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  • HPH283 : Modelling the embodied carbon of your build – with Tim Martel

    HPH283 : Modelling the embodied carbon of your build – with Tim Martel

    Tim Martel explains how to model the embodied carbon of your build using PHribbon, a tool that plugs in to PHPP (Passive House Planning Package).

    Interview with Tim Martel

    Tim is a qualified architectural technologist and Passivhaus designer. He also works for the AECB and is a course tutor for the CarbonLite retrofit course. Helped by a background in programming he has used his research and experience of working on new builds and retrofits to create PHribbon – a tool which enables people to model the embodied carbon on their build.

    PHribbon is designed to specifically work with the PHPP software

    While there are other specialists who do work on embodied carbon, PHribbon is unique in that it has been designed to work specifically with the Passivhaus Planning Package (PHPP). This is a benefit because around 80% of the information needed is already in PHPP. The additional information needed will be the things that aren’t covered by PHPP, such as internal walls, floors and roof coverings.

    PHribbon front screen

    The calculation is built around a RICS document

    The Royal Institute of Chartered Surveyors (RICS) wrote a document in 2017 called ‘Whole Life Carbon Assessment for the Built Environment.’ It’s a statement of what members have to adhere to and sets out in detail what is expected of the calculation. While the RICS calculation can only be done once a building is complete, Tim is able to use quantities that are in PHPP to give a good estimate of what the embodied CO2 of the building is likely to be.

    Information is gathered from Environmental Product Declarations

    The RICS calculation uses information from Environmental Product Declarations (EPDs), which are documents that work to European EN standards and which quantifiably demonstrate the environmental performance of a product. RICS also go through the whole lifetime calculation with detail on what should be done at each stage and what assumptions should be used. Assumptions being necessary sometimes for standardisation, because of the inconsistencies of different people coming up with different answers even for the same building. With lots of companies producing these declarations, (Tim now has around 200 in PHPP covering many different materials) the challenge might be in convincing manufacturers of products with lower environmental credentials to share their information.

    CO2 results can be shown in different ways

    As long as you are able to provide the net internal area (NIA), results can be shown as kilograms of CO2 per metre squared of net internal area. In addition the graph can be customised to show total CO2 for the whole building, kilograms of CO2 per metre squared of TFA (that’s usable space in Passivhaus language), and even CO2 per occupant.

    Awareness is drawn to potential inaccuracies

    Tim stresses this isn’t an official calculation, but it does closely follow the RICS standard. There will however be some inaccuracies, and these are highlighted by a colour coded system in PHribbon to draw attention. Some EPDs they can be fairly certain about so will be coloured green, but others that they’re less confident of will be orange or red. They might be ones that are based on RICS assumptions like 300km being the assumed transport distance from various manufacturers to the site if its a national product, whereas in reality it’s likely to be more or less than that.

    Generally speaking, the information is likely to get more accurate as more EPDs are produced, and with more available it’s highlighting just where the missing information is. In particular, it would be useful to show information for the end of life stage, and include reuse and recycling benefits.

    Results can be tailored to show alternatives

    With several examples already completed, Tim says his findings show a typical semi-detached house as having around 14 tonnes of CO2 for the whole life of the building, with about 10 tonnes of that just for the materials themselves. The benefit of using PHribbon is that comparisons can be made in a graph by using different options, such as what the figure might be if the house was made out of brick, as opposed to timber.

    Example of whole building using timber, PIR versus brick
    Example showing 100m2 wall using timber, cellulose versus brick

    More information is needed about the end of life stage

    With some of the more typical timber constructions where I-beams and cellulose are used, both of those have quite a large storage component so a large bar represents that storage which offsets all of the emissions in the RICS calculation.

    Tim says there’s a catch with this though, as one of the assumptions is that in order to include storage you have to do a full life calculation. That then uses the RICS assumption that 75% of the timber is incinerated at the end of life stage, with the other 25% going to landfill. Unfortunately there isn’t currently enough information about recycling and reuse to produce those in the EPDs as an alternative.

