Climate change stories to be cheerful about

It has been a very difficult year for several reasons. But it was not all bad. To cheer us up over the holiday, here are my favourite good news stories from 2020 - including coal consumption down, renewables up, beavers for flood management, hope for the survival of coral, help in eating more plant proteins, and changes to our travel behaviour.

Is the gas industry promoting uncertainty as a delaying tactic?

We have to decarbonise our heating systems, but there are competing options as to how this is best done: electric heat or green gas. Whatever happens this is going to be very disruptive for industry sectors including oil and gas supply and appliance manufacturers - some very large corporations face an existential threat. So it is hardly surprising that the gas industry is lobbying our government intensively, arguing that green gas is a practical, inexpensive alternative to electric heat. It is not clear that they have successfully driven policy decisions in their favour, but it is possible that they have achieved delays to measures that are needed urgently. Or are ministers simply putting off decisions that they believe will be unpopular? As one consultant said (of decarbonising heat policy): Anything that puts people’s bills up is a big issue. And anything involving intervening in people’s homes is a big issue. You’ve got them all. It’d be an absolute car crash. [1]

This blog post is inspired by two journal papers by UK academics Richard Lowes and Bridget Woodman from the University of Exeter, and Jamie Speirs from ICL. You can find them here:

[1] Disruptive and uncertain: Policy makers’ perceptions on UK heat decarbonisation (Energy Policy) 2020

[2] Heating in Great Britain: An incumbent discourse coalition resists an electrifying future (Environmental Innovation and Societal Transitions) 2020

As academic papers go, these are very readable. I particularly like the extensive quotes in the first one, one of which you have read in my first paragraph. Both are based around interviews with people who have influence over policy - from Ministers and civil servants to industry reps, 3rd party consultant and NGOs.

What next for the 2050 Pathways calculator?

The 2050 Pathways Calculator was a tool to help us understand how to reduce our CO2 emissions by policy changes and behaviour shifts across all sectors of the economy. It was originally developed by the Department of Energy and Climate Change for the UK and launched in 2010 – and then adapted for other countries and a global one. The UK one is out of date now but new versions are in active use by policy makers in governments, by children in schools, by NGOs and individuals. Last Thursday I spent a day at a conference about them, with delegates from all over the world – Mexico and the USA, Malaysia, and Thailand, India, Nigeria and many from Europe too. There is a new UK calculator in the pipeline and one for the EU - both are bigger, better and easier to use.

Upgrading our electricity distribution networks.

Electricity North West plans to reduce the voltage of their customers' electricity supply which will reduce bills by up to £60/year - and be hardly noticeable except it will take a little longer to boil the kettle [1]. In this post I take a look at the Smart Street trial they have run to test out their concept [2]. As well as energy savings a key purpose of the trial was to evaluate new voltage regulation equipment that could delay the need to upgrade the distribution network. Reducing the voltage reduces the delivered energy and peak load, so the existing infrastructure can cope for longer.

Savings on customers bills are welcome but even more importantly (for climate change) we need to be able to install more distributed generation and run bigger loads due to heat pumps and electric vehicles. How much will that cost? A case study on low carbon heating in a town in Scotland has some answers to that [3]. The cost of the network was much less than I expected - much less than the heat pumps anyway.

How is a house like 3/4 of a cow?

One way to decarbonise our home heating is to use anaerobic digestion (AD) to process biomass (such as grass) into biogas. So we can grow grass as cattle feed or to heat our homes. How do cows and houses compare in terms of grass demand? Here is a back of the envelope calculation - and the conclusion is: one house is about 0.75 cows. Based on this (rough) figure, if we repurposed all our land that currently supports sheep and cattle to grow grass for biogas, we could supply about 13 million households, a little less than half the current number in the UK (27 million) [1].

The grass these cows are eating could be used to heat our homes instead.

Low carbon heating in real houses

The quick way to get to low carbon heating is to replace our gas boilers with heat pumps. We don’t have to wait for low carbon gas or district heating infrastructure to be installed - we can do it tomorrow. However, it isn’t always that easy. The Energy Systems Catapult (ESC) have done a fantastic job of modelling how this could work in five real homes [1]. They envisage a staged conversion in each case, usually starting with fabric upgrades and moving on to a heat pump (or district heating) later on, over 10-15 years. Each house (two semi detached, two terraced and one detached) has its own story, but I am not going to worry about the paths, just about the end points. Interestingly, in two cases they envisage keeping a boiler in place as well as the heat pump, running the heating in a hybrid scenario.

