Here's a demonstration of a domestic fuel cell, from Ceres. These systems behave like gas boilers from the point of view of generating hot water and heating, but have the added benefit of using the wasted energy to generate electricity, at a level of up to a kilowatt or so. This has the effect of reducing carbon emissions and also reducing the consumer's electricity bill.
Ceres are in the process of getting their micro Combined Heat and Power boiler to the market place. Based on a quick trawl across the internet, there are a couple of boilers already on or close to the market which do this - the Baxi Ecogen, which is expensive (the boiler itself seems to cost around the £6000 mark) and relatively powerful (it is capable of providing 24 kW of heating for water), and the e-on Whispergen, which seems to be less expensive but also less powerful (around 12 kW of heating). I just checked our boiler - which is a combi boiler, so has to produce hot water on demand - but it's capable of an output of 30 kW. All the mCHP systems I've seen seem to work on the basis of using a hot water tank. Maybe the next boiler we get is going to require us going back in the direction of having a tank....
Showing posts with label environment. Show all posts
Showing posts with label environment. Show all posts
Wednesday, January 26, 2011
Saturday, April 17, 2010
The ash cloud
The volcanic ash cloud has generated a lot of hot air and serious economic fallout, but few facts of substance. Given what we have heard in the media, I am not convinced that the decision to close airspace completely was based on scientific analysis, but rather a manifestation of "nanny state" and the fear of being sued.
We have been reminded repeatedly of the occasions in the last 30 years where aircraft have been affected by volcanic ash. Very serious incidents they were too - Boeing 747s with all engines shut down or damaged. It is certainly the case that aircraft should avoid significant ash clouds. But is it really necessary to shut all the airspace, at all levels, over whole countries, when any ash in the atmosphere is pretty diffuse? At what level of concentration does the ash represent a threat to aircraft engines? Bear in mind that following Mount St Helens, within two weeks the dust from the explosion had circled the earth. So there were measurable concentrations of ash in the atmosphere then. That didn't shut down the world's air traffic.
There are all sorts of threats and risks to aircraft. Aeroplanes can "fall out of the sky"* as a result of flying in cumulonimbus clouds - here's a reminder of the damage that can be caused by weather which wasn't as well avoided as it could have been. CB clouds show up on weather radar, if it is used properly - and pilots work their way around them. Volcanic ash doesn't show up on radar - but dangerous concentrations can be tracked, and the systems have existed for years whereby airspace can be closed dynamically by air traffic control. Similarly, cosmic background radiation and solar magnetic storms - even the Millenium Bug! - have an impact on aviation, but don't result in the wholesale shutdown of airspace.
I'm not saying the decision to close airspace was wrong. However, we have had little information of substance - safe concentrations of ash, what the concentrations actually are at the moment at different levels, anything more sensible than a hand-to-mouth closure of large swathes of airspace. The volcanic ash is being presented to the world not as something for which a proper risk assessment has been carried out, but as an unknown, out-of-control bogeyman. The media have lapped this up - queues at airports and train stations, disruption, cancelled holidays, phlegmatic travellers all make good airtime. But at some stage, someone is going to have to open the airspace again. And given the way it has been presented up to now, the response of an unnecessarily large group of people will be to say - "Hmm, I don't know. It doesn't look any sunnier now than it did when the airspace was closed. How can they tell it's safe ...?"
*Just to be clear, that is journalistic hyperbole. Aeroplanes fall out of the sky if they blow up or their wings drop off. People don't survive such events to write about them. So if you read about an aeroplane falling out of the sky, you should understand that somebody isn't really describing what happened. In the case of the BA 747 which "fell out of the sky" following its encounter with volcanic ash 28 years ago, it actually descended (albeit in terrifying circumstances, in darkness and turbulence) as it would on a descent to an airport from above 35000 feet to 12000 feet, I believe, before the crew managed to restart one of the engines.
