Are you including the general public education on how to implement energy use efficiency measures in number 4 in your list? To me, that is one of the critical steps on implementing these measures, you can have the government and the private sector behind you but if the public just fails to understand their role, it will not matter much. That is just my opinion. Thanks. Julio

Hmm.. this is interesting. I guess people's awareness on energy efficiency is a cross-sectoral issue, because people is playing a key role at home, but also at work (in the office, in the shops, in factories), and as consumers.

We commented this is the RESPONDER Sustainable Housing workshop in Barcelona last month, we can provide best energy saving technology in a house, but if people do not know how to use it properly it may be totally useless or even more energy consuming. So I agree with you, awareness, information, education is an important issue to consider, I will keep it in mind when compiling information on all the groups, but especially in the last one "Shaping the city to reduce energy consumption".

Thanks very much, Julio. Nice contribution.

The main question to be asked is whether the energy consumption to implement new and renewable energy is sustainable, considering the concept of energetic memory of all products entering the system. Cristian Bulbuc, Horting, Romania, [email protected]

One of the biggest things is just information in general. People don't tend to know the scope of the problem. In Austin, TX if you sell a building that is over 10 years old, you must get an energy audit to be given to the perspective new owners. However, surveys indicate that people do not understand them well. Better information is needed, but even better communication is needed. The bar needs to be so low to adopt energy efficiency measures that you can trip over it and it becomes the path of least resistance.

I agree with the tendency of the previous answers, information and awareness of the end-user is an important point, as it will shape the city by the laws of request on the market. However, the question on how to inform the user (or potential buyer/investor) about the influence of his building on the energy consumption of the block, the city or even the greater surroundings, is more tricky. I tend to believe that data collection and data creation play a great part, as information must necessarily base itself on such numerical input. We (Simmlab, UFRGS, Brazil) are working on several project that collect and create data (for example concerning the radiation or other environmental data), write them into a data point cloud and either create a graphical output in order to evaluate it or even automate a project via parameters. This approach has proven to work particularly well for urban spaces, as resolution is not a big issue here.

Resuming, I think that data and the way it is administrated will be the key to efficiency.

The shape of the city and the cultural habit have the main impact on the energy use....but they are also the harder to move the right way...

so for me n°4, isn't really needed, since you can't really change the shape of a city, unless you have a strong political will to do so (and enought funding, and the support of the population) or in extraordinary time (after a big natural disaster or a war)

cultural habit of consumption are determined by the culture, the environment, the technological and economical level of the country....etc

so here, rather than focusing on few point (to the risk to be blind to others side of the problems), it could be more interesting to determine which stakeholder impact the energy consumption/production (national and local government, private sector and people) and then see how they can impact the efficiency in energy use

Hi Joachim,

I see your point but I don't agree with removing number 4. As you mention, cultural and citizen habits are very difficult to change. For this reason, it is more important to show and highlight stories of success. I know there are some, and I think it is important to spread those experiences. I am thinking on the Convenant of Mayors, the Transition Towns movement, and so many other experiences. I recommend the "30 Energy Cities’ proposals for the energy transition of cities and towns" from energy-cities (http://www.scribd.com/doc/97202740/30-Proposals-for-the-Energy-Transition-of-cities-and-towns).

On the other hand, in so many places we are currently living an extraordinary time, as the economical crisis is not a war, but for sure it is a change of paradigm for many people. It presents many constrains but it can also be seen as an opportunity to change the previous way of doing things. To do the same with less resources needs a component of innovative ideas and courage to apply them. So, this fact reinforces the need to gather real experiences and their results.

I'll take your tip and try to describe the drivers involved in the energy production and consumption and the way the can reinforce energy efficiency as a cross-cutting issue along the 4 points.

Thanks for your comment.

I think that one of the most important issues is number 4, shaping the city to reduce energy consumption. A lot has to be done for example to reduce the heat Island effect.

Cristian,

what do you mean by the concept of energetic memory? Can you provide some references? I have never heard about it before.

Thanks

Dear Raquel,

Very interesting topic.

I believe that the combination of strategies, as you are listing above, is the (only) way of reducing energy in urban areas, because -as opposite to rural areas- the diversity situations requires different approaches.

Though, as for the physical issues to be considered, I agree that UHI effect makes the energetic problem of urban areas quite specific. In addition, I find that an understanding of the impacts of climate change (i.e. climate change projections and predicted impacts for specific regions) has to be encountered.