Are hybrid heat pumps the solution for low carbon heating?

The Committee on Climate Change has just published their view on the role of hydrogen in a low carbon economy [1]. Their recommendation for people currently on gas is to insulate your home as much as possible and then install a hybrid heat pump/boiler system. You can get hybrid systems now, only burning methane gas rather than hydrogen. The idea with a hybrid is that the heat pump supplies all the heat most of the time, but with a boiler for backup when demand is very high or electricity supply is expensive. In theory, a hybrid system should supply around 90% of the heat from the heat pump - however, this is only the case when the system is configured correctly. In field trials the proportion of heat from the heat pump has ranged from 96% down to 30% [2]. No wonder the RHI subsidy requires that hybrid heat pumps have metering to actually measure how much renewable heat is supplied through the heat pump [3]. If hybrid heating systems are to play their part in a sustainable future we have to learn how to manage them properly.

How much energy can you get from rain?

Researchers in China have created a hybrid solar panel that can also make electricity from rain [1]. This has obvious advantages, especially for regions where you get more rainfall in winter than in summer because it will help to even out generation through the year. But how much energy can you actually get from rain? How does it compare with solar energy - and is it worthwhile? Here is a back of the envelope calculation.

Uncertainty about pollution from wood stoves

In my previous post on air pollution, especially fine particulates (PM2.5), in Cambridge I concentrated on traffic, hardly mentioning wood stoves  as a possible source. However, wood burning is cited as an important source of pollution in parts of London [1] so why not Cambridge? To be honest I steered clear of the issue because there is such a huge amount of uncertainty I felt unable to present any facts with confidence. The National Atmospheric Emissions Inventory (NAEI) estimates that 35% of PM2.5 in the air is from domestic wood burning[2] - or it could be 10 times less [3].

The issue is so uncertain that the government is running a call for evidence on the issue. This runs until 27th Feb.  In their call for evidence they say [4]:

• Burning wet wood (i.e. not properly seasoned wood) generates at least twice the emissions from dry wood.
• Estimates for the proportion of wood that is burnt wet range from 80% (from the wood industry) to 20% (from a survey by BEIS).
• Estimates of how much wood is burnt in total range for 3 to 6 million tonnes per year
• Burning on an open fire generates up to 10 times the emissions from a modern wood stove.

Is waste incineration sensible, a health disaster or a white elephant?

Amey have submitted a planning application for an Energy from Waste plant at their waste handling facility in Waterbeach [1]. Is this a good thing or a bad thing? There are potential concerns about air pollution, carbon emissions and disincentive to reycle. But it will divert stuff from landfill and probably reduce GHG emissions overall.

The facility will process residual waste – the stuff that has come through the Mechanical Biological Treatment and not been picked out as valuable, and the stuff that was rejected from the dry recycling plant, plus construction and demolition waste. This waste would normally go to landfill.

The waste will be burnt in a furnace at 850°C to produce electricity and also heat; they hope to supply district heating for new developments in the area.

Amey's main EfW inputs and outputs [1, section 4]

The cost of building too many solar farms

Solar panels give us plenty of power in the summer when we don’t need so much and not much in the winter when we do. Building solar is like going to the shops to buy a winter woolly and buying a stack of T-shirts instead. Last time I wrote about this I focussed on our pattern of energy demand and how that can best be matched to wind and solar generation patterns. I concluded that we need some solar now but less in the future. That post was criticised for ignoring costs. So this time I will discuss the extra costs of investing in the wrong sort of renewables.

How much water do power stations use?

It is world water week and the power generation sector is often blamed for high water consumption - how high is it really? First the headline figures. Current water consumption by UK power stations comes to around 13 l/person/day [1][2]. That is less than a tenth of the amount we use at home [3].

However, the amount of water used depends on the technology. Wind and solar power generation need no water at all but most nuclear and conventional power stations use water for cooling. Coal power stations use more water than gas, partly because they use water for cleaning sulphur out of the flue gases as well as for cooling. Nuclear power plants also use more cooling water than gas. This is partly because they are less efficient so they have to dump more heat and also because they don't generate any hot flue gases, so all their heat has to be dumped through the water cooling system.

What does a sustainable energy system for 2050 look like?

