Growing up in Pembrokeshire, surfing was simply something my mates and I did.
Most weeks we’d throw the boards in the car, head for one of the beaches and spend a few hours getting thrown around by the Atlantic.
Well…
I say surfing.
At six foot four and built more like a radio mast than a surfer, I was never particularly good at it.
Standing up for more than a few seconds always seemed to be optional.
What I did gain, however, was a healthy respect for the sea.
A wave that looks harmless from the beach suddenly feels very different when you’re sitting out beyond the break waiting for it to arrive.
The sea isn’t just water.
It’s energy.
Enormous amounts of it.
That got me thinking.
If the ocean contains this much energy, why aren’t we generating huge amounts of electricity from it?
The answer, as I discovered, is that wave power isn’t really an energy problem.
It’s an engineering problem.
The misconception
Most people assume wave power should be easy.
After all…
The waves arrive for free.
The fuel never runs out.
The ocean is already moving.
Just drop a generator into the sea and let nature do the work.
If only it were that simple.
The very thing that makes waves attractive as an energy source is also what makes them incredibly difficult to exploit.
The ocean is one of the harshest engineering environments on Earth.
Everything corrodes.
Everything moves.
Everything gets battered.
Eventually…
Almost everything breaks.
Where does the energy actually come from?
One thing that surprised me while researching this was that wave power isn’t really powered by the sea.
It’s powered by the wind.
Storms transfer energy into the ocean surface.
Once that energy has entered the water, it can travel across entire oceans.
The water itself barely travels.
The energy does.
A storm forming hundreds or even thousands of miles out in the North Atlantic can send wave energy all the way to the Pembrokeshire coastline days later.
The waves I spent my weekends unsuccessfully trying to surf were carrying energy generated by weather systems I’d never seen.
In a strange way, wave power is really delayed wind power.
Harvesting the waves
Over the past fifty years, engineers have developed dozens of different approaches to capturing wave energy.
Some devices float on the surface.
Some are anchored to the seabed.
Some sit on the shoreline.
Others are almost completely submerged.
Common concepts include:
- Point absorbers that bob up and down
- Oscillating water columns that use compressed air to drive turbines
- Hinged floating devices that flex with the waves
- Overtopping systems that capture seawater above sea level before releasing it through turbines
Every design is attempting to solve exactly the same problem.
Convert irregular, constantly changing wave motion into smooth, reliable electricity.
That turns out to be remarkably difficult.
The hidden supply chain
Unlike coal, gas or biomass, wave power doesn’t really have a fuel supply chain.
The energy arrives naturally.
Instead, the supply chain revolves around manufacturing and maintenance.
It depends upon:
- Marine engineers
- Offshore construction companies
- Steel fabricators
- Specialist mooring manufacturers
- Cable installation vessels
- Diving teams
- Survey vessels
- Electrical engineers
- Offshore maintenance crews
The fuel is free.
Keeping the machinery alive is where the money gets spent.
Insurance and operational risk
From an insurance perspective, wave power is one of the most fascinating renewable technologies.
Every major risk comes from the same place.
The sea.
Storm damage
Wave energy converters spend their entire lives being battered by the environment they depend upon.
They must survive:
- Atlantic winter storms
- Rogue waves
- Floating debris
- Constant cyclic loading
- Saltwater spray
- Marine impacts
Ironically, the conditions producing the greatest amount of electricity are often the same conditions most likely to damage the equipment.
Corrosion
Saltwater is relentless.
Steel corrodes.
Bearings wear.
Electrical connections degrade.
Protective coatings slowly fail.
Every year spent offshore increases maintenance requirements.
Marine engineering has always been a battle against corrosion.
Wave power is no exception.
Fatigue
One thing people rarely consider is fatigue.
Unlike a bridge experiencing occasional heavy traffic, a wave energy device never really stops moving.
Every wave applies another loading cycle.
Thousands every day.
Millions every year.
Eventually, microscopic cracks begin forming in metal components.
Managing fatigue becomes just as important as managing strength.
Access
Repairing offshore equipment sounds simple.
Until the weather turns.
Engineers can only safely access many installations during suitable weather windows.
A relatively small fault may have to wait days—or even weeks—for sea conditions to improve.
During that time…
The equipment generates no electricity.
Technology risk
Perhaps the biggest commercial challenge is that nobody has yet produced the definitive wave power design.
Unlike wind turbines, which have gradually converged on a similar appearance, wave energy remains full of competing concepts.
Floating systems.
Submerged systems.
Articulated systems.
Shore-based systems.
That creates an unusual investment risk.
Build today’s technology…
Only for somebody else to produce a dramatically better design five years later.
Why hasn’t wave power taken off?
This was probably the biggest question I had.
The resource is enormous.
The fuel is free.
The coastline isn’t going anywhere.
So why don’t we see wave farms everywhere?
The answer seems to come down to economics.
Generating electricity isn’t the difficult part.
Generating it reliably…
For decades…
While surviving some of the most hostile conditions on Earth…
At a price that competes with wind and solar…
That’s the difficult part.
Many prototypes have successfully generated electricity.
Far fewer have generated profit.
The strategic lesson
Thinking back, I probably learned more about wave power while repeatedly falling off a surfboard than I realised at the time.
The Atlantic has an incredible amount of energy.
Anyone who’s spent time in the water knows that.
The challenge has never been finding the resource.
It’s building machinery capable of surviving it.
Sometimes renewable energy isn’t limited by nature.
Sometimes it’s limited by our ability to engineer something tough enough to work alongside it for the next thirty years.
Gareth Winterman