When does grid parity happen in the south of Spain?

A view of grid parity from someone who has been living off grid for 10 years.
The date of writing this post is 8th July 2017.

What is Grid Parity?

Grid parity  occurs when an alternative energy source can generate power at the same  price as buying power from the electricity grid. Or to put it another way: After installing an alternative energy system how long will it take the before the cost of installation will be the same as if the house had been connected to an electric company. This is called pay back time.

The Quick Answer

In case you just want a quick answer in my opinion it would take 8 and a half years.
Below I will explain how I calculated this figure.

Calculations

Our annual electricty usage is 2005 kWh per year.
This is in our  house which is not connected to the grid.
The average occupation is about 4 people.
We do not use electrity for heating, cooking or AC.
The biggest electricty use we have is the swimming pool pump.
We live a fairy normal life and we have a freezer and  fridges.
We very occasionally have to use a generator when there is a prolonged cloudy spell but the cost is minimal. Maybe 20 euros per year.

We calculate the costs of the electric company by looking at the electricty bill we have for another house. The name of the company is Iberdrola.

We use the figure of 3000 watts as the maximum amount of power that can be used at any one time. (la potencia) The figure we use for the price of electrity is 0.16 euros per  kWh. There are other expenses such as electricty tax (impuesto), equipment hire (alquiler) and VAT (IVA).

The price per year of electricity from the GRID.

The cost if we bought the electricty from the grid would be 598 euros per year.
224 for additional costs and 374 euros for the electricity.

How much our solar electrical installation would cost.
To replicate our system you would need
1250 watts of panels – 840 euros 
50 amp combined inverter charge controller 750 euros
12 x 2v Lead Acid batteries 800 amp hours. 3500 euros.

Total cost 5090 euros

Total installation cost divided by GRID cost is 8.5

So time to parity is 8.5 years

Conclusion:
There are lots of other variables such as battery life and efficiency of the batterys which we have not considered here but 8.5 years  is a good basic figure and it feels about right..  

If I lived in a city would I cut off from the grid?
No probably not. If you have solar power  you always have to be a bit conscious of the time of day and if there is sun or not. The battery technology is the most important factor.  Batterys like the TESLA powerwall sound very promising and could provide about the bare minimum which would satisfy most people. I imagine that within 10-15 years in the future we will see a green energy revolution with excellent power storage and the  demise of the internal combustion engine.

The best thing about this situation for me is that we have been here for 10 years so our electricty is now effectively free. I just hope that our existing batterys can hold out long enough so that there are very good possibilities are available when the time comes to replace them.  

Aparently  450g  of carbon dioxide is put into the atmosphere per Kwh for electricty bought from the grid.

According to these figures we have not caused 9 metric tons of C02 to be released into the atmosphere.

 

 

 

Novella Carpenter – Urban farmer

Novella Carpenter

Novella Carpenter

There are not many people crazy or weird enough to actually enjoy producing food on a small scale so for me it was really great to read Novella Carpenter’s book. Farm City: The Education of an Urban Farmer.
Her book describes how she got into urban farming in a rough barrio in Oakland California using a vacant lot next to her house. She also has kept pigs, goats, chickens, bees, made wine, grown vegetables, planted trees etc but in an urban environment. The video below has an interview with Novella and it gives a very brief idea of what she does. Like us, Novella is a sociable person who would not want to be socially isolated on a farm in the middle of nowhere. Part of her childhood was spent in the middle of nowhere and it seems that the urban farm satisfies both the urge to be sociable, be part of a city  and also  the appreciation of nature and a more rural life. We ourselves have a similar dilemma but we solve this problem by having visitors and volunteers. If you like the idea of self sufficiency this book is a great read. Novella has a very pleasant way of writing and I particulary like her no nonsense style which includes plenty of  swearing. If I were inventing a fantasy neighbourhood including the most interesting people  I would definately have Novella as one of my  neighbours. She also has a blog here

The book is available at Amazon UK
or Amazon USA

 

Batch Water Heater – Free Hot Water

Batch Water Heater – Free Hot Water

batch_water_heater_on_roof

Probably the cheapest, simplest way of getting free hot water from the sun is a solar batch heater.  All you have to do is use a tank of water placed in the sun which will act as a pre-heater for the water which normally goes into the  hot water system.

