tag:blogger.com,1999:blog-78259573726758977782024-03-19T05:21:37.866-07:00Energy Thoughts and SurprisesAs I discovered while writing my book - <a href="https://www.uit.co.uk/all-books/energy-and-carbon-emissions.html">Energy and carbon emissions: the way we live today</a> - it isn't always obvious how our everyday choices add up in terms of energy use and carbon emissions. This blog aims to paint you an objective picture - and sometimes surprise you.Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.comBlogger406125tag:blogger.com,1999:blog-7825957372675897778.post-6866230086621014512024-02-19T04:30:00.000-08:002024-02-19T04:30:29.863-08:00A whole street of heat pumps - noise levelsHeat pumps make noises, of course they do. The question is, will their noise be a nuisance if every house on the street has one? The short answer is - not usually. Here I explain why we are not disturbed by ours, and why a whole street of heat pumps does not sound much louder than a couple. In urban areas, other noises are much more noticeable. In rural areas, you might be disturbed by yours but Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com1tag:blogger.com,1999:blog-7825957372675897778.post-39891958606237943702024-02-10T08:28:00.000-08:002024-02-10T08:28:52.758-08:00 Rainwater harvesting: dammed by regulationFor the whole of the East of England water supply is an increasing problem. Here in Cambridge we need to reduce the amount we take from our aquifers by about half in order to protect the chalk streams. This will be achieved with a combination of reducing leakage, reducing demand and increasing supply (by building large reservoirs). One way to reduce demand is to harvest rainwater for use where itNicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com4tag:blogger.com,1999:blog-7825957372675897778.post-11409327154062051462024-01-09T02:09:00.000-08:002024-01-09T02:09:41.339-08:00Shifting policy costs on energy bills - revisitedAs I said in a previous blog post, the current price ratio between electricity and gas means that switching to heat pumps often means bills increase - a major deterrent to many households considering taking on low carbon heating. Part of the problem is because of the way 'policy costs' are loaded mainly onto electricity bills instead of gas so when you switch to a heat pump you end up paying far Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com2tag:blogger.com,1999:blog-7825957372675897778.post-56180190138435211722023-12-28T04:54:00.000-08:002023-12-28T23:27:59.306-08:00 A New Year wish – autonomous cars.Driverless vehicles are in the news again. (Driverless cars: Tech possible for UK motorways by 2026, transport secretary says). The usual justification given for needing driverless cars is safety because most car accidents are caused by human error. I disagree because it seems unlikely driverless cars will ever be demonstrably and significantly more safe than cars driven by humans. However, Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com2tag:blogger.com,1999:blog-7825957372675897778.post-72753785423389798272023-11-21T03:11:00.000-08:002023-11-22T03:57:23.608-08:00Should we shift energy taxes to make heat pumps cheaper to run?Tariffs vary but averaged across the country, under the current OFGEM price caps, electricity costs four times gas per kWh. This means that by my estimate [1] unless you go off gas completely (hence avoiding the fixed daily charge) you need a heat pump efficiency (SCOP) of 360% to get similar costs. This is not unknown but considerably better than average. If you do go off gas completely, you Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-84938526263244696042023-10-31T09:06:00.001-07:002023-10-31T09:06:22.301-07:00Understanding the costs and savings on your EPC recommendationsOn your home energy performance certificate (EPC) you may find a list of recommendations for energy saving measures you can make. For each one, there is a range given for ‘typical’ installation cost and a value for ‘typical’ annual savings. However, looking at a sample of EPCs I was shocked to find that the ‘typical’ cost of each measure is the same regardless of the size or type of house. On theNicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-77012602262933050652023-09-30T05:30:00.001-07:002023-10-09T02:20:00.707-07:00 How much can you save from solar PV and battery with a heat pump?You can substantially reduce your electricity bills if you have solar panels and a battery. What about if you have a heat pump? It certainly does make a difference but most of your heating demand is in the winter and most of your PV generation is in the summer. You would need an enormous battery to save enough in summer to use in winter. Suppose you put in enough solar panels to match your annualNicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-12467920769295439152023-09-10T06:10:00.002-07:002023-09-11T02:15:22.290-07:00 Are hybrid heat pumps a good thing?A hybrid heat pump is normally a combination of a gas boiler and an air source heat pump (HP). The simplest arrangement runs either one or the other at any one time. For example, you can use the boiler (possibly your existing boiler) for