We know energy is essential – it propels trucks, warms homes and powers industry. But it goes far beyond that, and it’s the ‘far beyond’ we must get right even though it’s hardly on the radar.

For starters, the climate crisis is itself an energy crisis. Mother Earth still receives much the same energy from the sun, but thanks to everything we’ve dumped into the atmosphere, she’s now unable to radiate enough back into space to keep cool and is slowly heating up – at least, slowly in human terms, but at lightning speed compared with the past 2000 years.

However, the stuff we’ve dumped into the atmosphere is an energy issue, too. The arch-villain is CO 2 from burning fossil fuels over the past 200 years, propelling the spectacular temperature rise that starts at the red arrow. We must slash fossil fuel use.

This brings us to the elephant in the energy room: the economy and ‘net energy gain’.

Contrary to the common perception, we run an energy economy, not a monetary one. “The economy functions,” writes economics researcher Tim Morgan, “by using energy to access raw materials and convert them into products and services.”

There’s extensive evidence showing that a flourishing economy needs not only abundant energy, but abundant surplus energy, or ‘net energy gain’, i.e. lots left after deducting the energy needed to get it in the first place.

Bingo! The economy is driven by ‘net energy gain’.

This is important. Energy-hungry societies like ours need a net energy gain of about 15:1 to 20:1. Sometimes called “energy return on energy invested” (ERoEI), it means we consume 15 to 20 times the energy needed to get the energy.

Really good hydro and gusher oil wells had an amazing ERoEI – about 100 (yielding 100 energy units to use for one to get them), but those days are gone. The ‘good’ hydro is largely developed, and global values for oil are, according to the Journal of Petroleum Technology, “plummeting” towards 6.7:1. “It is essential,” said its March 2023 paper, “that global stakeholders act swiftly to transition to more sustainable and renewable sources of energy …”

This has little to do with price or emissions and everything to do with how much energy we need to obtain the energy.

So, given that renewables seem to be the silver bullet, how much energy do we need to access them? Well, to be glib, far too much. In simple terms, renewables can’t sustain society as we know it.

And for those shouting “hydrogen!”, it’s not an energy source but a storage medium like a battery, but dramatically less efficient, wasting over 70% of its energy, which in an energy- challenged society, makes it a nonsense for everything but specialist applications.

So why all the rhetoric about the future being just like the present only powered by renewables? There are many reasons, price obsession being one, vested interests another. But a big factor is political: no MP wants to tell their electorate they can’t have their cake and eat it like they’re used to, that they can’t be climate-safe plus have an energy-abundant future, and should plan for lower-energy lifestyles. “And,” the MPs might add, “we don’t know how to deliver those …” Goneburger!

Happily, there are some silver linings on this cloud.

There’s clean-burning, underground ‘geological hydrogen’. Like coal, and unlike manufactured hydrogen, it is a source of stored energy. But the reserves are still being quantified, the jury is out on its potential contribution and downsides, and there’s no mention of prudent conservation.

Then there’s the electrification of just about everything. The 15-20 ERoEI for society is framed around the glorious inefficiency of the combustion engine. With EVs about three times as efficient, we should get more bang from our surplus energy. But even if, optimistically, society’s needs halve to an ERoEI of 8-10, renewables still fall short. Plus, factor in that any use of manufactured hydrogen pushes us the wrong way.

Finally, there’s a silver lining we should take seriously: we’re such an energy-profligate society that, like binge eaters, there’s a lot we can let go of with little likely downside.

A classic is our nonsensically wasteful car commuting. “There’s nothing less efficient than having roads filled with cars bumper to bumper,” says world data guru Hannah Ritchie. It’s inefficient to the nth degree and offers a galaxy of potential benefits if we address it well. For example, Transpower has just foreshadowed looming power outages, and NZ Inc is grumbling about serious balance of payment deficits. Both would improve under lower commuting energy, fossil fuel and electricity alike, along with attendant reductions in congestion, emissions, travel costs and more.

Whichever way we look at it, we’re heading for a society using substantially less energy. That doesn’t mean living like paupers; it means treating energy like the taonga it is and rapidly learning to use it wisely so we can target a flourishing future, while also combatting the climate crisis.