Part 4 – What about Energy Efficiency?

As discussed in the last section, we still will struggle to roll out renewables at a rate high enough to offset peak oil (which again would require putting 1.5-1.0 Tillion kWh/yr worth of energy production onto the grid each year) and mitigate dangerous climate change. One solution would therefore be to simply cut energy use by improving energy efficiency. When most people think energy efficiency they think of installing a few low-e bulbs and maybe lagging their boiler.

However, I’m talking about measures a bit more radical than that – Measures such as reducing the energy consumption of houses by factors of +50% or a mandatory caps on vehicle fuel consumption rates (which would essentially many urban SUV’s), or major changes to the electricity grid (as discussed previously).

Achieving such radical reductions are theoretically possible, but it would require a significant shift in peoples attitudes to the whole energy issue as well as some lifestyle changes (thought these lifestyle changes will pale in comparison to the alternative, i.e drive an energy efficient car or don’t drive at all because you can’t afford the fuel bill on you’re gas guzzler anymore!).

Question 4.1 – Building Energy use – towards Carbon neutrality
 
Question 4.2 – Getting around
 
Question 4.3 – Food For thought
 
Question 4.4 – Stuff you’re stuff!
 
Question 4.5 – Combined Heat and power – A possible quick fix?
 
Question 4.6 – Balancing it all

4.1 – Building Energy use – towards Carbon neutrality

Figure 4.1 – Thermal Imaging view of traditionally building apartment buildings and a newly built “Passivehaus” standard block on the right.

In most developed countries approximately 30-45% of ultimate energy use (depending on how you do you’re figures) is devoted to building, the vast majority (50-65%) is used for heating and cooling.

But we can now build homes with a near zero energy running demand (of course we mustn’t forget the embodied energy used to build it!),  by using extensive amounts of insulation, passive heat gain, solar collectors on the roof, ground or air source heat pumps, “smart” meters and electrical appliances with ultra high energy efficiency standards. Already in the UK government policy is pushing for all newly built homes will be “carbon neutral” by 2015. Of course, the question is how you define carbon neutral!

Figure 4.2 – Zero Energy Home concept design [Credit: Barratts]

But much of our building stock is already built and decades from needing to be replaced. Retrofitting all of the any nation’s existing building stock to zero-energy standards is going to be a tall order (bearing in mind how long it took and how much it cost to build it all in the first place). Retrofitting some buildings (particularly older buildings, articles on that here) maybe impossible. This is a particularly relevant comment as regards sprawling urban suburbs, which by forcing residents to be car dependent, have a fairly high carbon footprint.

It might ultimately be necessary to simply demolish many square miles of currently historic buildings, or sprawling suburbia, in pursuit of energy efficiency (a policy I don’t necessarily advocate, I’m just pointing it out as a possible option). Certainly it will be important to not repeat the mistakes of the past, and when building new urban areas plan them out to make everything more walkable or bicycle friendly, as well as more viable for public transport use.

Figure 4.3 – Linconshire council installing stray bale walls in housing project. Straw is a cheap natural material and has been used as a building material for centuries [Credit: The Guardian]
Figure 4.4 – An “Earthship” the ultimate in eco-homes is made from natural materials, has a low to zero net energy consumption rate for heating and cooling and gets all its electricity from renewable sources [Credit: Earthships.org]

Its also important to again raise the issue of “embodied energy”. Any future renovations or new buildings need to be designed to have a low an energy input as possible and to ideally source such materials from natural alternatives (Sheep’s wool, hemp, straw bales, etc.). The so-called Earthship movement are pioneers in this field but even “respectable” institutes are starting to realise the benefits of using low embodied energy materials.

4.2 – Getting around

Then we have to consider the energy used in transport as many cities are simply too spread out to make public transport viable (particularly, but not exclusively in the US). Many commuter belt suburbs (as noted earlier) may need to be similarly flattened and replaced with more compact living arrangements. Again, this feeds into the previous point as many of those homes are poorly insulated and have a higher rate of energy consumption. Too much of our manufactured goods come from too far away (China) which is itself dependant on distant resources (Australian iron ore and Middle Eastern oil) to function. These arrangements will have to change.

Figure 4.5 – Energy Consumption by speed and performance [Credit: adapted from J.D. Chapman (1989) Geography and Energy: Commercial Energy Systems and National Policies, New York: Longman Scientific & Technical]

And modes of transport with both a high oil dependency and a high level of energy use will have to be curtailed, where possible. For example, short haul flying, or commuting to work by car. Both are pretty energy in-efficient and such practices will have to be curtailed, either through economic means (remove all the hidden subsidies motorists and airlines get and let nature take its course) or political means (energy rationing, high carbon taxes, ban on engines sizes above certain levels, ban on short haul flights, etc.).

