My Plan to Achieve Energy Freedom - The Road to Zero Energy Bills

freddyuk wrote: »

In your equation what value do you put on
1. "grid independence" for the sake of it.
2. Controlling your own destiny
3. Feeling of satisfaction from self sufficiency
4. Education of how "stuff works" ie. energy usage in and around the home.
5. Understanding how the world produces energy and how we take it for granted.
6. The joy of sitting watching TV while your neighbour may be in darkness huddled round a candle freezing cold.
7. Learning how you can live within your "energy means" but if you want more over your "energy budget "you have to pay proportionately more

I feel all these things have a value which is not a monetary amount but very relevant to having a more energy independent lifestyle...

All of the above, except perhaps for "The joy of sitting watching TV while your neighbor may be in darkness huddled round a candle freezing cold.", are great positive side effects of trying this. I realised I didn't know much about how energy is generated, how I was using it and how I could get away from big energy bills. I have built a pretty solid understanding of these now, and it's been great so far. Researching and implementing the projects I list above will continue to build this knowledge, which has been very satisfying, as well as the money savings I mention.

freddyuk wrote: »

Just taking a quick point as that is a lot to go through.
Did you calibrate the energy meter? Switch a known load to check it is accurate (at least 1kw). These thing are very inaccurate below 200watts so you need to have a control baseline you can trust and then switch on your small loads on top of this to measure more accurately. Your electricity meter is going to be dead accurate so you can check this for 24 hours and cross reference with the monitor.

Yep, I have two meters to double check the measurements of individual appliances: one which clips onto the wire into the house beside the electricity meter, and one which is a plug meter like this one:

When we moved into our house, it had single glazed windows, no attic insulation, and a host of leaks. The wind basically blew straight through it, and it took the heat with it. After installing attic insulation, and adding new rubber seals around the windows and some doors, we decided one of the next moves we would undertake was to install double/triple glazed windows.

The double glazed windows ready to be installed:


I’ve been approaching these energy improvements formulaically since the start: How much does it cost to implement? How much will it save each year? How long will it take to pay for itself, and is there any other thing I could do before it with a better payback period? This one however, I think, may be a special case. When I do the maths around Double Glazed Windows, the payback is actually a lot longer than you might expect given it tends to be the Go-To energy saving measure that most people think of when they think about upgrading the energy performance of their house. We are looking at savings of €303 in gas costs per year (I can’t get that exact figure because I’ve installed a wood burning stove with a back boiler, which is also eating into the gas costs). At €7,000 for the installation of the windows, that means a payback period of €7000 / €303.21 = 23.09 year payback. Yikes! Switching to LED lights paid for itself in 9 months, and switching to the Electric Car pays for itself in 5.4 years. 23 years seems like a very long time indeed. So why am I considering it?

Well – I think it’s because all energy is not perceived equally. There’s a quality of life issue here as well. Loosing 10kWh per day on an inefficient dishwasher is a terrible waste, but it doesn’t make you cold when you’re eating your dinner. Poorly performing windows do. They also add to the security of the house (our previous windows would have taken approximately one point two seconds to break into), the reduced noise from the road and reduced maintenance on the new, higher quality handles and openings. These are not directly quantifiable into kWh (and hence cost and emissions) savings – but they heavily influenced our decision to proceed with the windows ahead of say, installing Solar PV panels, which would pay for themselves in about 11 years.

The Payback Analysis
Before the windows were installed, for the first five months of 2015, we used 7,896kWh of gas (in that same period, we used 15,792kWh of wood). I’m going to estimate a 20% saving in heat required by the house – we have some large bodies of glass, particularly in the living areas, and this seems to be the average quoted online. 7,896kWh for 5 months translated to 18,950.4 kWh of gas used per year before the double glazed windows are installed. If the windows save 20% of this, that means they save 3,790.08 kWh (18,950.4kWh * .2 = 3,790.08 kWh ). Gas costs €0.08 per kWh, which means 3,790.08kWh * .08 = €303.21 saved. €7000 / €303.21 = 23.09 year payback.

