The batteries of early electric cars take many hours to recharge. The small numbers of battery cars on the road today are usually charged at the home using standard three pin sockets on an off-peak tariff. The rate at which the batteries can be charged is severely limited but this is not important if the car is not needed overnight.

Public recharging points are different.  Here the speed of recharging is critical to the future acceptability of electric cars. If my car has a range of 100 miles and I need to travel further, I want a widespread charging network that allows me to plug in the vehicle, go to have a snack, and return to find it fully charged.  Quite rationally, the world’s car manufacturers decided they needed a global standard for the electronics, cables and connectors for these networks. Without such a standard my drive to Birmingham might be stalled halfway because the charging points weren’t suitable for my particular vehicle.

In the last few months the form of that international standard has become clear. Mercedes and Smart have committed their support and other manufacturers will follow by the end of 2010. Countries such as Ireland have also committed to creating a national network based on this standard. ‘7 pin’ refers to the number of pins in the connectors. 7 pin is capable of taking charge from 3 phase electricity, the type that is used in almost all commercial locations. So, for example, your office will probably have 3 phase power but your home will not. Broadly speaking, 3 phase power will is available everywhere the authorities are likely to want to put a charging point. Commercial operators, such as motorway service stations will all use it.  Importantly, 7 pin connectors can also be used to charge cars parked at home, using conventional domestic sockets. It is a flexible and robust standard.

The first mass market electric car to arrive in the UK is likely to be the Nissan LEAF in spring 2010. It will almost certainly have a 7 pin connector. For this car to have the success it needs, 7 pin public charging  points are vital.  Remember than Nissan intends eventually to make the Leaf in its Sunderland factory and it won’t look good if Nissan’s UK sales are held back by an inappropriate charging infrastructure.

The 7 pin system allows charging at a rate of up to 63 kilowatts, compared to less than 7 kilowatts at home. This greater charging rate can’t be fully utilised immediately because most cars will not themselves be appropriately equipped.  But commercial electric vehicles, such as the Modec urban delivery vans will probably soon be able to take the full power from 7 pin charging points, enhancing the commercial attractiveness of these British-made world leading vehicles.

All the evidence suggests that the 7 pin system will be installed in all the world’s electric cars from next year. London has chosen to ignore this. By this time next year it intends to have installed 700 public charging points, paid for by central government funds. None of the companies that have been allowed to compete in the tender have the capability to offer the 7 pin charging system and all are offering the older single phase alternative. Importantly, the single phase charging system that London intends to use has metal posts that are physically too small to accommodate 7 pin cabling and in the future.  When London eventually decides to replace single phase posts with the 7 pin alternative, as it eventually must, it will have to dig up the street again.

Why has this happened? Charging technology is moving fast and London didn’t realise soon enough that 7 pin would be the dominant worldwide technology. Public procurement rules meant that that the Mayor’s office had to ‘pre-qualify’ potential suppliers several months ago. This was before reliable supplies of 7 pin equipment from companies such as Chargepoint Services became available. But if London proceeds with the tendering process it will be locking itself into many hundreds of charging points that will be effectively useless by this time next year. This is costly and will delay the takeoff of sales of electric cars. Newcastle, which along with Milton Keynes successfully bid for government money to install a public network of charging points, has just agreed to admit 7 pin suppliers into the contract race. London urgently needs to do the same.

The two key problems are now well known. Food production systems in the developed world tend to produce about one unit of energy for every ten units of energy input. Therefore the recent – only possibly humorous - suggestion that the UK government should introduce electricity generating treadmills into prisons would therefore add to total energy demand, not reduce it. To remain at a stable weight, prisoners would need to eat more calories and these calories might take ten times as much energy to produce as the maximum amount of electricity generation derived from the treadmill. We need two kilowatt hours or so of energy a day to fuel ourselves but it currently takes 25 kWh to produce this.

Second, the footprint of food is dominated by that of meat and dairy products. Most estimates show that over half the emissions from a Western diet derive from meat. As people get richer, they demand more animal protein, increasing both direct emissions, particularly of methane, and also heightening the pressure to convert forest to food production. Stabilising and then rapidly reducing global emissions from the food production chain is appallingly difficult to reconcile with increased levels of prosperity.

The Fife Diet is a successful and well-regarded experiment to push people in eastern Scotland into thinking actively about the source of the food that they buy. It is similar to the Canadian 100 mile diet. (www.100milediet.org), which asks individuals to commit to only buying food grown in the local area.  It therefore isn’t just about local food, but also about buying seasonal produce and so help get a fuller sense of the connection between what we eat and how and where it is produced.

From a small base, the local food movement is gaining strength around the prosperous world. The detailed survey of Fife Diet members showed that the greenhouse gas emissions from the food that they bought, cooked and then disposed of are lower than the national average. But the impact of merely buying locally is small.

     Greenhouse gas emissions (CO2e) from food, per year per person

                                                            2.8 tonnes                   2.1 tonnes

                                                            UK adult average         Fife Diet members

The lower number comes not from the energy-saving benefits of buying local, which provides only 8% of the reduction, but from the smaller amount of meat and dairy eaten by the survey respondents. The impact of the higher level of organic food consumption, lower wastage and greater food production at home of the Fife Dieters did not produce a significant cut in their emissions compared to the UK average. The lower meat consumption cut emissions by over half of tonne, about three quarters of the total reduction. But at 2.1 tonnes a head, the Fifers still had emissions from food consumption greater than total per capita allowance for 2050. And it has to be said that the greater eco-awareness of the Fife diet people probably meant that they already had a much lower food footprint before becoming members.

