawn by oxen.  During their lifetimes five mills were moved to new sites either in one piece or in separate loads.  I have not studied the history of milling in the town, but I'm guessing that the early mills were built in the late 18th century to serve Brighton's growing population, however, as the demand for building land grew, the mills were displaced.  The screenshot shows the change of location of four mills, a fifth Preston Mill moved several miles to the north to Clayton where it is still in existence and has been restored and is now a listed building known as "Jill".  Towards the end of the 19th century the windmills came under the combined pressure of demand of building land and competition from steam and motor mills and their numbers dwindled.

Electricity Prices - The long view

Creating a time series of electricity prices compiled from actual bills has been a back-burner project for a few years.  I recently found a copy "Brighton and the Electric Revolution - 1882-1982" in the public library which provided data points for 1887 and 1893 and this has facilitated a revision of an earlier post.

Brighton on the south coast of England was one of the first towns in the world to have a public electricity supply.  Initially this was provided by private companies, towards the end of the 19th century, generation and transmission was taken over by the town council and later nationalized in the early post war years and then privatized in the 1990s.

Inevitably, getting like-for-like data for an industry which has been subject to technical, commercial and political change is difficult and thus the data in the graphs below should be treated with caution.  The gaps are being filled in as I find old electricity bills or advertising material.

The first graph is is from 1887 to 2015 with a log scale for the price in 2011 money which makes it possible to show a range of prices from 5p - 500p per kwh

The second graph starts at 1900 and has a linear scale for unit prices:

In the late 19th century electricity at £5/kwh in current prices was a luxury product but as generating capacity and demand increased, the prices started to fall and the displacement of gas as a means of domestic lighting began to accelerate.  Our family's experience suggests that it was only after the first world war that working families started to wire their houses for electricity in large numbers.  Initially electricity was only used for lighting, but by the start of the second world war many homes had vacuum cleaners, electric irons, radios and electric fires and a few had TV sets.  Often someone had to be ill before and electric fire was turned on because of the cost.  In the period following the second world war, prices were generally stable and possibly "cheap".  With the rise in oil and gas prices early in the 21st century, the prices of electricity started to rise and become a matter of political and economic concern.

Energy price forecasts can be a career graveyard, but it looks as if electricity prices in the 21st century will be higher than they were in the second half of the 20th.  The published "strike price" for nuclear power project appears to be around 9p/kwh and that for offshore wind around 12p/kwh, the consumer will pay transmission and distribution costs on top of these figures.  Nuclear and wind are only part of the energy mix, but it is not expected that oil and gas prices will remain at their current relatively low levels for a prolonged period.