Humanity has never faced a more monumental challenge.

After two centuries of burning fossil carbon, trashing the atmosphere, pushing Earth systems to the brink of collapse, industrial societies desperately need to develop other sources of energy that are renewable and clean — and quickly. The prospects are frightening.

But climate angst has an antidote: tested, renewable technologies of all sorts. Wind and solar come immediately to mind.

There’s another vast energy storehouse on half the world’s doorstep — Earth’s oceans. Covering three quarters of the planet’s surface, they store colossal volumes of heat, that can be tapped.

So can the energy from ocean waves and tides. This past week, in the Dutch capital of Den Haag, several hundred entrepreneurs and engineers came together to showcase innovative devices for doing just that, at the annual gathering of Ocean Energy Europe.

Listen to some voices I gathered in today’s podcast. In order of appearance: Alejandro Marques de Magallanes Crespo (Magallanes Renovables), Eunice Silva (CorPower Ocean) and Mike Robinson (PPI Engineering).

Click on the play button above, or go here.

Alejandro Marques de Magallanes Crespo, CEO of Magallanes Renovables (David Kattenburg)

Talking about the energy of ocean tides — rising and falling like clockwork under the influence of the moon — no better place to tap this huge resource than the Shetland Islands, on the northern tip of Scotland, and in the Bay of Fundy, between Nova Scotia and New Brunswick, in eastern Canada, with the highest tides in the world.

That’s what a company called Nova Innovation is doing. Simon Forrest is founder and CEO. In a quiet spot on the margins of last week’s Ocean Energy Europe conference, in The Hague, Simon and I sat down for a chat.

Petit Passage, on the Bay of Fundy, where a Nova turbine will soon generate tidal energy

Conferences are fun. Lots of interesting people to meet and sessions to attend.

Better still, heading out into the field. Especially if it’s North Holland. That’s where I went, this past Friday, on a bus trip organized by the Dutch Energy From Water Association, together with forty ocean energy innovators from around the world.

Our first stop: Den Helder, at the manufacturing facility of Symphony Wave Power, to see their wave energy demonstrator. Fred Gardner is Symphony’s founder.

Listen to Fred Gardner. Click on the play button above, or go here.

Fred Gardner, CEO of Symphony Wave Power, shows his wave energy converter (David Kattenburg)

Of all the forms of energy readily available to coastal communities around the world, none is more intriguing than salt.

To be more precise, salt gradients. Wherever fresh river water flows into salty ocean, that freshwater gets infused with sodium, calcium, chloride and sulfate ions, and salt gradients form.

Make this happen across a plastic membrane, under controlled conditions, and a voltage is generated. That voltage can be used to generate electricity. Reverse electrodialysis, it’s called.

No better place to see this in action – indeed, the only place in the world – than the Afsluitdijk.

Afsluitdijk

Check it out on a map. It’s that long highway, built on a dike between the Dutch provinces of North Holland and Friesland, separating the freshwater Ijsselmeer from the salty Waddenzee.

Right in the middle of the Afsluitdijk, a company called REDstack is bringing fresh and saltwater together, and putting electricity into the Dutch grid. RED stands for Reverse Electrodialysis.

REDstack electrodialysis membrane stack (David Kattenburg)

Listen to audio from our trip to the REDstack facility. The first voice you’ll hear is Peter Scheijgrond, Chairman of the Dutch Energy From Water Association, our tour leader this past Friday. Then Rik Siebers, REDstack’s Managing Director, and Michael van Oostrom, Head of Market Development.

Click on the play button above, or go here.

REDstack Managing Director Rik Siebers makes ions flow and a little propeller spin (David Kattenburg)

Thanks to Dan Weisenberger for his salty guitar instrumentals.