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Tidal Lagoon Swansea Bay: the mastering of the tide



Utterly predictable and with huge potential, could tidal lagoons provide the impetus that UK marine renewables need to thrive?

This article originally appeared in Blue & Green Tomorrow’s Guide to Sustainable Clean Energy 2014.

At Swansea Bay, there are sandy beaches, surfers and dog walkers. Sometimes, porpoises glide through the surf. Once, there were oysters. In a former life, the bay was the hub of a booming Victorian-era oyster fishing industry, but the molluscs were fished until there were no more.

But most of all, there is the tide. Swansea Bay has one of the highest tidal ranges in the world, with a maximum range of around 10 metres. It is why the bay, sitting on the upper reaches of the Bristol Channel, has been chosen as the site of an unprecedented renewable energy development.

The £850m Swansea Bay Tidal Lagoon, now in a phase of public examination, will be the world’s first tidal lagoon power plant. These plants are quite simply a manmade enclosure of the sea. In Swansea’s case, a six-mile horseshoe shaped sea wall will enclose 11.5 sq km of water, between the estuaries of the river Tawe and the river Neath.

One section of the wall will house submerged hydroturbines. As the tide comes in, the lagoon fills, and releases the water through the turbines, which turn and generate electricity. As the tide starts to ebb, the lagoon is emptied, again driving the turbines.  The lagoon would predictably produce power in four periods each day, totalling 14 hours of generation in every 24.

Swansea Bay is expected to generate 495 gigawatt hours (GWh) of clean, green electricity for every year of its 120-year lifetime. That is enough for 155,000 homes – or about 11% of Wales’ domestic use.

Tidal Lagoon Power Limited, the firm hoping to bring this pioneering technology into the world, hopes to follow Swansea Bay with five more full-scale tidal power plants on Britain’s coasts within the next decade. 

The firm believes this new wave of renewables could meet 5-10% of the entire country’s electricity demand at a relatively low cost.

A recent report from Pӧyry Management Consulting concluded that a series of three lagoons, including Swansea, would have a weighted average contract for difference strike price of £111 per megawatt hour (MWh). This compares to the £155 per MWh currently offered to offshore wind projects.

However, as development director Eva Bishop explains, the potential advantages don’t end there. “One of the fundamental advantages is that there is no guesswork. We know that the tides are going to happen. You don’t need the sun to shine or the wind to blow”, she says.

“Although it’s not baseload, it is an entirely predictable, reliable supply – so the National Grid can take that into account.”

The technology is reliable, too. Though the method is new, the component parts are all proven. “The wall has been used in construction around the world, the hydroturbines have been in use for decades. As far as investors or the general public are concerned, it is lower risk than some other technologies”, Bishop adds.

Then there is the speed of construction. If all goes well in the examination stage, Tidal Lagoon Power hopes that the Swansea Bay plant will be operational by 2018. With five more penciled in within a decade, the speed of delivery for such a large-scale renewable project is remarkable. Most of the fleet could be completed before any new nuclear plant powers a single lightbulb. 

But it is with Tidal Lagoon Power’s plans for Swansea that, Bishop says, it gets exciting: “The Swansea Bay lagoon will be much more than a power plant. We’re going to provide a unique amenity to the people of Swansea Bay. For starters, they’ll be able to walk, run and cycle around the seawall and participate in water sports in the lagoon. We’ll be building a visitor centre and hosting international sporting and cultural events, attracting 100,000 tourists per year.” 

It’s been suggested the lagoon could provide a huge boost to the local economy in an area hit hard by the recession. 

An independent report from the Cardiff Business School estimates that the project will directly invest close to £300m of regional spending spread over its three-year development period, while creating the equivalent of around 1,850 full-time jobs.

An education programme is also already underway, engaging with students from primary school to university, hoping to build a passion for their seafront and inspire new renewable energy enthusiasts.

Of course there are concerns, as well there would be when a company wishes to build a six-mile wall in the sea. Though consultation work reveals that the project has over 85% of local support, some fear the environmental impact. Construction is subject to an extensive environmental assessment, and must accommodate the surfers and the porpoises.

The project has the blessing of numerous environmental groups, however, including Friends of the Earth Cymru and the RSPB. Bishop hopes that, through partnerships with various organisations, including Swansea University, the lagoon can make a positive contribution to the bay’s ecology.

