Thursday, September 21, 2017

Energy In the Wind

Nature lovers far and wide are kvelling over renewable energy sources… by which they mean wind and solar. By their imaginings more natural, less industrial energy sources will help us to return to nature. Isn’t that what we all want?

Now, Matt Ridley explains the truth about wind energy. (via Maggie’s Farm)  It’s a harsh truth, so, take a deep breath before plunging in:

Even put together, wind and photovoltaic solar are supplying less than 1 per cent of global energy demand. From the International Energy Agency’s 2016 Key Renewables Trends, we can see that wind provided 0.46 per cent of global energy consumption in 2014, and solar and tide combined provided 0.35 per cent. Remember this is total energy, not just electricity, which is less than a fifth of all final energy, the rest being the solid, gaseous, and liquid fuels that do the heavy lifting for heat, transport and industry.

Such numbers are not hard to find, but they don’t figure prominently in reports on energy derived from the unreliables lobby (solar and wind). Their trick is to hide behind the statement that close to 14 per cent of the world’s energy is renewable, with the implication that this is wind and solar. In fact the vast majority — three quarters — is biomass (mainly wood), and a very large part of that is ‘traditional biomass’; sticks and logs and dung burned by the poor in their homes to cook with. Those people need that energy, but they pay a big price in health problems caused by smoke inhalation.

If we relied on wind, how many turbines would we need to build? Ridley has the answer:

If wind turbines were to supply all of that growth but no more, how many would need to be built each year? The answer is nearly 350,000, since a two-megawatt turbine can produce about 0.005 terawatt-hours per annum. That’s one-and-a-half times as many as have been built in the world since governments started pouring consumer funds into this so-called industry in the early 2000s.

How much land area would the new turbines take up?

At a density of, very roughly, 50 acres per megawatt, typical for wind farms, that many turbines would require a land area greater than the British Isles, including Ireland. Every year. If we kept this up for 50 years, we would have covered every square mile of a land area the size of Russia with wind farms. Remember, this would be just to fulfil the new demand for energy, not to displace the vast existing supply of energy from fossil fuels, which currently supply 80 per cent of global energy needs.

Do not take refuge in the idea that wind turbines could become more efficient. There is a limit to how much energy you can extract from a moving fluid, the Betz limit, and wind turbines are already close to it. Their effectiveness (the load factor, to use the engineering term) is determined by the wind that is available, and that varies at its own sweet will from second to second, day to day, year to year.

And, of course, you want to know how much energy it would take to build all of those wind turbines:

It gets worse. Wind turbines, apart from the fibreglass blades, are made mostly of steel, with concrete bases. They need about 200 times as much material per unit of capacity as a modern combined cycle gas turbine. Steel is made with coal, not just to provide the heat for smelting ore, but to supply the carbon in the alloy. Cement is also often made using coal. The machinery of ‘clean’ renewables is the output of the fossil fuel economy, and largely the coal economy.

A two-megawatt wind turbine weighs about 250 tonnes, including the tower, nacelle, rotor and blades. Globally, it takes about half a tonne of coal to make a tonne of steel. Add another 25 tonnes of coal for making the cement and you’re talking 150 tonnes of coal per turbine. Now if we are to build 350,000 wind turbines a year (or a smaller number of bigger ones), just to keep up with increasing energy demand, that will require 50 million tonnes of coal a year. That’s about half the EU’s hard coal–mining output.

The solution is not in wind and solar. It lies in natural gas. I am sure that you knew that already:

The truth is, if you want to power civilisation with fewer greenhouse gas emissions, then you should focus on shifting power generation, heat and transport to natural gas, the economically recoverable reserves of which — thanks to horizontal drilling and hydraulic fracturing — are much more abundant than we dreamed they ever could be. It is also the lowest-emitting of the fossil fuels, so the emissions intensity of our wealth creation can actually fall while our wealth continues to increase. Good.

And let’s put some of that burgeoning wealth in nuclear, fission and fusion, so that it can take over from gas in the second half of this century. That is an engineerable, clean future. Everything else is a political displacement activity, one that is actually counterproductive as a climate policy and, worst of all, shamefully robs the poor to make the rich even richer.


Sam L. said...

In Oregon, hydropower is considered to be NONrenewable. Expecting severe droughts, perhaps, or sinkholes forming upstream from the dams.

Ares Olympus said...

Stuart: The solution is not in wind and solar. It lies in natural gas.

Every on all sides loves their silver bullets. Amory Lovins' favorite is the negawatt, the energy we don't have to expend at all because of efficiency and conservation.

But even if climate change is a hoax perpetrated by the Chinese, and all we're doing is producing more plant food for our garden of Eden, fossil fuels always run down, and we have to go ever deeper, like the current fracking craze, for a while at least we can burn natural gas at a cheaper price than it takes to get it out of the ground, which is a good trick for investors who plan to get out before all the new debt is paid off in bankruptcies.

But back to negawatts, it certainly would be good for my state of Minnesota to go geothermal heat pumps for our cold winters, converting 1 unit of electricity to run the heat pump produce 10 units of cooling or heating from ambient heat in the ground. But since NG is literally cheap enough to burn, we'll keep burning away our one-time future, just in case our descendants discover warp power and dilithium crystals and save the day.

The only 1% renewables is a depressing number, and I expect one day our descendants will wish they could consume energy at 1% of our current consumption of a 100 million year old one-time stock sale.

I'm not sure if Sam L's right about the status of Oregon Hydro, but I thought it was silt accumulations was the real long term problem for large dam projects.

Ignatius Acton Chesterton OCD said...

Saw a Tesla vehicle today with the vanity plate XHSTLESS -- "exhaustless." Separated from the spent fuel or carbon footprint of the power plant that powered the vehicle, no doubt. What's at the other end of the plug?

Anonymous said...

Purdue studies of wind turbines came out last year.

Up to 400K birds, and 1.5M bats killed annually. Birds & bats eat nasty bugs, like mosquitos.

Mao had people kill birds. Result: Plagues of bugs.

Thorium/pebble bed reactors look promising. China & India are building them. -- Rich Lara

James said...

I am convinced that there is no such thing as a "Prius". They are actually a "Pius" and the drivers should be called Pharisees.