The conclusion is a painful one. Getting down to about 0.5 tonnes a head by mid-century will almost certainly require a portfolio of measures that combines near-total decarbonisation of the energy sources in food production (eg the farm tractor runs on electricity or sustainably produced bio-diesel) and a radical change in consumption habits. Vegan food, produced on largely animal free farms, will become the dominant source of nutrition if we are to meet our targets. (Unless, that is, we find a way of artificially producing meat in vats). Importantly, several recent studies show that vegan food that is manufactured to look/taste like meat (such as industrially produced tofu) often has a ‘foodprint’ not dissimilar to its meat equivalent. The food we will eat will have to be largely unprocessed wholefoods, such as complete grains. (3)

In other words we will need both changes in consumption patterns and substantial advances in technology. Neither shifting shopping patterns (eg just buying seasonal food from the region and cutting out most meat) nor relying on technological change will be enough.  We need both. The remaining problem is that the eco-greens who support local farming, mild vegetarianism and organic techniques are a very different set of people to the urban techno-greens who lead the drive for total decarbonisation of energy production, perhaps through nuclear power or tens of thousands of wind turbines in the Fife countryside. Building consensus over food is going to be as difficult as over energy supplies.

(1)    These are figures from a variety of sources but are in line with the recent report from WWF entitled ‘How Low Can We Go’.

(2)    Fife Diet: Carbon foodprint (sic): comparative study and member analysis, August 2010.

(3)    As a failed vegan, I find the research and advocacy at www.stockfreeorganic.net to be powerful and highly informative.

Details on the home with the new heat pump.

The ASHP was installed at a ground floor flat in a very large Victorian semi-detached house in north Oxford. The floor area is about 140 square metres/1500 square feet, compared to the average UK property of around 85 square metres. The walls are solid brick, a feature that makes the house quite difficult to heat economically.

The owners of the property have kept records of all their energy bills. Before the installation of the ASHP in May 2009, the house typically used about 2,600 kWh of electricity and 24,000 kWh of gas. The gas provided the fuel for space heating, water heating and cooking. These numbers are in line with UK averages for housing of this size and type.

Energy use in year before installation of ASHP

The ASHP provides space and water heating. So some gas is still needed for cooking. After installation of the ASHP, the first twelve months energy use was as follows

Energy use after installation of ASHP

As expected, the total energy demand went down very considerably. If we assume that underlying electricity use (lights and appliances) stayed the same as before installation, the ASHP provided the house with heat using 5,801 kWh of electricity. This replaced about 24,000 kWh of gas (this excludes my estimate of about 950 kilowatt hours of gas used for cooking).

At first sight, these numbers look suspiciously good.  Heating the house uses only one unit of electricity where four were used before. Most estimates of the efficiency of ASHPs suggest that they only produce about 3.15 units of heat for each unit of electricity. The explanation is that this house had an old and inefficient gas boiler. So although 24,000 kWh of gas were used for heating only about 18,000 would have produced usable heat. Divide 18,000 kWh by 5,801 kWh of electricity and the underlying performance of the ASHP was actually very slightly less good than predicted. (For fans of this index, the Coefficient of Performance was about 3.10). This is to be expected; a hard winter will marginally affect the efficiency of a heat pump.

So there was a real improvement in energy use. This is why many countries are strongly encouraging heat pump installation as a way of reducing the demand for fossil fuels. But what about the cash savings? Electricity is much more expensive than gas. My calculations used British Gas’s lowest online tariffs for Oxford and showed that the houseowners will have saved about £145 a year by buying a heat pump rather than replacing their old boiler with a new and much more efficient model.

The CO2 saving can also be calculated. Generating a kilowatt hour of electricity in the UK causes emissions of about 0.5 kg of CO2 compared to about 0.2 kg from burning a kWh of gas. The transition to an ASHP in this house saved about 1.1 tonnes of CO2 a year, or just over a fifth of total emissions from heating. This is a good saving and will rise as electricity generation moves to lower carbon sources such as wind and new nuclear. In other words, the government is right to push us into using ASHPs.

But heat pumps are costly. The one whose electricity use I measured cost about £4,000 more than a good new condensing boiler. So cutting your energy use in this way doesn’t come cheap. The government’s proposed Renewable Heat Incentive (RHI) will therefore pay householders an amount each year to compensate for the high cost of installing a pump. The RHI will make an estimate of a reasonable heat demand for a house (based upon its size and whether it has cavity walls) and then pay 7.5p for each kWh of heat that the ASHP is ‘deemed’ to replace. In the case of the house whose energy use I measured, the deemed heat use will probably be about 15,000 kWh – a little less than the actual figure before the ASHP was installed. So the yearly subsidy payment (for 18 years) will be about £1,125. This payment (which may be adjusted downwards before being finally implemented in April 2011) clearly provides a real incentive to spend an extra £4,000 when replacing an old boiler. In fact, you might say the payment was too generous: the rest of us will all be paying a little bit more on our gas bills for the next few decades to cover the cost.

What about the other worry I expressed in my earlier article? Did the house stay warm in winter? The owners were more than pleased, saying that their home was comfortable even during the coldest nights. My nervous scepticism was wrong; even in a old brick build house a good ASHP of the right size can provide all the heat we need.