The Planning System and Sustainability

Sustainability should mean leaving the planet in a more attractive state than you found it. And this is where many ‘sustainable’; developments fail.

The system we currently have for regulating sustainability consists of rules that tend to encourage ugly architecture and involve a serious waste of resources

nergy-saving issues are dealt with by the Building Regulations, and this is clearly the best place to deal with such issues. It is then dealt with by experts in accord with established national standards. Yet now following central government advice, every local authority started to double-up on the Building Regulations ‘Part L’ energy-saving requirements, with proposals of their own.

Some Local Planning Authorities require, say, Level 3 or Level 4 on the ‘Code for Sustainable Homes’, whereas others require 10% or 20% renewable energy. There are various definitions of ‘renewable’. Some local authorities apply the requirement applies to every house, others it only applies to developments or five houses, or ten houses or more. And each Local Planning Authority regularly changes its policies.

Because of this, when a Planning application is submitted, the applicant may, even for a small house, have to pay over a thousand pounds for a Code ’pre-assessment’ on a scheme that gets refused anyway. What a waste of resources when there is a set of sustainability measures in Part L of the Building Regulations with which all developments have to comply. Though, in fairness, I find that a chat with a Planner, explaining the situation, before submitting can help avoid the worst of the waste

If ‘sustainability’ were no longer a regular part of almost all planning applications it would cut down enormously on waste within local government, and waste for house owners, whilst effectively introducing a more rational national system.

Modern houses of around 2500 sq ft, built merely to the old 2006 Building Regulations , emit around four tonnes of CO2 annually. Yet, before the 2008 credit crunch, Lloyds TSB offered ‘air miles mortgages’. For the £700,000 needed to buy one of these houses, the family could then have visited New York a couple of times, thus emitting around 15 tonnes of CO2. In other words, about four times the annual output of the house. If there were a box in ‘The Code for Sustainable Homes’ that could be ticked for not selling to anyone with an air-miles mortgage, then that box would be worth as much as all other boxes put together. But a government may lose votes by restricting foreign holidays, whereas it can play games with the Building Regulations with relative impunity.

Photovoltaic cells

Lack of investment in power generation in Britain may soon cause a crisis in our power supply. The politicians’ answer is pure genius: invent a system whereby we pay three or four times more for our energy than we currently do, and persuade us we getting free energy!

There are two main facts the consumer needs to know: (i) the costs and (ii) the savings. The figures are simple to work out. Outputs of photovoltaic cells are usually quoted to kWp. This is the peak output under ideal conditions. But the relevant figure is the energy generated by the system in an average year. In southern England, for a south facing roof, in an unshaded position, you multiply the kWp figure by 800 to estimate the energy generated annually.

Thus an average system of 2kWp (around 16 square metres of panelling) would generate around 1600 kWh/year. The cost of installation might be around £8,000. The system is usually guaranteed for five years, though the claimed life expectancy is around 25 years. So a loan of £8k, for twenty five years, at an interest rate of 6%, costs £625 per annum. But, at 13p per unit, the true value of the electricity generated is just £208! (And the householder only gets to use around half of the ‘free’ electricity.)

There is something absurd but important to consider here, and that is the ‘Feed in Tariff’. This is a system whereby energy consumers who do not have photovoltaic panels (say, because they do own their own houses, or live in flats) subsidise their wealthy neighbours. The FiT subsidy is 21p per unit of power generated. So currently the FiT pays the owner of the 2kWp typical system around £335 a year

But does even this make it a good idea for a householder? Well, if you generate 1600kWh per year you’ll use about half of it, saving a little over £100. And you’ll sell half back to the grid at 3p per unit, netting you £24. The main benefit will be the Feed in Tariff which makes you another £335. So you gain around £460. But you repay £625 to the bank, and you need to budget another up to £200 a year to replace the inverter every ten years or so. So you lose more than £300 a year.

As other electricity consumers that pay for the subsidy, if more than a small minority of consumers take up this option electricity will get very expensive. Photovoltaic systems usually only generate around a third of your electricity needs, the other two thirds you buy in the normal way. So whilst your neighbours will be paying a huge subsidy to you: you will soon be paying a huge subsidy back to them. The 13p to 14p per unit you currently pay will rocket.

‘Sustainability’ is about leaving the planet in a more attractive state than you found it. Photovoltaic systems do the exact opposite, they are extremely ugly, and ruin the appearance of almost any house and the surrounding area. (There is the option of photovoltaic ‘slates’ and tiles, whose appearance less offensive, but they cost even more than panels.)