    “If you could say, ‘this building has been built so that it can be taken apart and recycled. This material is ideal for being recycled so it can be made into OSB, MDF or anything’, if that can be done and we can prove the figures for it with an EPD for that process then you could legitimately add that as another option.”

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  • HPH252 : How to reduce the embodied carbon of your new home – with Chris Magwood

    HPH252 : How to reduce the embodied carbon of your new home – with Chris Magwood

    Chris Magwood, a director at the Endeavour Centre in Canada, explains the importance of embodied carbon and how building with plant-based materials could transform our new homes into carbon sinks.

    Interview with Chris Magwood

    Chris Magwood has been working in sustainable building for the last 25 years. He’s also written several books such as Essential Sustainable Home Design, Essential Prefab Straw Bale Construction and Essential Hempcrete Construction.

    For the last 8 years he’s been teaching at the Endeavour Centre which is a sustainable building school based in Peterborough, Ontario.

    What is embodied carbon?

    Embodied carbon is the total carbon emissions associated with materials through initial harvesting of raw materials and through the entire transportation to manufacturing facility and everything that happens in that manufacturing facility. And then transportation to a job site and the associated emissions with actually doing the installation work on the job site.

    Carbon dioxide is an expression of all greenhouse gases

    As carbon dioxide is not the only greenhouse gas, other emissions are translated into a carbon dioxide equivalent.

    Chris says: “The expression that we use in the calculations is CO2-E – so, carbon dioxide equivalent. So, if it’s carbon dioxide, one molecule equals one. But if it’s methane, one molecule would equal twenty-five or whatever the number happens to be.”

    Energy isn’t necessarily a proxy for carbon

    For a long time the term that was being used was embodied energy, but it’s important to realise that energy isn’t necessarily a proxy for carbon.

    So, two factories could use the same amount of energy, but if one is all solar and one is all coal powered, then the emissions profile of the two would be very different.

    Even though in embodied energy terms, that number might look the same. So, this is specifically trying to make emissions the focus and not just energy use.

    The carbon footprint of building materials vary drastically

    While we probably understand that different building materials have different carbon footprints, when Chris crunched the numbers he was surprised by the extremes.

    Chris comments: “I was pretty stunned at the results in that some things just had such a huge carbon footprint and I had never really considered that impact being so big before. And then some things were miniscule.”

    Plant based materials give us the opportunity to turn our buildings into carbon sinks

    As plants grow they pull CO2 out of the atmosphere and release oxygen. Effectively they put the carbon into their physical structure.

    So if you’re building with a material that has atmosphere carbon stored in it – basically any plant material – in terms of the calculations, it’s a negative emission. In other words there’s a drawdown of carbon rather than an emission.

    “Building with a lot more plant material, we could not only reduce that carbon footprint to zero, we could actually take it into the negative numbers and make drawdown buildings that are in their way drawing down climate change rather than contributing to it.”

    Straw is one of the best materials

    Chris compares two plant-based materials as an example of how even a little processing can increase the embodied carbon.

    Although cork requires quite a bit of heat in its manufacture, it still ends up being a net store of carbon.

    Straw, however, has almost no emissions in terms of the harvesting and manufacturing. It’s also the waste product of an annually renewable crop. And in the case of grain straws, the carbon in the stalks would have just returned back to the atmosphere in fairly short order.

    Chris adds: “Even though all of these plants more or less store a similar amount of carbon, the amount of processing energy that’s gone into them does change the net profile.”

    Endeavour class at a straw bale raising
    Six carbon storing insulation materials

    Timber has a more complex picture

    It’s much harder to attribute carbon storage to timber because the carbon that’s in that tree, depending on when the tree was cut, that tree could have gone on drawing down more carbon as a living tree than it does as a stored tree.

    And if you only end up using about half the volume of the tree to make a timber product and the rest of the carbon from that tree ends up back in the atmosphere, you haven’t net stored any carbon. And if you’ve released a whole bunch of carbon from the soil of the forest floor, then it may be worse than a draw down. It might actually cause emissions.

