Author: Miriam Noonan, analysis and insights manager, Offshore Renewable Energy (ORE) Catapult
Offshore wind has proven to be a very wise investment for the future of our planet. It is now a key pillar of UK energy policy and is leading the way in the energy transition. With this successfully mobilised, many investors are now looking for ‘the next big thing’ in renewables. One of the foremost candidates is tidal stream power.
Orbital Marine Power – O2
The Interreg-part funded €45.4m Tidal Stream Industry Energiser Project (TIGER), which is actively supporting the design, consenting and installation to kick start up to 30MW of tidal stream capacity is providing hard evidence for the viability and future profitability of this new sector.
Tidal stream technologies are well developed and validated, and the UK has a powerful first-mover advantage. The biggest names in tidal stream development are all UK based – Nova Innovation, Orbital Marine Energy and SIMEC Atlantis, to name but a few.
In 2018, we forecast that by 2030 tidal stream could yield a cumulative benefit to the UK of £1.4 billion and support almost 4,000 jobs, rising to 14,500 jobs by 2040.  However without the interim public revenue support required by any new technology to achieve commercialisation, this UK benefit could slip away.
SIMEC Atlantis AR1500
We have the technical expertise within the UK to make this happen, we have the perfect geographic setting in which it can work, but the sector cannot get to market without the same government foresight and investment confidence afforded to wind, solar and nuclear energy.
The UK Government’s clean growth strategy sets out three tests to assess the viability of new forms of renewable energy, focusing on cost, the potential for the UK to lead the global market and impact on carbon emissions.
As the UK’s leading technology innovation and research centre for offshore renewable energy, we have found the answer to be resoundingly positive for every test.
- UK tidal stream energy is already comparable with imported diesel and with sufficient deployment capacity by 1GW deployed worldwide is on track to be cheaper than nuclear power (at £90/MWh once we reach 1GW deployed capacity) and possibly competitive with fossil fuels in the longer term.
- Our potential to lead is clear given the concentration of tidal pioneers in the UK and the natural resource we have. Just by deploying current technologies in 30 key sites, tidal stream could supply 6GW of power (enough to power almost 5.6 million homes). 
- And when it comes to carbon reduction, marine energy technologies have the potential to reduce national emissions permanently by up to four million metric tonnes within 20 years.
EMEC Fall of Warness tidal test site
What makes the case for tidal stream energy yet more compelling is its predictable nature. Wind and solar power are driving us towards our net-zero targets at an incredible pace, but they are not entirely predictable. When the wind blows or the sun shines is dependent upon the vagaries of the weather, but the tides work to schedule. Tidal stream can be a complementary technology to wind and solar that will help balance the flow of power to the grid. But there remains scepticism about the reliability of tidal and the sectors ability to reduce costs.
Impressive tidal stream technologies, such as those used by Meygen and Orbital Marine Power in Scotland and those developed by Nova Innovation in Shetland, the world’s first grid-connected tidal stream array, have demonstrated incredible performance. These projects have also far exceeded offshore wind’s UK supply chain content target of 60%: Nova Innovation and Orbital Marine Power  have both achieved more than 80% UK content for site construction in their most recent installations. Nova Innovation have gone on to retain 98% UK content in their operational supply chain.
All new technologies need “Launch Aid” to support early deployments and provide investor confidence for them to operate in a commercial market. Tidal Energy is no exception. Private sector investment in tidal has stalled leaving 120GW of new tidal capacity hanging in the balance pending clarity on future Government support in the Next Contracts for Difference auction round AR4 at the end of 2021 Many developers do need that final investment push to get them over the line to enable full-scale deployment.
A government energy subsidy auction round – AR4 – is due to open in December 2021. Offshore wind will be moved into its own pot, which is welcomed, but tidal stream energy still needs preferential treatment initially to enable it to successfully flourish. The strike price will need to be high, reflecting the new and emerging technology, but as our data shows, and evidenced by the cost reduction blueprint legacy from offshore wind that confidence now will reap rewards in the longer term.
We need to back this up with more frequent auction rounds, and we should consider new innovative methods of investment such as the Marine Energy Council’s proposed Innovation Power Purchase Agreement (IPPA), which takes the resulting short term high premium on strike prices away from consumer bills.
With appropriate Launch Aid, costs of tidal stream energy could drop to below £90/MWh with the first 1GW of deployment, and we could realise a £25bn UK export opportunity.  Beyond this, we have the potential to follow in the footsteps of offshore wind which delivered projects at £125/MWh after the first 2.5GW of deployment.  Long term, offshore wind will continue to dominate the picture in terms of affordability, but tidal stream can compete with the cost of UK nuclear power and provide similar reliability and predictability.
Tidal stream energy is on the launch pad, ready to become a key component of a cost-effective Net Zero economy as well as a driver of economic recovery and growth in regions of the UK which could benefit the most.
 Source: https://committees.parliament.uk/writtenevidence/19220/pdf/ – the calculation assumes 6GW of tidal at 40% capacity factor and a UK average home requiring 3.7MWh/yr.