We have been reminded repeatedly of the occasions in the last 30 years where aircraft have been affected by volcanic ash. Very serious incidents they were too - Boeing 747s with all engines shut down or damaged. It is certainly the case that aircraft should avoid significant ash clouds. But is it really necessary to shut all the airspace, at all levels, over whole countries, when any ash in the atmosphere is pretty diffuse? At what level of concentration does the ash represent a threat to aircraft engines? Bear in mind that following Mount St Helens, within two weeks the dust from the explosion had circled the earth. So there were measurable concentrations of ash in the atmosphere then. That didn't shut down the world's air traffic.
There are all sorts of threats and risks to aircraft. Aeroplanes can "fall out of the sky"* as a result of flying in cumulonimbus clouds - here's a reminder of the damage that can be caused by weather which wasn't as well avoided as it could have been. CB clouds show up on weather radar, if it is used properly - and pilots work their way around them. Volcanic ash doesn't show up on radar - but dangerous concentrations can be tracked, and the systems have existed for years whereby airspace can be closed dynamically by air traffic control. Similarly, cosmic background radiation and solar magnetic storms - even the Millenium Bug! - have an impact on aviation, but don't result in the wholesale shutdown of airspace.
I'm not saying the decision to close airspace was wrong. However, we have had little information of substance - safe concentrations of ash, what the concentrations actually are at the moment at different levels, anything more sensible than a hand-to-mouth closure of large swathes of airspace. The volcanic ash is being presented to the world not as something for which a proper risk assessment has been carried out, but as an unknown, out-of-control bogeyman. The media have lapped this up - queues at airports and train stations, disruption, cancelled holidays, phlegmatic travellers all make good airtime. But at some stage, someone is going to have to open the airspace again. And given the way it has been presented up to now, the response of an unnecessarily large group of people will be to say - "Hmm, I don't know. It doesn't look any sunnier now than it did when the airspace was closed. How can they tell it's safe ...?"
*Just to be clear, that is journalistic hyperbole. Aeroplanes fall out of the sky if they blow up or their wings drop off. People don't survive such events to write about them. So if you read about an aeroplane falling out of the sky, you should understand that somebody isn't really describing what happened. In the case of the BA 747 which "fell out of the sky" following its encounter with volcanic ash 28 years ago, it actually descended (albeit in terrifying circumstances, in darkness and turbulence) as it would on a descent to an airport from above 35000 feet to 12000 feet, I believe, before the crew managed to restart one of the engines.
Saturday, December 08, 2007
Tumble dryers and the environment
We just bought a new tumble dryer. Disgraceful - they are environmental disasters, as we all know. And yet ....
Previous years, when we didn't have a working dryer, we had to crank up the heating in the house to about 21-22 degrees, so that the radiators stayed on to dry the washing. This year, the house hasn't had to be heated to over 19.5 degrees.
The dryer we bought is a condenser dryer. Nothing is vented outside. So any heat that is generated by the dryer remains in the house, which also decreases the load on the central heating (on a related issue, see my previous post about energy-saving lightbulbs here). The water from the washing is stored in a tank, which can be tipped away later on.
If there is an environmental issue, I think my concern is more the amount of fluff that comes off dried clothes. They must be wearing at a significantly greater rate, which means that they don't last as long.
Of course, there are certain parts of the world where dryers are hardly required. For example, I understand that Phoenix, Arizona has 350 days of sunshine a year. And yet every house has its industrial-strength dryer....
Previous years, when we didn't have a working dryer, we had to crank up the heating in the house to about 21-22 degrees, so that the radiators stayed on to dry the washing. This year, the house hasn't had to be heated to over 19.5 degrees.
The dryer we bought is a condenser dryer. Nothing is vented outside. So any heat that is generated by the dryer remains in the house, which also decreases the load on the central heating (on a related issue, see my previous post about energy-saving lightbulbs here). The water from the washing is stored in a tank, which can be tipped away later on.
If there is an environmental issue, I think my concern is more the amount of fluff that comes off dried clothes. They must be wearing at a significantly greater rate, which means that they don't last as long.
Of course, there are certain parts of the world where dryers are hardly required. For example, I understand that Phoenix, Arizona has 350 days of sunshine a year. And yet every house has its industrial-strength dryer....
