Читать книгу Renewable Energy - David Elliott - Страница 13

While in general terms the prospects for the future of renewables may look positive, and the overall case for alternatives may look poor, the resistance of incumbents, and some of the arguments against renewables that they have adopted, do have to be faced. A central issue raised is the question of whether renewables can expand rapidly enough to meet global energy needs.

This was met head on in a scenario published initially in 2009 in Scientific American (Jacobson and Delucchi 2009) and then more formally in 2011 (Jacobson and Delucchi 2011) and developed in their subsequent studies. It was suggested that a global target of obtaining 100% of all energy from renewables by 2050 was viable, at reasonable cost. That was ridiculed by critics as impossible, and there were debates over methodology (Clack et al. 2017). However, now, with several countries already above 50% and many dozens of further studies from around the world suggesting that very high renewables shares are possible (Stanford 2019), the debate is more about total-system costs and whether it will ‘only’ be 70%, or more than 80% (of electricity), globally by 2050 (IRENA 2017a), or how to do better than that (Bogdanov et al. 2019).

The pace of technical development and market adoption has been startling, taking even enthusiasts by surprise (for photovoltaic solar especially), and can be contrasted with the slow pace of development of the rival technologies, nuclear (Pearce 2017) and carbon capture and storage (Simon 2017).

As the head of the UK government’s advisory Committee on Climate Change put it, they had initially been ‘overly optimistic about cost falls in some other technologies – nuclear for example’, but for renewables ‘innovation has been the key – driven by policy – in ways that we did not fully expect ten years ago. Globally, a clear goal to decarbonise, with co-benefits of improved air quality in cities, has stimulated commercial innovation’ (Stark 2019a).

However, there are inevitably issues with renewables. Some of them have been highlighted in recent critiques from, amongst others, pro-nuclear lobbyist Michael Shellenberger. He says that renewables cannot power modern civilization, given that the energy sources are variable and also dilute and diffuse, requiring the use of large areas and involving significant local environmental impacts, as well as risks to human and animal life, along with high costs for backup requirements (Shellenberger 2019). He is not alone in challenging the viability of renewables. There is a range of critical books, articles and reports at varying levels of coherence (Lomborg 2019; Montford 2019; Rogers 2018).

It is relatively easy to provide specific counters to these challenges and to the assertion often made that ‘nuclear is a better bet than renewables’. For example, on cost, it is clear that many existing nuclear plants in the United States are having to close because they are no longer competitive (Abdulla 2018) and that, globally, few new nuclear projects are going ahead. By contrast, renewables are winning out economically in most countries (WNISR 2019).

On safety, so far globally there have been around 192 people killed in accidents related to wind farms, mostly involving occupational accidents during installation or maintenance work, but some involving blade transport (CWIF 2019). By contrast, estimates for deaths associated just with the 1986 Chernobyl nuclear accident, although debated, range up into the thousands and possibly tens of thousands (Ritchie 2017). It is true that emissions from coal-fired plants lead to many more deaths, for example from respiratory illnesses, quite apart from any climate change-related impacts, but arguably the solution is to go for renewables like wind and solar, not nuclear, as an alternative.

The wider environmental impact issue is a bit more complex, as I have explored in detail elsewhere (Elliott 2019a). In general, renewables are land using, some more than others (e.g. PV solar can be on rooftops, offshore wind uses no land), but the complete nuclear fuel cycle, from uranium mining to waste deposition, also involves significant land use, with power plants, fuel-processing facilities and so on having to be protected by large fenced-off areas for security and safety. Nuclear plants do not generate CO₂ gas directly themselves, but, as noted in Box 1.2, producing the fuel for them is a very energy-intensive process, mostly at present based on the use of fossil fuels. By contrast, renewables like wind and solar do not need any fossil fuel to run, so they are totally carbon free in operational terms.

While most renewables have generally low, or even negligible, global environmental/climate impacts, some can have significant local impacts, large hydro in particular. For most other renewables (including small hydro), there are technical options that can reduce local operational impacts on wildlife, such as acoustic bird-scaring systems for wind turbines, and there are also ways to avoid or reduce local social impacts by careful design, siting and operation. Although there are areas of marginal land that can be used, biomass is probably the worst offender in terms of land use. Growing biomass energy crops is inevitably land using. That is one reason why there is now more interest in using biomass in the form of farm and food wastes since that already exists: using it can be part of a move to a lower-impact circular economy. In terms of climate impacts, since the CO₂ produced when biomass is burnt is re-absorbed when plants grow, biomass can in theory be near carbon balanced if the rate of use is matched by the rate of replanting. Nevertheless, as I will be illustrating, although it can be a renewed resource, the use of biomass as an energy source may have eco-impacts, depending on the type of biomass and its pattern of production and use.

There is also the obvious, more general point that there is a need to balance the variable outputs from renewables like wind and solar, the cost of this often being presented as a ‘killer argument’ against them. However, as I will be exploring in detail in subsequent chapters, it is not an insuperable problem. The grid system already handles variations in supply and demand and can be upgraded to continue to do that as more renewables are added, although it may take time to develop and deploy some of the new technologies that will be needed, including storage capacity. The extra cost of grid balancing has been put at maybe 10–15%, or perhaps less, if the proper measures are adopted (Heptonstall, Gross and Steiner 2017): some of the new grid-balancing measures may reduce system costs by matching energy supply and demand better, thus improving overall system efficiency (ICL/Ovo 2018).

A more substantial issue is that there will be a need to supply heat and transport energy as well as electricity, a somewhat harder task. Nevertheless, as I explain below, it can be done, although to understand how, and to get to grips with the full transition costs, we need to start looking at the energy system as a whole, not at individual components. Making system-wide changes may be hard and, although the commercial incentives to move ahead are now stronger, they may not be sufficient to accelerate renewable expansion and system change fast enough to deal with the urgent climate and pollution problems. So there may be a need for extra support from governments, for example via subsidies to enable accelerated programmes of development and deployment. That has certainly been the lesson so far: markets on their own have not been sufficient. The point may soon be reached when subsidies will no longer be needed, at least for the initial wave of renewables, but clearly there will be cost implications and political choices associated with making the energy transition (Carbon Tracker 2019). They are what this book aims to explore.