If you want to imagine the Western Hemisphere’s equivalent to China’s Three Gorges Dam, look no further than the proposed Severn Barrage, which at peak output will deliver over 8 gigawatts of electricity, or about 50% of what the Three Gorges delivers. Even though the Three Gorges output decisively exceeds that of the Severn Barrage, if this massive civil engineering project is ever completed, it will dwarf every other power station in the world.
Environmental groups bitterly oppose the Severn Barrage, and if they are to strive for consistency, they certainly should oppose this monstrosity. The ten mile long dam will connect the English coast to the Welsh coast across the Severn Estuary, one of the largest, most precious, environmentally sensitive estuaries on Earth. Why on earth would any environmentalist support this project, or any tidal energy project, for that matter? The problem, of course, is we have to pick our poison – energy production, like food production – in a world destined to accomodate 8-9 billion people who aspire to live in peace and prosperity, is doomed to be dependent on commercial scale operations that are disruptive and potentially dangerous. Pick your poison. Nuclear? Hydroelectric? Fossil fuels?
|The Severn Estuary and the
proposed barrage crossings.
The problem with tidal power certainly isn’t the scale – unlike wind turbines, which would have to be installed by the millions to make a dent in global power production, the Severn Barrage is a big deal. But to suggest the 8.6 gigawatt output is “equivalent to eight nuclear power plants” (presumably at 1.0 gigawatt each) is misleading.
Like other intermittant sources of energy such as wind and solar, and unlike nuclear power that operates continuously, tidal energy plants only operate at low tide, which is when the seawater sequestered behind the barrage during high tide can drain through the hydroelectric turbines. Like wind and solar, tidal energy has a “yield,” which in the case of the Severn Barrage is not quite 25%. In terms of actual average output, the Severn Barrage is only estimated to deliver 2.0 gigawatts of electricity, and at this point no serious discussion seems to be forthcoming as to how a fluctuation in grid input of 8.6 gigawatts is going to be offset. If there are designs that can smooth this massive energy flow, how much do they cost?
And what about the financial cost? At an average of 2.0 gigawatts of continuous power, the Severn Barrage will deliver about 17.5 terawatt-hours per year. Rounding up slightly from current estimates (because these projects never come in on budget), the entire project will cost about L 17.0 billion, or about $30 billion. Ouch! That equates to $15 billion per gigawatt-output, an amount that absolutely does not compare favorably to alternatives, including wind – installed, taking into account yields, probably half this amount or less – and certainly not natural gas, which can now be installed at about $1.0 billion per gigawatt output.
At $15+ billion per gigawatt (over $15.0 million per megawatt) installed, the Severn Barrage is a civil engineering boondoggle, being popularized based on global warming alarm and desire for energy security. While energy security is a compelling concern, it should be addressed in ways that reflect fiscal reality. A tidal energy system that costs $15 billion per gigawatt is not a financially competitive investment, even when compared to other alternative energy options. Try marine current turbines, which operate underwater on the ocean floor, or offshore wind – almost anything will cost less than the Severn Barrage, and almost anything would be less of a blight.
|The location of the Severn Estuary
in the southeast of the U.K.
While we don’t dismiss global warming concerns, only remain committed to publishing credible material from the skeptic community (read our Climate section), one must consider this: It is virtually impossible to eliminate CO2 emissions to the levels the alarmist scenarios declare we must to avoid catastrophe.
It isn’t going to happen, no matter how many precious estuaries environmentalist policies destroy, or rainforests that environmentalist policies burn to grow subsidized “carbon neutral” biofuel. Global warming alarm is being used quite effectively as a trump card in almost every policy debate imaginable, but by the alarmists own logic, it is an utterly futile exercise.
Environmentalists should hope whatever climate changes we’re experiencing are from natural cycles, and return their focus to things that they can influence – the world’s estuaries and rivers, forests and floodplains, wilderness and wildlife; protecting precious natural beauty and eliminating genuine pollution.
Severn Barrage (Wikipedia)
Severn barrage will be costly ecological disaster (Guardian.co.uk)