Insulation, insulation, insulation...

Could this be the makings of a new TV show?  Probably not quite as exciting as its similarly named long running hit.  However, insulation is critical to tackling the big problem no one likes to talk about (or at least relatively few).  Thankfully that is changing, and the world is waking up to the realisation that our fixation with the magic of electricity is in fact not going to tackle climate change on its own.  Heating is the problem or to be more precise our addiction to burning fossil fuels to warm things up (including our planet, sadly).

Heat accounts for HALF of the world’s energy consumption and around TWO-FIFTHS of CO2 emissions (https://www.iea.org/reports/renewables-2019/heat).  Of course, heat covers a multitude of end uses – from smelting metal ores in industry to making things to eat, drink and wear in factories to space heating (and cooling) and something as simple as sanitary hot water.  Like the more popular kid on the block, electricity, heat, (the quiet nerdy kid who will eventually become a billionaire while its flashy contemporary gets a blue-collar job paying minimum wage) is also predominantly used in buildings.  Unlike electricity, heat tends to be generated on site (and not hundreds of miles away in a power station, or, increasingly, solar or wind farm).  Consequently, the emissions from heat, scope 1 emissions, are the really tough ones to do anything about.

Governments and other concerned organisations are now desperately playing catch up to try and tackle heat (of course they did electricity first as it was relatively easy - it could be plugged in to the existing infrastructure and was also far easier for the existing vested interests to monetise – be that suppliers of fossil fuels, electricity companies or financial intermediaries able to make a fast buck).  Currently there is a lively debate about how best to tackle heat – district heating networks, electrification of heat or continuing to burn stuff (hydrogen or biomethane).  Each of these ‘solutions’ brings its own baggage.  

The first thing to do is to try and lower demand for heat – one such way is to reduce the demand for space heating (one of the largest components of heat energy) by making buildings less leaky.  The UK and other countries that were blessed with large reserves of stuff to burn never really took this sort of thing seriously.  If you are a coal baron or oil magnate, you don’t want people to burn less of the stuff making you rich.  So long as it is moderately affordable you keep the money-making machine going (and to heck with whoever has to pick up the cleaning bill once the party is over!).  However, if you are a country like, say, Denmark, which did not have access to cheap fossil fuels you make your buildings better insulated and you look for alternative ways of heating them.

Denmark is the world leader in district heating.  It makes a lot of sense to have a single source of heat production (like a power station for electricity – it gives you economies of scale).  Even better if that source can tap into what would otherwise be waste heat.  District heating is on the tips of a lot of tongues in other countries, now that heat is being looked at.  However, this solution is trotted out without much thought to how the heat is generated that will go into the heat network.  Again, the Danes do have one widespread solution that has zero emissions, but let’s come back to that later.

Electrification, through the use of heat pumps is being pushed quite hard (mainly by purveyors of heat pumps and their highly effective lobbying).  Indeed, heat pumps are in fairness a ‘good’ solution, so long as the source of electricity is renewable.  Given competing demands for electricity – conventional uses like lighting and running appliances are now competing with electric vehicles and heat pumps.  The grid is already struggling to match supply and demand (and there are a lot of great companies coming up with novel ways to do that with intelligent fridges and dynamic pricing structures to punish / reward people for using electricity at the wrong / right time of day / year).  The big issue with renewable electricity is matching supply and demand.  What happens when there is no sun / wind, in the winter / night or the opposite – too much wind / sun and not enough demand.  Electricity is really difficult to store (comparatively speaking).  Conversely heat is actually very easy to store (so long as you remember the adage insulation, insulation, insulation….).  There are other practical problems with heat pumps – they are tricky to retrofit; they operate in a relatively narrow temperature range and both the initial cost and operating costs don’t necessarily look that attractive.

