Wires beat pipes hands down, according to energy expert Richard Keech, who says gas has a bigger emissions footprint than most of us realise.
Off the back of the latest IPCC report, we have renewed impetus to take real and effective action in response to the threat of climate change.
When it comes to the role of the built environment, I think the most effective pathway for response can perhaps be framed as “electrification plus efficiency, plus PV”. The efficiency and solar PV have been extensively discussed. In this piece I want to consider electrification.
When we talk “electrification”, we mean powering our buildings entirely with electricity. In practical terms this mostly means phasing out the use of (so called) natural gas.
Many are familiar with the argument that gas is an affordable and low-emission fuel. For much of the last twenty years, the discussion about reducing emissions in buildings has been dominated by the mistaken idea that low-emissions gas is preferred to high-emissions grid electricity.
Now things have flipped. We’re on the cusp, I hope, of it becoming widely accepted that gas is actually a damaging high-emissions fuel source. On the other side, Australia’s power grid is rapidly transforming before our very eyes as low-cost, low-emissions wind and solar re-shape the economics of energy delivery in this country.
The trouble with methane
What’s wrong with this picture? So-called “natural gas” is fossil methane. We need a clear-eyed view of the reality of using methane as a fuel in our buildings. As I see it, the key issues with using methane here in Australia are that the real-world emissions are much higher than generally supposed because of the un-burned methane that is released into atmosphere. Two things – global warming potential, and the amount of methane released to atmosphere – make methane release highly problematic.
Unburned release. The way we get methane as a fuel involves a pathway of many steps – prospecting, production, processing, (sometimes) storage, transmission and distribution, and end use. At every point in this complicated system there is a degree of methane, CO2 or other things, that get released to atmosphere before the methane can be fully burned. Note, I’m careful not to generalise this as “leakage”, because sometimes, alarmingly, methane release is entirely deliberate and part of the designed operation of the system.
Wrong GWP. Whenever we reckon the climate impact of a greenhouse gas, we scale it to equivalence with carbon dioxide by multiplying by a number called the global-warming potential (GWP). The complication with this is that different materials stay in the atmosphere for different times (“residence times”). Methane is a more potent greenhouse gas than CO2, but its residence time is shorter – only about twelve years.
The right GWP. Scientists generally calculate both one-hundred year and twenty-year time horizons when looking at different greenhouse gases, and apply a different GWP to each timeframe. The one-hundred-year GWP of methane is 28, but over twenty years it is a massive 83 times more potent than CO2. Generally, in climate accounting, the one-hundred-year values are used. However, I’m of the view that we should use the time horizon that best matches the time frame for meaningful action. No one who properly understands the climate emergency thinks we have a century left to fix this. We’ll be lucky if we have twenty years. So, if we apply a GWP of 83 to methane, then straight away that scales up the measured impact of unburned methane by a factor of three. An example of a jurisdiction that is already using the twenty-year GWP instead of the one-hundred-year is the state of New York.
Release rates: official. The total emissive impact of the unburned release is equal to the GWP multiplied by the amount that gets released. The government reference document for emission accounting is called the National Greenhouse Accounts Factors, which is updated every year. According to this document, using methane from a pipeline, the impact of release of unburned methane is only 7 per cent of the total greenhouse impact of using methane as a fuel. By my calculations, this means the government is assuming that the net rate of release of unburned methane is only about 0.3 per cent.
Release rates: realistic. Looking at the many reports and studies, I’ve formed the view that realistic rates of unburned methane release, in eastern Australia, are more likely to be at least 3 per cent, and possibly much more. At a net release rate of greater than 3.4 per cent, the emissions from releases exceeds the emissions from burning alone (assuming GWP of 83). Study after study suggest that we’ve been systematically underestimating the emissions from gas.
Unconventional gas. As time passes, gas gets progressively worse from an emissions point of view as the best quality gas fields get used up. As the conventional gas fields in eastern Australia decline, we’ll become increasingly dependent upon unconventional gas. Many new gas fields are on the cusp of being opened in Australia. The emissions impact of opening these carbon bombs needs to be avoided at all costs.
So what does this mean? I like this from Rachel Golden of the Sierra Club:
“There is no pathway to stabilising the climate without phasing gas out of our homes and buildings. This is a must-do for the climate and a liveable planet”
There’s an emerging awareness that powering our homes entirely from electricity is superior to the dual-fuel (gas-plus-electric) approach we’re familiar with in Australia. It’s already cheaper to build and cheaper to run an all-electric home than a typical dual-fuel home in Australia. I’ve written a book on efficient all-electric homes called The Energy Freedom Home, published by Scribe. If you want to drill down to the economics of all electric homes, have a look at the excellent study by Renew called “Household fuel choice in the National Energy Market” from 2018. Renew’s work shows that retrofitting for efficiency and all-electric will nearly always save money in the long term.