Tuesday, March 27, 2007
Global warming: "Everything you know is wrong"
I haven't watched The Great Global Warming Swindle yet, though it's only a matter of time, I guess. But even without watching it, I am aware of certain presumptions that are made in the debate that seem rather shaky.
I spoke below about the fact that low-energy lightbulbs aren't as unequivocally good as people suggest (particularly those who are making them) - because at some times of year, the heat generated by lightbulbs means that the heating system doesn't need to be on so much.
The March 10 New Scientist had an article (abstract only - payment needed for the full article) pointing out that carbon offsetting is not being properly regulated, opening the door to "Enron-style accounting" (as Amsterdam-based lobby group Transnational Institute put it - though if ever there was a tag for a libertarian, globalising, free-market lobby group, that would be it). Also, in the case of forestation, offsetting merely delays the arrival of CO2 in the atmosphere - the assumption being that in a hundred years or so when these trees come down again, we will have managed to sort the problem out. Given that India and China seem to show little inclination to do anything that would hamper their economic growth, and the focus in some parts of the developed world seems to be on buying our right to continue generating CO2 from other countries, it seems likely that we are simply handing the problem to our grandchildren after all.
Incidentally, for those Westerners who think that this is all the fault of India and China, the New Scientist article has a reality check, in the form of a table of emissions per capita. CO2 emissions per capita per year in India are about 1 tonne. In China, about 2.4 tonnes. In the UK, 11.2 tonnes. In the US, 20 tonnes. I've had Americans commenting on here getting huffy about the air quality in Beijing. But can they really insist on the right to generate as much CO2 as eight people from China?!
On a slightly more positive note, could somebody tell me what exactly would be the problem with doing what is supposedly unthinkable - burying thousands of tonnes of plastic underground? It doesn't decompose for ages, we are told, and yet by weight it is predominantly carbon. Surely this must be one of the securest ways of getting significant amounts of carbon out of circulation?
From my point of view, as I believe I have written before, I think that as a steward of God's creation, it is right for me to do what I can to use it in a sustainable and careful way. So I will continue to do what I can to try and reduce my environmental impact. One side effect of my recent change in job is that I should be driving several thousand miles less this year, though my career is hardly renowned for its overall environmental benefit ....
I spoke below about the fact that low-energy lightbulbs aren't as unequivocally good as people suggest (particularly those who are making them) - because at some times of year, the heat generated by lightbulbs means that the heating system doesn't need to be on so much.
The March 10 New Scientist had an article (abstract only - payment needed for the full article) pointing out that carbon offsetting is not being properly regulated, opening the door to "Enron-style accounting" (as Amsterdam-based lobby group Transnational Institute put it - though if ever there was a tag for a libertarian, globalising, free-market lobby group, that would be it). Also, in the case of forestation, offsetting merely delays the arrival of CO2 in the atmosphere - the assumption being that in a hundred years or so when these trees come down again, we will have managed to sort the problem out. Given that India and China seem to show little inclination to do anything that would hamper their economic growth, and the focus in some parts of the developed world seems to be on buying our right to continue generating CO2 from other countries, it seems likely that we are simply handing the problem to our grandchildren after all.
Incidentally, for those Westerners who think that this is all the fault of India and China, the New Scientist article has a reality check, in the form of a table of emissions per capita. CO2 emissions per capita per year in India are about 1 tonne. In China, about 2.4 tonnes. In the UK, 11.2 tonnes. In the US, 20 tonnes. I've had Americans commenting on here getting huffy about the air quality in Beijing. But can they really insist on the right to generate as much CO2 as eight people from China?!
On a slightly more positive note, could somebody tell me what exactly would be the problem with doing what is supposedly unthinkable - burying thousands of tonnes of plastic underground? It doesn't decompose for ages, we are told, and yet by weight it is predominantly carbon. Surely this must be one of the securest ways of getting significant amounts of carbon out of circulation?
From my point of view, as I believe I have written before, I think that as a steward of God's creation, it is right for me to do what I can to use it in a sustainable and careful way. So I will continue to do what I can to try and reduce my environmental impact. One side effect of my recent change in job is that I should be driving several thousand miles less this year, though my career is hardly renowned for its overall environmental benefit ....