In terms of emissions savings, 3,790.08 kWh / 11.4772 kWh per M^3 = 330.2269 M^3 per year, and gas emits 2.13793103448275 kg of CO2 per M^3, so the emissions savings are 330.2 * 2.14 = 706 kg CO2 per year. That will amount to 21,180 kgCO2 over the 30 year lifetime of the windows. Twenty one thousand kg of CO2 prevented with one measure is a pretty good haul.

The Numbers

• Cost of Installing Double Glazed Windows: €7,000
• Yearly Heating Savings from the Windows: €303.21
• Savings: €303.21 per year | 3,790.08 kWh per year | 706 kgCO2 per year
• Payback Period: 23 years
• 30 year payback: €2096.3 (30 years * €303.21 saving per year = €9,096.3 – €7000 original installation cost = €2096.30)
• 30 Year Return on Investment: 29.9%
• Annualised Return on Investment: 1%

The Installation
The installation of double/triple glazed windows is not overly long or difficult. It took three days in our house. The windows are measured in advance and manufactured to fit the exact measurements so when the windows arrive, the process is as such: (1) remove the old windows and frames, (2) slide in the new window frames (3) spray expanding insulating foam around the frames so they are fully sealed (4) re-finish any areas on the window boards or walls around the windows which were damaged so everything looks as good as new.

It took three days for this process in our house, and have been fully fit into the house for eight months.

The new (Black) and old (brown) front door. The difference in terms of weatherproofing is phenomenal. The wind used to literally blow through the old front door. The new one is fully sealed, both to the cold, and to noise from the outside. Also, it looks much better:


I wanted to experience a winter with the new windows before writing this post, so I could fully understand the difference they make in cold temperatures. The difference has been huge – like the wood burning stove, they have contributed hugely to the feeling of cosiness in the house. The hall is no longer a place you have to run through on cold evenings – the new front door is fully sealed against the searing South Westerly winds hammering against it during the yearly winter storms. The downstairs rooms are also noticeably warmer.

Finally, because heat lasts longer in the house, they have increased our ability to heat the house solely with wood. Once it’s above about 4C outside overnight, we can light the fire in the wood burning stove in the evening, and that will contribute enough heat to keep the house warm overnight without the need to add additional heating with the gas boiler. Previously, we needed to turn on the gas late at night every night in Autumn and Spring. That gets us a lot further along the route to energy independence, and saves us a decent bit of money. The verdict: The financial payback is quite long, but the intangibles (comfort, security, noise reduction) are very valuable. If you currently have singled glazed windows, installing double or triple glazed windows is definitely worth doing.

ted1 wrote: »

With regards the gas calculations for the Windows you didn't allow a drop in usage for summer months. To give a true payback you need to make correct allowances.

Yep - my knowledge of thermo-dynamic modelling extended as far as reading the relevant Wikipedia pages when I was figuring out the relative savings of installing Double Glazed Windows vs Attic Insulation vs Internal or External Wall Insulation vs a Wood burning stove vs Solar PV to rank them from best to worst, so some of the calculations may be simplistic. At the same time, I think they are within the right order of magnitude relative to each other, so should rank them correctly. I'm learning a lot as I go having now implemented several projects (Radiator Heat Reflectors, Double Glazed Windows, Rubber Seals around doors connecting to the outside, Wood Burning Stove with Back Boiler) so I'll get better at the modelling aspect with each project implemented. If nothing else, it's been a great learning experience. Understanding energy consumption and generation hasn't been half as intimidating as it would seem from the outside.

While I cycle to work and most other places, the other half is reluctant to become a carless household. This means we need to find a way of achieving motorised transport without significant expense and emissions. I expect this is a universal hope across most households, so let's get it worked out. Since we started the journey to energy independence - freeing ourselves from fossil fuels, and energy bills in the process, one of the main aims was to get away from oil powered transport. Very happily, this is now a reality. We'll never be going back to a fossil fuel car!



