Today the Committee on Climate Change published its ‘Next Steps for Heat Policy‘.
Heating and hot water for UK buildings make up 40% of our energy consumption and 20% of our greenhouse gas emissions. It will be necessary to largely eliminate these emissions by around 2050 to meet the targets in the Climate Change Act and to maintain the UK contribution to international action under the Paris Agreement.
It’s been widely welcomed for highlighting the stalling of Government policy in recent years. But one point sticks out to us in particular:
New-build. Buildings constructed now should not require retrofit in 15 years’ time. Rather, they should be highly energy efficient and designed to accommodate low-carbon heating from the start, meaning that it is possible to optimise the overall system efficiency and comfort at a building level.
The document expands on the potential for heat pumps and district heating, but where is the option of zero-heating? Why not build homes so they don’t need central heating? Whose heating system helps with summer cooling? And use solar PV and wind to top up efficient immersion heated water stores when renewable power supply surpasses time-critical demand?
It can be done, with existing technology and skills, at roughly the same cost as a new home built to building regulations alone, and here’s our energy use from the last 15 years, and a related temperature study to prove it.
The average energy use by the homes at Hockerton Housing Project has consistently been less than a third of that used by the ‘average’ UK household, and two-thirds of that demanded by the Passive House standard. 
So why is this approach not being followed more often?
- The Government’s preferred energy performance calculation (RdSAP and SAP) can’t calculate the benefits from interseasonal storage.
- There is no great commercial incentive to lobby for this low-tech and affordable approach. It profits residents rather than manufacturers or standard-setters.
- There’s an assumption that high thermal mass, in the form of concrete, is inherently bad. It’s not if it removes the need for heating, reduces maintenance, and increases the durability of the home. Parity with timber-framed homes is reached at about 20 years.
- That’s it.
And here’s the small print:
- 5 homes, averaging 2 adults, 1-2 children
- Increase use over time reflects increased home-working and children becoming teenagers. Savings in the general population are not mirrored as homes at Hockerton have always had energy efficient lightbulbs, sought the most efficient appliances, and had energy-aware residents.
- Temperature tracking was undertaken when home was drying out and with low occupancy in that first winter, so not a perfect study, and overheating is now minimised through shading of conservatory sunspaces during summer. Even before this, the instances of overheating met the requirements of the Passive House standard.
- When space heating is required, it can be delivered by small electric heaters with far lower capital and operational costs. Such occasional use is included in the usage graph above.
- The ‘average household’ energy use data is taken from UK Government statistics for household energy use.
- Readings are taken manually so some of the quarters are thirds, or very small quarters. One particular peak can be put down to our Christmas party in 2012! If anyone wants to fund/test automated reads, do get in touch!
Every 3 – 4 months we read our 50 power and water meters to check how we are doing in terms of consumption, generation and export.
Each household pays for their share of consumption relative to use, with any income from the export of renewable energy shared equally between us.
The resultant figures help us remain aware of our use, not least because we see it relative to (or in competition with?!) our neighbours. It also reminds us how well these houses perform. This can become easy to forget when the house is your home – until heatwaves like this week, when we could feel the difference as the thermal mass soaked up any heat that made it through shaded windows.
* Our average daily energy use was around 23% of a standard house (per house, not incl the garages).
* We exported 38% of what we generated, compared with 48% in the winter
* We earn around 4p for a kWh exported but pay on average 7.5p per kWh we use, so over the last 4 months we’ve missed out on energy worth £145.
* In the last 4 months we’ve generated the equivalent of 95% of our total household use (not including our shares in our community-owned wind turbine of course).
* And we are using 260 litres of water a day per house on average. Potable: non-potable is 1:11. This is a similar ratio to that in the first quarter but an increase overall. Average usage per person is 82 litres, compared with Code for Sustainable Homes Level 5 and 6 target of 80 litres – perhaps due to higher number of washes during peak vegetable gardening season!
This week we popped in to one of the homes that we retrofitted in 2010/11 as part of a Government-funded project, Retrofit for the Future, to find out how it was performing.
