A more sustainable energy future?
Author: Ian Byrne Date: 05/03/2014
Ian Byrne writes in the February issue of the environmental SCIENTIST journal. Energy is fundamental to modern life. We need it to heat our homes, power our iPads, cook our food, drive our cars and manufacture all the goods that we think are needed for life in the 21st century. Yet most people ignore energy until they see the gas or electricity bills or fill up with petrol. Little thought is given to why we use the amount of energy that we do, or where it comes from.
The energy trilemma
Behind this is a trilemma: how to provide affordable energy with security of supply and – not least – the minimum possible damage to the environment. Politicians seem too willing to focus on only one of these at a time and often ignore good science when the public is obsessed with price; environmental scientists have to find the sweet spot where all three are taken into account.
Despite concerns about the cost of ‘green’ taxes, high prices are more often a symptom of excessive demand. Rather than increasing supply, our first response should be to ask where energy is being wasted, and how this could be avoided. We should remember that a unit of energy that has been avoided is not just the cheapest, but also the cleanest. We also need to understand why theoretical energy savings often fail to be achieved – the so-called performance gap. Only after we have stopped using unnecessary energy should we focus on its production. Are we generating it where needed, and could decentralised energy production help?
Next step, renewables
The next step is to look at renewable energy. As costs fall, solar PV appears to be the obvious choice, providing we can manage demand – and the grid – to cope with differing patterns of generation. But other renewables may have hidden environmental costs – will increasing use of biomass, wind or tidal energy affect wildlife and biodiversity? Introducing a monoculture of a non-native grass or flooding the Severn estuary may be good for renewables but less good for ecosystems. And carbon savings from biomass and biofuels might not be immediate: most calculations assume a continuous cycle, but carbon released by burning may not be recaptured in new growth for many years. So, could carbon capture and storage help for biomass as well as fossil fuels?
Even with reduced demand and more renewables, we will need conventional energy sources for many years; these need to be as clean as possible. Should we promote nuclear as a low-carbon source (good) or limit its use because of long-term radiation risks that cannot yet be properly managed (bad)? A shift to lower-carbon fossil fuels will also still be needed. But what should environmental scientists make of shale gas – not just because of much-publicised local environmental effects (often in the greenest and most pleasant places), but because their exploitation adds to the sum of recoverable fossil fuel reserves. Has increasing gas production helped or simply allowed us to continue to waste energy affordably?
This issue of the environmental SCIENTIST will not answer all these questions, but does provide a stimulating introduction to some of the burning topics surrounding a more sustainable energy future.