For instance, in a study a made for London, with specific regards to predicted increased winter rainfall, the addition of sustainable urban drainages (SUDS) would provide (also) benefits in terms of reducing the increased predicted temperatures.

As for your point 4, I am not sure what you intend with 'shaping' the city, when most of it is already built; do you mean large retrofit interventions?

Conference Paper Adaptation to flooding within the city-block scale

I agree it's important to share information on succefull (and unsuccesfull) projet to help others to give birth to new project and to make them evolve to be more effective (in a lot of different ways, economical, social or environmental)

are you gathering these information to make your own project or to publicate something on the topic?

Dear Raquel

There are many challenges for energy efficient in urban areas: these can be summarised as follows:

How to reduce the impact of Urban Heat Island Effect (UHIE):

Approaches:

a) Building roof including: cool roofs and green roofs

b) Bright colour materials for pavements.

c) Site orientation

d) Use of Renewable energy

e) Vegetation

f) District cooling/heating

g) Building Fabric efficiency

h) Road pavements

I hope this will help.

Best,

Prof Aboulnaga

To be direct, extreme energy use in urban areas, small area, and environmental restrictions.

Hi Raquel,

It's important to focus on the big targets first - energy efficiency in electricity generation is the elephant in the room. It accounts for much of the energy and CO2 consumed. Now most of this is not generated in urban areas anymore. This displacement of the site of energy generation and use creates problems (transmission losses being the most obvious).

So on technologies for electricity efficiency - CHP has to be one of the most important. Re-using that wasted heat sensibly for space heating, water heating, low temperature commercial and industrial uses can typically increase the efficiency of energy supply. But also displaces inefficient means for meeting energy demand in those uses I mention. Its also cheap and capable of providing the quantity of energy (energy density) cities require.

This whole 'recycling of energy' concept can go much further, and given the colocation of varied diverse activities in cities, the distance problem can be overcome in many instances.

This said. I would like to stress the importance of laws and regulations which in many circumstances prohbit or limit the introduction of energy efficient solutions made capable by recycling energy. These can include restrictions on who you can sell what type of energy to who, across what distance or infrastructure, whether capital infrastructure can be modified etc etc etc. As a concrete example, Edisons first generators in I think New York were designed to sell heat, as demand for electricity for lighting was nascent and small. But once his generators needed to get bigger he was forced to move them out of the centre of town (by regulation) and the heat was no longer used just wasted. The efficiency fell.

These regulatory barriers are often much harder to overcome than technological ones.

For a very good overview in the US see these presentations by Tom Casten:-

Recycled Energy Development, January 11, 2009

Deploying clean energy: Overcoming regulatory barriers, by Tom Casten and Dick Munson.

http://www.recycled-energy.com/newsroom/publication/deploying_clean_energy_overcoming_regulatory_barriers/

MIT NESCAUM Symposium, August 12, 2009

Energy efficiency: a capital offense, by Tom Casten.

http://www.recycled-energy.com/images/uploads/tc_ca_energy09_09.pdf

Benjamin

Other issues to consider beyond the physical layout include financial ability and incentive for urban property owners. (ie: poorer neighborhoods without the capital to invest upfront in energy renovations or landlords who do not benefit from more expensive, energy-efficient upgrades)

Four or three thousands years ago, people were building temples (huge, big and small) because it was good for business and good to make a political statement. Two or one thousands years ago, people started building castles and big churches for the same reason as before and also they realized that those ancient temples are no longer practical. Furthermore, population grew, energy demand increased, transportation got faster. Hundred years ago, people started making houses and buildings for the same reason (good for business) as well as they realized that castles and big churches are no longer practical. Again, the population grew, energy demand increased, and transportation mode becomes bigger (SUV for one person), powerful and faster. Not to mention more energy intensive. In Toronto, there is probably more parking spots, highways and malls than residential areas. These things do not make positive contributions to the environment.

If you want to improve efficiency in energy use, you have to make a great leap ahead of current times. In other words, we all have to abandon our current way of living, use of transportation, and way we make business (or run an economy).

