How are you calculating your carbon footprint?

I would add a requirement for new public and private buildings to either incorporate a solar roof (more attractive than added solar panels) or at the very least orientated so that panels would be effective if added at a later date. If gas is to be phased out within the foreseeable future then new buildings should have ground source heat pumps.

There is only so much economically accessible latent heat in the ground. Is an infinite number of heat pumps sustainable?

I am glad Keith specified “electrifying rail lines”; it worries me that the government and others consider electrification to be impractical or unaffordable and keep looking for alternative sources of power such as batteries or hydrogen.

Batteries are not especially efficient, require scarce resources to manufacture, and are heavy and take up space; they also require charging with electricity [which can, of course, be done out of peak demand times using renewable energy but requires more infrastructure such as tidal power to provide the assurance and reliability not offered by wind power].

Hydrogen power is not particularly efficient either and requires a disproportionate amount of electricity to produce the hydrogen which then has to be distributed to and stored on board the train where it is used to make electricity for driving the motors; the hydrogen production process can also [and should] utilise off peak renewable energy but more specialised infrastructure will therefore be needed.

The beauty of electric traction, powered conventionally through overhead lines or a third rail, is that there is a national grid network supplying power throughout the country to wherever it is needed [capacity enhancement will be required in places but a general increase in energy efficiency throughout all uses means the extra demand can possibly be contained within the existing overall provision for railway purposes]; it also means that the hauled weight is reduced because there is no requirement to carry batteries or store fuel and once the entire system is electrified any train can run any where on any track. Electric trains can also use regenerative braking which puts surplus power back into the grid. Battery and hydrogen locomotives would not provide the amount of power needed for freight haulage so unless the line has been electrified we are back to diesel engines.

I have a worry that we will become totally dependent upon one fuel, electricity, for all our activity – transport and heating particularly. Diversifying its origins, solar, wind, tidal, nuclear, is one way to help security but its distribution is wide open to disruption, whether from natural or mischievous causes. How do we deal with this?

That’s definitely the way we’re going. More efficient photocells, more use of geothermal energy and possibly a concerted and government-backed scheme to create tidal power lagoons would be a start but will it all keep the lights on becomes the question.

If we are to get rid of fossil fuels it limits the alternatives substantially. Heat has to come from electrical resistance or fire, or electrically assisted pumps. As you say, there diverse ways of producing the energy, but its distribution has to be by cable and grid unless each house has its own supply. For that to happen there would be a need for the house to have some form of expendable material that would need replenishing regularly. Currently, off grid, it’s oil and Calor gas or electric generator. Fuel cells would need a supply of hydrogen. Natural sun and wind are not reliable enough to use as a sole power source on a local basis. We are very poor at storing energy. Batteries are bulky and run flat quickly. Stone and other heat absorbent materials are also bulky and, as the Romans knew, need a good strong energy source to keep them warm. It is why energy comes from outside and is converted when it reaches its destination. I don’t see that situation changing any time soon. There are too many practical problems to overcome unless each house has a nuclear cell installed. We’d all be radiated to hell but even that would need renewing every so often.

Not necessarily; miniature fusion cells have been proposed by Sci Fi writers many times. Whether that will happen in our lifetimes is, however, open to debate.

Fiction can always dream up propositions. We need science fact to come up with workable solutions That is, unless we destroy the world in the meantime. Small nuclear power stations might enable local power to be independent of a disruption to the national grid.

The problem with conventional reactors at small scale is contamination. I’ve been re-reading Asimov’s Foundation Series and it’s fascinating how much he conceived in 1948 about the present day. Miniaturisation was a theme of Foundation and Foundation and Empire. However, small reactors currently available could easily power a small town. The real problem is probably fuel handling.

Silvi – Thank you on behalf of the planet Earth for your contribution to reducing its carbon footprint. It’s a good example of how everyone can help.

