Credit: Vikramdeep Sidhu on Flickr

Turning up the heat on renewables targets

Credit: Vikramdeep Sidhu on Flickr

Lewis Harvey

Right now there are huge amounts of waste heat pouring out of various industries which could be used to heat homes.

The hot topic in the energy sector right now is renewable energy and with companies like Scottish Power going 100% wind powered, hitting our renewable energy targets will be a breeze, no? Well, this is where we run into some confusion. Renewable energy is not the same as renewable electricity. Often the two are conflated by the media to the detriment of public knowledge and the general awareness of our progress towards energy targets. The Institute of Mechanical Engineers describes the UK energy consumption split as roughly being 40.5% heat, 33.1% transport and 26.4% electricity. As you can see, heat is the biggest slice of our consumption, dwarfing the electrical demand by a factor of one and a half. The UK renewable energy directive calls for us to produce 15% of the total consumption by renewable means, and if we are going to hit that target we will have to tackle heat consumption and renewable heat production.

Now, it’s not as simple as just using one of our lovely big wind turbines – which not only decorate our horizons but produce clean energy from literal thin air – to power a little electric space heater. This is because when you convert energy into another type you incur some loss, so electrical space heaters are not an efficient or smart use of useful energy like electricity. Every time energy is changed into heat, in particular, it cannot be totally recovered as it dissipates into its surroundings. One way to avoid this type of loss is to use heat energy that is currently going to waste. Think of an engine: it must be cooled as the combustion process produces heat while turning fuel into mechanical work. For example, if you ever fancied a somewhat greasier burger than normal, you could definitely use that waste heat to fry a few quarter pounders under your bonnet. Right now there are huge amounts of waste heat pouring out of various industries which could be used to heat homes (or to cook some “à la car” burgers). This isn’t strictly generation of renewable heat, but it is reducing energy waste, and in turn consumption, which is as equal a partner in sustainability as clean energy generation.

When waste heat from an electrical power plant is used to supply a matching heat demand it is called combined heat and power (CHP). CHP can improve the efficiency of large fossil fuel power plants by up to 30% and can be their biggest opportunity to reduce emissions. The Simpsons’ picture of nuclear power plants is one of the huge cooling towers which discharge rejected steam to the atmosphere. But what if this steam was used instead to heat Springfield’s homes? Perhaps then they wouldn’t need to huddle together on that sofa quite so close.

The number one enemy in waste heat distribution is distance. The losses are huge but the solution is simple: use it where you lose it. Who lives close to power plants? No one if they can avoid it. This outdated stigma near enough entirely rules out district heating using waste heat in the UK. However, power plants are perfectly capable of being cleanly run, and in order to set up effective district heating schemes, power plants need to be moved closer to populated areas. Moreover, they need to be moved to affluent areas in order to cure the cultural aversion they currently engender: “Bearsden biofuel” has a particular ring to it. A novel example of using waste heat can be found on Islay in the form of a heated swimming pool. The pool is heated using spare hot water from the Bowmore distillery, offering a more eco-friendly and family-friendly way to get sloshed.

We may be leaving the EU but on some fronts, the EU is leaving us behind when it comes to generating energy from waste itself. The Spittelau plant in Vienna is a waste incineration facility located right at the centre of the 9th district and produces enough heat to heat 60,000 Viennese homes a year. Not only does it burn waste to produce electricity and heat homes, it also acts as a tourist attraction.

In the world of renewables, we will have to use any and every method to decarbonise the atmosphere and produce clean energy. Not all the solutions will garner equal public approval. This is why behavioural and cultural aspects must be considered and tackled. In terms of heat and energy from waste, the innovations – though not as endearing as those aesthetic wind turbines mentioned earlier – are critical to progress and projects like the Spittelau plant are a great example of such. This progressive and inclusive attitude towards renewables is something which has to be nurtured if the UK is to succeed in hitting our targets. Whether it be “ugly” wind turbines or “dirty” power plants, moving generation closer to energy consumers is an easy and proactive step towards building a varied renewable portfolio and closing the gap between our goals and reality.


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