Onshore wind: Increasing efficiency and higher outputs

Once again high wind speeds made a significant contribution to the electricity supply in the UK as the Didcot B large gas plant was hit with a fire and a number of the country’s nuclear power plants currently offline.

The previous record of 22% of the electricity supply from wind power set in August of this year was overtaken on Sunday as 24% was supplied by wind for the entire day. This strong showing saw it out perform nuclear power from Friday evening through to Monday morning and led to a number of coal plants being taken offline as they were surplus to requirements.

It also set a new peak record of 7,998 MW over a 30 minute period early Saturday afternoon according to National Grid statistics. Based on average consumer consumption for October this is the equivalent of powering 17 million homes.

The fire at the Didcot B power station, which has a capacity of up to 1,360 MW, led to an instant loss of 700 MW. There are also four nuclear power plants (nine reactors in total) also currently offline due to unintended outages and maintenance which has reduced the generating capacity by 5.3 GW.

RenewableUK’s Director of External Affairs Jennifer Webber said: “This year has seen successive new records for wind generation and this latest evidence shows it’s more than capable of stepping in when traditional sources of generation go offline without warning. As we can expect more of these outages in the future, it’s reassuring to know we have wind filling the energy gap.”

“Wind power is often used as a convenient whipping boy by political opponents and vested interests; all the while, it’s been quietly powering millions of homes across the UK and providing a robust response to its vocal detractors.”

We have previously discussed how energy from wind has achieved cost parity with other generation sources and has proven to be as reliable, if not more so, than these alternative sources. Technology is advancing to increase this level of efficiency in both hardware and software so it can be expected that these records will continue to be broken as renewable energy instillations take onboard these new developments.

One such is the Simulator for Wind Farm Applications (SOWFA), a software tool developed by the US Energy Department’s National Renewable Energy Laboratory (NREL). This programme calculates how undulating ground, surface temperatures, whipping blades, and other variables affect the air flow and production levels of onshore wind developments.

Its key innovation is that it replicates a wide range of factors including local weather patterns, the space between turbines and the movement of the air flow. This gives a complete picture of an operational instillation and shows how manipulating each turbine can influence the direction of turbines wakes and detect the effect this has on turbines downwind as well as assisting in the understanding of how local atmospheric conditions affect the wind flow around the development.

This therefore is the first tool the allows developers to monitor and improve the performance of an entire wind farm and as it is an open source community software platform it is available free to developers, manufacturers, and academics plus it has an open support forum where potential issues can be discussed.

One application of SOWFA is the simulation and design of coordinated control of individual turbines in order to maximize plant-wide output. Using these controllers, upstream turbines can yaw their rotors to redirect their wakes away from downstream turbines, substantially improving power capture. Wake losses at wind farms can reduce total power production by 10%.

Where you see one wind turbine you tend to see more as they provide an economy of scale it makes sense to install multiple turbines as one system. However this in itself can cause problems as the wind which turns the turbines can be disrupted causing a wake reducing the power of the wind and therefore affecting any turbine which lies downwind, sometimes up to 800m, of the initial one.

However SOWFA shows turbine manufacturers and developers how a yaw can impart a thrust that curves that wake around the downwind turbine. “Wake, from a power perspective, is lower-energy wind,” said NREL Senior Engineer Paul Fleming, one of the engineers using SOWFA in his research. “If you can move away that deficit of energy, you will have faster winds and more overall production at the wind farm.”

“In the past, wind farms have relied on dissipation to control that energy loss—they just move the turbines farther away from each other,” said NREL Senior Engineer Pat Moriarty, a leader of the SOWFA team. “Now, we can control it in a different way. And there are other ways to achieve more control.”

As these technological advancements increase the efficiency of wind turbines more clean renewable energy is being delivered on a daily basis at a time when more traditional sources are proving not as reliable as once thought. We understand however that wind is not the complete answer and a varied mix of energy sources is way to ensure energy security. Therefore we must embrace the technologies that drive us forward and will ultimately release us from carbon heavy fossil fuel reliance. Initially outlay may be high however onshore wind has proved that with reducing costs and increasing reliability there are genuine alternatives.


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