Orkney Islands Use Renewables to Generate 103% of Power Needs
David Simpson posted on February 11, 2016 | 8832 views
(Photo courtesy of David Simpson.)

(Photo courtesy of David Simpson.)

The Orkney Islands in Scotland have become very well known for their use of renewable energy. 

The main electrical supply for Orkney comes from a mix of wind farms, small point-of-use windmills, and solar panels installed on homes and businesses. Approximately 50 vehicles on the roads in Orkney are battery powered electric vehicles (EV), reducing the need for expensive imported motor fuels. 

These established installations supply the local energy needs, including a portion of their motor fuel demand, while enabling the export of excess power to the mainland. 

In addition to the current wind and solar capacity, Orkney is a test bed for experiments in tidal and wave power. At any given time, a significant portion of power on the grid might be from the ocean.

According to www.VisitScotland.com, the Orkney Islands are a group of approximately 70 islands (20 are inhabited, the largest of which is called “Mainland”) located about 10 miles off the coast of Scotland.  Mainland has an area of 202 square miles, and the island group has over 1,000 miles of coastline.  Population of the islands is 21,349 according to the 2011 census, with 17,000 of this number living on Mainland. 

The main industries of Orkney include farming, fishing and tourism, with power generation becoming an ever-larger employer.  There are no heavy industries on Orkney, and they have something under 100 miles of roads (compared to over 4 million miles of roads in the US.)

Orkney is well situated to exploit renewable power sources.  While the Scottish coast is subject to lengthy periods of minimal sunshine, the prevailing winds are strong and more consistent than most places.  The tides and waves at Orkney’s location contain large amounts of recoverable energy. With evolving technology, this means Orkney is poised to eventually become a significant power source for the mainland, provided they can correct their current grid deficiencies.  

With all these advantages that come from the Orkney Islands’ location,, there are times that actual power generation exceeds demand, and they are able to export power to the mainland.

However, there are also times that the renewables do not meet local demand for power, which then requires importing power from the mainland. 

The net since 2013 is export, but no one’s iPhone or EV is charged from net power or average power.  In 2015, Orkney imported power every month of the year, and was a net importer seven months of the year. The amount of power exported in the other five months was greater than the amount imported in the other months. 

Without a damping force such as access to the Scottish mainland grid, or a far greater amount of storage than is currently installed, there would regularly be brown-outs or black-outs on the islands.

In fluid mechanics, we have a concept called “similitude” which says that in order for one system to be a suitable model for another system, it must match at least two dimensionless parameters, such as the well-known Reynolds Number (the ratio of inertial forces to viscous forces) or the lesser known Weber Number (the ratio of inertial forces to the forces of interfacial tension.)

Unfortunately, there are no clearly defined parameters that allow you to see if a given power-generation technology is suitable for a given location.  However, there are some parameters that can hint at applicability without the rigor of fluid mechanics. 

The data I’m working with came from various energy sources and uses this link for Orkney. The Scottish data came from “Energy in Scotland 2016,” and the national level data came from the EIA statistical database. 

I’ve converted all of the data to the same set of units so that it can be compared (since adding short tons to barrels to kW-hrs doesn’t result in a meaningful analysis.) 

I did not attempt to exclude fuels burned to generate electricity from those columns, but I did not add in energy sources that are only used to generate electricity but don’t occur on Orkney (i.e., hydro and nuclear):

Table 1:  Basic statistics

 

Population

Non- electric (GWh)

Electric (GWh)

Total (GWh)

Nameplate renewable capacity (GW, % total installed nameplate)

Orkney

21,349

364

142

506

0.05 (?)

Scotland

5,295,000

118,284

25,873

144,157

0.3 (2.7%)

UK

64,100,000

2,044,130

319,000

2,363,130

1.7 (1.8%)

US

318,900,000

25,582,878

3,820,000

27,414,878

3.2 (0.3%)

Canada

35,160,000

2,729,696

525,000

3,254,696

0.8 (0.5%)

The Orkney numbers are included in the Scottish numbers which are included in the UK numbers.  There are diesel generators on Orkney, but I was unable to determine their rated capacity. The backup power supply from the Scottish mainland is 97.3% non-renewable and most months a non-trivial amount of that power is imported.

