Wild weather and extreme rainfall, why wind-farms may not be the friend we thought they were: a brief review and some surprising geographic meta-analysis based on wind farm distribution and real meteorological data, by Dr Chris Barnes, Bangor Scientific and Educational Consultants e-mail doctor.barnes@YAHOO.CO.UK

Dr Barnes Homepage http://www.drchrisbarnes.co.uk

Abstract

A brief review of contemporary publications suggesting that there may be potential weather and climatic problems associate with wind farms is made. Recent changes in UK rainfall geographic distribution appear to be a sort of incontrovertible evidence based on meteorological data that wind farms are seriously disturbing the UK climate and may not be the friends we once thought they were. Due to the way in which wind farms disturb the atmospheric boundary layer and create infra-sound and AGWS we have effectively filled our country with a vast number of additional mountain ranges and we are all aware of how these influence rainfall.

Introduction

Wang and Prinn 2010 have provided an insight into potential problems with wind farms. They state that meeting future world energy needs while addressing climate change requires large-scale of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fuelled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 °C over land installations. In contrast, surface cooling exceeding 1 °C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Finally they conclude that additional theory and new field observations will be required for the ultimate validation of their hypothesis.

Somewhat earlier, Keith et al 2004, reached similar conclusions. They found that large-scale use of wind power can alter local and global climate by extracting kinetic energy and altering turbulent transport in the atmospheric boundary layer. They reported climate-model simulations that address the possible climatic impacts of wind power at regional to global scales by using two general circulation models and several parametrisations of the interaction of wind turbines with the boundary layer and found that very large amounts of wind power can produce non-negligible climatic change at continental scales.

Roy and Tratuer 2010 stated that utility-scale large wind farms are rapidly growing in size and numbers all over the world. Data from a meteorological field campaign show that such wind farms can significantly affect near-surface air temperatures.

Satellites have even been used to visualise the wake effects of large wind farms, see Chrisitan and Hasager 2005.

Barrie and Kirk-Davidoff 2010 actually show that wind farms in the USA could significantly alter the track of cyclones across the Atlantic.

Adams and Kieth 2007 have attempted a climate parametrisation model including

The fact that large wind turbines can have indirect effects on the local climate by influencing surface fluxes, advection of heat and moisture, and turbulent transport in the boundary layer.

Given the almost unchecked and universal use of wind energy throughout the World, it is perhaps somewhat surprising that the above half dozen or so references is representative of the total body of research work in this area. It is further surprising that most of these studies are theoretical or involve modelling and that very little practical data has been gathered.

Meteorological Data

In large countries with sparse populations near wind farms, significant local effects may ,conceivably, go unnoticed. An ideal testing ground might be expected to be a small, relatively densely populated, maritime island such as Britain.

Rainfall distribution in years gone by is well documented for the British Isles, see Figure 1. More recently however, there have been freak weather events and unusual rainfall distributions in the UK. The present author has previously attempted to explain some of these effects as being probably due to the increasing use of aviation.

Figure 1 : Typical UK Rainfall most of period prior to existence of many wind-farms

Figure 2 Comparison of recent 2014 rainfall distribution and wind-farms

However, in the recent winter storms of 2013/2014 a close examination of the excess rainfall distribution reveals, via a simple visual meta-analysis style inspection of the two maps in figure 2, a surprising disclosure. Put simply there is excess rainfall in virtually every part of Britain where the inland wind farms are not.

Even the 2012 UK total rainfall distribution is similar, see Figure 3 below.

Figure 3 UK 2012 Rainfall Distribution

Discussion

Any of the references quoted in the introduction of this work are sufficient to support the observed results. The further hypothesis of the present author is that wind farms by disturbing the topology of the boundary layer act rather like mountain ranges. Mountain ranges create mountain wave cloud, mountain infra-sound and AGW, convectional windward side rainfall and leeward side rain shadow. In this respect wind farms do virtually the same thing. Keith 2004 has warned us that wind farms would be expected to cause non- negligible climate change at Continental scales. Little wonder then that we now have what would apparently seem like incontrovertible evidence of the awful disruption they may be causing to our tiny maritime island.

We will, perhaps, need to think very carefully in future about sighting and operation of turbines. In this respect the author has provided further detail of how this might be achieved in a recent UK patent application. Interested parties are welcomed to make contact with their NDA'S.