The headline finding is that the house is now using 9% of the energy it previously used for space and water heating; down from 12493kWh to 1133kWh. Overall energy use has been reduced by 75%, with the carbon emissions from the remaining use offset by a cost-effective investment in off-site renewables.
We visited after one year and found that actual energy use was 47% less than that predicted by SAP. There has been a further significant fall since then. Over the intervening years, the average energy use has been 30% of the use originally predicted for space and water heating, ventilation and lighting; and total average use has been 50% of use in that first year.
We expect heat usage to remain steady at this lower level (for the current occupancy patterns) as the fall can be attributed to one-off factors in that first year:
- the building was drying out
- the thermal mass had no heat stored as the build completed in early autumn
- the winter of 2010/11 was particularly cold
Use of energy for appliances and cooking remains the largest influence on energy use, forming two-thirds of annual use on average. As highlighted in previous posts this is very dependent on working patterns and the number of residents. The final 3% of energy use is by the metering system itself – with metering on 8 rings in the house to enable this analysis.
Last, but certainly not least, was the residents’ feedback. The most notable problem was a rain sensor on the automated Velux windows in the sunspace, but that has been repaired quickly enough, and the occupants continue to enjoy the comfort of their old but cheaper-to-heat home.
This autumn, HHP is racing against the clock to install further solar PV roofs funded by local community energy co-op Sustainable Hockerton.
The plan is to install two roofs on local businesses – one of 10kW and a further one of 27kW. The businesses benefit from lower cost power, Sustainable Hockerton members benefit from continued returns from their investment, and the community benefits from a village sustainability fund.
These new installations will be funded by the co-op’s income from its 225kW wind turbine, potentially with some top-up loans from its members, and will help further diversify the renewable energy systems in our parish.
The clock is, as many of you will know, ticking. The Government plans to substantially cut the feed-in tariff and, as of 1 October, removed the ability to pre-register schemes for the feed-in tariff, removing the certainty that community schemes need to raise investment. These cuts appear far too big and far too early, whilst the attack on investor certainty pushes up costs – which is no way to help reduce energy bills in the long-term. We have sadly also begun to see the impact of specific cuts and a wider policy vacuum on jobs, with the loss of an estimated 1000 jobs at Mark Group and Climate Energy.
We can only hope this attack on renewables is a last gasp from a system historically reliant on the fossil fuel industry. Interest in our approach continues to engage and inspire other communities (pictured above are York Community Energy on a recent visit); and at a crucial time in the run up to Paris talks, the climate now has the Pope, Barack Obama, the governor of the Bank of England and Nanny McPhee firmly on its side.
It is, to say the least, disappointing that the UK Government is no longer leading the green agenda, but this is a global challenge and, as the business world opens its eyes to the high risks it faces, it feels like the balance is shifting.
If you want to find out more about what we’ve achieved at the street and community level, our next Sustainable Living tour is on Saturday 7 November.
Motivated by planning restrictions on our use of fossil-fuelled cars, between us we’ve now got experience of owning or leasing 3 EVs, a Nissan Leaf, a Volkswagen e-up!, and a Renault Zoe, and one PHEV [1], a Mitsubishi Outlander. We’re often asked about the running costs, but it’s not all about the money. If you’re thinking of getting one, here’s who we think they work for, and who they don’t…
Yes – if you want lower running costs.
Our Leaf and e-up! get around 4 miles per kwH, which at our off-peak tariff costs 2p per mile. This compares with 8p for a comparable petrol-fuelled up!
All-electric cars [2] have zero Vehicle Excise Duty (VED), even after upcoming changes, saving £140 each year from the second year of ownership. Hybrids and PHEVs don’t get such a good deal under this Government’s restructuring of VED.
If it is a company car both company and employee pay less the more efficient the car, with employees currently paying 5% benefit-in-kind rates, compared with a maximum of 37% for the least efficent cars.
