May 17, 2020

Tidal Energy Slowed by ROCs

2 min
Tidal power struggles to be an economical energy option, relying on Renewable Obligations Certificates (ROCs) in the UK
TO ENHANCE YOUR READING EXPERIENCE, VIEW THIS ARTICLE IN OUR INTERACTIVE READER! Written by Jonah Heller Unlike many elements of the natural world, tid...


Written by Jonah Heller

Unlike many elements of the natural world, tidal fluctuation occurs twice everyday, with almost clocklike precision. But capturing the highly predictable ebb and flow of tides as a renewable energy source is not quite as simple.

Similar to hydroelectric power, tidal energy is captured as water flows across a fence or dam, which spins a turbine, generating electricity.

One setback is that tidal flow isn't continuous, and goes to zero while transitioning between high and low tides. Therefore the potential power generated from tide dams is estimated to be less than half that of river dams, while the costs are almost identical.

The moon, gravitational fields, and pure economics dictate that only absolutely ideal locations be developed with this type of sustainable technology. Additionally, the Department of Energy has claims that only 40 such locations exist on earth.


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In comparison to other renewable energy sources, tidal energy is relatively expensive. But Blue Energy of Canada is optimistic they can generate electricity at rates less than $0.05 per kWh, putting them in competition with traditional power companies.

In other parts of the globe companies are slightly less hopeful. The United Kingdom for example, where the probability of building a large scale tidal energy facility is very much dependent on Renewable Obligation Certificates or ROC's.

At the moment the future of renewable energy and ROC's in the UK is unclear. David Robinson CEO of PD Ports Group based in the UK has said “There is a major reluctance to invest in this sector until the government sets the level for ROC's which will determine what proportion of their power that UK electricity suppliers must generate from renewable resources”. Until that time, projects are likely to sit on hold.

Peel Energy, a UK development group headquartered has been planning to install a tidal power system in the Mersey Estuary (near Liverpool) since 2005. But with a £3.5 billion ($5.63 billion) price tag, the project is currently stalled and unlikely to move forward without an increased subsidy.

Unfortunately, it looks like the tide could be going out for this renewable energy source, but only time will tell.


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Jul 30, 2021

Major move forward for UK’s nascent marine energy sector

3 min
The UK’s nascent marine energy sector starts exporting electricity to the grid as the most powerful tidal turbine in the world begins to generate power

Although the industry is small and the technologies are limited, marine-based energy systems look to be taking off as “the world’s most powerful tidal turbine” begins grid-connected power generation at the European Marine Energy Centre

At around 74 metres long, the turbine single-handedly holds the potential to supply the annual electricity demand to approximately 2,000 homes within the UK and offset 2,200 tonnes of CO2 per year.

Orbital Marine Power, a privately held Scottish-based company, announced the turbine is set to operate for around 15 years in the waters surrounding Orkney, Scotland, where the 2-megawatt O2 turbine weighing around 680 metric tons will be linked to a local on-land electricity network via a subsea cable. 

How optimistic is the outlook for the UK’s turbine bid?

Described as a “major milestone for O2” by CEO of Orbital Marine Power Andrew Scott, the turbine will also supply additional power to generate ‘green hydrogen’ through the use of a land-based electrolyser in the hopes it will demonstrate the “decarbonisation of wider energy requirements.” 

“Our vision is that this project is the trigger to the harnessing of tidal stream resources around the world to play a role in tackling climate change whilst creating a new, low-carbon industrial sector,” says Scott in a statement. 

The Scottish Government has awarded £3.4 million through the Saltire Tidal Energy Challenge Fund to support the project’s construction, while public lenders also contributed to the financial requirements of the tidal turbine through the ethical investment platform Abundance Investment.

“The deployment of Orbital Marine Power’s O2, the world’s most powerful tidal turbine, is a proud moment for Scotland and a significant milestone in our journey to net zero,” says Michael Matheson, the Cabinet Secretary for Net-Zero, Energy and Transport for the Scottish Government. 

“With our abundant natural resources, expertise and ambition, Scotland is ideally placed to harness the enormous global market for marine energy whilst helping deliver a net-zero economy.

“That’s why the Scottish Government has consistently supported the marine energy sector for over 10 years.”

However, Orbital Marine CEO Scott believes there’s potential to commercialise the technology being used in the project with the prospect of working towards more efficient and advanced marine energy projects in the future. 

We believe pioneering our vision in the UK can deliver on a broad spectrum of political initiatives across net-zero, levelling up and building back better at the same time as demonstrating global leadership in the area of low carbon innovation that is essential to creating a more sustainable future for the generations to come.” 

The UK’s growing marine energy endeavours

This latest tidal turbine project isn’t a first for marine energy in the UK. The Port of London Authority permitted the River Thames to become a temporary home for trials into tidal energy technology and, more recently, a research project spanning the course of a year is set to focus on the potential tidal, wave, and floating wind technology holds for the future efficiency of renewable energy. The research is due to take place off of the Southwest coast of England on the Isles of Scilly

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