The Power of Rubbish

in our second print issue, Mikey Jarrell and Peter Armstrong discussed the Glasgow Recycling and Renewable Energy Centre in Polmadie and what happens to our rubbish when it’s thrown away.

Image: Michael Paley

By Mikey Jarrell and Peter Armstrong 

So, what’s the big deal with the Glasgow Recycling and Renewable Energy Centre?

It’s that big place run by Viridor in Polmadie that turns your green bin waste into energy.

Wait, my green bin waste? I thought it was a recycling centre? 

Yes, but it doesn’t process your recycling.

I’m already confused.

I’m not surprised. But bear with me. Your blue bin ‘dry mixed recycling’ that you so carefully clean and separate goes elsewhere to be made into new products. 

Or sold overseas…

Let’s not get into that right now. What the Polmadie centre does is process all of Glasgow’s green bin waste so that it doesn’t go into landfill. Or nearly all of it – 90 percent is saved from landfill and their target is to get that up to 95 percent by 2025. In total, they process the weight of two aircraft carriers in rubbish every year. 

Ok, so what do they do with all this lovely black bag waste? 

They turn it into heat and electricity through state-of-the-art technology. It’s one of the first places in the country to do it. 

But how can you turn rubbish into power? Surely burning it is bad for climate change?

Yes, it is. And that’s what a lot of plants do. But here they don’t burn it. They actually have two different processes that both generate clean energy. In the first one they separate all the organic and food waste and feed it to bacteria.

Lucky bacteria. 

Sort of. It gets turned into ‘sludge’ first by shredding it and mixing it all up with water. Like a really gross soup. 

OK, I take that back.

But the bacteria like it. They digest it and produce methane ‘biogas’ which is burned to produce energy. It doesn’t produce waste greenhouse gasses like burning fossil fuels does. It’s fairly widely done around the world. 

What about all the rest of the waste that isn’t organic or recyclable? 

That makes up about 75 percent of all the waste that they receive, and this is the clever bit. They superheat it without oxygen to around 800 degrees until it turns into a ‘synthetic gas’.

Isn’t that just burning it though?

Pay attention. There’s no oxygen, so it isn’t actually burned. The gas produced can be burned more cleanly though, and that heats water into steam which turns a turbine to produce electricity. Fossil fuels and nuclear plants also heat water into steam in the same way – the difference is just where the heat comes from. 

So, they actually turn all the non-recyclable landfill rubbish into a gas?

It’s a brand-new technique called Advanced Conversion Technology. Or just ‘gasification’.

That rolls off the tongue a bit better. What do they do with all the heat and power?

At the moment, the electricity goes to the national grid, and they use some of the heat to run the plant. But in future they plan to use it for district heating.

Hang on, I’ve heard of this. It’s where we don’t heat our own houses anymore, and the heat is piped in instead?

That’s the badger. It’s one of the many ideas being tried around the world to make our energy more efficient and combat climate change. All the heat in a district would be produced by one green power plant, like in Polmadie, and then piped into everybody’s homes and businesses in the area. Our plant could in theory heat 8000 homes.

Does that mean that plumbers will finally fix the climate problem?  

Well, they are good at fixing things. In theory, every area could have its own futuristic energy recovery facility just like Govanhill does. But in the future the plants could also heat their districts too. In Scotland, district heating is part of the proposed Green New Deal. And rubbish has such a key part to play. And all you have to do is put it in the bin.

Amazing, I’ll stop trying to cut down my waste then will I?

Hold your horses. This is all pretty fancy, but it still produces some byproducts and isn’t the ideal scenario for your non-recyclables. The best thing for the planet is still to reduce the amount of waste that you throw out. Check out the Zero Waste Scotland website for loads of easy tips on how to do it. You’re welcome.