The oysters may even be returning, symbolically – the offshore visitor centre will take the form of a 3,500 sq metre shell – and perhaps literally. Almost a century after they disappeared, plans are afoot to reintroduce the missing moluscs. 

“We hope that in time the wall will be used as an artificial reef structure. We hope to see colonisation of the marine wall structure, as a rocky habitat which could support various species”, Bishop adds. 

There is a way to go yet. There are assessments to pass, a minority of locals yet to convince, and the small matter of building the thing. But if Swansea Bay can achieve each of its ambitious aims and generate growth, jobs, biodiversity and local pride alongside limitless clean energy, its impact could be huge.

“I think tidal lagoons have an enormous role to play in transforming the public perception of what renewable energy can achieve”, Bishop says. 

“When you deliver renewable energy at scale, with reliability, low costs and a positive local impact and with the ability to supply up to 10% of the UK’s electricity, you start to show that we do have the capacity to deliver on our low-carbon goals. 

“We want to make renewable energy an accepted technology and an accepted option. I think that tidal lagoons certainly have the ability to do that.”

Photos: Tidal Lagoon Power  

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Further reading:

Tidal lagoon renewable energy plants could add £27bn to UK economy

Good Energy invests in Swansea Bay Tidal Lagoon

Swansea Bay Tidal Lagoon plans accepted for consideration

Renewable energy accounted for 15% of UK electricity in 2013

The Guide to Sustainable Clean Energy 2014



Will Self-Driving Cars Be Better for the Environment?



self-driving cars for green environment
Shutterstock Licensed Photo - By Zapp2Photo |

Technologists, engineers, lawmakers, and the general public have been excitedly debating about the merits of self-driving cars for the past several years, as companies like Waymo and Uber race to get the first fully autonomous vehicles on the market. Largely, the concerns have been about safety and ethics; is a self-driving car really capable of eliminating the human errors responsible for the majority of vehicular accidents? And if so, who’s responsible for programming life-or-death decisions, and who’s held liable in the event of an accident?

But while these questions continue being debated, protecting people on an individual level, it’s worth posing a different question: how will self-driving cars impact the environment?

The Big Picture

The Department of Energy attempted to answer this question in clear terms, using scientific research and existing data sets to project the short-term and long-term environmental impact that self-driving vehicles could have. Its findings? The emergence of self-driving vehicles could essentially go either way; it could reduce energy consumption in transportation by as much as 90 percent, or increase it by more than 200 percent.

That’s a margin of error so wide it might as well be a total guess, but there are too many unknown variables to form a solid conclusion. There are many ways autonomous vehicles could influence our energy consumption and environmental impact, and they could go well or poorly, depending on how they’re adopted.

Driver Reduction?

One of the big selling points of autonomous vehicles is their capacity to reduce the total number of vehicles—and human drivers—on the road. If you’re able to carpool to work in a self-driving vehicle, or rely on autonomous public transportation, you’ll spend far less time, money, and energy on your own car. The convenience and efficiency of autonomous vehicles would therefore reduce the total miles driven, and significantly reduce carbon emissions.

There’s a flip side to this argument, however. If autonomous vehicles are far more convenient and less expensive than previous means of travel, it could be an incentive for people to travel more frequently, or drive to more destinations they’d otherwise avoid. In this case, the total miles driven could actually increase with the rise of self-driving cars.

As an added consideration, the increase or decrease in drivers on the road could result in more or fewer vehicle collisions, respectively—especially in the early days of autonomous vehicle adoption, when so many human drivers are still on the road. Car accident injury cases, therefore, would become far more complicated, and the roads could be temporarily less safe.


Deadheading is a term used in trucking and ridesharing to refer to miles driven with an empty load. Assume for a moment that there’s a fleet of self-driving vehicles available to pick people up and carry them to their destinations. It’s a convenient service, but by necessity, these vehicles will spend at least some of their time driving without passengers, whether it’s spent waiting to pick someone up or en route to their location. The increase in miles from deadheading could nullify the potential benefits of people driving fewer total miles, or add to the damage done by their increased mileage.

Make and Model of Car

Much will also depend on the types of cars equipped to be self-driving. For example, Waymo recently launched a wave of self-driving hybrid minivans, capable of getting far better mileage than a gas-only vehicle. If the majority of self-driving cars are electric or hybrids, the environmental impact will be much lower than if they’re converted from existing vehicles. Good emissions ratings are also important here.