Social media. There’s also a great community of interest around electrification on social media, as recently reported by my friend and colleague Tim Forcey. So, join the My Efficient Electric Home Facebook group f you want to learn more.
My own experience. Between 2007 and 2013 I retrofitted my suburban Melbourne family home from typical to terrific. In 2006 my three-bedroom timber home wasn’t very efficient, and I used gas for heating, hot water and cooking. Over the course of seven years, I transformed my home through adding solar panels, making it thermally more efficient, and switching inefficient gas appliances for readily available electric appliances and devices. The net results were that I reduced my home’s consumption (gas and electricity combined) from 80GJ in 2006 to 20GJ in 2013, despite unchanged occupancy. At the same time the home is much more comfortable than it was. That remaining energy consumption is fully offset by the solar on my own roof. Those measures were not cheap (as an early adopter of solar), but they’ve now fully paid off. I estimate that my avoided energy spend since January 2007 is $68,000. Note, that large amount is, in part, thanks to legacy feed-in tariffs that are no longer available to new customers. If my feed-in tariff were the standard one, then my avoided energy consumption is estimated at $18,000.
Heat pumps are the key. The key technology in the transition to all-electric homes is the heat pump. My retrofitted home now gets all its heating from reverse-cycle split systems running as heaters. My own experience, and that of many people I know, is that using split systems as heaters will reduce the energy cost of heating by at least two thirds when compared to common gas-fired, ducted heating. Heat pumps can be so efficient because they draw free, renewable ambient heat energy out of the outside air. This is not a metaphor. Heat energy is drawn, literally, from thin air, is an enormous and little-appreciated renewable energy resource.
Building all-electric homes at scale. We’ve shown that all-electric homes work and save money. How can we make the transition at scale? Around Australia we now have many examples of entire new housing estates that are all-electric from the outset. The standout example is The Cape development at Cape Paterson in Victoria, which is the brainchild of Brendan Condon, and where I now call home. Other examples are:
- Salt, Torquay, Victoria. This small residential estate is being developed sustainably by Barwon Water;
- The Paddock, Castlemaine, Victoria. This small medium-density development has high energy performance and is being developed all-electric;
- Ginninderry, ACT. Located in the north-west suburbs of Canberra near the NSW border, this large greenfield estate is being developed sustainably. It is all-electric and Green Star certified;
- Lonicera, Woodend, Victoria. This very small residential estate by Villawood was its first all-electric development;
- Redstone, Sunbury, Victoria. Also by Villawood, this large urban estate has no gas connected;
- Narara Ecovillage, NSW. This estate is on the NSW central coast is all-electric and has a 7-star minimum home thermal performance requirement;
- Nightingale Housing, various. There are several Nightingale Housing sustainable apartment projects, either completed or in development. With the exception of the very first one (The Commons in Brunswick), they are all being developed without gas;
- All-electric social housing. Initiatives like the Victorian government’s Zero Net Carbon Homes initiative applied to social housing in Melbourne;
- Replacing aging gas heaters. The Victorian government’s social housing upgrade program includes replacement of aging and inefficient (mainly gas) heaters with efficient split systems.
Electrification: the big picture
The role of the grid changes
Sharing. When buildings produce large amounts of their own electricity with solar PV, they usually export surplus to the grid at various times, often to the benefit of non-solar neighbours. In these situations, those with solar effectively use the grid as a sharing system, not just a supply system. Re-thinking the role of the grid in this way helps underscore the fundamental change going on with energy.
Transport. With the emergence of electric vehicles, the use of the electric grid for everyday transport is another part of how the role of the grid shifts. The ability to charge your car at home is a huge benefit compared to how we re-fuel internal-combustion-powered vehicles.
The one grid
Three grids. Electrification amounts to consolidating three “grids” (existing electric, gas, transport fuel) into one. There’s a wonderful synergy that happens when multiple, diverse, uses of energy share a common mode of energy transport. This synergy leads to improved levels of average use, because the diverse use patterns consume energy at different times. There’s also overall reduced costs, improved safety, and reliability.
Benefits of scale. We’ve seen this type of diversity effect before with the internet. Early computer networking pioneer Bob Metcalfe expressed the idea, now known as Metcalfe’s Law, that the value of a communications network is proportional to the square of the number of connected users. We see this today with the power and breadth of the internet, able to carry a huge range of services for everyone. I think that electrification of energy is like that too.
