National Geographic Channel Efficient House

If you live in Portugal and if you are interested in knowing a little more about reducing your Ecological Footprint in your everyday life, you should go to Pavilhão do Conhecimento, Parque das Nações.
National Geographic Channel and EDP have installed there an efficient house. It is a 100 square meter T2 house with two bedrooms, living room, kitchen, bathroom and a small garden. It advises people on good practices and it has also some technical stuff about materials used in construction and solutions for water heating.
The house can be visited until the 5th July. Entrance is free.

Passivhaus

Passivhaus refers to energy efficient residential buildings.
This term was created by Professors Bo Adamson, a sweden enginneer, and Wolfgang Feist, a german engineer, and the first passivhaus was built in Darmstadt, Germany, in 1990. Dr Feist founded the Passivhaus Institute a few years later, in 1996.
What makes a passivhaus so different than an ordinary house?
The thermal comfort of the passivhaus is guaranteed solely by re-heating (or re-cooling) the fresh air that is required for satisfactory air quality. This means that there is no heating system, except for heat recovery through the ventilation unit.
Houses are built accordingly to five key principles:
1. Wall insulation - thick layers of insulation (around 40 centimeters expanded plastic) to prevent heat losses.
2. Windows - small percentage of the surface area occupied by glass windows. Large windows should be to the south to maximise incoming light and heat from the sun in Winter. 40 per cent of the total winter heating should come from the sun.
3. Bridges that conduct cold into the houses are avoided by using special prefabricated materials.
4. Airtightness - refers to the loss of air through cracks, airbricks, poor door seals, windows. Passivhaus must loose less than 60 % of the volume of air in the house per hour. This can be achieved in pre-fabricated houses with factory made components that fit together very tightly.
5. Ventilation system - mandatory for air renovation. In the winter, cold air that enters passes over ducts containing warm and humid air leaving the building.

Passivhaus diagram

Energy requirements comparison

The diagram was downloaded from 100k House

Electricity consumption in Portugal

Today I received a message from EDP, the only portuguese electricity company.
It's about electricity labeling, that is, knowing where the electricity offered by EDP comes from.
In 2008, electricity that was generated in Portugal came from conventional thermoelectric stations fed by coal, natural gass, fuel-oil and biomass, and hydroelectric plants and wind. The rest of it was imported from Spain.
The following figure (in portuguese) shows the electricity offered by EDP per technology.


Nuclear power is responsible for 5.3%, all of it imported from Spain. There are no nuclear power plants in Portugal and yet we consume electricity from that source.

Fossil fuel still represents the higher share in electricity production with 61.1%. Renewables represent 33.7%.

Monthly share of electricity consumption per technology (2008 data)

The figure shows the irregularity of hydroelectricity production. Fuel-oil reaches almost 10 % in December, but has lower shares throughout the year.

Air emissions in 2008

Air emissions are a consequence of that electricity mix.

Ten technologies to save the planet: carbon sequestration

Chris Goodall also talks about carbon sequestration.
Greenhouse gases, particularly carbon dioxide, can be trapped instead of released to the atmosphere in the conventional electricity generation processes.
There are several way to capture it, but most of them need extra energy.
What I found particularly interesting was the possibility of capturing carbon dioxide directly from the air. Global Research Technologies formulated a plastic that attracts and holds carbon dioxide molecules. When the strips of the plastic are fully loaded, they are placed in a humid atmosphere. The plastic also attracts water molecules, which push the carbon dioxide directly away from the strips so that it can be captured.
GRT states that its air-capture system is about one thousand times more efficient than a tree of equal size. The extra energy needed is due to the recovery of the sorbent that has higher economic value.
Here is a picture of the air-capture system on a massive use scale.

There is a very interesting article in The Economist about this subject. It explains in a more detailed way how is carbon dioxide captured from the air and it also mentions the possibility of producing synthetic hydrocarbons from the captured CO2 and hydrogen. Of course this would not solve Mankind's dependency on fossil fuels, but it can be an alternative before turning into renewable energy production.

Ten technologies to save the planet: renewable energy

In the renewable energy dedicated chapters, the author writes about the unpredictability of renewable energy in the short-term, particularly wind electricity generation.
He refers to the disconnection of turbines in Spain in March and April 2008, because they were generating up to 40 per cent of the countries electricity requirement and small percentage changes in wind output could overwhelm the ability to import instantaneously electricity from France or switch on backup power stations.
The solution to this problem lies in three different approaches:
1. Importing Remote power - good electricity connections to their neighbours (currently Spain can only import a maximum of 5 % of demand). Major investments in power distribution networks are required, i. e., increasing the number and size of electricity transmission links between different countries and between regions inside countries.

2. Storing electricity to meet short-term needs - through pumped storage (movement of large quantities of water uphill into a storage reservoir), batteries and hydrogen production, which is a vector of electricity. It can be interesting coupling wind electricity generation and mini-dams.

3. Managing demand to meet supply - load shredding, which consists of disconnecting industries for a short period of time from the electricity grid. The industries that agree to this have lower electricity bills.

Book review: Ten technologies to save the planet

I've been reading the book Ten technologies to save the planet by Chris Goodall

(http://www.amazon.co.uk/Technologies-Save-Planet-Chris-Goodall/dp/184668868X)

It is a very interesting book. The only negative aspects I found were that the author does not present referrences and that he has a almost exclusively climate change oriented vision.

The book is roughly about renewable electricity production (wind, solar and wave and tidal energy), energy efficiency (industrial and in houses), alternatives to fossil fuels in transportation (electricity and biofuels), carbon capture (industrially and through soil and forests). The last chapter puts it all together.

Electric Cars

I found an interesting article on the BBC news about the UK plan to boost electric cars.
This article identifies some negative aspects of the electric and hybrid vehicles. They include the autonomy of the battery, the charging battery time and the size of the car (two seats).
The figure shows a comparison of autonomies and battery charge time.


The article also points out that investment in public transportation and places to recharge the vehicles is also needed, as well as guaranteeing that electricity is produced with the least environmental impacts possible (high share of renewable energy).

The article is available here:
http://news.bbc.co.uk/2/hi/business/8001254.stm