Wednesday, April 24, 2024

Buildings as batteries. For net zero, we need bright ideas like this

There’s a joke about the economist who thought he saw a $20 note on the ground but didn’t reach down for it because he knew that, if there had been such a note, someone else would have picked it up long ago. Sometimes we don’t see what’s there to be seen because we aren’t expecting to see anything.

Have you ever been in the city at night, looked up to see all the office blocks with lights ablaze, and wondered why they were wasting so much electricity? Perhaps it’s because people are working late, or the cleaners are busy. In any case, it’s not lighting that uses so much power: it’s heating and cooling.

But your instincts are right. All those office blocks have an important part to play in our efforts to limit further climate change. How? Keep reading.

As every sensible person knows, but prefers not to think about, the most important single challenge we face as a nation is to play our part in achieving the global goal of reducing emissions of greenhouse gases to net zero by 2050.

This is far more important to our kids’ future than the housing calamity or the cost-of-living crisis, both which will pass soon enough.

And, as most people realise, the main strategy we’re pursuing to reduce emissions is to eliminate the use of coal and gas in the production of electricity, then use this clean power for as many of our energy needs as possible. The move to electric vehicles is a big part of this.

All of which is much easier said than done. We’re already getting much of our energy from renewable sources – solar and wind power – but we need a lot more of it. And we need it to be available before our ageing coal-fired power stations give up the ghost. We can use some gas to tide us over, but it too must go.

Another part of the problem is reconfiguring our huge system of “poles and wires” transmitting electricity around the country. We need high-voltage powerlines joining up the eastern states. Currently, powerlines mainly transmit from huge coal-fired power stations located near coal mines to the nearest big city.

Trouble is, the solar and wind farms replacing the old power stations are spread all over the place. And then there’s the need to link all the solar systems on people’s roofs into the network.

Further complicating the transition from fossil fuel to renewables is the problem all those looking for an excuse to do nothing love pointing to: what happens when the sun’s not shining and the wind’s not blowing?

The short answer is that we have to capture and store some of the free energy that’s coming while the sun is shining, so we can use it at times when it isn’t. Batteries are the obvious way to do this. But we can achieve the same effect by pumping a lot of water up a hill, then letting it run back down to power a generator at night. Or you can do something vaguely similar in an office block.

While we’re working on all this, however, climate change is making our summers hotter and increasing the demand for air conditioning. The way we see it at present, we have to increase the capacity of our electricity transmission network so we can cope with peak demand on a few very hot afternoons each year without blackouts.

But this extra capacity goes unused for all the other days of the year, which is wasteful. Surely there must be a cheaper way to avoid blackouts?

This is where Craig Roussac, founder of Buildings Alive, a company that helps commercial building managers to better manage their use of energy and so reduce their emissions, has had a bright idea, which he’s developed with Dr Richard Denniss, boss of the Australia Institute.

On hot summer days, building managers could turn their cooling a degree or so lower in the morning, then let the temperature rise slowly in the afternoon, while everyone else had their air conditioners going full blast.

Because the wholesale price of electricity jumps at times of peak demand, this would save the building owners money. Lower peaks being cheaper, this would reduce the average retail price being paid by the rest of us.

It would also reduce the need for new investment in transmission capacity – the cost of which is passed on to electricity users. Above all, it would immediately reduce emissions, at zero extra cost.

But if it’s such a smart idea, why aren’t people doing it already? Mainly because the electricity industry makes its living by selling more of the stuff, not less. But also because the energy efficiency ratings awarded to buildings don’t encourage businesses to change the timing of their demand.

Now, obviously, sorting out our office buildings would make only a small contribution towards achieving net zero. But the idea of changing the timing of our demand during peak periods could be spread to other classes of buildings, including apartment blocks and even detached houses.