Monday, February 19, 2007
Low energy lightbulbs
... have to be a good idea, right? The Energy Saving Trust said, on "You and Yours", the Radio 4 consumer programme, that they'd like to see the selling of tungsten lightbulbs phased out, so that only low energy ones were available in the fullness of time. If every house in the UK used three, then over their lifetime they would save enough energy to power the UK for a year (or something like that).
But hang on, correspondents pointed out. The truth isn't that simple. The low efficiency ones are less efficient because they generate more heat than light - a 100W lightbulb generates 80W of heat. If those watts of heat aren't being generated by lightbulbs, the house will be being warmed up less by the lightbulbs, which means that the heating will have to generate more heat to compensate. So there is no net benefit.
But hang on. The truth isn't that simple, either! Firstly, you have to take into account the environmental impact of manufacturing different sorts of lightbulbs. If the impact of making just one low energy lightbulb is lower than that of making the five or so inefficient ones, then this represents an advantage that needs to be considered. Also, for a significant proportion of the year - say six months - homes aren't heated using central heating. So for this part of the year, the heat energy that is produced is simply gradually dissipated - that is, used to directly warm up the atmosphere! - through open windows. Also, a lot of us have lights outside the heated part of the house - in porches, for example. In these cases, all of the heat energy is just lost in any case. And finally, you have to take into consideration the relative environmental impact of the energy sources used - is 80W of heat generated electrically in a lightbulb - with perhaps efficient generation but less efficient distribution - more environmentally friendly than 80W of heat generated through central heating.
The bottom line is that low energy lightbulbs are probably not as good for the environment as the manufacturers would like us to believe. But neither are they as "neutral" as the "You and Yours" correspondents were suggesting. It would take some careful research to get to the real truth of this question.
But hang on, correspondents pointed out. The truth isn't that simple. The low efficiency ones are less efficient because they generate more heat than light - a 100W lightbulb generates 80W of heat. If those watts of heat aren't being generated by lightbulbs, the house will be being warmed up less by the lightbulbs, which means that the heating will have to generate more heat to compensate. So there is no net benefit.
But hang on. The truth isn't that simple, either! Firstly, you have to take into account the environmental impact of manufacturing different sorts of lightbulbs. If the impact of making just one low energy lightbulb is lower than that of making the five or so inefficient ones, then this represents an advantage that needs to be considered. Also, for a significant proportion of the year - say six months - homes aren't heated using central heating. So for this part of the year, the heat energy that is produced is simply gradually dissipated - that is, used to directly warm up the atmosphere! - through open windows. Also, a lot of us have lights outside the heated part of the house - in porches, for example. In these cases, all of the heat energy is just lost in any case. And finally, you have to take into consideration the relative environmental impact of the energy sources used - is 80W of heat generated electrically in a lightbulb - with perhaps efficient generation but less efficient distribution - more environmentally friendly than 80W of heat generated through central heating.
The bottom line is that low energy lightbulbs are probably not as good for the environment as the manufacturers would like us to believe. But neither are they as "neutral" as the "You and Yours" correspondents were suggesting. It would take some careful research to get to the real truth of this question.
Wednesday, December 13, 2006
Interesting environmental fact of the day
Every kilogram of carbon-based fuel that is burnt releases around 3 kilograms of carbon dioxide. So when 2500 kg of fuel is burnt on a UK domestic flight, that is over 7 tonnes of carbon dioxide produced. A sensible-sized tank of car fuel (40 litres/9 gallons) when used releases about 100 kg of carbon dioxide into the atmosphere.
Monday, December 11, 2006
The price of tax on aviation fuel
A lot of fuss is made in some quarters about the fact that airlines don't pay duty on aviation fuel. This makes it cheaper to travel by air, we are told, than by surface transport.
It is true that travel by air is generally cheaper than surface travel in the UK. It is also more comfortable and generally more reliable. From a capitalist perspective, it's not surprising, because air travel is in many ways a deregulated, commercial market. Where there is regulation (for example, in the carriers that can offer the prized routes from London to the US), prices are kept substantially higher than where regulation has been removed. Different providers have had to fight for market share through competition - which has meant investing in the service they provide, driving down costs, and marketing themselves effectively.