Decentralised. Another way in which electrification is like the internet is that both are associated with less centralised operation than that which preceded them. In energy, we see that decentralisation in terms of lots of generation happening all throughout the grid. This is a healthy improvement on the centralised power grid. Concentrations of power, whether they be physical, economic, or political, usually lead to systemic distortions, which are unhealthy. And so it is with energy. Decentralisation is a common good – unless, of course, you own a large centralised power generator.
In the same way as the ubiquitous internet is a single common network, we can expect great things from consolidating our energy supply and use around an improved electricity grid.
Wires beat pipes
Electrical marvel. The use of electricity is so commonplace that perhaps we’ve forgotten what a marvel it is. Electronics and wires are a “solid-state” technology. At its heart electricity’s amazing utility comes from the fact that it can carry both power and information. Electricity has an amazing versatility. It can be transformed easily to light, sound, heat, motion. These transformations are reversible, mostly.
Intrinsic benefits. There are no products of combustion where the electricity is consumed. It is intrinsically simpler, more reliable, and safer than an energy system involving combustion and pipes. An example is the common safety switch, now found in every recent meter box. With the slightest leak of electricity to ground, the safety switch will trip immediately, keeping occupants safe.
Smart control. Since electricity carries both power and information, it means that power electronic systems are much more amenable to simple digital control than comparable gas-fired systems. Electric power systems are just fundamentally a better fit with digital technology because they’re both electrical in nature. For example, it’s easier to have a smart electricity meter than a smart gas meter. It’s much easier to retrofit fine-grain control and monitoring to electrical systems than systems that need mechanical valves and pipes.
Localised generation. Another thing that electricity gives us is the scope for localised generation – mainly through solar PV. This is a game changer, compared with gas and petrol.
Scale of use. Another amazing thing about electricity is how electrical and electronic systems scale so well. Devices can be the size of a hearing aid and right up to a massive hydro-electric generator.
Scale of build. In terms of manufacture, there’s a debt that the energy system owes to computer technology. Many will be familiar with Moore’s Law – the ideal that computers get exponentially more capable as time passes. This is due largely to steady and cumulative improvements in electronic fabrication that has driven down unit price incredibly. The same scaling and improvements in manufacture apply to solar panels and is the reason why the cost per watt of solar-panel capacity has reduced by over 90 per cent in the last twelve years. This, now, is driving sustained reductions in wholesale electricity price.
Storage at scale. Another area where this broad scaling is expected is with battery energy storage systems. Some systems, like pumped hydro schemes, only work at large scale. Battery systems, on the other hand, scale from tiny (think hearing aid) right up to grid scale batteries (like the Hornsdale Power Reserve in SA). These same economies of scale are bringing down the cost of energy storage.
Will the grid cope?
One concern sometimes expressed about electrification is that the grid won’t cope with everyone switching to all-electric appliances. This has already been addressed. Yes, there will be challenges. We may need more electrical generation overall. However, there are reasons to think that the challenge to the grid won’t be as big a problem as some may imagine.
Heat pumps. As already mentioned, heat pumps are a key technology in the replacement of gas. In terms of the role of heat pumps in the broad scale of electrification, they’re the main reason we won’t need to scale up the amount of generation by as much as the amount of gas energy displaced. In other words, each gigajoule of gas energy displaced by electricity will require much less than a gigajoule of electricity in cases where the final energy service required is low-grade heat of the kind easily provided by a heat pump. In the built environment today, gas is almost exclusively used for low-grade heat.
Surplus generation and flexible demand. Another reason to think that the grid, with straightforward upgrades, will cope okay with electrification is the combined effect of three things:
- we’re heading towards having abundant energy much of the time during daylight hours because of solar PV;
- we’re likely to see a lot of new energy storage; and
- many of the new electrical loads will be flexible in nature, such that the use of the loads can be coordinated to better match real-time demand with affordable supply.
Flexible demand 1: EV charging. Charging EVs is very often amenable to flexible control, possibly by third parties. If an EV takes, say, six hours to charge, and there are sixteen hours between arriving home and leaving for work, then that gives great scope for coordinating when that charging is to occur to take advantage of the best tariffs. A form of this is already readily available. Solar-aware residential chargers such as the Zappi allow car charging optimally from surplus solar energy. In other words, the rate of charge is regulated to keep the energy consumption within the envelope of surplus solar energy. This allows for best use of a home’s solar energy. It’s easy to imagine smart aggregation of this type of charge management to allow charging of many vehicles in the optimal way for the grid to avoid grid congestion.
Flexible demand 2: Pool heating. The amount of gas energy currently used in large aquatic centres is considerable. This type of energy use is both amenable to substitution by heat pumps, and sufficiently flexible that the operation of the heat pumps could be coordinated like the EV charging to help avoid grid congestion.
Richard Keech is a freelance consultant in building energy efficiency and renewable energy.
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