Comments on: Harnessing the power of wind and waves

Ireland is in the right place to generate electricity, and a lot of it, out of oceanic surges, but it won't be easy sailing.
Video: Ocean-based renewable energy

[afterhours]

Needs more work

The materials science guys need to consider this contraption.
They want to make it out of steel or concrete. Why not
polymers? Or is there a reason the weight is important (inertia
of the mass, etc.)? I seem to recall the test unit off the coast of
Oregon (USA) was doing well, before it sunk.

This technology is another small piece of the energy stopgap
measures needed as the petroleum decline accelerates. Coupled
with such revolutionary concepts as conservation ('Conservative'
is the ultimate oxymoron here in the States), wind, solar, nuke
and cellulosic or algal biofuels, the species may survive the
post-petroleum energy starvation. Of course, we'll have to have
WWIII to facilitate the necessary population reduction. Perhaps
the 'my god is better than your god' types will get that going.

[spothannah]

Maybe, but then again, maybe not.

What if humans were able to reconsider their belief systems? I don't mean about gods. I mean about the ability to work together for a common goal for a common good. I don't want to sound pollyannaish and at the same time is it theoretically impossible for people to cooperate? I'm not talking probability here I'm talking possibility. All I'm asking is "do you think it is POSSIBLE for people to cooperate?" Just wondering.

[theBike45]

I love the outright lies

It's required of every alternative energy backer topoint out that "if XXX could be fully developed it could produce YYY terrawatt hours of power, nearly enough to power the entire nation." The problem is that msot alternative enegies are uncontrollable and unreliable - they give the power when they want to, which is never when you need it. Since power demands fluctuate gigantically, Ireland will be lucky if they could use 1/3 of the "20 terrawatt hours" of potential power. And the waste and added expense of unreliable power doesn't stop there - every watt
of unreliable generative capacity must be duplicated when power demand inevitably grow in succeeding years - in effect, that very expensive wave power will actually cost nearly twice as much as its proponents claim. That's the reality of unreliable power and why solar thermal, geothermal, biocoal and biomass and nuclear have such gigantic advantages for producing carbon fre power. Its carbon free that's important, not whether the power is "renewable," a totally irrelevant characteristic at this point in time. Ireland will pay thru the nose in order to avoid
her sillly fears of nuclear and end up with a
primitive, costly melange of power generation
technologies.

[k2dave]

unreliable power

I don't think the unreliability of wave, wind, solar is a deal breaker. By diversification you can smooth out some of the unreliability, and some seem to be mutually complementary, such as solar and wind, as stormy days have little sun but excess wind. In order for these to really become a dominate power source however a way to store power will be needed.

Some have proposed pumping water to a upper reservoir when there is excess capacity and releasing it to generate energy where there is not enough. Also I've heard storing compressed gas in underground caves to do the same thing. In countries where power is unreliable, many people have battery banks where power is stored up when it is available then the house is run off of battery power when the main line power goes off.

So from the home level to the city level there already exists ways, both real and theoretical to smooth out the unreliability. As this type of power becomes more common, more need for power storage will be needed and better technologies will come along.

[44lefty]

Tidal energy

This is all well and, perhaps, good. But what will be the effect of increased tidal drag on the rotation og the planet? Tidal drag is significant, and over time has lengthened the day considerably. What happens to the weather, the ambient temperature, etc. if we do something to lengthen the day even more.

There really is no free lunch.

[duggerdm]

Think past changes.

As I understand it - while you are technically correct, you are not completely correct regarding tides effecting the earth's rotation. There are also countering effects that shorten the day - gravitational radiation (by about 8 zeptoseconds per year), the Poynting- Robertson effect (about 30 nanoseconds per year), etc. There is a lot of discussion about forces that effect the rotation of the earth. Tidal drag from surface changes is pretty far down in the list significant effects - certainly from a human planning perspective.

The oceans are rotating essentially at the same speed as the planet. Only sudden momentous changes in their flow would significantly effect planet rotation and orientation - over-riding more significant effects. From the human perspective, the planets surface is in a constant state of change - providing more or less surface to the tides over time. Tidal "drag" is a relatively insignificant force as are its effects. Gravity waves between the sun, moon and planets are far more overshadowing in effect.

If you think about the continental drifts of the past - when Pangia existed for example, or the before the connection of the North and South American continental damn - the tidal pathways have changed dramatically with little or no limiting affects to life on earth. Any changes that man makes in earths surface will likely not be separable from natural changes or recordable in its rotation due their gradual nature and the far greater effects of extrarestrial gravities. In the end - those species that adapt survive - business as usual on earth. Man has far greater problems than a few nano-seconds in the earth's rotational speed - if it changed.

[duggerdm]

Your good comments - plus these to consider.

To your list of considerations for wave and tidal power - add anti-fouling which is never mentioned by proponents, but which is a substantial unsolved technical and economic hurdle and of tremendous environmental concern - since most if not all anti-fouling agents are toxic by their nature and eventually impacting almost all food chains. The maintenance efforts of keeping these in-water structures from being dynamically overcome by the weight and drag of marine organisms growing on their surface is a substantial portion of the systems operating costs - and their cost per KWH. Discussions of alternative energy sources which don't involve honest recognition of their technical and economic challenge details are... dishonest.

Unfortunately, the current thinking that is being done on any of these crises - doesn't seem to reflect addressing them with a co-ordinated whole science approach. Perhaps the best example is the fossil fuel crisis. If nothing else is clear - it should be clear that future energy needs will have to come from multiple sources - many of which are not steady state producers - wind, solar, tide, wave, etc. (I don't include biofuels because they are rarely even carbon neutral and far more economically and environmentally problematic than current proponents want to admit.) To effectively use multiple sources of energy we first need a new up-dated and up-graded national (international?) power grid system capable of taking advantage of multiple types of energy inputs - and their various peculiarities and limits - so they can be essentially "averaged" out over a North American grid system. Anyone observed the US government making any proactive progress on the design and implementation of this new power grid system? When you see an alternative energy compatible power grid infrastructure design being addressed in a serious way - you'll know our government has finally become intelligently aware of the energy crisis and begun to prepare for its solutions. I know, I know - we are far too busy examining our leaders' sex lives, religions, and hair cuts to be side tracked by anything as mundane as our children's (and theirs) ability to live a life at least as good as what we have.

I particularly like (and agree) the comment that addressed the primary cause of most of our problems today - over population. The 800 lb. gorilla in this discussion room is not only population reduction - and its most probable agents, but the extension of the population reduction problem solution - that of a viable economic system. Humans don't have and have never had a working economic system model for static or declining populations. - at least one that doesn't look like the Dark Ages - it's ignorance, plagues, quite literal warts and all. All successful economic systems to date - require population growth for success. Given the total lack of foresight by world leadership - it will interesting to see when an if the necessary actions come to address all of these problems and if they will be 11th hour - or 13th. Another problem with ponderous species populations - they get in their own way in critical survival events.

[reidhb]

I think underwater currents through the english channel are consistant and powerful enough to power small diameter turbines for plenty of kilowatts, and if all of the alternative sources were applied for at the same time (wind, wave, tide, and current) there would be plenty of power for peak hour surge demands.

[litesong]

To anyone worried about drag force on the earth:

If ten thousand 10 MW tidal machines operated at continual maximum output in our oceans, they would increase the drag of our oceans on the rotation of the earth by only 1 part in 1,000,000.