Institution news
This summer Britain experienced an unusually long period of calm weather. Dubbed the 'wind drought', this phenomenon meant that output from British wind turbines fell sharply in mid-June and the stayed unusually low for over a month. The graph below shows a particularly stark plunge in wind power when production plunged from a peak of 8,000 megawatts to almost zero in less than 24 hours and remained low for over a month. Generators had to ramp up gas-fired power stations rapidly to fill the gap.
Data courtesy of www.gridwatch.templar.co.uk
This coincided with a prolonged period of hot weather across the Europe, which presented other challenges for the region's electricity producers. Norway, which usually has so much hydroelectric power that it can export large quantities to Northern Europe, has reduced output due to a lack of water. Meanwhile some nuclear power plants were forced to decrease the power produced, or even shut down, due to the higher-than-normal temperature of the cooling water derived from rivers or the sea.
Both electricity generation technologies at a local level and our whole electricity grid at a system level must be designed to withstand the environment in which they will operate, especially during extreme weather events. Natural hazards can affect all types of energy technologies, but fortunately engineers are very good at making our energy system resilient to all but the most extreme and unexpected events.
For example, wind turbines rely on the wind to generate electricity, but above certain speeds the turbines need to be protected from damage. In order to do this, the turbines constantly measure wind velocity and the blades are designed to 'feather' once it exceeds a specified design limit to reduce the force they must withstand.
Solar farms also have to be constructed to withstand high winds, but early designs suffered from damage due to a different threat: hail. However, like the glass on your phone screen, the toughness of solar panels has been improved over the years. The panels are now tested by firing ping pong ball size spheres of ice at them at high speed to ensure they can withstand extreme storm conditions.
As well as designing specific energy technologies to withstand one-off extreme weather events, we can also design energy systems to cope with supply shortages in the event of, for example, a wind drought.
A plan has been put forward to turn Hoover Dam in America into a 'giant battery'. This would involve using excess solar and wind power at times of low demand to pump downstream water beneath the dam back into the reservoir, so it can be used to produce hydroelectricity when demand is high again. This would enable more efficient use of the region's water, thus building in extra resilience to drought conditions. Pumped hydro is actually one of the most common energy storage techniques, including in the UK at the Dinorwig facility in North Wales, but it has never been attempted at this scale. The UK unfortunately does not have the terrain to produce new hydropower on this scale easily, but we can make use of the resources of neighbouring countries.
Having a diverse supply of different domestic energy and storage technologies increases system resilience, but another way is to increase flows between countries with different patterns of weather and sources of energy. We have interconnectors, giant underground cables, to import and export electricity from France, the Netherlands and Ireland, and we are planning to build more. There has even been a plan put forward to connect with Iceland, a country that is blessed with much more geothermal energy than it can use itself.
Despite scare stories about the wind not blowing and nuclear plant outages, our energy system is resilient and this is largely due to good engineering (also well-functioning markets), but transitioning to a low carbon energy system will present challenges. Although this article has focused mostly on electric power, other sectors like heat, transport and industry will also face hurdles to overcome. The Institution of Mechanical Engineers is one of many organisations working to put forward solutions. We are part of a global alliance of engineering institutions that are working to come up with national energy plans to meet our decarbonisation objectives. Through the Future Climate – Engineering Solutions initiative we are collaborating with other engineering institutions in the UK to design a 2050 national energy plan that reduces greenhouse gas emissions and promotes good engineering principles to ensure system resilience. The full report will be published next year.
This article was originally hosted on the website www.businessgreen.com