    We could become more intentional about what our buildings are doing

    Chris is not advocating that all buildings need to be entirely plant based, but he does see a massive opportunity to be more intentional.

    “If you can weigh up the carbon storing materials with the carbon emitting materials, you can actually plan a building to land on a target that you’re aiming for, whether that’s carbon neutrality, storage or a slight number of emissions.”

    Environmental product declarations report the environmental profile of a material

    In carrying out this research, Chris used environmental product declarations, an ISO standardised way of reporting on the environmental profile of a material.

    This is third party document where the third party goes in and looks at a manufacturer and traces the entire chain of that product and essentially does a calculation to look at its global warming potential from harvesting of the raw materials through the entire manufacturing process.

    Chris explains how he used this information: “I’m basically using those numbers to then multiple it out on my own buildings. So, if a particular environmental product declaration says there are two kilograms of CO2-E per kilogram of this material, then I figure out how many kilograms of that material are in my building and then I can multiply that out and do that for all of the materials and then total that up and get a net, whether it’s a net emissions or a net storage.”

    Concrete, glass, foam and steel all have high carbon footprints

    Perhaps as one might expect concrete, glass, foam, and steel all have significant carbon footprints associated with them.

    Building a Passivhaus will not necessarily have any impact on embodied carbon

    If you’re building a Passivhaus, then your choice of materials is really important.

    “The way a lot of people will achieve Passivhaus standard here in Ontario, Canada, is they’ll throw a whole bunch of foam insulation at that building. And when I modelled that, the embodied carbon footprint, the upfront emissions of making that building, don’t ever get paid back by the energy reductions. So, if somebody was using that strategy because they thought they were doing something for climate change, they’ve actually done exactly the opposite.

    The carbon profile of the grid varies according to where you live

    This goes back to energy not necessarily being a proxy for carbon.

    Energy efficiency – in terms of carbon emissions – is only useful if you use dirty energy (with a high carbon content).

    “Here in Ontario, we shut down our coal plants a few years ago, and so our electrical grid is relatively carbon free. And so, savings in energy efficiency, especially moderate ones, our code is now pretty good in terms of baseline energy efficiency. Going from that to Passivhaus, while it may have good implications for the owner in terms of lower bills and comfort and all that kind of stuff, from a carbon emissions profile, it’s almost meaningless with the difference between a code built house here in Ontario and a Passivhaus in terms of the emissions profile of operating that building, it’s negligible because the carbon profile is so clean on the grid.”

    Canada’s Greenest Home

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  • HPH126 : When is it right to demolish and rebuild? – with Simon Sturgis from Sturgis Carbon Profiling

    HPH126 : When is it right to demolish and rebuild? – with Simon Sturgis from Sturgis Carbon Profiling

    Architect Simon Sturgis explains the circumstances around whether it’s best to retrofit or rebuild.

     

    Interview with Simon Sturgis

    For the last 8 or 9 years, Simon Sturgis has been looking at the issue of carbon in construction. This followed a period of doing a lot of retrofit work where it seemed that huge amounts of only partly used materials were wastefully being thrown away. They decided their challenge was to be whether this could be quantified, which developed into the idea of carbon valuing: a valuation using carbon as a currency of sustainability.

     

    “To make anything takes up energy, and depending on where it’s made, it determines the sort of energy”

    People were already familiar with measuring energy usage in buildings, but Simon explains they were keen to come up with something equally familiar that related to materials, and the problems around the negative aspects of how they’re made.

    Where the material is made will determine the kind of energy that is used to make it. For example in Norway it would probably have been made using hydroelectric energy, however in the UK it would more likely have been using gas and oil.

    “So it’s really understanding that and trying to redirect our ability to make things away from, if you like, damaging carbon intensive technologies.”

     

    Ensure any new building has the ability to be recycled and re-used

    Simon discusses what you should consider if you’re thinking about demolishing a run-down old building to replace it with something new. He says that if it’s falling apart then it’s probably better to take it down and dispose of and recycle it as best you can, but build something in its place that fulfills the durability factor that the previous building didn’t have.