Of course some flying will still be necessary, as there’s simply on other way of getting around the world without planes. Similarly driving will still be necessary. But we’ll have to make cars and planes more energy efficient, better streamlining of aircraft and use of propfan engines could be a solution. We could well see planes getting slower in future not faster.

And this applies doubly so for cars, which will likely have to get smaller, lighter (composites rather than steel) and more energy efficient. There are various powertrain options that can be applied to vehicles, ranging from conventional (but ultra lightweight vehicles), such as the concept shown in figure 4.6, BEV’s (Battery Electric Vehicles), as well as series and parallel hybrid vehicles. I discuss all of these options in more detail here.

Figure 4.6 – The Loremo AG concept car which using a conventional 2-cylinder Diesel engine offered a performance of 157 mpg! [Credit: Treehugger]

One of the advantages of the fuel cell engine is that it is twice as fuel efficient as an IC engine. But what if fuel cells never take off? Well, there’s the Stirling-Hybrid engine, which offers a modest 50% gain in fuel economy. Similarly the micro-gas turbine offers slightly higher efficiency and improved performance. Both also have the advantage of being much more tolerant of alternative fuels (in theory anything that burns can run a Stirling engine and a gas turbine will burn any fuel in a liquid or gas form, given appropriate modification first). Either way the vehicles of the future will need to be smaller, sleeker and lighter.

Of course fans of the motorbike would often point out that they are capable of much greater fuel economy than cars (today without any new technology!). A Scooter can deliver fuel economy of 150 mpg, while motorway legal bike’s (500 cc engine) capable of 80-100 mpg’s are available. However, the fuel economy of any vehicle does bare a relation to driving style, and unfortunately riding a motor bike hard and fast can quickly cancel out some of its fuel saving benefits. Also, this low fuel consumption doesn’t apply to every bike. So-called superbikes, with 30-40 mpg can be as bad or worse than a car (although certainly better fuel economy than a supercar such as a Ferrari, which they can equal in terms of speed). So I’m afraid the line “well I had to buy a Ducati to help save the rainforests!” isn’t going to get you very far!

4.3 – Food For thought

Similarly, is it really necessary to fly in out of season fruit or transport it thousands of miles from where it is produced to where it is used? Food production currently has a very high energy footprint, both due to long transport distances (a failure to source produce locally), intensive processing and packing as well as excessive use of pesticides and fertilisers. There is considerable room for saving here too. Vegans would also point out the environmental benefits of Veganism and its lower rate of energy consumption.

4.4 – Stuff you’re stuff

A big chuck of our energy use is also tied up with “stuff” a catch all term I use to describe everything from small electrical gadgets to all manner of consumer products and services or out of season fruit from far away (as already mentioned). These can all have a particularly high carbon footprint, which will need to be cut.

Figure 4.7 – Too Much stuff! A common problem

Naturally the shipping vast amounts of electrical gadgets in from vast distances overseas is very wasteful in terms of energy, and unsustainable. The simplest way for most of us to cut our energy demand is by buying as much local produce as possible. This also has the advantage of supporting the domestic jobs market.

Then there is recycling to consider, I think the message has gotten lost over the years but there are many reasons to recycle. Eliminating the need for landfill or incineration of waste is one. Preventing the serious pollution that arises from our “throw away” society is another. Future civilisations will I suspect not remember us for landing on the Moon, nor even for being the idiots to melt the icecaps, no we’ll be remembered as the guys who turned much of the world’s oil endowment into trillions of plastic shopping bags that they will still be digging up a thousand years from now!

Figure 4.8 – The Great Pacific Garbage Patch, seen here off of Midway in the Pacific, is now so large it is one of the few man made objects visible from space! [Credit: Treehugger]

But there is another reason to recycle, and it boils down to energy. To convert aluminium from bauxite ore into a sheet metal costs about 300 MJ/kg. Recycling aluminium costs about 7 MJ/kg to do the same job (2.3% a 97.7% energy saving!). Something to consider next time you go to throw a drinks can in a bin or accept a plastic carrier bag at a shop.

Also, as I point out in this article the life cycle energy costs of products needs to be considered not just the energy use. Consequently a product with a long service life is better, as it allows for the embodied energy invested in it to last much longer.

4.5 – Combined Heat and power – A possible quick fix?

