Coyote Blog

I still contend that wind is, except in a few niche applications, probably the worst alternate energy source.   Other forms of energy like solar have issues, but there is a lot of reason to believe these a fixable over time with better technology.  Wind is just a plain dog.

One of the biggest problems with wind is the need for backup power.  Because wind's lapses are hard to predict, a lot of fossil fuels have to be burned in spinning, hot backup capacity ready at a moment's notice to take over.  In Germany, the net effect has been very little substitution of fossil fuel burning despite an enormous wind investment

As wind power capacity rises, the lower availability of the wind farms determines the reliability of the system as a whole to an ever increasing extent. Consequently the greater reliability of traditional power stations becomes increasingly eclipsed.

As a result, the relative contribution of wind power to the guaranteed capacity of our supply system up to the year 2020 will fall continuously to around 4% (FIGURE 7). In concrete terms, this means that in 2020, with a forecast wind power capacity of over 48,000MW (Source: dena grid study), 2,000MW of traditional power production can be replaced by these wind farms.

Natural gas makes this situation a little better, as natural gas turbines can be brought up much faster than, say, an oil or coal-powered plant.  But the duplicate investment is still necesary

Britain's richest energy companies want homeowners to subsidise billions of pounds worth of gas-powered stations that will stand idle for most of the time.

Talks have taken place between the Government, Centrica, owner of British Gas, and other energy companies on incentives to build the power stations needed as back-ups for the wind farms now being built around the country.

It is understood 17 gas-fired plants worth about £10 billion will be needed by 2020.

The Energy Department has been warned that without this massive back-up for the new generation of heavily subsidised giant wind farms, the lights could go out when the wind dies down.

Sam Laidlaw, chief executive of Centrica, said renewables, such as large-scale wind energy, were intermittent and required back-up generation, a role gas was uniquely qualified to fill.

But as power stations that operate only intermittently would not be financially viable, Laidlaw said: 'The building of new gas-fired capacity must be incentivised so that gas can fulfil its role as a bridging fuel.'

Great.  So we have wind power, which is not financially viable so it must be subsidized, that required backup power plants to be constructed, which will not be financially viable so gas plants must be subsidized.

I have an idea, why not have gas plants which are financially viable serving the base load and just get rid of wind and this double subsidy all together?

I was having a back and forth with a reader about wind power and how much fossil fuel capacity must be kept on standby to support grid reliability with wind.  Here are some excerpts of what I wrote:

Forget all of the studies for a moment.  I used to operate power plants.  Any traditional capacity (fossil fuel, nuclear) except perhaps gas turbines takes on the order of a day or more to start up - if you don't take that long, the thermal stresses alone will blow the whole place up.  During the whole startup and shutdown, and through any "standby" time, the plant is burning fuel.   Since we don't have a good wind energy storage system, some percentage of wind capacity must be backed up with hot standby, because it can disappear in an instant. We are learning now, contrary to earlier assumptions, that wind speeds can be correlated pretty highly over wide geographies, meaning that spreading the wind turbines out does not necessarily do a lot to reduce the standby needs.  And since plant startups take time, even gas turbines take some time to get running, the percentage of wind power that required hot backup is pretty high -- I would love to find this percentage.

I found at least one source for such a percentage, which posits that for England, the percentage of hot backup needed is as high as 80%:  http://www.ref.org.uk/Files/ref.for.decc.28.10.09.i.pdf

I quote from page 6-7:

On any view, including the square root rule of thumb referred to above, the result, imposed for purposes of maintaining adequate response and reserve requirements, implies that a high degree of conventional (dispatchable) plant capacity is retained in the system to support wind generation. Thus, for 25 GW of installed wind capacity only 5 GW of conventional plant can be replaced leaving 20 GW in the role of standby capacity (also known as "Spare" or "Shadow Capacity").3

So 80% of the expected production from wind has to be backed up with hot spares burning fossil fuels.  They go on to say that the percentage of required spare capacity may be lower if the grid area is substantially larger, but not a lot lower.  I had not considered hydro power, but apparently that can be used to provide some quick response to wind production changes.  The report also talks about diesel generators for standby since they can be started up quickly, but these are seriously inefficient devices.  Despite the report's conclusion that the situation might be a bit better on the continent with a larger and more diverse grid, a report of the largest German utility seems to argue that German experience may actually be worse:

As wind power capacity rises, the lower availability of the wind farms determines the reliability of the system as a whole to an ever increasing extent. Consequently the greater reliability of traditional power stations becomes increasingly eclipsed.

As a result, the relative contribution of wind power to the guaranteed capacity of our supply system up to the year 2020 will fall continuously to around 4% (FIGURE 7). In concrete terms, this means that in 2020, with a forecast wind power capacity of over 48,000MW (Source: dena grid study), 2,000MW of traditional power production can be replaced by these wind farms.

It is hard to tell, because 48,000 MW is the nameplate capacity which is virtually meaningless, but my guess is that they are not doing better than 80%.

The other day I wrote to beware of rated capacity for wind and solar, because such plants tend to run way below their rated capacity on a 24-hour average.  MaxedOutMamma reads the wind report of the largest utility in Germany, which is as a country is among the largest adopters of wind power.  She finds this interesting bit:

As
wind power capacity rises, the lower availability of the wind farms
determines the reliability of the system as a whole to an ever
increasing extent. Consequently the greater reliability of traditional
power stations becomes increasingly eclipsed.

As
a result, the relative contribution of wind power to the guaranteed
capacity of our supply system up to the year 2020 will fall
continuously to around 4% (FIGURE 7). In concrete terms, this means
that in 2020, with a forecast wind power capacity of over 48,000MW
(Source: dena grid study), 2,000MW of traditional power production can
be replaced by these wind farms.

This is an even lower substitution factor than I mentioned previously, and is so because this report looks not just at the percent of time wind is blowing at full speed, but also at the peak load conventional power plants that must be kept running on standby due to the unreliability of wind.  At this 24:1 substitution ratio, folks like Al Gore and Boone Pickens will bankrupt us.  But of course, their investment portfolios, laden with alt-energy investments, will be paying off.