    In your new building, consider whether it is capable of easy recycling or adaptability and re-use. If you’re constructing it from brick then you might be confident it will last a couple of hundred years, but if you’re using timber you might say that it’s not going to last as long but at least it can be adapted, re-used or moved to do other sorts of things with it.

     

    A change of mind-set is needed

    People need to change their way of thinking to a ‘circular economy’. Simon explains that in the City of London office buildings have an average life expectancy of around 17 or 18 years, which clearly is going to have a huge carbon investment. He believes that there should be planning at the outset for a building’s eventual disposal, and with the expectation that when you’ve finished with the building it can be taken apart and the elements distributed to be re-used in other buildings, not necessarily in the same place.

    If you intend to re-use things you need to consider right at the beginning how they will be put together, in order to make it possible to dismantle and re-use them, i.e. using a lime mortar that can easily be removed from bricks, instead of cement mortar.

    Simon uses the example of a two-storey office/shed type building where, because of its steel bolt and aluminium construction, they were able to help a client to take it apart, move it to a more suitable location, and re-build it, while tidying it up as they went along. They were able to re-use around 70% of the materials and along with significant carbon benefits, it cost 25%-30% less than a new building of the same size.

     

    The cost of recycled products can be prohibitive

    This may seem counterintuitive at a glance, but it’s cheaper to buy new bricks than old ones. Largely this comes down to the cost of cleaning up the bricks from a dismantled building is high.

    However Simon suggests that if the process of cleaning the bricks was paid for through social value, for example being done by people who might otherwise be in prison, then not only could the recycled brick be bought for the same price as a new one, but you’re also contributing to social issues and turning the demolition process into a positive one.

     

    You can’t necessarily demolish any building

    If thinking about demolition, consider the following:

    • Whether it has listed building consent or is in a conservation area.
    • Possible health and safety issues if the building you’re demolishing is next to a sensitive site or railway line, etc.
    • Whether there are issues to be resolved due to party walls.

     

    A high standard of retrofit may have the lowest carbon impact

    Sturgis Carbon Profiling produced an article looking at carbon emissions over a period of time in 3 different scenarios.

    The first scenario was the carbon cost of maintaining an existing Victorian terraced house – principally in heating and energy use.

    The second scenario looked at taking that same Victorian terraced house and upgrading it to a high standard. While that does take a lot of material going into the building, it does make a huge difference to the performance and requirement for heating.

    The third scenario looked at building an entirely new Passivhaus, with its high levels of insulation and airtightness.

    Their analysis considered both the carbon emissions from the materials used, together with carbon emissions from day-to-day use. What they found was that, based over a 60 year period, it was better to retrofit the existing terraced house to a high standard than it was to build the new terraced house. The reason for this is because there is so much energy used in producing bricks and other materials for the new build.

    “So it’s not necessarily the case to say you should demolish Victorian buildings if you want to get a highly efficient carbon outcome. You need to make them work better… And in a sense we’re doing society a good service by re-using things rather than flattening them.”

     

    Transcript

    Download a transcript of the interview with Simon Sturgis.

     

    Find out more

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    The Hub update

    The Hub is an extra learning and networking resource, tying together everything we’ve learnt from our podcasts, together with extra information and interviews. We have video case studies and currently have a number of short videos showing the different stages of the Long Barrow Passivhaus project that we’ve been following. We’ll also soon be confirming details of our second case study.

    Each month we’re also adding a new module which lays out different parts of the self-build process in simple steps.

    Our current beta launch price of £45-a-year, which is a lock-in price that you will keep every time you renew, is going to expire at 9pm GMT on 30th April 2016. After that the price will go up to £99-a-year. Find out more.

     

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  • HPH081 : Rainwater Harvesting From Your House – with Cath Hassell from ech2o consultants

    HPH081 : Rainwater Harvesting From Your House – with Cath Hassell from ech2o consultants

    Cath Hassell from ech2o consultants explains what rainwater harvesting is, why it’s useful and how to get started.

