L R AS Published on Sunday 25 August 2019 - n° 286 - Categories:the American PV, on request
700 MW wind + solar + storage plant in Oklahoma
NextEra will build a 700-megawatt combined cycle power plant in Oklahoma for a group of rural electricity cooperatives. This complex will include 250 MW of wind power, 250 MW of solar power and 200 MW / 800 MWh of battery storage. This project exceeds that of NextEra signed with Portland
General Electric in February, which will be online by the end of 2021 and which forecasts 300 megawatts of wind power, 50 megawatts of solar power and 30 megawatts / 120 megawatt hours.
This 700 MW hybrid package will provide cheap renewable energy while mitigating intermittency. The configuration offers a cost-effective alternative to a natural gas production facility for peak demand.
Until now, such projects have been impractical due to the cost of storage, the difficulty of identifying sites that are equally suitable for both wind and solar power, and having the grid infrastructure to support significant transmission capacity.
These projects are also inherently more difficult to design than conventional installations: optimising one factor is fairly easy, two factors are more difficult, combining three elements is complicated. Even more so if you want to take into account the duration of storage.
Such an installation is cheaper than a gas-fired plant thanks to tax credits. The battery will respond faster than a gas-fired plant and will be able to absorb excess energy capacity, which will be useful on Oklahoma's windiest days.
This facility differs from the one built for Portland General Electric, where solar represents only 1/6th of the wind capacity.
This 700 MW facility is more balanced. It will be built with tax credits in mind; the battery will be one of the largest in the world, exceeding the capacity of Australia's Tesla battery and that of AES (100 MW / 400 megawatt-hours) and will be above that of Vistra at Mist Landing (300 megawatts / 1,200 megawatt-hours) planned for the end of 2020.
This installation requires extensive calculations to optimise the respective productions. The synchronisation of wind and solar generation in Oklahoma extends availability throughout the day. The battery offers additional capacity to switch from the weakened wind generation to the more productive solar energy and vice versa. This does not solve the whole problem of intermittency. If it helps the power company to mitigate peaks and troughs in production, it will be of enormous value.
The result does not fit the conventional utility categories of a permanent base plant and a peak unit on demand. The package envisaged is more dynamic than the base load and more stable than the peak unit, allowing a daily power supply to be provided in line with the customers' demand curve.
GreenTech Media of July 25
Editor's note This wind + solar + storage combination has a great future because it smoothes production and stores excess energy. This requires a reasonable storage price, and in order for this solution to be extended, a storage time longer than four hours. In addition, it is a credible alternative to gas-fired power plants designed to supply energy during peak demands. This formula will develop.