space heating when it is cheaper to run, thus reducing your bills. This typically means using the boiler when the outside temperature is low. You might also use Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-33527012742697142072023-08-06T10:09:00.003-07:002023-08-06T10:09:50.872-07:00What happens to the wood we grow?A recent article in New Scientist, and the peer reviewed paper behind it [1], opened my eyes to the staggering amount of wood from managed forests that goes up in smoke, if not immediately then after quite a short lifetime as something useful. This is a shame, given the potential for using wood to store carbon. The article includes a rather fine flow digram of what happens to the wood we cut at Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com1tag:blogger.com,1999:blog-7825957372675897778.post-52898766373584802002023-07-15T05:22:00.001-07:002023-07-15T05:22:12.497-07:00 Smart meter for detecting water leaks Many of us now have smart meters for electricity and gas, but we are starting to see smart meters for water too. They may help you with reducing water use – which is very important because of climate warming as well as the growing population. However, one of the key benefits is going to be detecting leaks – for water companies and for consumers. We had a water leak a few years ago and we would Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-86537619468937402692023-06-30T02:22:00.001-07:002023-06-30T02:22:49.984-07:00On 15 minute neighbourhoods15 (or 20) minute neighbourhoods are an immensely good idea. The goal is to reduce the need for use of cars by ensuring that routine daily activities are in range of walking, cycling or possibly public transport. This encourages active travel, with associated health benefits, as well as reducing GHG emissions. There is no single accepted definition of what this actually means in terms of distanceNicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com1tag:blogger.com,1999:blog-7825957372675897778.post-26338679315275992962023-05-18T04:13:00.003-07:002023-10-06T02:24:18.802-07:00Why my heat pump performed worse this winterOver the first winter my heat pump (space heating only) gave me an average COP (efficiency) of 3.1 which was higher than I had been told to expect. I was moderately pleased. This winter it was only 2.9 which was a great disappointment.The difference is due to the weather. The mean COP for one year is not necessarily a guide to the next. The mean temperature is part of it but colder days require Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-63436238795614045062023-04-15T09:50:00.002-07:002023-04-15T09:50:44.061-07:00Air source heat pumps heat the outside air even when heating your homeStanding in front of a heat pump when it is working hard you will feel an arctic blast of cold air. So you would think that if every house has one the outside air will get colder. After all, we know that cooling buildings with air conditioning (A/C) adds to the urban heat island effect. Since cooling our homes makes the outside air warm, you would think that heating our homes would make the Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-31692911663553052632023-04-04T04:29:00.004-07:002023-04-05T03:59:48.180-07:00 Why do heat pumps get less efficient in warm weather?This post has been modified 5/April/23 after discussion on twitter with @AR_Clark convinced me that the reason for the continuing decline in efficiency in warm weather is due to increasing use of the immersion heater for hot water heating. This is hopefully less common now, as heat pumps can provide all the hot water necessary except for sterilisation cycles, and sometimes even then.We know that Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com3tag:blogger.com,1999:blog-7825957372675897778.post-54961531335726125482023-02-14T07:53:00.000-08:002023-02-14T07:53:36.470-08:00Avoiding the rated power fallacyHow much energy does an oven use? Today I have seen examples both on the BBC Food Programme and on the Uswitch website [1] where this question was answered by multiplying rated power by hours of use. This is totally wrong because ovens have thermostats. They turn the power off when they are up to heat. The power of the oven is mainly used during the initial heating phase. After that it turns downNicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-30045800345055228292023-02-05T04:24:00.001-08:002023-02-05T09:09:20.749-08:00 How long can we rely on cheap rate electricity?A number of my friends are considering or have already installed a Tepeo zero emissions boiler (ZEB) with storage as a low carbon heating solution for their home. This is less disruptive than installing a heat pump but it is only 100% efficient compared to 300% or so for a heat pump. It relies on cheap electricity to keep energy bills at a sensible level – either economy 7 overnight, or similar, Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-36775328791094144512023-01-10T02:47:00.001-08:002023-01-10T02:48:28.601-08:00 Greenhouse Gas Removal – and checking it worksAccording to the Climate Change Committee (CCC) balanced pathway to net zero, we should be capturing and storing 58 MtCO2e/year by 2050 [1]. This is called greenhouse gas removals (GGR) or sometimes carbon dioxide removals (CDR). It is hard to see how we can get to net zero without some GGR, but there is very little of this happening right now. There are several strategies likely to be deployed. Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com1tag:blogger.com,1999:blog-7825957372675897778.post-89287575274521602962022-11-25T02:42:00.002-08:002022-12-15T02:41:34.902-08:00Keeping warm in cold conditions - field studies of personal heating devicesMy last post discussed how much we need to heat our homes to keep them healthy. The short answer was, about 8°C warmer than outside. This could mean temperatures as low as 12°C or even less. So how do we keep ourselves comfortable? Wearable devices, warm cushions, portable electric heaters? This post reviews some field studies described in academic literature. It seems to be a hot topic in Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com1tag:blogger.com,1999:blog-7825957372675897778.post-84851829912551544212022-11-25T02:41:00.001-08:002022-11-25T02:43:01.585-08:00How warm should your house be to keep it healthy? During the gas shortage some of us are turning our heating down to save money and some are turning it down to reduce demand and keep prices down generally. How low can we go? There is our own health to consider but fit adults wrapped up warm and with personal heating devices such as jackets and gloves can be comfortable in surprisingly chilly conditions (see the next post). What about the house? Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-86917925997354947122022-10-23T06:01:00.005-07:002022-10-23T06:01:50.074-07:00How to recycle solar panels: the cheap and cheerful approachA recent journal paper suggests a new approach to recycling solar panels [1]. This is very much a cheap and cheerful approach (my words) compared to the gold standard ‘full recovery end of life’ approach. A comparison of the two methods is illuminating. The main author of the paper, Pablo Dias, has since set up a company called Solar Cycle to commercialise his process. It is great to hear of Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-61201128923892760502022-10-12T07:28:00.004-07:002022-10-12T07:28:39.033-07:00The effect of reducing radiator temperature on room temperatureHeating engineer experts have been complaining for years that condensing boilers were not being installed correctly to achieve the claimed efficiencies. A gas condensing boiler that is supposed to give you 92% could be giving you 85% or even less, if it has been set to heat the radiators at 70°C or hotter. Now that we have an energy crisis, this is one of the few things you can do to make Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-23036391748103860382022-09-15T07:13:00.003-07:002022-09-19T03:41:37.940-07:00Can reducing the thermostat 1°C really save 10%?It seems extraordinary that reducing the thermostat setting by just one degree can save more than 10% on your gas bill. A back of the envelope calculation suggests this has to be an exaggeration. However, when you take into account other sources of heat it can be an underestimate. Of course it depends on various factors and for a less well insulated house the relative saving is less, though the Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-30857636535875466612022-08-16T04:59:00.002-07:002023-10-26T12:00:17.457-07:00Would water trading between regions reduce future costs?Water supplies are under pressure again due to the very dry weather. So here are some facts about water usage: how much we use at home compared to businesses and industry, how this is expected to change, and how the cost of trading water between regions compares with new supply.Public water supply – 57% is for householdsUsing data from Discover Water, here are some statistics on the public water Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com0tag:blogger.com,1999:blog-7825957372675897778.post-77541066379537610882022-07-07T03:54:00.004-07:002022-07-07T03:54:30.762-07:00Is using your home for energy storage really practical?Electricity demand varies through the day, and the cost of supply depends largely on the demand peaks. Therefore reducing peak demand can bring cost savings. Most of us are going to be using electric heating in future, mostly with heat pumps, and this will be a major part of peak demand in cold weather. (Peak time currently is typically 4-7pm, including cooking time for many households.)You can Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com2tag:blogger.com,1999:blog-7825957372675897778.post-52876086054425230912022-06-07T09:54:00.001-07:002023-10-06T02:24:43.861-07:00How big should your heat pump be?Most people have combi-boilers and the size of the boiler required is often dictated by the need to heat hot water for baths and showers quickly rather than space heating. With heat pumps, you normally have a cylinder for hot water and it is the space heating requirement that dictates the size you need. So how big should it be? Hearsay tells me that even with boilers, sales-people love to sell Nicolahttp://www.blogger.com/profile/09162244617407392907noreply@blogger.com2