How To Increase Wind-turbine Output by 10 Times

Considering the fact that wind-turbines have been with us for over 100 years (See here) you might be forgiven for thinking there's nothing more for us to learn about using them to generate electric. It's a mature technology, end of story.

However, researchers at the California Institute of Technology (Caltech), don't agree. They've been experimenting with the layout of a small windfarm and they've realised there's still plenty to learn. Their findings suggest that conventional farms waste too much space and just don't use the available wind energy efficiently.

They conclude that turbines can be made shorter (= cheaper and less intrusive) and placed closer together (using less land per turbine) if VAWTs (Vertical axis wind turbines. See picture for an example) are used.

By spacing them in a certain way and ensuring neighbours turn in opposite directions, they found that they could harvest almost all the energy available without them interfering with the efficiency of the others. The result: 10 times more power than you can get from a conventional set-up.

Their next steps will be to scale up the size of the farm and look at the design of the VAWTs but it certainly appears like windfarms will look a lot different in the future.

See here for the full report.

What is a Toyota Prius Plug-in?

Next year Toyota will start selling their new Prius plug-in. It represents the next stage in the evolution of the Toyota Prius and promises to give the owners well over 100 miles to the gallon.

I'm a Prius owner myself but I didn't exactly know how the plug-in was different. So I decided to do some investigation and here is what I discovered.

As you may know, a normal Prius is what's known as a 'hybrid' car. That is, in addition to standard engine, it has another way of moving the car forward: An electric motor. This motor runs off a NiMH battery. The battery is charged up from the energy generated during braking, and the car itself usually decides when to use the electric motor or the engine. The end result is that the Prius uses far less fuel than a similarly sized car because that electric motor is helping out.

The Plug-in Prius (See picture above) is a clever twist on all this. You'll be able to plug it in for as little as 90 minutes and charge up a separate pair of batteries which'll give you around 12.5 miles on the electric motor, with a maximum speed of 62 mph. Once they've run out, you're back to a normal hybrid. So you could be doing around 108 mpg! Another way to look at it is: If you have a relatively short commute, then you're effectively doing it in an electric vehicle with none of the associated problems of an EV (Like running out of charge, and long charge up times). Two cars in one!

The cost of a plug-in? Early estimates are around £22,000 in Britain after taking into account a £5000 grant from the UK government.

How are they charged? Standard mains power socket. It even gives you a countdown on how the charge is doing.

The only question I've got left is how many charges will the batteries manage before they give up and how much to replace? With a 12.5 mile range, you'll be charging the battery up far more often than a standard EV battery and that might mean it has a shorter lifetime by comparison. And these heavy duty batteries don't come cheap. Still, even if they do die on you and you can't afford to replace them, at least the car will still go.

More on plug-in here and here. My posts on Prius ownership here and here.

UK Wind Turbines Generate Less Than Half Their Capacity

The right-wing newspapers seem to love undermining renewable energy. So, when a conservation charity called the John Muir Trust came out with a report saying UK wind energy could not be relied on, those papers must have thought it was Christmas!

Under headlines like "Blow for green energy as wind farms are exposed as unreliable" and "A lot of hot air: Windfarms working at just 21% of capacity", they gleefully wrote off wind energy as a failure.

Fortunately, they got it all wrong (see here for more). The report focuses it's attention on a very narrow set of data: Mainly Scottish on-shore. Ignoring all off-shore which is known to give better performance, and most of the rest of the UK, which would have 'smoothed-out' the dips in energy production.

Something else the papers got wrong is the assumption that 20 to 30% of capacity somehow makes the turbines unviable. In fact, they are not expected to operate anywhere near 100%. The UK government is looking for 30% from off-shore, whilst Germany and Denmark want just 20%. At present, official UK government figures based on ALL the data put the on-shore production at between 26-30%, whilst off-shore is 27-35%.

So the newpapers get it wrong again. Big surprise.