    If you haven’t heard our first podcast interview with Cath on the topic of saving water, check that one out first!

    cath-hassell

     

    Interview with Cath Hassell

    Rainwater harvesting is just one way of stopping rainwater from getting into our drains and sewers.

    If the house is in a city and rainwater is going into a combined sewer, then there will be more waste water to treat and there may be times when water treatment plants can’t cope and so the water spills out into local rivers or the sea.

    Keeping rain out of the stormwater stream reduces the likelihood of this occurring.

     

    What is Rainwater Harvesting?

    Rainwater harvesting is collecting rainwater that falls on the roof of a building. It’s taken from the roof because this is usually the cleanest water. This water is then stored outside but it can be used back in the building (for flushing the toilets, cleaning purposes, in washing machines, etc.) or it can be used outside the building for gardening.

    installing-a-rainwater-harvesting-tank

     

    Water is Stored Underground Because It’s Heavy

    There are two main reasons why water is stored underground:

    1. It’s heavy and therefore it does not want to be kept high up on top of a roof

    2. The water will be cool if stored underground reducing the risk of bacteria

     

    Water tanks can take up quite a lot of space so this might be another reason why it’s best to locate them underground.

     

    Setting Up Rainwater Harvesting is Easier for New Build

    In a new build house there is already going to be earth-moving equipment on site and so it becomes cheaper to dig a big hole.

    While it can be done in a retrofit situation, the initial set-up may cost more. There may also be issues such as no access to the back of a house (in a terrace, for example).

     

    Rainwater is Not Fit For Drinking or Bathing

    Astonishingly, in the UK, rainwater is actually given the same classification as water that has been swept from abattoir floors or contaminated with nuclear waste. For this reason there needs to be different pipework which runs to domestic taps, than for that which runs to toilets, washing machines etc.

     

    An Air Gap is Required to Prevent Water From Syphoning Back Into The Pipework

    The air gap is basically the space in between where the water can’t touch the taps. If a sink was overfilled the water would go down through the overflow or spill onto the floor and there would be no risk of the potentially dirty bathing water from re-entering the mains system through the taps.

     

    A High Carbon Load Damages The Reputation of Rainwater Harvesting

    The air gap does result in a loss of mains water pressure which can be overcome by pumping it to where it is needed, though using electrical pumping obviously does have a financial and carbon cost associated. The performance of the pumps can however be optimised by using particular valves.

    A high carbon load is one of the arguments that gets used against rainwater harvesting, but Cath would welcome research to be carried out looking at how taking rainwater out of the stormwater stream impacts on the reduced carbon load of the sewers and sewage treatment plants by reducing pumping there.

     

    Decisions About Rainwater Systems Can Influence The Designs of a New Building

    Cath suggests that if you’re planning a green roof she would not recommend rainwater harvesting for use back in the building. This is because the water run-off from the green roof will be discoloured and residents of the building may start using bleaches and cleaning products to remove the staining to their toilet pans.

    There is no reason why rainwater couldn’t be harvested by other areas of the building which do not have a green roof, and simply designed in with the gutters and downpipes.

     

    A Calculation Determines The Size of The Required Rainwater Storage Tank

    The storage tank holds approximately 5% of the anticipated rainwater that will be harvested in a year, which equates to around a 3 week supply. This is usually enough as the rain falls year round in the UK but there will still be some times where the tank will be too full or too empty. When empty the supply can be switched temporarily back to the mains, and when too full the overfill can be directed back towards the stormwater drains or into areas of garden that can cope with being inundated by water.

     

    Cath Has a Kickstarter Project to Produce a Book Designed to Help Educate Children

    A lot of Cath’s work is designing systems for schools. She has a Kickstarter project which will enable her to produce a book explaining about how the toilet systems work which she will be able to use when talking with the children.

