The respondents were free to use the baseline values suggested by Berkeley Lab (see table, below), or use their own values.
In the case of onshore wind, their alternative median baseline costs of energy were significantly lower than those suggested by Berkeley Lab: $64/MWh compared with $79/MWh. But for offshore wind the proposed alternative baseline cost of energy was higher than that offered: $189/MWh against $169/MWh.
Although there were some variations in the predictions, the median values suggested onshore wind costs would come down by 10% between 2014 and 2020, by 24% by 2030, and by 35% by 2050. More substantial reductions in offshore wind costs were anticipated: 30% by 2030 and 41% by 2050 for fixed structures; but a more modest 25% by 2030 and 38% by 2050 for floating structures.
The baseline parameters are summarised in the table (above), and the graph (below) shows the trajectories for levelised costs. The baseline value for onshore wind of $79/MWh is expected to fall to $58.5/MWh by 2030 and $50/MWh by 2050.
The baseline value for fixed-structure offshore wind is $171/MWh, which is anticipated to fall to $120/MWh by 2030 and $101/MWh by 2050. Floating structures deliver higher-cost electricity offshore, but by 2050 are only slightly more expensive than fixed structures at $105/MWh.
Modest drop for floating offshore
Lower capital costs were considered one of the principal factors in lowering the costs of energy. These are expected to fall by 12% by 2030 for onshore wind, 14% for fixed offshore, but a more modest 5% for floating offshore.
Operating expenses are predicted to come down by around 9% in all cases, and as the industry gains more experience with offshore wind the cost of capital is likely to come down. However, capital costs for onshore wind are not expected to fall.
A number of other factors are likely to contribute to the overall cost reductions including larger rotor diameters, rotor design advancements, taller towers, improved manufacturing techniques, more efficient plant layouts, and integrated turbine-level design.
By 2030 a typical onshore wind turbine is likely to have a rotor diameter of 135 metres and a rated output of 3.25MW. Fixed offshore machines are expected to have rotor diameters of 190 metres and power outputs of 11MW. Floating offshore turbines are predicted to have a lower power rating of 9MW, but the same rotor diameters.
There were comparatively modest variations in the cost estimates for onshore wind, but a wider spread for offshore. By 2030, for example, the lower quartile cost estimate was just over $100/MWh while the upper quartile was just over $150/MWh.
In the light of the most recent announcement from Vattenfall, the projections for offshore wind could be pessimistic. The Swedish developer has secured contracts for two Danish offshore wind projects — Vesterhav Syd and Vesterhav Nord — with a bid of DKK 0.475/kWh.
That corresponds to just $71/MWh, though the figure does not include grid connection costs. These would be modest as the projects are only around eight kilometres from shore. Allowing for them, the total cost of energy is likely to be around $100/MWh.
AT A GLANCE: This month's report conclusions
Forecasting Wind Energy Costs and Cost Drivers: The Views of the World's Leading Experts. Wiser, R et al. Lawrence Berkeley National Laboratory, in collaboration with the International Energy Agency, June 2016 By 2030 onshore wind energy costs will have fallen by 24%, and those for offshore by up to 30%.