Of course there are still costs, which will now fall on your electricity bill. Annoyingly there is no smart tech built into our chargers, or the car, to easily track usage and costs, but hopefully that will come.
Yes – if you care for the global environment
We have long been aware of the environmental impact of batteries – our homes are grid-connected for this very reason. Battery technology is now evolving in a way that addresses some of this impact, but this is not just a question of a battery, or even low carbon transport.
EVs are central to the planned decarbonisation of the grid, provided the right tariffs and signals come forward to enable them to soak up otherwise unwanted renewable and low carbon energy, and supply to homes during peak demand hours.
Yes – if you care for the local environment
I’ll assume that if you read this blog you would charge from renewable power so are not simply adding to pollution levels elsewhere! The Government claims that the adoption of ultra-low emission vehicles could prevent 29,000 premature deaths each year from air pollution.
Yes – if you are happy to plan ahead.
Don’t base your choice of vehicle on the claimed range. Cold weather has a big impact on battery efficiency.
Consider what charger type the car uses. The language used around these is unclear, as is a future standard, so our recommendation is to be flexible. When you get a charging point, don’t get a built-in cable
Work out where you are going to charge, which for us is normally at home. It may take time to arrange a home charging point, so do consider whether you have an interim solution, which could be as simple as a standard outdoor socket.
Yes – if you don’t like planning ahead.
For all the talk about range anxiety, the standout benefit of EVs is no longer having to build petrol station visits in to your travels. For most of us, charging just means plugging in when we get home.
Yes – if you don’t like noise pollution.
Some critics cite the danger of quiet cars. Yes, you’ll find yourself giving pedestrians and cyclists an (even) wider berth, but do so in the knowledge you are cutting noise, as well as air, pollution.
Yes – if you have solar PV or other renewables.
At HHP, we estimate we’re losing £500 a year exporting power we can’t use onsite. The more we can store power in EVs or our immersion heaters, the less we need to draw from the grid, and the greater our autonomy.
Yes – if you want the best parking space
OK, this is only going to be the case whilst EV user numbers are low, but the free charging at service stations, the local Park&Ride, and Ikea(!) also means accessible spaces even on the busiest days.
Maybe – if you regularly travel long distances
Whether this is a problem depends whether your wallet is in Tesla territory, but even if you are not, there are options. Either take up the PHEV option or consider whether you are happy to stop for a coffee break. Both work for us, but there have been teething problems with some of the charging points on motorways.
Also, be warned that the Government’s Office for Low Emission Vehicles (OLEV) has allowed a patchwork of propietary charge cards to develop, meaning you have not only to work out where chargers are, but what charge card you need, and sign up accordingly.
In any case, there’s always the train!
Maybe – if you need to tow manure/sheep/caravans
Your choice will be limited, and this need was the major factor in the selection of the Outlander by one household. Pure EVs, and for that matter hybrids such as the Prius, don’t have this capacity.
If you do go down the PHEV route, take a look at online forums to understand real-life mpg for your type of journeys.
No – if you can’t charge at home.
Convenience is the EV’s unsung benefit. If you can’t charge at home and are not within easy walking distance of a public charging point, the hassle is probably not worth it. If you are close to one, you are probably also close to public transport – why not use that?!
No – if you are in it for the cost savings alone
The Treasury won’t easily give up the £31.58 billion [3] it earns from Fuel Duty and VED, as seen in this summer’s budget which undermined the fiscal incentive to purchase efficient petrol cars. Don’t expect ‘free’ charging points to remain free, or to always have a tax advantage over fossil-fuelled cars. If and when they become the norm, we should expect to see some radical changes to VED in response to the loss of revenue from Fuel Duty.
And finally…
A few more good things: the acceleration; increasing your range going down a big hill; more data for us energy geeks; and some decent cupholders too.
[1] Plug-in hybrid electric vehicle, which can travel up to 30 miles on a single charge before switching to hybrid mode.
[2] That cost less than £40,000
[3] http://www.racfoundation.org/motoring-faqs/Economics