     

    The Storage Tanks Are Generally Either Made of GRP (Glass Reinforced Polyester) or Polyethylene

    In the early days of rainwater harvesting the storage tanks tended to be made of concrete. Nowadays the two options are GRP (mostly for larger tanks) or poly (mostly for smaller tanks).

    A life cycle analysis was carried out on the two by Judith Thornton (CAT, AECB) who found that poly tanks were far better in terms of overall carbon footprint.

     

    Use Rainwater Harvesting Purely For The Garden if The Demand is Great Enough

    Cath recommends that for a domestic situation where you have a large requirement for garden watering, that you just use the rainwater for that and do not try and bring it into the house. Her reasons for this are because of the extra pipework and pump (for the mains backup) that will be needed. An additional outdoor mains tap will provide extra if required.

    If you’re harvesting rainwater purely for garden use then a different calculation for the storage tank is required. This reflects that as much water as possible will be collected during the non-growing months, in order to provide the best supply for the growing months.

     

     Find Out More

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    Transcript

    Download a transcript of the interview with Cath Hassell.

     

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  • HPH012 : Should You Invest in Renewable Energy? – with Dr Derek Taylor from Altechnica

    HPH012 : Should You Invest in Renewable Energy? – with Dr Derek Taylor from Altechnica

    Dr Derek Taylor from Altechnica weighs up the pros and cons of various renewable energy sources and shares his thoughts on whether you should be generating at home. He also talks about his role in creating one of the UK’s most energy-efficient homes.

     

    Interview with Dr Derek Taylor

    Dr Taylor trained at the Architectural Association but got interested in renewable energy and low energy building design in 1972. From then he started to pursue more of a renewables orientated career and did a masters in designing wind turbines and renewables, and came to the Open University. He is particularly interested in bringing together renewable energy and architecture to try and make it much more effective.

     

    There are still Fossil Fuels Available But CO2 Emissions are the Problem

    A lot of people believe we have reached peak oil and that we are now at the point of depletion. There’s still a lot of coal in the ground and a fair amount of gas available but their CO2 emissions are a big concern for climate change. It’s clear we need to make a step change. The scientists say we need to cut CO2 emissions by 80% in the next few decades.

    Cooling tower

     

    UK’s Best Renewable Energy Source is Wind

    In terms of renewable energy Dr Taylor believes wind energy and offshore wind energy offers the most promise to the UK. He explains that 40% of the potential wind energy resource in Europe is actually in the UK. That figure is looking at land based resources, with even more potential offshore.

     

    Phenomenal Increase in Wind Power

    Dr Taylor has recently been updating the wind energy section of the Open University renewable energy course. He noted that in the year 2000 there was about 30,000 MW of wind energy globally whereas in 2010, there was 38,000 MW installed in just one year. Now globally there is over 200 GW. Dr Taylor is impressed with the progress. The UK currently has the largest offshore wind farm in the world, which is off the coast of Thanet (installed by Swedish company Vattenfall), and they’re currently building a third offshore wind farm in the Thames Estuary, called the London Array, which will produce a fair proportion of London’s electricity needs.

    Wind-farm-on-hill

     

    Floating Wind Energy Technology Has a Huge Potential

    Tapping into floating wind energy technology, the wind energy resources in UK waters would be equivalent to the Gulf Oil reserves but every year.

     

    Renewable Energy Solutions Fit into Different Scales

    Generally there are three types of solution: building scale, an intermediate scale – which Dr Taylor calls neighbourhood or community scale – and large scale.

     

    Solar Makes The Most Sense For Buildings

    In terms of buildings, solar energy often makes the most sense for electricity generation, hot water and also for reducing space heating loads. In the summertime it can be used for cooling.

     

    Heat Pumps

    The temperature of the ground below a certain depth is constant throughout the year, so this provides another ambient source of energy.

     

    Wind Energy Isn’t Normally a Good Solution for Urban Areas

    The usability of renewables depends on the location as to whether they will perform effectively. Wind energy can make sense but in most cases it doesn’t in urban areas. Wind energy technology usually starts to make sense at community scale upwards, for example, a medium scale turbine might be appropriate for a village or a town. Costs can then be spread amongst householders.