The Payback analysis:

• Cost of the Leaf: €16,000
• Cost to run the petrol car yearly: €3250.56
• Cost to run the Leaf yearly: €295.76
• Savings: €2,954.8 per year | 11,224 kWh per year| 1630 kgCO2 per year
• Payback Period: 5.4 years
• 10 year payback: €7,548 (from baseline of current gasoline car, allowing for a new battery after 5 years costing €5000 and €1000 of maintenance costs, and assuming a depreciation of the entire value of the car over 10 years)
• 10 Year Return on Investment: 40.7% (Total cost = €21,000, Total savings = €29,548)
• Annualised Return on Investment: 4.1%

How it's worked out
Way back in the initial look at home energy consumption, the breakdown of energy costs came to this: Heating our average house consumes 29kWh per day. Powering the house's electronics consumes 13kWh per day, but the car.. That consumes a whopping 40kWh per day! So if you drive a petrol / diesel powered car, then this energy spend is enemy number one - a whopping 40kWh per day!


The car consumes a disproportionate amount of energy for a few reasons:

1. Cars weigh 1500kg+, you weigh less than 100kg. Most of the petrol in the tank is consumed moving the metal that surrounds you rather than you. (Hence, if you want to be truly efficient, then cycle {LINK TO Transport Costs and Energy Consumption}.. If you can't cycle, then drive an electric car).
2. Internal Combustion Engines are only 10-15% efficient. That means 85% of the gas you pump into your car's fuel tank is turned into heat and noise which is of no use. The more efficient cars turn 15% of the chemical energy in the fuel into forward momentum when you depress the accelerator. But only if the engine is at the optimum temperature. That means short journeys are particularly expensive in terms of $ / km - when the engine is warming up, it consumes significantly more fuel.
3. "Normal" non-electric/hybrid cars don't use regenerative breaking. That means that once the engine has ignited enough petrol or diesel to power the car forwards, when you stop at a traffic light, all of that energy is dumped into the brake pads as useless heat, and the process starts again with that energy removed from the equation.
4. Certain driving styles consume far more gasoline than others, but most people don't know this. Internal Combustion Engines rarely give any feedback to the driver of their fuel economy so the cars tend to be driven inefficiently.

From an energy point of view, this just won't do! Wouldn't it be great if when you hit the brakes, the engine ran in reverse and started pumping fuel back into the fuel tank. But there is! It comes in the form of a Lithium Ion battery. An electric vehicle removes these inefficiencies, to use the money you pump into the car in the form of electricity into far more efficient momentum.

The Battery Revolution
Battery technology is experiencing an explosive growth as transport and renewable energy companies pour money into research in the area. The range of the Nissan Leaf has gone from 110km / 70 miles in 2011 to 150km / 93 miles in 2014, to 172km / 107 miles in 2016 and a projected 500 km (310 miles) for the 2017 model. Nissan have increased the storage of the Leaf battery from 24kWh (2011 to 2014) to 30kWh (2016) to 60kWh (2017) in the same amount of space inside the vehicle. It's obvious that battery density per unit space is experiencing its own Moor's Law. I suggest reading the fantastic Wait But Why article on Tesla and the Battery Storage Revolution to understand the monumental change that will bring in terms of removing people's dependence on fossil fuels and the associated costs.

For me, this meant moving to an electric car. Like everything on this thread - this was an investment intended to create a mutually beneficial situation in terms of personal wealth creation, and environmental impact reduction.

Cost / Payback Analysis
First the baseline cost of running our current car
Cost Baseline: To work out the cost and energy savings, I started with the weekly millage of about 300km per week (if you drive more, then an electric car will pay for itself faster). Our previous car was a 15 year old 1.4 litre Nissan Almera, from which we were getting 32 MPG (UK Gallons). Converted to km per litre, that's is 11.36 KM/L (or 8.8 Litres per 100KM). So 300km driven per week / 11.36KM/L = 26.4 litres of petrol per week. That's about 1372 litres per year. Petrol ranges from 1.259 €/Litre to 1.698 €/Litre in Ireland for the last few months, so taking the average of €1.48 per litre means €1.48 * 1372 = €2030.56 ($2200 per year). Another cost factor was the average of €1100 I was spending in maintenance on average, each year for the last 5 years - the car generally ran well, but something tended to go in the engine or gear box each year. Finally, in Europe, cars are taxed according to emissions. The tax on the Almera came in at €570 per year. All in, it cost €2030.56 + €1100 + €120 = €3250.56 to run the petrol car.

Emissions Baseline: The Almera's stated emissions was 158g CO2/km, however given what's come out from VW's emissions testing and about the tests themselves, I'm going to bet this was atleast 200g CO2/km. At 250km per week or 13,000km / year, that means the emissions were 200g * 13,000km = 2600kg CO2.