Energy use efficiency in urban areas can not be treated as an isolated situation. It is like a spider web, urban energy is connected to many things (not just technological thing) For example, lets assume for argument sake here, that we have developed a very energy efficient town. The town has excellent technicians and managers that keep that town the way it is. However, politicians of the town are different folks and they want to beef up town's treasure coffers because that will increase their salary. They do so by bringing into town more industry, businesses or increasing immigration. Soon or later a town becomes overwhelmed and its efficiency will start to deteriorate. Therefore urban planing is a planning from top to bottom and in many aspects. The best answer for you in this case is to visit places (as many as you can afford) that seem to you to be energy efficient and look beyond technological gadgets. Observe things like how they commune, live, eat, work, travel, spend money, how they celebrate things, how they treat children and old people, how they do farming etc. Keep in your mind to treat urban centre as a centre of spider web. And have a lot of fun. Hope that helps.

Dear Raquel:

Efficiency is a problem with at least 3 main challenges. The more obvious is the "technology", which is where almost everybody contribute.

The second one, and on my perspective the most important one is "education". We won't achieve efficiency in any system if the user of this system don't understand how it works, which are the main components, etc.. i.e: we may install the most efficient heating system in our house, but if we ventilate the house while the system is on, we never get efficiency of that system.

The third is what I call "ongoing issues" like maintenance of technology or planning of use or scale effects. Any technology need maintenance to sustain a high level of efficiency, but that include an extra cost that we must be prepared to assume and some times this cost may be even less efficient than a normal technology. In other hand, it is well known that public transport system is much more efficient that individual transport, but less attractive as well.

Finally I think that measuring efficiency is quite tricky, because you must measure the whole life cycle of the technology to fully know how efficient it is. Some time a technology may be very efficient for use, but the maintenance, the production or the waste disposal are less efficient than others and comparison must be done considering the whole life cycle. i.e: solar panels or nuclear energy v/s hydro power

That's my small contribution to your interesting question

Mauricio

From what I have read in the answers I would add the rebound effect which can be a major obstacle in realizing energy efficiency and stresses the fact that technological solutions can easily fail if behavioral aspects are not taken into account.

You might want to check: Horace Herring, Steve Sorrell (Eds.) (2009): Energy efficiency and sustainable consumption. The rebound effect. London: Palgrave Macmillan (Energy, climate and the environment series).

1) Identifying high fluctuations in demand

2) Identifying Key demand seekers whether it is a particular residential community or

particular Office Buildings

Dear Raquel,,

The problem is how do you define efficienxy? It is just a ratio and its meaning depends on exactly what is on either side of the relation. Without a clear understanding of this, answers are meaningless.

Very well spotted Nick, that is the start: definition of efficiency of a particular context.

Bravo N Tyler. Challenges will remain for URBAN reasons, from the beginning the sustainability of a village, town and city progressively reduces. Cities were created due to Economics and stopped the self-sufficiency, increased trade (claimed to be more efficient than person to person exchange) this is the economies of scale.

Energy is a commodity, therefore it will be provided on the basis of profit, like everything else in the city.

Therefore it is difficult to make “Energy use Efficiency” (N Tyler & L Toledo, are right you have poorly focused the whole question) judgements if based on Economic (who is the cheapest provider of energy) or Environmental Impact (who is the best on sustainable/responsible energy generation, transmission are we talking Microgenerated Energy or Macrogenerated, Grids or Off-grid).

Local Governance unless in a Central Economy will also be driven by Economics and would not be permitted to provide sustainable/responsible energy generation.

Financial structure to support sustainable/responsible energy generation, yet again will be hampered by urban economics.

The cities are shaped by economics, the Trading, the Economy of Scale and will not permit this truly Energy Efficient use.

This is why towns and cities are Heat Islands and no amount of good will and intentions will make them any more efficient under current approach of shoe-horning new buildings into place. The way we are working is also changing, just look at the vacant offices in the cities, major changes are necessary.

Hi Rachel - In Europe, one third of the produced energy is used in households. Beside energy efficient technology, it is necessary to win the users to an informed, aware and responsible use of energy, as consumption behavior and routines decides significantly about energy consumption. Easy said, but not easy done. So, the question is: HOW CAN I WIN/MOTIVATE THEM? One difficult in that respect is that we as users mostly have only a confused idea of how much energy we use, for what, and how much we spend for it. At least in Germany, there are many large and small scale initiatives for informing and giving tipps, but despite a successfull participation they seem to be generating only small savings.