Also there is CHP, or combined heat and power. The energy efficiency of most thermal power stations is around 30-45%, with the remaining 70-55% of energy simply thrown away as “waste” hot water or saturated steam (info on that and CHP here and here). CHP proposes to use this heat for some useful purpose, such as running some thermal industrial process, or pumping the hot water into a district heating system. Many EU countries already utilize CHP heavily so its proven technology, and the choice of fuels is more varied (from biomass to refuse as well as the more traditional coal and natural gas). Using CHP we can raise the effective efficiency of power generation from its present level (33-45%), to between 60-80%. At present CHP probably represents the easiest and most effective way of reducing carbon emissions, and reducing fossil fuel consumption. Using so-called Tri-Generation (paper on this topic here) it can also be used in conjunction with a heat pump to provide a large cooling load in summer.

Figure 4.9 – High efficiency micro CHP units such as this can be run of off a variety of different fuels, save energy, reduce carbon emissions and serve to diversify electricity generation helping to supplement more intermittent renewable resources [Credit: Lowenergyhouse.com]

However, the CHP plant must be located close to the source of heat demand and most power stations are built some distance away from most cities. Fortunately CHP plant can be sized from multi giga-watt power stations right down to the scale of units to fit a small flat (so called Micro-CHP).

Figure 4.10 – CHP unit with Tri-generation, producing hot water, cooling water and electricity [Credit: 2G Energy]

But CHP use requires careful load balancing, the demand for heat/cooling has to tie in with the demand for electricity. The economics of CHP work best with situations where there is a large heat/cooling demand more or less constantly throughout the year (report on that here). A so called “anchor load” for the system (a swimming pool, care home, brewery, food prep, oil refineries, hospitals, etc.) is essential. Even so substantial savings could be achieved with a roll out of CHP, although it will likely greatly alter the shape of the electricity grid in favour of lots of small power stations, rather than a few big ones, probably resulting in a loss of economies of scale, thought this will be offset by reduced fuel demand for heating.

4.6 – Balancing it all

Energy efficiency measures like what I’ve proposed above could easily cut global energy use by 2-3% per year and sustain such cuts for several decades (thought obviously not indefinitely!), probably bottoming out with an energy consumption level half our current levels according to most experts. However, before we get carried away, there are one or two serious problems. Firstly timing and cost. The big problem with peak oil (or its evil twin climate change) is the pace at which we are going to have to implement the change over, as it is likely to be fairly steep. Knocking down large sections of major cities or junking our existing car fleet by the tens of millions or converting all our power stations and gas boilers to CHP, these are all fairly major projects. It would take decades and countless trillions of dollars to implement them.

But who is going to pay for all this? While yes, buying a Hybrid car might make sense if you’re throwing away you’re old car, but it makes economic little sense if you’ve just bought a new SUV (of course one could say, well what a fool you are buying a Hummer in the middle of an energy crisis), as it would mean essentially throwing away all the capital you’d just invested in it.

Similarly, convincing the owner of, say a hotel, to spend tens of millions ripping out all that expensive air-con kit he’d just installed 10 years ago and replacing it all with air-source heat pumps (or a CHP Tri-generation plant) isn’t going to be easy. The price of oil and energy will have to go fairly high before it becomes economic for him to make this change over. By the time the energy costs are high enough thought, he may well have spent all his cash paying these higher fuel bills and can no longer afford to pay the capital costs of changing everything over. Again it’s the time in the middle when were short of fuel and energy cost rise to alarming levels that’s the worry.

Finally there is the issue of the law of diminishing returns. It is a fact of life that we are subject to a form of “energy inflation”. The more efficient we become at our energy use, the more energy people use, the so-called Jevon’s Paradox, further expanded in the 1980’s to produce the so-called Khazzoom-Brookes Postulate. Thus while for example, car engines these days are a lot more efficient than in the past, cars are also much larger and have all sorts of energy hungry gadgets fitted (like air-con which is now practically standard in many countries). Consequently the average fuel consumption has recently been increasing, rather than the other way around.

Similarly, while we’ve made our homes more energy efficient with low-e bulbs and lagging the loft, we’ve also started buying lots of energy hungry gadgets like plasma TV’s and computers. We also have our heating on a lot more these days, even though energy prices are much higher (we’ve become used to warmer indoor temperatures).

Consequently the energy consumption of the typically household has soared over the last 30 years, even though it should be falling (due to improving energy efficiency. Again, it’s the law of diminishing returns in action.

And of course energy efficiency means saving energy, not magically creating new energy out of thin air. A Toyota Prius (or the Loremo shown earlier), even one driven extremely carefully and slowly by an energy conscious driver still runs on gasoline. And it doesn’t matter how slowly you drive it that fact doesn’t change. In other words, we still need to get energy from somewhere, and in the case of the Prius that means we still need to put oil in its tank from time to time. So in short there are practical limitations to how far we can push the whole energy efficiency paradigm.

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