In our case we used a 150 litre immersion heater tank which had stopped working. I am sure that in many countries there would be recycling centres which would let you have old immersion heaters for free. You can even chain them together in order  to make a very large capacity pre-heating system. The only possible drawback could be that if you live in a very cold climate they could freeze up in a prolonged cold spell.  In this case it would be a good idea to disconnect them during the coldest months.

To make some sort of calculation about the energy that my batch heater could expect to absorb I asked a question on a forum. The answer is here My tank is about 50cm radius by 1 metres length so it probably has a power intake of around 400 watts.

According to my own energy calculator it would take over 11 hours  to get the water to shower temperature.

“It would take 11 hours 27 minutes to heat 150 litres of water from a starting temperature of 15 C to a final temperature of 40 C when 400 watts is applied. The energy consumed is 4.58 kWh. The cost in Spain would be  0.87 euros.”

It is not possible to give exact figures but  our current setup consists of a 50 litre black PVC pre-heat tube, the 150 litre batch heater in this post and a 150 litre thermosiphon solar heater.
One one day last week that was  enough for 5 powerful hot showers at the end of a full day of sun. After that the water ran cold.

Batch water heater creation

Hannah preparing the hot water heater

The first thing to do with an immersion heater is to strip off the insulation. I decided to only strip off the insulation which is facing the sun and leave the rest.  I cut off the mild steel covering with an angle grinder then hacked away at the foam insulation with chisels. In the photo above Shep is helping Hannah (our very pleasant Canadian volunteer) to strip the foam off.

Batch water heater in cold frame

Batch water heater in cold frame

I put the tank in an old cold frame made out of plywood. I sprayed expanding builders foam behind the tank.

Solar water heating system

Solar water heating system. 150 litre  thermosiphon, batch heater and PVC plastic tube

The window pane is from an old house before we had double glazing. It was very simple to connect the water to the tank using flexible plumbing fittings. The water that goes into the tank is pre-heated in a long piece of pvc tubing mentioned in another post

The only cost involved was the flexible plumbing tubes for just a few euros.
I estimate that this could save us over  120 euros per year.

 

Pickled Walnuts – How to make them

Pickled walnuts

Pickled Walnuts – This is the finished product. These have been in vinegar since last year. I made 8kg last year but only have 2 jars left.

I have always loved pickled walnuts. The green immature nuts are pickled before they go hard. Apparently they are very popular in England especially before strong tasting Indian spices because available.  Their main use is with cheese in ploughman’s lunch type meals. We add them to salads and I occasionally  eat one neat right out of the jar. Before writing this post I visited about 12 other pages about pickled walnuts. Most of them have an almost identical recipe.  The main variations are the amount of salt to put in the brine, the amount of time to leave them in the brine and to either boil them after brining or to leave them in the sun. There is a lot of difference in how sweet people like them, the commercial ones are quite sweet.

I have made them for the last 3 years but each year I forgot how I did it the previous year so hopefully this blog post will help me improve them scientifically.

It is possible to buy pickled walnuts but they are incredibly expensive. In the USA a 390g bottle costs $16  Click here to buy pickled walnuts at Amazon That would mean that the the batch I am making this year would be worth $615 or $51 per month, that is enough to pay for the internet connection.  In the UK you can buy pickled walnuts in the shops I think they are made by  Crosse & Blackwell. (or is that Branston Pickle?)

The amount of salt
If you look at other recipes they often give very inexact instructions about how much salt to add. In the end I have decided to use a 10% brine solution. Just put all the green walnuts into a bucket. Weigh the bucket with some weighing scales. Add the water until they completely cover the walnuts, then weigh the bucket again. If you are using the metric system the increase in weight is the same as the amount of water so in our case 7.6 kilos is 7.6 litres.  Then I used the brine calculator on this page

What is the salt doing? I don’t think any fermentation is going on in this recipe. The function of the salt is to draw the liquid out of the walnuts and to enable them to dry out without rotting and then replace the liquid with preservative vinegar. By the way 3 years ago I made them much too salty before pickling. I corrected this by putting them in water for a day. 