Finally, to add to the daftness, and in order to further encourage the use of this expensive and ugly technology the government changed the planning laws to allow solar panels to be installed on any slope of roof, even front roof slopes, even in conservation areas. The only stated prohibition is that they must not project beyond the plane of the roof by more than 200mm, and must not be higher than the ridge of the roof. But in the usual confused manner of modern government, the revised order also states

(a) solar PV or solar thermal equipment installed on a building shall, so far as practicable, be sited so as to minimise its effect on the external appearance of the building;

(b) solar PV or solar thermal equipment shall, so far as practicable, be sited so as to minimise its effect on the amenity of the area

So, plenty of scope to challenge any installation on a front roof slope! Did the householder use the least obtrusive technology? Might he have used (expensive) photovoltaic tiles in order to minimise the effect? Might an unfortunate householder be required to remove his £12k installation?

In summary: encouraging the use of ugly technology to produce energy that costs three times the current cost, with very confused legislation, is not the answer to our current problems.

Ground Source and Air Source Heat Pumps

In most houses heat pumps are even more pointless than photovoltaic cells. The main advantage of heat pumps is as a way of getting your ‘renewable energy’ box ticked when submitting a planning submission.

Ground source heat pumps are powered by electricity, and work on the principle that you receive, in theory, around 3.2 units of electricity for every unit you put in for underfloor heating, and around 2 units of electricity for every unit for hot water. Trouble is that gas costs around 3p per kWh, and electricity costs 13p. So, clearly, a conventional gas-fired system provides cheaper energy than a ground source heat pump. And the heat pump doesn’t even allow you to enjoy a smug feeling that you’re saving CO2: the government sponsored ‘Energy Saving Trust’ admits that no CO2 is saved and states “heat pumps are not recommended for homes on the gas network”. This is, of course, due to the way that grid-energy is generated in this country.

Many consultants admit that in reality the coefficient of performance for space heating is not 3.2, it’s often a good deal less.

A ground source heat pump involves digging up much of your garden to a depth of 1.5 to 2m, and coughing up perhaps an extra £12,000 for your heating system, and you get nothing in return. But at least you can’t see ground source heat pumps, and so unlike most other renewable energy systems they’re won’t form a local eyesore.

Are air source heat pumps better? The simple answer is no. Companies that sell both systems tend to suggest that an air-source system is what you use when ground-source is impractical. They work best in summer (when you need the heat least) and poorly in winter (when you need it most). On average air-source pumps give you 2.5 times the electricity you put in (if used with underfloor heating, and rather less with radiators). So, they’re less efficient than ground source pumps; won’t last as long, and you need somewhere to put the rather ugly, and noisy, units. But at least they don’t involve digging up the garden, and so are cheaper to install. Again, their main use is as a box-ticking exercise for Planning applications.

Wood Pellet Stoves and Boilers

This is another favourite of local authorities. But if gas is available, then wood-pellet heating is an expensive and inconvenient alternative. You pay more for your fuel than you would with gas-fired system, and you need a suitably large storage area for the wood, and you may need to regularly feed the stove or boiler yourself. Other drawbacks can be the smoke and the thought that perhaps the wood came from a resource that might otherwise have grown crops for hungry people. The theoretical advantage is that the wood has previously absorbed as much CO2 as it releases when it’s burned.

However, if you have a house with a heavy thermal mass, and a central hall with a fireplace: a 2kW HETAS-approved wood-burning stove might provide genuinely useful heat to the whole house, in a carbon-friendly way. If used ten hours a day, six months a year, 3600 kWh of carbon-neutral energy have been generated. And that could count as more than 10% of the energy requirements of a large (350 square metre) detached house. It could be a way of keeping the local authority satisfied with a new house’s green credentials, and provide an attractive feature within the house. It should be relatively cheap to install (compared to photovoltaic cells, or a ground source heat pump) and you needn’t actually use the stove if you don’t like the cost, or hard work, of burning wood.

Stoves can of course be used in conjunction with other ‘green’ energy to boost your ‘renewables’ figure. So, perhaps lots of advantages, especially when it comes to box ticking at Planning application time. (But, sadly, the standard methods of assessing carbon, for Code or SAP calculations do not seem designed to take account of the advantages of such stoves.)

Optimum insulation for cavity walls

I tend to design houses with a 75mm insulated cavity. Most architects specify at least 100mm; and it’s not unusual to see, featured in magazines, up to 200mm.

In 2010 I asked the man who prepares my Energy Performance Certificates to re-enter a 100mm cavity width (in lieu of 75mm) into his computer, - for a new 2200 square feet detached house. He told me that the saving on the gas bill would be about £11 per year. However the thicker external walls would have reduced the floor area by twenty two square feet and the house was worth £350 per square foot. So, excluding the extra cost of the insulation, longer wall ties, extended cavity closers, etc, you end up with the fact that you’ve wasted £7700 in order to save £11 a year. A simple payback period of seven hundred years. We’re nearer in time to the Battle of Agincourt than to the time the extra insulation will have paid for itself! The interest alone on the £7700 is likely to be forty times the savings. If you sponsored an off-shore wind farm you’d recoup your £7700 in perhaps twenty years. Still not commercially sensible, but thirty five times less daft than 100mm cavity insulation.