The world needs renewables that scale and produce dependable, valuable energy at acceptable cost.

The key to expanding the development of offshore wind energy is bringing down development and operating costs. This would spur innovation and expand the market for off-shore wind, but how do we get there?

Offshore wind must either provide significantly cheaper energy or overcome intermittency issues in order to preserve the value of the power it generates. Both options present significant challenges, but new innovations for these are evolving, so how can developers and investors best navigate risks in this market?

Storage makes renewables viable

Storage will become an essential component of more electricity grids as the proportion of energy from renewables rises. Once a grid is depending on renewables for 30-40% of its power, the intermittency issue becomes a threat to supply. 

There are different options for storing offshore wind energy, some more cost effective than others. It could be done on a development-by-development basis, with storage at each wind farm that it could use to even out peaks and troughs in generation. Wind turbines are now available with small, integrated storage that can help even out generation in gusty winds, for example.

Alternatively, third parties could enter the market, getting paid to supply storage as a service to manage intermittent sources – including wind – and supply energy on demand. With spot prices for wind near zero at certain times of day, there’s a clear opportunity to store energy and sell it when prices are higher. 

In emerging markets such as the USA, it’s vital developers and grid operators keep an open-mind about the offshore wind business model. The challenges are real, but the potential for cost effective renewable power is there and it’s increasingly achievable.

Cameron Dunn

Associate Principal, Americas South Operations Director, Arup

Designing down the costs

How else can the costs of offshore wind be reduced? Bigger turbines are one option – enabling the same power from fewer turbines whilst reducing the associated infrastructure. Offshore turbines have now reached 12MW, but how big is too big? Larger turbines are more challenging to install which pushes up the costs and there’s already talk about a new generation of installation vessels to cope, so the industry should look elsewhere for cost efficiencies.

The focus has moved to the design of foundations. Monopiles have proven their worth, but bigger turbines in deeper water push the limits of this technology. The European market has looked to jackets – truss structures with piling – as a solution but has so far struggled to deliver them on time or on budget. In the long term, floating turbines may be the answer and encourage innovation but in the meantime the industry must commit to jackets and refine their fabrication to reduce cost, risk and schedule.

Sizing up substations

The cost of substations could be reduced through new structural approaches. Currently, substations typically weigh more than 2,000 tonnes – more than a turbine-installation vessel can lift – so they need specialist heavy-lift vessels. While these aren’t usually expensive, they are in short supply in the US market. Smart design of infrastructure can reduce the size of substations and make them self-installing, enabling significant cost reduction. 

Then there’s the issue of who owns the substations. In the mature European market, it is utility companies, leaving wind farm developers to concentrate on the turbines. Emerging markets such as the USA, Japan or Taiwan face a choice between this approach or asking developers to take all the risk and build not only the turbines, but also the substations and other infrastructure needed to get the electricity to shore. A clear approach to substation development from the outset of a programme can make distribution of generated power less complex. Establishing a strong relationship with local network operators is key to this and can untimely reduce risk and cost.

Realising the potential

It’s not impossible to overcome the sector’s current challenges, but the earlier decisions are made – such as opting for substations that require heavy-lift vessels – will ultimately have a big impact on costs and viability. By keeping technical innovation at the heart of a proposed development, costs can be lowered and the true commercial potential of offshore wind can be realised.

It’s essential to look at offshore wind development  as one entire programme rather than split into segments, with a trusted and experienced supply chain to support the development. In an emerging market, costs can escalate and risk can be heightened, but by having the right experts on board the risks and cost implications can be successfully navigated.