Energy Consumption (kWh) Baseline: Finally, 1 litre of petrol contains 10 kWh. 1372 litres a year means 1372 * 10 = 13,720 kWh per year.

So now I knew what I was using, I was able to estimate the potential savings to evaluate this investment. After some scouting, I found a second hand Black 2014 Nissan leaf Acenta with 5000km on the clock for €16,000. While I live here in Ireland, the UK has a significantly bigger second hand car market. Usually, there would be an import tax of around €5k to import a car to Ireland, which car dealers in Ireland lobbied the government to introduce to protect their trade. However, I realised this tax is based purely on tailpipe CO2 emissions. The Nissan Leaf has zero tailpipe emissions. Huzzah! Importing the car was free. So that was a good start.

Estimating the running costs of the Nissan Leaf
Cost Estimate: Firstly, the road tax of €570 drops to the lowest emissions category for the Leaf: €120 per year.
Because the Leaf on sale was only 8 months old, it was still warrantied for 5 years, so no significant maintenance cost for the next 5 years. We replace the petrol from petrol stations with electricity from our house, and from public charging stations. Funnily enough, all public charge points in Ireland are completely free, and I'm lucky enough to live within 2km of two fast charge points. So it would actually be possible (and I know several people who do) drive with no energy costs whatsoever, but let's work out a baseline based on charging at home.
We drive roughly 300km per week. The range of the Leaf is 150km and has a 24kWh battery pack. That means it will consume 48kWh per 300km, and hence 48kWh per week. We had a smart electricity meter installed by our utility when we got the electric car which allowed us to move to a day / night rate of €0.17 / kWh during the day and €0.07 at night. Hence, charging will cost 48kWh * €0.07 = €3.36 per week, or 3.38 * 52 = €175.76 per year. That is a somewhat incredible saving of €2030.56 (which it cost to run the petrol car) - €175.76 = €1854.8 per year.
So the yearly cost of the Leaf is €120 + €175.76 = €295.76.
In total, that means the Leaf saves €3250.56 - €295.76 = €2954.8 per year.

Energy Consumption (kWh): The leaf has a 150km range, and a 24kWh battery. That means we'll be consuming 48kWh driving 300km per week, or 48 * 52 = 2,496 kWh per year. Our petrol car consumed 13,720 kWh to drive this far, meaning the electric car uses 2,496 / 13,720 = 0.1819 or 18.1% of the energy to drive the same distance. The electric car will save 13,720 - 2,496 = 11,224 kWh per year to drive the same distance.

Emissions: The emissions of an electric car are no longer due to the combustion of petrol in the engine. They're due to the generation of electricity in the power stations from which you draw power. That means they could vary from virtually zero if charged from solar, wind or nuclear, to close to that of a lower-emitting petrol car if the electricity is generated by coal power stations. The electricity grid emissions for Ireland are posted online in real time by Eirgrid here. This is today's picture:

So, today the electricity generation is 389 gCO2 / kWh. At this level, driving 300km per week, which consumes 48kWh results in 48 kWh * .389 gCO2 / kWh = 18.67 kgCO2 per week, or 18.67 * 52 = 970.9 kgCO2 per year. Our petrol emitted 2600kg CO2 to drive this same distance, so the yearly emissions savings is 2600 - 970 = 1630 kg CO2 per year.

Car Rental to cover long journeys
One extra factor that I considered here is the cost of renting a petrol car for longer journeys. The west of Ireland has some of the best surf (due to having some of the worst weather!) in the world, and so we drive to remote parts of the west 4-5 times a year. It costs about €50 to rent a car for a weekend off peak, so this would come to about €250. However, we're surrounded by family and friends who like driving the Leaf, so I think we'll just be able to swap cars when this is required. It's certainly an option however for people without this option. If we're saving in the region of €3k per year with the electric car, it would likely still financial make sense for people who need to drive long distances into areas not covered by charging infrastructure to move to an electric car for their commuting and city driving, and to rent a petrol car for the longer trips.

