Archive for July, 2012

Fundy Tidal Power

Saturday, July 28th, 2012

When the first tide-driven turbines were placed in Minas Basin, the tides basically ripped them up within a few weeks. At the north end of the Bay of Fundy, tidal amplitude in the Basin reaches about 15 meters, and the sea moves in and out with the tide at up to 12 knots. These really are astonishing numbers, and you have to see them to believe them.

The Bay of Fundy funnels the tide to ever greater amplitude, reaching 15 meters or more in Minas Basin (yellowmaps.com)

At the mouth of the Bay of Fundy, though, the tides are less, about 6 meters, or 20 feet, and run at only about 4-6 knots, still impressive if you happen to try to navigate the area in a small boat. And there, near Eastport and Lubec, the first commercial-scale tidal-power generator in the US is now being placed.

This one ought to work. The turbine is about 100 feet long, 15 feet high, with long curved foils. Ocean Renewable Power Company is in charge, and a lot of outside investment has made the event happen.

The 98ft turbine sits on the bottom, fastened to a tide resistant supporting framework (pressherald.com)

There are a few ways to bring something new, like a wind farm, or a fish farm, or in this case underwater turbines into a coastal community. The method makes all the difference. It can be done secretly and aggressively, without concern for buy-in from the local community, and most likely it will fail. If it fails, nobody in the community cares.

Or it can be done with the extensive involvement of the local community.

The Eastport community has certainly been involved in the tidal power initiative there. Fishermen have advised on the best sites for placement of the turbines. Local conservationists have been consulted. Where possible, local contractors have been employed. Community officials have been included in making decisions. Restaurants and B&Bs have remained open beyond the usual three month tourist season.

The town of Eastport, Maine is as far east as you can go in the US, lying at the mouth of the Bay of Fundy just across the border from New Brunswick (treehugger.com)

The turbines at Eastport will start to generate power in October. Not much at first, but it’s a start. Over the next few years, more turbines will be added. In time, they should serve the needs of most of the town.

What works for Eastport should work for the many other coastal communities along the Bay of Fundy, and elsewhere around the world where tidal currents run fast enough.

This is not large-scale power generation. But it is community-based, and the community appears to be strongly supportive. It should succeed.

Where coastal communities are involved in all aspects of an initiative, whether it is a fish farm, wind farm, coastal fishery, or tidal-power generation, conflicts are reduced, and success is more likely.

Consultation, inclusion, integrity and transparency are all essential components.

Interesting, isn’t it, that we seem to have learn this lesson over and over again?

Moaning the Blues

Thursday, July 12th, 2012

Blue Whales are in the news just now, with a few feeding off the coast of California and around Sri Lanka where enthused whale watchers can see them. An adult that weighs 200 tons and is 30 meters long, twice the size of the largest dinosaur, is an extraordinary sight, and a rare one.

A Blue whale breaches backwards, exposing the rorqual or expandable folds of its huge throat. This is an iconic picture, a view seen by very few. (binbrain.com)

They were hunted almost to extinction in the 20th Century. In the Southern Ocean, 200-300 thousand of them once fed on the huge schools of krill feeding along the Antarctic ice edge. By the time the International Whaling Commission agreed 1n 1973 on a moratorium on hunting the Great Whales, perhaps 700 were left in the Southern Ocean. That’s very close to the edge.

Though the Southern Ocean population was by far the largest, smaller populations roamed elsewhere. In fact, three subspecies probably exist, varying a little in size at maturity and maximum size, isolated from each other in different oceans. One lives in the North Atlantic and the North Pacific, with 1-2,000 whales in each region, genetically connected by migrants through the Arctic ocean. Another population of about 2000 is the remnant of the slaughter of the last century in the Southern Ocean. The third, known as Pygmy Blue Whales because they only grow to about 24 meters long instead of 30, lives in the Indian Ocean, with somewhere between 2 and 10 thousand individuals.

Close view of the blow hole and bow wave of a Blue Whale (nmfs.noaa)

So some recovery has occurred – about 7% increase overall per year. That sounds pretty good, but remember where they started. The population in the Southern Ocean is currently about 1% of its size before the whalers hunted them, and is still considered ‘Endangered’.

So what lies ahead for the Blue Whales? They turn up where krill become most abundant, even if only temporarily – this is what has brought some this year to the coast of California. An adult Blue needs a lot of food, and may eat about 4 tons of krill (40 million krill!) per day.

Krill are euphausid shrimp that eat phytoplankton, grow to 5-10cm, and prefer cold, upwelling water (sciencepoles.org)

But we are also fishing for more krill in the Antarctic now. As well, as climate change continues to warm parts of the Antarctic, particularly around the West Antarctic Peninsula, krill competitors like salps are doing well. They are too low in food value to nourish whales, or humans for that matter.

A ball or swarm of krill – but imagine one that is several km or miles wide: in ideal conditions along the edge of the Antarctic ice sheet, they once got that big (anniekatek.blogspot.com)

An adult female Blue whale should reproduce every 2-3 years when she is well fed. When she is not, she is unlikely to reproduce at all. When krill supplies are diminished, further population growth of the Blue whales will be very limited.

A female Blue whale with its calf. A calf is 7 meters long at birth, weighs 2700 kg, drinks 400 liters of milk per day, and gains 90 kg per day. (expeditions.com)

Blue whales call when they are not actively feeding. The calls sound like very low, down-sweeping moans, and males probably do all the moaning, trying to attract females, and perhaps warn other males of their presence. We don’t know much about this.

A moan typically lasts about 30 seconds, at a very low frequency of 10-40 Hz. That is really low – we can’t hear anything below 20 Hz, and 40 Hz is still a rumbling base we find barely audible. Such low frequencies travel far in the ocean, but at the same time they can get lost in the background of the noises our ships produce.

Living in such relatively small and dispersed populations, calling to each other in a noisy sea, Blue Whales have a huge challenge of finding one another.

Still, it is tantalizing to think we might again share the oceans with this amazing beast. We are generally attracted to things that are very big and we tolerate other animals that don’t compete directly with us.

Blue Whale of the north Pacific population.

But there isn’t a whole lot left in the sea for us to eat. A large and hungry competitor for that food we want to have instead has is playing a hand it cannot win.

The Age of the Great Whales ended when they were hunted out of all the oceans. Remnant populations may continue to exist. But the Age of Great Whales will not return. We can’t afford it.