One of the most common objections I see to the idea that the world needs to move to renewable forms of energy is that renewables just aren’t up to the task. Critics point out how renewables only produce about 2% of our electricity (and less of our total energy use, once you consider things like transport) and how wind, sun, tides, and so on are all variable.
This morning, I dreamed up a metaphor that might serve as a quick partial response:
Imagine a colony founded in a previously uninhabited area, far from the mother country, and with no prospect of future resupply. It is founded with a large stock of non-perishable food: hardtack, flour, lard, biscuits, etc. Good stuff. They also have seeds and the land around them. Imagine now that they are at a juncture in time where 98% of their food comes from the rations they brought along with them. They would not be saying: “Look what wonderful, everlasting sources of sustenance this hardtack is! It is all we will ever need!” Rather, they would be intensely concerned that they were only producing 2% of the food they need for any given year, while drawing down their one-off stock, which would be better saved for emergencies.
Obviously, the colonists need to learn to farm and garden. They also need to learn to cope with seasonal variability. Since the most ancient civilizations, we have had to deal with the fact that food is more abundant at some times than at others. Unlike some mammals that balance it out by storing and drawing down fat (think of whales and penguins that go without eating for months at a time), we use external food storage systems and techniques, from granaries to salting and canning.
Unfortunately, electricity is not so easily stored as food. Nevertheless, we have many options for energy storage. We can balance renewable production between energy sources (wind, solar, geothermal, etc) and between regions. We can store energy in pumped hydroelectric storage and multi-reservoir tidal systems. We can use electric vehicles as a storage and load balancing system, and work to improve batteries, flywheels, and capacitors.
Of course, the metaphor emits much that is relevant to our situation. Fossil fuels are different from stored rations in important ways. For one, we don’t know just how much we have. More importantly, using them causes severe harm – both in terms of toxic pollution and in terms of climate change. Finally, the metaphor takes our energy needs as essentially fixed. When it comes to our society, we could do many of the same things we do now, while using a lot less raw energy.
Those issues aside, I think the metaphor has promise as a quick response to the ‘renewables will never be up to it’ argument. In the long run, we really don’t have a choice.