On the other hand, the increased demand for autonomous vehicles could put more pressure on factory production, and make older cars obsolete. In that case, the gas mileage savings could be counteracted by the increased environmental impact of factory production.

The Bottom Line

Right now, there are too many unanswered questions to make a confident determination whether self-driving vehicles will help or harm the environment. Will we start driving more, or less? How will they handle dead time? What kind of models are going to be on the road?

Engineers and the general public are in complete control of how this develops in the near future. Hopefully, we’ll be able to see all the safety benefits of having autonomous vehicles on the road, but without any of the extra environmental impact to deal with.

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New Zealand to Switch to Fully Renewable Energy by 2035



renewable energy policy
Shutterstock Licensed Photo - By Eviart /

New Zealand’s prime minister-elect Jacinda Ardern is already taking steps towards reducing the country’s carbon footprint. She signed a coalition deal with NZ First in October, aiming to generate 100% of the country’s energy from renewable sources by 2035.

New Zealand is already one of the greenest countries in the world, sourcing over 80% of its energy for its 4.7 million people from renewable resources like hydroelectric, geothermal and wind. The majority of its electricity comes from hydro-power, which generated 60% of the country’s energy in 2016. Last winter, renewable generation peaked at 93%.

Now, Ardern is taking on the challenge of eliminating New Zealand’s remaining use of fossil fuels. One of the biggest obstacles will be filling in the gap left by hydropower sources during dry conditions. When lake levels drop, the country relies on gas and coal to provide energy. Eliminating fossil fuels will require finding an alternative source to avoid spikes in energy costs during droughts.

Business NZ’s executive director John Carnegie told Bloomberg he believes Ardern needs to balance her goals with affordability, stating, “It’s completely appropriate to have a focus on reducing carbon emissions, but there needs to be an open and transparent public conversation about the policies and how they are delivered.”

The coalition deal outlined a few steps towards achieving this, including investing more in solar, which currently only provides 0.1% of the country’s energy. Ardern’s plans also include switching the electricity grid to renewable energy, investing more funds into rail transport, and switching all government vehicles to green fuel within a decade.

Zero net emissions by 2050

Beyond powering the country’s electricity grid with 100% green energy, Ardern also wants to reach zero net emissions by 2050. This ambitious goal is very much in line with her focus on climate change throughout the course of her campaign. Environmental issues were one of her top priorities from the start, which increased her appeal with young voters and helped her become one of the youngest world leaders at only 37.

Reaching zero net emissions would require overcoming challenging issues like eliminating fossil fuels in vehicles. Ardern hasn’t outlined a plan for reaching this goal, but has suggested creating an independent commission to aid in the transition to a lower carbon economy.

She also set a goal of doubling the number of trees the country plants per year to 100 million, a goal she says is “absolutely achievable” using land that is marginal for farming animals.

Greenpeace New Zealand climate and energy campaigner Amanda Larsson believes that phasing out fossil fuels should be a priority for the new prime minister. She says that in order to reach zero net emissions, Ardern “must prioritize closing down coal, putting a moratorium on new fossil fuel plants, building more wind infrastructure, and opening the playing field for household and community solar.”

A worldwide shift to renewable energy

Addressing climate change is becoming more of a priority around the world and many governments are assessing how they can reduce their reliance on fossil fuels and switch to environmentally-friendly energy sources. Sustainable energy is becoming an increasingly profitable industry, giving companies more of an incentive to invest.

Ardern isn’t alone in her climate concerns, as other prominent world leaders like Justin Trudeau and Emmanuel Macron have made renewable energy a focus of their campaigns. She isn’t the first to set ambitious goals, either. Sweden and Norway share New Zealand’s goal of net zero emissions by 2045 and 2030, respectively.

Scotland already sources more than half of its electricity from renewable sources and aims to fully transition by 2020, while France announced plans in September to stop fossil fuel production by 2040. This would make it the first country to do so, and the first to end the sale of gasoline and diesel vehicles.

Many parts of the world still rely heavily on coal, but if these countries are successful in phasing out fossil fuels and transitioning to renewable resources, it could serve as a turning point. As other world leaders see that switching to sustainable energy is possible – and profitable – it could be the start of a worldwide shift towards environmentally-friendly energy.


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