[ exact phrase in "" • results by date ]

[ Google-powered • results by relevance ]


Add NWW headlines to your site (click here)

when your community is targeted

Get weekly updates

RSS feeds and more

Keep Wind Watch online and independent!

Donate via Stripe

Donate via Paypal

Selected Documents

All Documents

Research Links


Press Releases


Campaign Material

Photos & Graphics


Allied Groups

Wind Watch is a registered educational charity, founded in 2005.

News Watch Home

Cape Town professor’s research picks holes in claims about wind energy 

Credit:  By: Terry Mackenzie-hoy | Creamer Media's Engineering News | Jul 10, 2015 | www.engineeringnews.co.za ~~

Professor Philip Lloyd works at the Energy Institute at the Cape Peninsula University of Technology. He recently sent me a copy of a paper he had written, entitled ‘An Assessment of the Impact of Wind Energy on Energy Supply’.

The paper addresses a number of concerns that power system engineers have with wind energy. Putting aside the visual and noise impact of wind turbines (and bird and bat strike), there is the matter that wind energy is often referred to as being ‘nondispatchable’ – the output of a wind farm can go from maximum to near zero, and there is nothing that the grid operator can do.

To keep the power supply to the load going, wind turbines then have to be backed up by ‘spinning reserve’ in the form of a generator that can be brought on line, if necessary, in a few seconds. Spinning reserve in this context refers to gas turbines. It is well known that gas turbines run up very quickly and consume great quantities of hydrocarbon fuel. Thus, using a gas turbine to back up a wind turbine is hardly a combination which can be described as being green.

Another characteristic of wind turbines is that they have a load factor which is low, compared with other generation. ‘Load factor’ is the ratio of the energy supplied by the wind turbine divided by the total possible energy that could be supplied by the wind turbine. It has been widely claimed by wind turbine suppliers that this load factor can reach 50% – at least half the total installed capacity.

What Lloyd has done is to examine the power output of the UK grid. This information is available from the UK Gridwatch (www.gridwatch.templar.co.uk) and shows, with five-minute updates, what energy is being supplied by nuclear, coal-fired, hydro, wind, gas turbine power stations (as I am writing this, Gridwatch records that 10% of the UK grid is being supplied by wind and a third is being supplied by gas turbine).

Lloyd examined the figures for a four-year period. He found that the number of shifts in wind power supply where the shift was greater than 200 MW and lasting longer than five minutes is increasing and went from 10 shifts in 2011 to 80 shifts in 2014. He also found that, while in the last five years a 20% load factor is attainable in the UK, it is unlikely that this will ever improve.

Further, the maximum production from Britain’s wind system is 55% to 60% of installed capacity. This is a vital piece of information because it allows developers and investors to understand exactly what financial model applies to wind power development. What’s more, the UK wind farm capacity is about 1 000 MW. The figures indicate that it is quite possible on some days for this entire capacity to be unavailable owing to a lack of wind.

Lloyd notes: “Clearly, while it is true that the wind always blows somewhere, there are times when that ‘somewhere’ is a very small region in a very large system.”

He adds: “The implications of this are that it is essential to increase the spinning reserve as the proportion of climate-dependent renewable energy feeding a grid increases. Moreover, the increase in spinning reserve should be proportionately greater than the increase in the renewable energy. As spinning reserve is more costly than other sources of energy, the costs can mount rapidly. This needs to be taken into account in planning the expansion of renewable sources of energy.”

It is very unlikely that Energy Minister Tina Joemat-Pettersson even grasps this concept distantly. However, it must be understood, and understood clearly, that this very important piece of research by Lloyd has shown us the following: no wind farm will ever operate at a load factor greater than 20%. The maximum production from any one system cannot exceed 60% of installed capacity. The faster one grows renewable energy, which is climate based, still faster must one grow spinning reserve in the form of gas turbines. This paper is a landmark publication by the professor. I take off my hat and I bow.

Edited by: Martin Zhuwakinyu
Creamer Media Senior Deputy Editor

Source:  By: Terry Mackenzie-hoy | Creamer Media's Engineering News | Jul 10, 2015 | www.engineeringnews.co.za

This article is the work of the source indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.

The copyright of this article resides with the author or publisher indicated. As part of its noncommercial educational effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Send requests to excerpt, general inquiries, and comments via e-mail.

Wind Watch relies entirely
on User Funding
   Donate via Stripe
(via Stripe)
Donate via Paypal
(via Paypal)


e-mail X FB LI M TG TS G Share

News Watch Home

Get the Facts
© National Wind Watch, Inc.
Use of copyrighted material adheres to Fair Use.
"Wind Watch" is a registered trademark.


Wind Watch on X Wind Watch on Facebook Wind Watch on Linked In

Wind Watch on Mastodon Wind Watch on Truth Social

Wind Watch on Gab Wind Watch on Bluesky