People can do a lot more through small changes to their lifestyle – the amount of clothing they buy, the number of miles they travel, the sort of food they eat, not replacing things that are still working satisfactorily, making the optimum use of daylight. Reading a book for a couple of hours instead of watching television or spending time on a computer can make a positive difference to energy consumption and self-improvement.

Of necessity, the on-line carbon footprint calculators [such as the one referenced in the Introduction to this Conversation] can only give a broad-brush approximation of any individual’s or household’s environmental impact but at this stage that is still helpful in getting people to think about decarbonisation of everyday functions and lifestyle changes that will make a positive difference. It might not satisfy purists and it might show that we are a still a long way off the target.

The lack of information is a drawback on the things you have mentioned – life-cycle analysis of replacement versus continued use – and some of the considerations, as we get closer to the target, will require sophisticated and expert scientific assistance to identify the best route. But at this point in the journey it is like being at the South Pole – you can turn left or right or any way you like but you will still be going North, so any movement in the right direction on carbon reduction will be a good thing and will provide a platform for further development. I don’t think we need to get over-specific on the details yet; the main thing is to point everyone in the general direction of travel and get their vision fixed on the objective.

This whole process will require strong leadership in the UK and across the world. One bad actor can ruin the project, and that is a serious worry. Getting unanimity of purpose on climate change has been an uphill struggle, and many people take the ‘not in my lifetime’ line to excuse themselves from action. We can all influence the future through our families and friends, through the things we do and the goods we buy, and by learning more about what will make the best net contribution to carbon reduction in each sphere of activity.

This will be challenging, for the task is immense and almost beyond our capacity to contemplate because it will mean, by 2050, unpicking the habits and expectations of a century of development – or what used to be labelled ‘progress’. This is to benefit generations as yet unborn to whom we have a collective duty.

I believe plenty of people will be willing to embark on this as individuals but I am not convinced the right mind-set is yet in place at corporate levels, whether industrial, commercial, or in public services. There could be a competitive scramble to have a final fling before changes become compulsory. Consumerism is an enemy of the project and, as Alfa has commented above, the tendency to make token offset gestures, or to pay penalties to avoid compliance, remains strong.

I found the carbon footprint calculator illuminating [I have indicated the results for our household above*] and a useful way-marker for future action. It might not be perfect but it is a good starting point.
* https://conversation.which.co.uk/sustainability/carbon-footprint-calculators-coronavirus-lifestyle/#comment-1601861

Evolution – I’m interested in the lifecycle analysis of replacing a boiler, but have my concerns about whether this would be a good move. My present boiler is about 22 years old and is in good working order, but is not a condensing boiler, so is less efficient than a modern one. On the other hand it has a cast iron heat exchanger which can last for many years. The one in my previous home worked fine for at least 35 years. Modern boilers usually have aluminium heat exchangers that can corrode and leak within 10-15 years. They are much more complicated, so there is more to go wrong. A friend who lives locally had a Worcester-Bosch boiler leak after 13 years. I suggested that it would be advisable to look for a different brand with a more durable stainless steel heat exchanger, but the easiest option was to fit another W-B. 🙁 I cannot make up my mind and will probably keep my present boiler for the time being.

Replacing a car with an EV seems an easier choice because the old one is no more likely to be scrapped prematurely even if it changes hands.

I’ve a Worcester condensing boiler now 12 years old and still going strong (is that tempting fate). I’d check how much gas you would save by switching; it is said that a condensing boiler may use between 80% and 50% of the gas used by a conventional one. That might make the financial decision easy.

I’m not convinced by an only electric car, partly because of the breaks that need to be arranged in long journeys and the time spent charging. Fine if all journeys are shorter. My choice if I were to change my diesel car would be a plug-in hybrid if it had a decent range on the battery so I could switch to electric in built up areas and use petrol on the rural roads.

My Potterton Suprima 80 appears to have an efficiency of 78.8% which is good for a non-condensing boiler. New boilers must have an efficiency of at least 88%.

The best that the user can do to prolong the life of an aluminium heat exchanger is to use a suitable corrosion inhibitor and to top this up periodically because the active components are lost with time even if the system is not drained.