The Recipe
Date: 5th June 2015
10kg walnuts
7.6 litres water + 843g salt (10% brine solution) 

Date: 22nd June 2016
17.4kg walnuts
18 litres water +2000g salt (10% brine solution) 

Date: 26th June 2018
16kg walnuts
15 litres water 1500g salt (10% brine solution) 

Date: 19th June 2019
21kg walnuts
16 litres water 1778g salt (10% brine solution) 
The pricking process for 1 person was 250g per minute.
The walnuts this year are very big.

Date: 17th June 2020
11kg walnuts
12 litres water 1200g salt (10% brine solution) 

Date: 19th June 2021
5.3kg walnuts
5 litres water 500g salt (10% brine solution) 

Method
Pick green walnuts with no hard shell inside: (in early June)
Prick them all with a fork
Leave then in salt water brine for 3 weeks. (move them around with your hand occasionally)
Drain the water leave them in the sun until they are dry and black. (3 days)
Put them into jars and pour vinegar over them.
Add pickling spices to the vinegar.
Malt vinegar is probably best with you can also use cider vinegar with a couple of bottles of balsamic vinegar mixed in.

New idea 2020. Instead of keeping the walnuts in jars in vinegar I store the walnuts in a dried condition. When a jar of pickled walnut is finished I just add some dried walnuts and top it up with some more vinegar. They are ready to eat about 5 days later. This method uses a lot less vinegar and it means that the vinegar does not have to be very strong. One problem with picked walnuts it that the vinegar is very strong. Recently I have started putting then in water for a couple of days before eating and the vinegar is much less sharp. I have also started doing this with pickled beetroot. Just boil up small batches of beetroot from the garden and recycle the beetroot vinegar. If they are only going to be in the jars for a few weeks a weaker vinegar can be used. I have been using pear wine vinegar which came from a batch of wine which went wrong. 

By the way: The best place to buy malt vinegar is in the Asian supermarkets in Sparkbrook Birmingham UK. It is possible buy it  in 5 litre containers at low prices.

picking_walnuts

Kayley and Ian Picking walnuts

This is Kayley our Maori volunteer  from New Zealand and Ian from Scotland picking walnuts. Shep the dog tried a walnut but ended up vomitting. I tried a raw one last year and it almost made me vomit. The haircuts are done with  battery operated clippers from Lidl.

Green walnuts in the tree

Green walnuts in the tree

The green walnuts read around mid June. If you push a knitting needle through them you should meet no hard bits.

pricking_walnuts

Here we are prickling the green walnuts with a table fork about 4 times each nut. I did warn Kayley and Ian  that it is best to use rubber gloves but they liked the idea of having brown hands for a few days.

walnuts

Some of these nuts have blemished. It does not matter because they all turn black in the end.

Here is a the wikipedia entry for walnuts

I will put some more pictures up as the process continues.

 

Losing weight with vegetarian food

Cutting up vegetables

Cutting up vegetables

We had a very pleasant Canadian vegetarian visitor to stay for 3 weeks, her name is Hannah. As an experiment we decided to be vegetarian for the time of her stay. Sarah made a 21 day recipe plan with as many vegetarian dishes as she could think of. 

Rather than feeling deprived for the 3 weeks we actually thought that vegetarian food was really tasty.  One of the most interesting aspects was that we started to lose weight with no effort. Steve, another visitor lost 3 kilos and I lost 2 kilos. We drank wine most nights and ate to almost bursting point several times. 

So after this experiment we have decided to become flexitarians. That is vegetarians who only eat meat occasionally. If you actually investigate the facts it is a wonder why most of us are not vegetarians.

Click here for a page of interesting facts about vegetarianism