Installed renewable capacity was limited to wind/solar/tidal to make it consistent with the Orkney data. 

 

Comparing Orkney to the rest of Scotland, the rest of the UK, the US and Canada shows some interesting relationships:

Table 2:  Derived data

 

Per cent of power from electricity

Per capita power consumption (MWh/person)

Electric power consumption (MWh/person)

Orkney

28.11%

23.72

6.67

Scotland

17.95%

27.23

4.89

UK

13.50%

36.87

4.98

US

13.98%

85.97

12.02

Canada

14.93%

92.57

14.93

 

The basic question is, “Does the Orkney power-generation model scale up to all Scotland, all of the UK, or to unrelated economies like the US or Canada?”   

In Table 2, it is clear that in Orkney the power consumption per capita is far less than in the other areas, which is due to the very low level of industrialization.  The electric power consumption per capita on Orkney is a bit more complex.  Many heavy industries (e.g., automobile assembly) are very large electric users, and that power load is then spread over the population of industrialized nations. 

Table 3 looks at the portion of power that comes from electricity.  Reaching Orkney’s electric percentage of total power consumption by installing new renewable sources would be expensive: 

  • Scotland would have to invest $4.3 trillion (17 times 2013 GDP)
  • The UK would need to spend $102 trillion (38 times their 2013 GDP)
  • The US would need to spend $1.1 quadrillion (69 times 2013 GDP, but only 52 times the current national debt)
  • Canada would need to spend $116 trillion (63 times 2013 GDP)

These numbers would be impossible to achieve without bankrupting the countries involved.

Table 3:  Cost of catching up

 

New nameplate capacity required to have renewables 28.11% of consumption (MW [% of current nameplate])

Cost of new capacity ($trillion)

Scotland

1,547 (14.1%)

$4.364

UK

36,470 (38.8%)

$102.847

US

409,233 (38.5%)

$1,154.037

Canada

41,183 (30.5%)

$116.137

Assumes 70% wind at $2,230/kW and 30% solar PV at $4,180/kW for a total of $2,820/kW, costs from EIA.

 

The reasons for these staggering numbers are that the drivers of the various economies discussed are so very different. 

In Orkney, the primary industries are farming, fishing, and tourism—none of which is particularly energy intensive.  Adding a chemical plant, a foundry or a manufacturing assembly plant would result in a dramatic shift in the electric/non-electric mix. 

The other entities on this list are all industrialized and must plan on powering many energy-intense industries.  No one is proposing using solar panels to power aluminum processing or a blast furnace.  This just wouldn’t be practical.

The Orkney Islands represent an ideal location for extensive use of renewables, and for the most part the technology deployed there is the best available technology for the application.  Any location with very light industrial loads, reasonably reliable wind, wave or tidal action and the occasional cloudless day, as well as a huge safety net in the form of a wire into a reliable power supply, could apply this model effectively. 

Without that safety net, the Orkney’s would not be a net power exporter and would be running inefficient diesel generators to supply up to half of their power.  This model probably works in many islands that are close to a significant source/sink that can accept excess power, or provide power during periods of deficiency. 

For example, a place like Santa Catalina Island, located 26 miles off the coast of California, might be considered a candidate for this model. Santa Catalina is not industrialized, has reasonably consistent wind velocity and direction, has better access to solar power than Orkney and has a permanent population of about 5,000.

This island looks like a good candidate, but it is not connected to the mainland. This means Santa Catalina isunlikely to be able to remove any of its six diesel generators or 23 propane powered microturbines and replace them with renewables. The installation of renewables would still require running the current generating capacity at idle, waiting for the inevitable night and/or the wind stopping, without saving anything.

A place without any safety net, such as the US, could not implement this model.

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