In the meantime, the road network is blocked up by private cars (also the fruit of a capitalist system, I guess) and trucks carrying freight that ought to be travelling long distances by rail. The rail network swallows substantial public subsidies, can't apparently afford to invest in improving infrastructure, and generally doesn't offer a pleasant passenger transport experience.
The UK government nonetheless does tax the aviation industry - through Air Passenger Duty, which will be doubled from early next year, and which has no counterpart for rail, bus or sea transport, as far as I know. At the short end of flights, as it happens, the amount of duty levied per seat is comparable to the amount that it would cost if fuel were taxed. Let's suppose that aviation fuel were taxed at 40p per litre. What effect would that have on ticket prices? The fuel burn in a typical narrow-body aircraft from London to Edinburgh is about 2400 kg, and given the density of fuel, this equates to around 3000 litres. At 40p per litre tax, this represents £1200 tax per sector. If the aircraft is carrying 120 passengers, then the additional cost would equate to £10 per passenger - a price similar in size to that of APD.
However, I estimate that a 777-200ER flying from London to Los Angeles might burn around 120 tonnes of fuel. That's around 150000 litres. The tax on the flight would be about £60,000. Divided between 280 passengers, this is an intimidating £215 per passenger - each way! - obviously substantially more than Air Passenger Duty, and arguably a price that would seriously inhibit longhaul airline travel.
As Simon Calder points out in his column here, in talking to bmi CEO Nigel Turner, the increase in APD will have no impact on the environment. My suggestion for making aviation more environmentally friendly? Make APD payable per seat. There would then be an incentive for airlines to make sure that their aircraft were as full as possible. Heavier aircraft burn more fuel - but not in proportion to the additional number of passengers carried. And don't penalise them for cancelling a flight if there aren't many passengers on it.
It is true that travel by air is generally cheaper than surface travel in the UK. It is also more comfortable and generally more reliable. From a capitalist perspective, it's not surprising, because air travel is in many ways a deregulated, commercial market. Where there is regulation (for example, in the carriers that can offer the prized routes from London to the US), prices are kept substantially higher than where regulation has been removed. Different providers have had to fight for market share through competition - which has meant investing in the service they provide, driving down costs, and marketing themselves effectively.
In the meantime, the road network is blocked up by private cars (also the fruit of a capitalist system, I guess) and trucks carrying freight that ought to be travelling long distances by rail. The rail network swallows substantial public subsidies, can't apparently afford to invest in improving infrastructure, and generally doesn't offer a pleasant passenger transport experience.
The UK government nonetheless does tax the aviation industry - through Air Passenger Duty, which will be doubled from early next year, and which has no counterpart for rail, bus or sea transport, as far as I know. At the short end of flights, as it happens, the amount of duty levied per seat is comparable to the amount that it would cost if fuel were taxed. Let's suppose that aviation fuel were taxed at 40p per litre. What effect would that have on ticket prices? The fuel burn in a typical narrow-body aircraft from London to Edinburgh is about 2400 kg, and given the density of fuel, this equates to around 3000 litres. At 40p per litre tax, this represents £1200 tax per sector. If the aircraft is carrying 120 passengers, then the additional cost would equate to £10 per passenger - a price similar in size to that of APD.
However, I estimate that a 777-200ER flying from London to Los Angeles might burn around 120 tonnes of fuel. That's around 150000 litres. The tax on the flight would be about £60,000. Divided between 280 passengers, this is an intimidating £215 per passenger - each way! - obviously substantially more than Air Passenger Duty, and arguably a price that would seriously inhibit longhaul airline travel.
As Simon Calder points out in his column here, in talking to bmi CEO Nigel Turner, the increase in APD will have no impact on the environment. My suggestion for making aviation more environmentally friendly? Make APD payable per seat. There would then be an incentive for airlines to make sure that their aircraft were as full as possible. Heavier aircraft burn more fuel - but not in proportion to the additional number of passengers carried. And don't penalise them for cancelling a flight if there aren't many passengers on it.
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