I develop and manage research projects around the topic "Energy", and I have just posted the Technical report of one of these, called "Sense4En". The project focused on addressing the user through feedback DURING the consumption, making the relationship between action and consumption it induces clear (Smart Metering is a more common denomination for this approach). The large scale experiment with 7'000 households we performed won average 23% energy savings in the shower, and the process is described there. In the references, there are papers evaluating a large number of large scale experiments (for example, Ehrhardt-Martinez et al.) in the urban residential sector: I hope this helps you. 

If I understand your question well, there is an other project I handled which embraces energy planning at the urban level and which might be useful to you: It's called "Neighborhood Demonstrators". I had the chance to develop and manage the German activities (www.ndemo-germany.tu-berlin.de/), and among those there is the use of 3D city models for energy planning. Here the question is: HOW CAN THE CITY PLAN INTERVENTIONS AND INVESTMENTS; MAP AND EVALUATE THEM TOGETHER WITH THE RELEVANT STAKEHOLDERS? The work has a special meaning in Berlin (where I work), as the city owns an advanced city model. It is relevant to embed the work within the initiative of the EU commission INSPIRE, which in steps is implementing this kind of geo-data based modelling for all EU countries and preparing the tools for energy (but not only) national reporting to the Commission. The teams focused on building retrofitting as an application, in Berlin and London (www.youtube.com/watch?v=c8TRchvO9Kw, www.youtube.com/watch?v=1e3h94oeDRY).

Kind regards, Ivana

Hello,

Energy efficiency is depending of the scale (even if in principle it should not...). The more best energy efficient of a component might not match with the optimal efficiency of a system. When we look at the building scale, some indicators like shape ratio (S_envelope/V_inner) would not identify tall tower as efficient. However at city scale the energy efficiency has to include transportation which as a great impact of a city. From this point of view, high density city (i.e. with tall buildings) appears to be more efficient (even at the building scale the shape is not optimal). Asia cities are globaly ranked in more efficient city as european and then north america. One important parameter is the urban planning impacting the distance between work, leisure and living place. If you are living where you are working (and if the leisure are reduced...) then the global energy efficiency of the city will be greatly improved. However, there are not many individuals who are willing to go through this.

Best regards

Dear,

I agree with Dr. Mohsen. He summarized the key points.

Two points are the most important in my opinion: solar energy and natural illumination.

Regards,

Vanessa

awareness of the different energy efficient solutions and after implementation maintenance along with condition monitoring to predict any deviation in the energy use efficiency.  basically compliance to ISO 50001 standards.  you can refer to it where it is clearly mentioned

There are several ones 

I think urban density is quite relevant 

You may find my attached study useful 

Regards

Article Effect of housing density on energy efficiency of buildings ...

https://www.crerc.landecon.cam.ac.uk/files-and-documents/fuerst-wegener-dec-2013.pdf

Article The Next Level of Energy Efficiency: The Five Challenges Ahead

http://www.nardep.info/uploads/Brief17_RuralEnergyConservation.pdf

Multi-owner, managed apartments. Common in France. We are supposed to meet twice a year to decide on who collects the waste bins, but even that never happens. Almost impossible to get agreement on any action even when required by law (for example the facade renovation). The roof has been leaking for 6 years and the property management company are unable even to organise to get that repaired. So any thought of a coordinated building wide strategy or investment in energy efficiency forget it. That will only happen if (a) the building collapses or (b) a property developer offers us all cash to sell and move out, then they knock it down.

Regarding the what to put on either side of the ratios. For a physically correct and meaningful answer it should be some expression of the 2nd law of thermodynamics.

See also urban metabolism literature, e.g.: Article Exploring urban metabolism - Towards an interdisciplinary perspective

Inefficient urban mobility as this generate CO2 emissions in urban areas.

Dear, Raquel Ubach

Your question is very interesting. I suggest you study these two books.

• The Very Hungry City: Urban Energy Efficiency and the Economic Fate of Cities pp. 1-366 (2015)
• Energy Efficiency in the Urban Environment pp. 1-266 (2012)

These scientific contributions analyze the issues of energy efficiency in urban environments from various points of view. I would like to add that, I agree with the responses of the researchers Adam Szewczyk , Vanessa Meloni Massara , Hamit Can and Benjamin Warr

Recent estimates and case studies have suggested that in many energy-intensive sectors of developing economies, energy-saving technologies may backfire, meaning that increased energy consumption associated with lower energy costs because of higher efficiency may in fact result in higher energy consumption.