Hydrogen has enormous potential.  It can most likely be used in the existing gas network with relatively minor adjustments to the huge installed base of infrastructure.  Moreover, when burned it produces nothing more harmful than water.  It really could be the magic bullet we need.  The only drawback at present is that making hydrogen isn’t terribly easy.  There are two methods – one produces lots of emissions which end up being worse for the environment than if you had just burned a fossil fuel in the first place.  The other requires huge amounts of electricity (you have to put in more energy than you get out).  The latter solution has some merit because it could be a useful way of storing surplus electricity from solar and wind.  There are other very promising hydrogen producing solutions out there, but nothing that is yet commercially viable or already at scale.

Biomethane is enjoying the limelight at the moment.  I’m sure there is an analysis somewhere explaining how burning methane that is from renewable sources as opposed to that coming from old fossils is somehow less damaging to the environment.  The argument being that it would have been released into the atmosphere anyway so we might as well burn it and turn it into CO2 instead.  Thus, leaving the fossil fuel methane in the ground (or not if it gets released as a bi product of the oil industry anyway).  Being able to continue burning the stuff in existing boilers and selling it through existing energy cartels (and earning tax revenues) is naturally appealing to some and could explain its current popularity in government and other circles.

Having looked at the range of ‘solutions’ available there is one rather unfashionable omission.  Solar thermal.  Capturing the heat from the sun and using it for hot water, space heating, cooling (yes cooling!) and industrial processes is a very old solution.  With the exception of storing and putting the heat into district heating (widespread and growing in places like Denmark) most solar thermal heat is used at source.  This means that there is no need to export back to the ‘grid’ (less easily done with heat than electricity) and the ensuing issues that would create in the world of electricity.  All of the heat can (indeed must) be used on site.  This tackles the really tricky issue of scope 1 emissions.  Sceptics would question what happens when the sun isn’t shining – at night or in the winter.  Diurnal (day to day) storage is easily achieved with nothing more complicated than a hot water cylinder.  Inter-seasonal storage is admittedly trickier as it requires a lot of planning and more complicated / expensive infrastructure to store larger volumes of heat.  That said it is entirely possible and has been demonstrated widely.  Given the winter requirement for space heating this really does put the emphasis on good insulation.  If buildings are built to the highest standards even in winter the need for space heating can be minimal.  That means all the effort can go into the production of sanitary hot water which is needed in both the winter and summer (and is possibly the simplest use of solar thermal with the most scope for expansion).

In the world of solar thermal insulation is also very important.  Little or no insulation means heat is lost to atmosphere, especially with colder ambient temperatures.  Moreover, unlike electricity (at least as far as the average consumer is concerned), heat comes in different flavours – that is to say different temperatures.  Low temperature heat (30C) may be suitable as a pre-feed for another technology to boost the temperature or could be used for something like under floor heating or swimming pools.  Higher temperature heat (below 100C – for anything over that the technical complexity of dealing with steam creates new challenges) is far more useful for sanitary hot water or use in conventional space heating systems (radiators).  It is also much more useful for commercial and industrial processes such as food and drink manufacturing.  Very high temperatures are needed for industrial processes.  More complex forms of solar thermal collector using concentration can provide that kind of heat too.

Returning to the subject of insulation.  The best form of insulation is a vacuum.  It keeps hot beverages hot for long periods of time in the form of vacuum flasks.  Evacuated thermal collectors or vacuum tubes employ the same principle to ensure higher temperatures are achieved (irrespective of ambient temperature) and thermal losses are minimised.  Vacuum tubes have the largest installed base of any solar thermal technology and have been deployed all over the world for decades.

So, if we are really to solve the challenge of emission free, affordable renewable heat insulation is key.  Insulation of buildings to reduce waste / demand in the first place and deployment of high efficiency well insulated solar collectors (with well insulated long-term storage).  This really can make a material impact on the world’s largest energy use and one of the highest sources of CO2 emissions.  Joined up thinking is needed, and the vested interests / status quo must be challenged.  We have reasons to be optimistic.  Irrespective of the politics, people and organisations are taking the provision of clean energy into their own hands.  The momentum is there to make burning fossil fuels a thing of the past.

Naked Energy offers a range of evacuated tube solutions to decarbonise the generation of on site thermal and electrical energy. Pictured is VirtuPVT producing heat and power in South Africa.