     

    Former Watermill Sites Could Have Potential for Hydro Power

    The best sites for hydro tend to be in mountainous areas, but Dr Taylor suggests that former watermill sites could be good places to generate. It’s important to note that when watermills were in use there was less water extraction so there was more water running through the system. Dr Taylor did a renewable energy study for Merton Council which found that a short stretch (19km) of the River Wandle once had about 90 watermills in operation.

    Old Water Mill

     

    Biofuels Make Most Sense When it’s a Waste Product

    Growing energy fuels is very difficult to justify when you haven’t got much land. A forested area can obviously provide wood as a fuel. Dr Taylor believes the situation with biofuels probably makes sense if you can use it as waste, such as food waste and oil waste. You can then process that with biology to produce gases and fuels. In Denmark there are community digesters where manure, food waste and sewage combine to produce methane – the process mimics a cow’s stomach and produces gas that can run small power stations.

     

    Tidal Barrages Expensive to Build and Maintain

    The main problem with tidal energy is that it’s been exploited using tidal barrages, like a big dam across an estuary. These are very expensive to build and can impact on the rich eco systems. In France, there is an example of a successful barrage called La Rance.

     

    Tidal Stream Technology Shows Promise

    Essentially they are underwater wind turbines which capture the currents as they flow around the coasts. One of the big advantages is that because water is 800 times denser than air for a given size of rotor diameter you get a lot more power out compared to wind turbines because air is very low density. This means much smaller devices can give more power output. The downside is that these devices are situated in difficult locations and have to be able to cope with the water reliably. They’re still in the early stages of development.

     

    Devices Built to Harness Wave Energy Have to Survive The Stormiest Seas

    Dr Taylor reckons that wave energy is an even more difficult one to achieve. The energy resources from the waves are substantial but you have to build devices which can survive 24/7 in the most stormy seas.

     

    Failures Important to Progressing the Technologies

    Very few of the wave energy projects actually go through the iterative stages that are needed to develop a technology. Lots of funding goes into building one device and that fails and there’s no money to carry on. Those failures are vital to progressing the technology.

     

    We Can Use Fossil Fuel Reserves Much More Effectively

    While fossil fuels might still be available, Dr Taylor believes that the price will be the main constraint to using them. He stresses how in other countries they’re actually much further on with many aspects of design, performance of houses and also the use of wind energy.

     

    Combined Heat and Power Makes Use of Waste Heat

    One approach for district heating is to use the waste heat from power stations to heat houses. Dr Taylor calculated that if you add up all the energy being lost from the cooling towers around Britain, it amounts to more energy than is used to heat all the houses in Britain. Currently this energy is just allowed to go into the atmosphere or into the sea at coastal locations. In Denmark 65% of houses are heated this way or from large scale boilers. To achieve this heat mains are laid under roads or gardens and each house is then connected up. Part of the difficulty is that electricity networks are privatised and they would rather do what they’ve always done.

     

    Heat Stores Play an Important Part

    Dr Taylor explains that Battersea Power Station was a combined heat and power station when it was operating. There was a pipe under the Thames which provided heat for 4000 houses in Pimlico. They’ve subsequently re-installed a small combined heat and power station at Pimlico which delivers the same thing. Part of that scale of development enables very large heat stores to be built in, so that heat can be stored when you’re generating electricity for use later. Heat from other sources such as solar or wind energy can also be used to charge up the heat stores.

    London Battersea powerstation

     

    Nuclear Energy is Expensive and Funding Must Be Offset to Look After The Waste

    In France about 80% of their electricity comes from nuclear, but this doesn’t mean its future is clear. Not only is it expensive but disposing of nuclear waste is still a big problem. How much money will be needed in the future to look after nuclear waste from the past? There are also discussions about what’s going to be the most useful type of fuel after uranium.

