Monday, 22 November 2021

Squatting on the Grid?

A friend has been complaining to me about EV charging stations being unusable for months on end - Soham and Sutton EV chargers in particular were mentioned. What is the hold-up? It could be equipment problems, or perhaps delays in getting capacity on the grid to supply - or is it unscrupulous business practice? It seems complete madness to me but Euan McTurk talked about this in an interview with Robert Llewellyn on his Fully Charged Show (12th Nov, about 4 minutes in). He seems to think large companies may be grabbing up capacity on the grid for fast chargers and not bothering to commission or maintain the equipment - but while they are there no-one else can get on without paying huge sums for a grid upgrade. 
These charging points in Soham have been 'coming soon' since December 2020


Can this be true?

Friday, 12 November 2021

Review of the Heat and Buildings Strategy

Last month the government announced the long awaited Heat and Buildings Strategy [1] which sets out plans to convert this sector to net zero GHG emissions. This came out almost at the same time as the wider Net Zero strategy [2]. One aspect I was particularly interested to see was the plan for hydrogen in heating – there is still indecision in this area we will have to wait until 2026 for more certainty. Another aspect is the balance between electricity and gas energy costs, also support for retrofitting heat pumps into homes and building up the supply chain for retrofit. There are definitely some good things in this policy but some serious gaps.

Scenarios: high hydrogen, high electric or in-between? 

The future role of hydrogen is still uncertain and the Net Zero Strategy refers to three scenarios for heating in the future. In all cases, heat pumps have a very large role. As well as the net zero in 2050 target there is an interim target to reduce GHG emissions from this sector by about two thirds by 2035.

By 2035, the target is for 13 million homes to be on low carbon heating of which two million will be on heat networks. For the rest there are different scenarios. If hydrogen does not work out, almost all the rest will be on heat pumps. If hydrogen does work out, then we can expect up to 4 million on hydrogen gas by 2035 and 7 million on heat pumps. Or, it could be something in-between.

Whatever happens, at least a third of homes in the UK need to be heated by heat pumps by 2035 – a lot more than on hydrogen.

Tuesday, 26 October 2021

How much does it cost to install a heat pump?

The recently announced Net Zero Strategy includes a boiler upgrade scheme with a £5000 grant towards installing a heat pump. How does this compare with actual heat pump costs? To be fair, you should bear in mind that when you upgrade your boiler you only need a new boiler slotted into the same space as the old, whereas when you convert to a heat pump there are additional one-off costs for plumbing and other work. So subsequent heat pump upgrades will cost less. Still, there is no doubt that heat pumps cost more than just replacing a boiler, which is usually £2,000 to £3,000. Here are some top level estimates for a heat pump installation – as you can see they vary greatly We will break this down in a minute.

Energy Savings Trust (2021)£7,000 - £13,000
Renewable Energy Hub (2019)£5,000 - £8,000
EDF Energy (allows 20% for installation costs)£5,000 to £10,000
Heat Pump Retrofit in London (Carbon Trust, 2020)£7,000 (3.5 kW) - £11,000 (11 kW), mean £8,800
Cost of domestic heating measures (Delta EE, 2018)£9,000 (8 kW) - £15,000 (16 kW)
Development of trajectories for residential heat decarbonisation to inform the Sixth Carbon Budget (Element Energy , 2020) – excluding the fabric upgrades.£10,000 (mean).

Thursday, 16 September 2021

Turning down the radiators in unused rooms

To reduce our heating bills we are often advised to turn down radiators in rooms that we are not using. However, this can be a bad idea if you have a heat pump. The adjacent rooms leak heat into the colder room which means the working radiators have to work harder. This is generally OK with a boiler but not with a heat pump which gives better efficiency at low temperatures. With the radiators working harder they need to run hotter which often means you end up using more energy rather than less [1]. I have done some modelling to see what this effect looks like. The savings on the overall heating demand is probably smaller than you might think – typically 3.5-5.5%. On the other hand the impact on the radiator heat demand surprisingly high – 20% or more.

Tuesday, 7 September 2021

How much methane do oil and gas wells leak

Methane leakage matters – it is a relatively short lived but powerful greenhouse gas. Until recently, methane leakage has been hardly monitored and it is still not regulated. However, new techniques for monitoring are making it harder for energy companies to brush their emissions under the carpet.
 
Satellite data is increasingly used for tracking emissions
At current rates of global emissions (as far as we know), methane has a similar global heating impact to CO2, in the first few decades after release. [1]. The main sources from human activity are agriculture (especially cattle) and extraction of fossil fuels. There is also some methane released from landfill sites. However, it is really hard to be sure about these impacts, because emissions are not consistently measured. Recently we have developed techniques to measure methane in the atmosphere and track down where it is coming from. We have learned how to use satellite data for this and a new satellite is to be launched next year dedicated to this task [2]. In the interim we mainly use observations from boats or planes over small areas and coverage is sparse. 

Leakage from oil and gas wells vary by at least an order of magnitude
In this post I focus on emissions from oil and gas extraction. As yet there is no regulation on this, even in the EU. Emissions vary by at least an order of magnitude from one region to another and even one well to another. A considerable proportion of leakage is accidental which means it varies over time as well. The highest emissions are from fracked wells. 

Saturday, 21 August 2021

Comparing blue hydrogen with natural gas emissions

Hydrogen is in the news a lot lately, because of the publication of the UK government hydrogen strategy document. I was alarmed to find a recent article [1] saying that blue hydrogen (made from methane gas with carbon capture) is hardly better than grey hydrogen (made from methane without the carbon capture). The authors are Robert Howarth from Cornell University and Mark Jacobson from Stanford University). I have recently been saying that blue hydrogen is at best about a third the emissions from methane gas, which I think is bad enough - but this article suggests even that is naively optimistic. 

Obviously there are some vested interests trying to paint blue hydrogen as white as possible (pun intended). So I decided to dig deeper into the assumptions behind the analysis. There are three main sets of assumptions involved - about the upstream emissions, about the capture rates and about the source of energy used in the hydrogen conversion plant. Plus you can choose to use 100 year global warming potentials for methane or 20 year ones. Given the climate emergency, the 20 year timeframe seems more appropriate. Also I have chosen to compare blue hydrogen with natural gas, which is the fuel it would mostly replace. Depending on the assumptions you choose, you can make blue hydrogen decidedly worse or significantly better. I can only get it down to 1/3 the emissions of natural gas using the 100 year time frame, not over 20 years. 

Emissions from natural gas and blue hydrogen with the original assumptions in [1]. NG is natural gas, Blue is blue hydrogen, 100 years/20 years means using the 100/20 year global warming potential for methane 


Friday, 13 August 2021

Insights from studies of water shortages

Water shortages are increasingly common as an impact of climate change. Rainfall is not predictable, but most places have sufficient water reservoirs that shortages happen slowly and can be foreseen. At some point consumers are asked to be careful, and as disaster looms nearer these messages become increasingly frantic. Does this remind you of anything else? Climate change also happens slowly and not exactly predictably and exhortations to reduce emissions are becoming increasingly frantic.  Whether or not we will avert disaster remains to be seen. In this post I discuss insights from three journal article relating to damage limitation in drought. The first is about the near disaster in Cape Town during 2017/2018, from the view of the Cape Town water supply management. The second is also about Cape Town but from the view of residents – how the shortage affected different kinds of people. The third discusses how residents of Fortaleza (in Brazil) responded to increasing water prices during a drought.