{"id":13465,"date":"2016-03-07T14:23:13","date_gmt":"2016-03-07T13:23:13","guid":{"rendered":"https:\/\/www.ferrovial.com\/blog\/en\/?p=13465"},"modified":"2025-12-12T11:55:24","modified_gmt":"2025-12-12T10:55:24","slug":"buildings-that-consume-no-power","status":"publish","type":"post","link":"https:\/\/www.ferrovial.com\/blog\/en\/2016\/03\/buildings-that-consume-no-power\/","title":{"rendered":"Buildings that consume no power"},"content":{"rendered":"

Our recent step into the 21st century may in some ways seem like a step into the future (perhaps because it came with a change of millennium), yet we still do things the way other generations \u2013 for whom the world changed in a matter of years \u2013 did<\/strong>. My grandparents\u2019 generation went from animal-drawn transport to using fossil fuels. Something that spread rapidly throughout the world: fossil fuels were cheap, and they did what they were supposed to do.<\/p>\n

Oil has, to a much greater degree than almost all other drivers of pollution, taken us down a rather dirty and relatively predictable technological path, but its days are now numbered. And there may even be oil left in the world when we stop using it. \u00a0As Jos\u00e9 Luis Cordeiro said, \u201cthe Stone Age did not come to an end because we ran out of stones<\/em>\u201d. Humans found a better alternative material to use instead of stone.<\/p>\n

Other materials or sources of energy, other than oil, can be exploited in the future. These sources are already relatively well known today and are slowly increasing their percentage contribution to world energy. Energy Matters published an article<\/a> on how the use of coal, oil and gas derivatives are very slowly declining, to be substituted by cleaner energies such as biofuels, geothermal and biomass, hydropower, wind and sun (amongst others).<\/p>\n

 <\/p>\n

Energy consumption in our cities<\/h2>\n

Our cities today are highly polluted due to the very large numbers of vehicles in them. <\/strong>In many cities throughout the world, people must wear masks to avoid breathing in this pollution and suffering from respiratory problems in the future. An added problem is that a large proportion of the electricity generated throughout the world must travel hundreds of kilometres to supply the buildings that need it. Cities are gigantic structures using up resources.<\/p>\n

In 2014, Madrid\u2019s estimated energy consumption was close to 10,000 ktoe<\/a> ( ktoe<\/a>, kilotonnes of oil equivalent), of which 75% was fossil fuels. Although Madrid and other cities in Spain are shifting towards use of green energy sources<\/strong>, this change happens very slowly.<\/p>\n

Most of us will have seen solar farms, large swathes of land given over to wind turbines, or even the Pelamis<\/a> \u201csea serpent<\/em>\u201d, or wave power generator. But how can we merge together these different energy sources in order to generate energy where it is needed, when it would seem that they all require large areas of space? How can power generation be integrated into building construction? Is this even possible?<\/p>\n

\u201cZero energy\u201d buildings and energy returns<\/h2>\n

Zero energy buildings<\/strong>, or buildings with zero net energy, are self-powered buildings<\/strong>. In other words, they do not require an electricity supply for their energy needs, because they themselves generate all the power they consume.<\/p>\n

Despite the fact that the concept of such buildings is not new (pioneering buildings using solar power in their architecture date back to 1977<\/a>), social and political awareness is what has made these buildings a reality today, and what will make it a compulsory way of building in the future. The first zero energy home was built by Torben V. Esbensen and Vagn Korsgaard<\/a> for the Technical University of Denmark[1]<\/sup><\/sup><\/a>. It was a house that could be heated all winter using only solar energy.<\/p>\n

The first challenge to overcome in order for a building to be truly \u201czero energy\u201d is what is known as the \u201cenergy returned on energy invested (EROEI)\u201d. EROEI is the ratio calculating the amount of energy generated by a particular energy source compared to the amount of energy used to build that energy source. In some cases, this comparison takes into account not only the cost of building the energy source, but also the cost of its design, manufacture and maintenance.<\/p>\n

For example, solar energy using collectors has an ideal EROEI of between 1.6 and 1.9. A collector will, at the end of its useful life, have generated an amount of energy equivalent to between 1.6 and 1.9 times the cost of installing it in the first place (including energy costs for design, manufacture, transport, installation and maintenance). This means that if a collector breaks down two or three years after installation, it will have an EROEI of less than one and will therefore not have provided any power, it will only have consumed power.<\/p>\n

Passivhaus,<\/em> passive houses<\/h2>\n

The passivhaus<\/em> is a building standard first developed in 1988 with a view to building homes and offices with an almost \u201czero energy\u201d rating, through the use of different techniques. These techniques<\/a> are, essentially, as follows:<\/p>\n