     

    Low Energy Buildings Fall into Two Strands

    Historically there are two strands of developing low energy buildings. One is known as the super insulated approach that tends to be a lightweight construction with lots of insulation. The other approach is known as passive solar, which is reliant on lots of solar orientation, lots of glazing and high thermal mass. The solar gains are trapped in the thermal mass so that it acts like a storage heater.

     

    Super Passive Solar

    In the UK passive solar hasn’t worked well in the spring or autumn times when there tends to be quite high cloud cover. There is also not much benefit in the winter time whereas super insulation then works well. So a super passive solar approach combines the two so you have a high level of thermal mass but it’s inside a super insulated envelope. Dr Taylor worked on a house in Herefordshire which might be one of the UK’s most energy efficient homes.

     

    Super Passive Solar Goes a Step Further Than Passivhaus

    Dr Taylor really likes the Passivhaus standard although he finds it unfortunate that they chose the name Passivhaus as it’s easily confused with passive solar. It is really an ultra super insulation approach. The Passivhaus design system doesn’t really take into account the thermal gains from thermal mass, so you can’t get that extra point further of actually optimising the design to get to zero space heating, although a lot of Passivhaus buildings are getting pretty close to that.

     

    With New Builds, Push the Envelope as far as You Can

    For new buildings Dr Taylor thinks you have to push the building’s envelope as far as you can because it’s much more difficult to upgrade. If you can design as much insulation as possible and get to Passivhaus standards then it will be well worth doing and shouldn’t cost you a great deal more on top of the building.

     

    If You Have The Money, a Passivhaus Retrofit Can be a Good Investment

    Upgrading an existing building to Passivhaus is not a cheap option. However it’s probably better using that money to go into the building’s fabric rather than getting an expensive new kitchen!

     

    Internal Insulation Must be Done Correctly or You Risk Damaging the Building

    External insulation is a much easier solution but risks affecting the aesthetics. The problem with internally insulating walls is that there will be a reduction of floor area. Also, with solid walls, for instance, prior to that wall being internally insulated, it’s been kept warm by the space heating of the house but once the insulation is between it and the heating then it’s obviously a cold object and it’s a cold surface. So, unless the internal insulation is done correctly, if any vapour gets into that structure it will hit the cold wall and condense. This can cause rotting problems.

    craftsman insulating a wall

     

    Combined Heat and Power Could Buy us Some Time to Retrofit

    Dr Taylor refers back to how we might reduce the CO2 emissions from buildings. Investing in combined heat and power, and district heating would enable the existing buildings to start to use heating which is actually low carbon. It would also buy some time to upgrade the performance of the existing housing stock.

     

    We Only Have One Chance to Make our Homes Energy Efficient

    In order to reach 80% reductions in CO2 Dr Taylor believes that we must go beyond a little cavity wall insulation. He thinks we only get one shot at this and it should be done properly. The challenge will be funding it. If there were a scheme where everyone was connected to a heat network then there’s a potential revenue stream for the sale of that heat to people which could be used to fund insulation of buildings down the road.

     

    Incremental Improvements Should Have a Long Term Plan

    Try and have a plan or a strategy so you’re not going to foreclose on the options. Do the thinking upfront so that improvements compliment each other. If you have a loft that can be insulated then certainly the more upgrades you can do to that the better.

     

    Dr Derek Taylor’s company

     

    Transcript

    Download a transcript of the interview with Dr Derek Taylor.

     

    Goals for House Planning Help in 2013

    Ben Adam-Smith outlines his objectives for making House Planning Help an even better resource. This includes:

    • Getting more detail into each podcast episode
    • Creating more videos for the House Planning Help YouTube channel
    • Hand-picking more industry experts as guest bloggers
    • Hosting Google+ Hangouts to debate key issues

     

    Regen Media Wants to Help Your Business

    Regen Media produces the House Planning Help Podcast. Ben Adam-Smith explains how if you are in the UK and you need video or audio for your business, then Regen Media wants to help you. It is very important to have a presence on multiple platforms in the age of the Internet so that your company can be heard above the noise! Regen Media can create media that will do this and market your business in a much more dynamic way than advertising. Contact us today to find out more.

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