Our experience with the Leaf so far
In summary, the Leaf has worked out very well so far indeed. We haven't had any problems, the driving experience is far superior to our old petrol car with increased acceleration, more reliable handling, on-board electronics (things like rear facing camera for reversing with augmented reality overlay of where the car will end up, the car is internet connected, excellent heating / cooling systems), and we're saving a considerable amount of money on energy. It's led to some further benefits around understanding our energy usage and moving our other appliances to the night time electricity rate. We haven't run out of battery yet, and I don't expect that we will. After buying the electric car, I came to the conclusion that Range Anxiety was invented by motor-media reviewers to have something negative to say about electric cars. No one runs out of petrol on the side of the road. That's because they plan their journey and gas station stops around the range limitations of the petrol tank. The same holds true for an electric car - you simply plan your journey in such a way that you don't drive somewhere further away from somewhere you can charge than you have range left in the battery. 99% of our journeys are less than 150km anyway, so we mostly don't have to worry about it at all - we just charge the car at night when we're asleep. This holds true for probably 95% of urban dwellers.

For longer journeys, the electric car charging network is pretty good in Ireland:


From keeping up with EV owners in Ireland, there certainly have been some teething problems, but the motorway network is well built out with fast chargers, so it's possible to drive most places in the country using these. The fast chargers charge the Leaf to 80% in about 20 minutes from empty. The charging network is currently completely free, and it seems it will be so for at least the next year. We've mostly charged at home, and so I calculated the above running costs exclusively charging at home, but each charge from one of these points reduces some of the running cost. We’ve had some opportunities to charge in some nice places. You may recognise Lahinch, Co Clare from the Big Wave surfing documentary Wave Riders:


As of the December 2015, the car has had 39 fast charges and 518 slow charges. The Leaf Spy app gives very granular information into the health of the batteries:


It reads the battery capacity at 90%, although that varies from 88% - 95% depending on the temperature of the battery when it was measured. An interesting point about electric cars is that there are very few moving parts to break. In fact, the only thing that will likely need replacing at the traditional "end of life" of a car will be the battery. That means, as battery technology develops, I can simply replace the battery with the latest model, increasing the range of the car and essentially giving it a new lease of life until the next battery upgrade. This currently costs about €5000. I suspect that we'll need to replace the battery after about 5 years. Going by the current battery density development of new Leafs, in 2019, the density will have gone from 24 kWh (150km range) to perhaps 100 kWh (600km range).

There have been a few other added bonuses:

• The Nissan leaf is an energy nerd's best friend in just about every way. The dashboard screen gives you granular energy consumption charts at the click of the screen. As we already know, if you can't measure it, you can't reduce it, so this feedback is invaluable to reduce energy consumption of your driving. Even the heater employs a heat pump rather than electric resistance heating to squeeze another 10km of range from the battery in cold weather.
• It's great to no longer be pumping pollution and particulate shown by the World Health Organisation to cause cancer, particularly in children, into the air my children and the people around me are breathing.
• I can now log into my car from my phone to turn on and off charging, turn on de-icing and climate control.
• We had a smart electricity meter installed by our utility when we got the electric car which allowed us to move to a day / night rate of €0.17 / kWh during the day and €0.07 at night. We immediately moved all of our programmable appliances to run during the night hours - watching machine, dishwasher, etc.
• When I install Solar PV, I will have 24 kWh of storage connected whenever the car is there. That's enough to power the house for two whole days, or a few more if we're careful, if we install an inverter.

We went for a nearly new Leaf, because of the slightly longer range compared to older models, but I see 2011 Nissan Leaf models on the market in Ireland and the UK for about 50% of what I paid. The same is likely true in the US and other places around the world. If you currently have two fossil fuel powered cars, and your daily commute is, under 70km per day, then replacing one car with an older used Leaf would give a payback of 3.38 years @ 300km driving per week.

The Summary
This is a serious coup as an energy investment towards energy freedom. We haven't been to a petrol station in over a year. We're saving €2,954.8 per year with a 11,224 kWh reduction in energy use, and saving 1,630 kgCO2 per year in the process. At this stage, we've switched to all LED lights, installed insulation, installed a wood burning stove (next post!) and switched to an electric car, the money is starting to stack up pretty fast into our energy savings fund. We’re well on our way to energy independence! Viva le progress!