Dave Elliott: Since some sources of renewable energy are variable, at times power generators may produce output that is not needed. In the absence of energy storage systems, the surplus may have to be dumped or the power plant output turned down or switched off for a while. That may also have to happen if the grid cannot handle the power. Either way it is called “curtailment”. Some specific reasons for curtailment include: Weak grids: there may be congestion on the grid, especially local grids, making it hard for local projects to feed power to users when other projects are also employing the grid; Inflexible capacity: there may be large inflexible plants on the grid, e.g. nuclear plants, that cannot be turned down to allow use of power from variable renewables when it’s available; Over-capacity: it is likely that, in order to be able to meet average demand with variable renewables, more renewable capacity will be installed than is needed when demand is lower. In each case, the result can be wasteful: the potential output is not used. In recent years, the scale of this curtailment has grown; in some countries it’s become quite significant. For example, in China, where grid upgrades have not kept pace with the rapid expansion of wind energy generation, 20% of potential wind output was curtailed in 2016. China has been trying to deal with it, as I’ve noted in earlier posts. In the UK, with well-developed grids, the problem is smaller. Indeed, the Policy Exchange puts the loss from wind in 2017 at just 1.5 TWh of wind, representing 0.4% of total UK power demand. Even output is sometimes being curtailed, which is wasteful environmentally and economically. Wind power companies, like most generation companies, have negotiated contracts to protect themselves from this. They get compensation payments, so-called “constraint payments” for power not generated or used. So far, the payments to wind projects have been a small proportion of the total constraint payments given to generators as a whole. They can nevertheless be provocative and, as wind and other renewables expand, the proportion will grow unless measures are taken to improve grids and balancing, including the provision of storage. Curtailment can be dealt with, by improving grids but also by using the surpluses, and operating the power and pricing system in different ways. As we heard earlier, some think curtailment may in any case not be a major problem. Although, perversely, low prices may be a problem as they make it hard for suppliers to earn enough to invest in new capacity, curtailment needn’t be a show stopper. It can be dealt with and doing so may open up interesting possibilities and net overall benefits, as long as there are not large inflexible plants on the grid making flexible balancing hard.
Physics World 10th July 2019 read more »
The UK government must show it is serious about its legal obligations to tackle and prepare for climate change, the independent Committee on Climate Change (CCC) said today as it published its Reducing UK emissions – 2019 Progress Report to Parliament. Tom Greatrex, CEO of the UK Nuclear Industry Association, said the report rightly highlights the “significant policy gap” that exists just to reach the nation’s previous, less ambitious decarbonisation targets. “As the committee have concluded, technologies which can offer firm and flexible power, such as nuclear, will be required to reach net-zero. The scale of deployment required by 2050 means we need to make rapid progress across all electricity sources. That is why it is both prudent and responsible for the government to assess the potential of a Regulated Asset Base model to fund large energy infrastructure,” he said. The Regulated Asset Base is a number which represents past investments, comprising what investors paid when the assets were originally privatised plus subsequent capital expenditure adjusted for depreciation. Greatrex added: “The government has the opportunity in the forthcoming Energy White Paper to address the concerns of the CCC today, set out an enduring policy framework that will take the UK to net zero, and be a blueprint for other developed nations to do the same.”
World Nuclear News 10th July 2019 read more »
The government should create a route to market for solar and onshore wind, the Committee on Climate Change (CCC) has said in its 2019 Progress Report. Solar and onshore wind both being effectively blocked from the Contracts for Difference (CfD) scheme is limiting the potential speed of decarbonisation and adding to costs. The CCC said the government should outline plans for a route to market in the forthcoming Energy White Paper.
Solar Power Portal 10th July 2019 read more »
The UK will only be able to achieve net zero emissions by 2050 if “immediate action” is taken to overhaul transport, heating, and electricity systems in the UK. That is the stark assessment offered today by National Grid, as the company becomes the latest influential organisation to warn that reaching net zero emissions will require large swathes of the UK’s industrial and commercial energy demand to electrify, at the same time as millions of electric cars and electric heat pumps are deployed across the country. Such a drastic overhaul of the UK’s energy system could push up electricity demand from 348TWh per year today to 491TWh in 2050, significantly above the 422TWh a year National Grid believes will be needed under a 2C warming trajectory. Peak demand could spike at around 115GW in 2050, almost twice today’s level, the company added. This surge in electricity demand would require 20 per cent more electricity generation capacity to be built by 2050, as well as the mass rollout of smart charging and vehicle-to-grid technologies to alleviate periods of peak strain on the grid, National Grid said. Business and industry would also have to adopt more demand response measures, it added, to flexibly manage at least 13GW of capacity load during times of high demand.
Business Green 11th July 2019 read more »