The National Grid recently published their annual 'Future Energy Scenarios' report which describes alternative futures for electricity and gas supply and demand to 2050. There are four scenarios of which only one satisfies our carbon commitments but I am struck by how similar they are in terms of electricity generation - where they differ greatly is in gas demand and use of smart technologies to manage infrastructure - including smart meters and time of use pricing.

Swansea Bay Tidal Lagoon - do we really need it?

I have been reading the Hendry report on Tidal Lagoon technology [1]. Should we go ahead with a 'pathfinder' project like Swansea Bay or not? I say yes - but not because it is good value for money or has the potential to meet a large portion of our electricity needs - in fact the potential is quite limited. What swings it for me is that tidal lagoon technology has the potential to provide useful energy storage.

The overall UK potential for power generation from tidal lagoons is quite small. Hendry puts the likely limit at about 18 GW capacity providing a total 30 TWh per year. This compares to 14 GW capacity of onshore and offshore wind installed now - providing 40 TWh in 2015 [2]. So the maximum generation from all the tidal lagoons we are ever likely to build (in the UK) will supply less energy than the wind turbines we already have. On the other hand, we only have 2.4 GW pumped storage and tidal lagoons could, theoretically improve on this substantially.

If we had a referendum on renewables

This chart shows public attitudes to renewables and fracking [1] alongside the Brexit referendum results [2]. We are much more positive about renewable energy than we were about Brexit. This is despite the costs of subsidising renewables (which we overestimate) and despite negative newspaper stories. The oil and gas industry is now a net loss for the treasury and the government is finding ways to tax renewables.

Attitudes to renewables energy compared with the referendum results [1][2]

Heating our homes with bio-gas - how much can we grow?

Ecotricity have released a report claiming that their green gas mills (making bio-gas from grass) could generate enough gas to heat 97% of our homes by 2035 [1]. Is bio-gas a practical solution for low carbon heating? It would certainly be less hassle than converting the grid to hydrogen (see Converting the gas grid to hydrogen, starting with Leeds) or installing expensive insulation. Let's look at some numbers.

According to Ecotricity:

• One gas mill supplies 3500 homes (now) or 5000 homes in the long term, because gas use is falling - a reduction of 30% per home.
• 5000 gas mills could supply 97% of households (maximum scenario).

From despair to determination - Trump will be president of the USA, not the world.

My first reaction to Trump becoming president of the USA was utter despair. But then I remembered - the USA is only accountable for 15% of global climate emissions. So even though they will doubtless wobble for a few years that need not be the end of the world, provided the rest of us act responsibly.

Emissions by country 1959 to 2014 according to the UNFCCC. Data from
UNFCCC (May 2015) and Boden, TA, Marland, G and Andres, RJ 2015. Global, Regional, and National Fossil-Fuel CO2 Emissions, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., USA doi 10.3334/CDIAC/00001_V2015, via http://www.globalcarbonproject.org

Does the UK need solar electricity?

I am not against solar PV panels in other countries where the pattern of demand is different, but in the UK our peak heating demand is in the winter time when solar power is low. Wind on the other hand peaks in the winter too so is a natural fit for our demand pattern. But does wind generation really match our demand well, or do we need mix of other types of generation? The answer was not as clear cut as I expected.

Electricity is getting cleaner - should you heat or drive with electricity now?

Increasing renewable electricity (and less coal) in our mix is having a real impact on the carbon emissions from electricity. I used to say that electricity cost (roughly) three times as much as gas and generated three times as much carbon emissions - but now electricity is only twice as much as gas for carbon emissions. This has implications where you have a choice of fuels. For example, heat pumps for heating will now generate less carbon emissions than gas even if their performance is well below average. Also it increases the benefits of switching to electricity for cars. However, decisions made today are often based on out of date carbon factors.

Carbon emissions factors for grid electricity. DUKES is most up to date - DEFRA lags by 2 years (other differences are described below). Natural gas is added for comparison, based on gross calorific value (as appropriate for a condensing boiler)

Is it worth getting battery storage to go with your solar PV?

Now that the Feed in Tariff rates are reduced and PV is hard to sell, some solar power companies are pushing battery storage instead, to people who already have PV. Unless you are very eco-minded you probably expect the system to at least pay for itself but it is very hard to estimate savings. I have just been visited by salesmen who made some rather misleading statements. Here are some things to ask and some very simple calculations you can use to fact check what the salesman tells you.

Also, always get at least two quotes.