Renewable Energy Focus is proud to be the official "Innovation in wind technology" media partner for this year's All-Energy event in Aberdeen, taking place on 23-24 May. The All-Energy Exhibition & Conference is the UK's largest renewables event devoted to all forms of clean and renewable energy. It is being held at an important time as the UK continues to assume a dominant role in the offshore wind sector and many companies look to the immense supply chain opportunities this brings.
Potential and policy
Calculations from the UK's Carbon Trust show that building an offshore grid could reduce costs by 25% for offshore wind in the long-term. At the same time, in order to accommodate the expected 40 GW of offshore wind in the North Sea region by 2020 and beyond, grid investments of €11-€28 billion are needed (source – European Wind Energy Association, EWEA).
But technology is not the only challenge (see part 1 of this article) – policies, ownership and cross-border co-operation make up a Gordian knot.
Elisabeth Harstad, managing director of DNV says, “what makes [connecting offshore wind in a grid] so complicated is that it requires a combination of technology and politics – and not just politics in one country, but across borders.”
She believes a major challenge is to stop thinking of electrical grids as national infrastructure. An offshore grid serves several political purposes: reliability of electricity supply; market integration; contributing to a single European electricity market, and integrating large amounts of renewables. The U.S. has already started looking at the possibilities for an offshore supergrid on its Atlantic coast, but to build an offshore grid in the North Sea has the added challenge of international politics. “Europe consists of many States that have to cooperate to achieve something here – and that's quite a challenge,” Harstad adds.
One question is who would be the owner and operator of a North Sea offshore grid. Eriksson says one model could be to have a North Sea Grid ‘entity’ operate the grid, owned and financed by the countries around the North Sea. Another possibility would be an EU ‘entity’. But no matter what model is decided upon, this is not something that will happen overnight.
Another challenge has to do with maritime spatial planning, where offshore wind is caught between conflicting uses and rules from different sectors and jurisdictions. In addition, regulations and conditions for the connection of renewable plants are different.
There are different types of support mechanism as well, as varying levels of state support exist for offshore wind in the respective countries. And these differences between national support schemes may hamper the development of offshore grids, as countries do not want their own support schemes to ‘leak’ i.e. support the generation of renewable power abroad, and support other countries' renewable energy targets.
Offshore grids underline a need to either harmonise incentive schemes on an EU level, which is unlikely to ever happen, or for some kind of agreement to facilitate the cross-border transport of electricity.
One way to overcome these challenges is to look at the reliability and robustness of offshore systems, Eriksson believes. DNV itself recently entered an agreement with the Swedish Transmission Research Institute (STRI), a specialist consultancy for accredited testing and advanced studies of high voltage power transmission systems. Eriksson says combining STRI's knowledge with DNV's expertise in offshore installations (amalgamated since oil was found in the North Sea) can lead to solutions: “By combining the two competencies, we can contribute to setting new, smart demands on what is needed to develop the technology, and how to make it robust and reliable enough to generate large amounts of electricity offshore.”
The first results are expected to be ready next year, with methods for assessing the reliability of offshore electric grids.
As has been heard at numerous offshore wind conferences too, both Eriksson and Harstad believe there are benefits to be had from teaming the wind industry up with the offshore oil and gas sector - in terms of leveraging expertise, experience and knowledge. Harstad says: “The developing offshore wind market is becoming a very exciting market. We have some players with onshore experience with wind, and some players with offshore experience from oil and gas, but there are perhaps not that many that have both”.
And she adds, “it is so large and complex that it is hard to achieve anything with just one type of competence. When grids are going offshore, it could be good to have competencies within grid and offshore experience – like offshore cabling, offshore installations and reliability studies offshore.”
The long and windy road
Eriksson sums up the challenges facing a North Sea offshore supergrid: “There is a real technology challenge in how to make a HVDC circuit breaker. Then there are challenges in the form of policy – how should the grid be owned and operated; and how do you handle the production of electricity under different support regimes, and then send it to a country with a different support regime?
“Time is also running too quickly – a lot of wind is being built now, which is good, but there are no standards for a master plan, or a master specification for how to connect it all. The more is being built, the less is the likelihood that we can reach a solution where we can connect it all – and then electricity will become more expensive, as you cannot reap the benefits of building a grid rather than connecting each installation individually to the respective countries.”
DNV and offshore wind
- DNV has been involved in onshore wind since the 1980s – primarily in Denmark - and the company has followed the industry offshore. DNV already has extensive offshore experience through North Sea oil & gas
- Around 50% of all offshore wind farms in the North Sea have been approved by DNV;
- DNV has developed standards for offshore wind equipment, floating structures and service vessels;
DNV is currently looking at the development of specifications for floating offshore wind structures.
DNV's Technology Outlook 2020
Earlier this year, DNV published its Technology Outlook 2020, which looks at technology trends for this decade, and includes renewable energy and transmission grids.
Key findings include:
- The era of ‘cheap oil’ is coming to an end, but oil, gas and coal will still cover around 80% of global energy supply by 2020;
- New grid solutions and energy storage will be essential elements in future power systems;
- Managing variable power generation from renewable energy will be the key challenge for many power systems in 2020;
- Wind could provide 8% of global electricity production in 2020;
- Offshore wind will be developed further and further from the shore, in deeper waters;
The key enabler for multi-terminal DC networks is a DC circuit breaker.
About the author: Kari Williamson is a freelance journalist specialising in renewable energy. She is the former Assistant Editor at Renewable Energy Focus and Renewable Energy Focus U.S.