NZEB + EV: The decarb combo

Are you aware of these stats?

  1. Buildings account for 40 % of energy consumption and 36 % of energy emissions (EU data)
  2. Road transport accounts for 25 % of energy consumption and 20 % of energy emissions (EU data and EU stats)

Then, what happens when we combine NZEB buildings (net Zero Energy Buildings) with local renewable generation and EVs (Electric Vehicles) charging in these NZEB?

NZEB & EV.png

It’s obvious… -> We can decarbonize 65 % of the energy system!* Sigue leyendo

Upcycling sun-tennas

The following picture was taken in Casablanca from the Kenzi Tower one month ago. It isn’t the best example, though, for example, in Cairo, it strikes more to the eye.

What do you see?…

Antenas techo

Actually, there are approximately 200 TV antennas on the roof-tops. Let’s zoom in a bit:

Antennas 25 In this portion, corresponding to one building alone, you have around 25 units.

With the advent of cable television, wireless video streaming and other technology, these antennas could soon become stranded assets in many countries. Imagine how many could be left useless and need recycling. While thinking about asset utilization and the sharing economy, I couldn’t help but think:

What can they be used for instead?… Sigue leyendo

The grid as an emergency supply?

It’s official. Finally Spain has the most toll-intensive consumer power generation (what is called self-consumption) law in the world. The so-called “sun tax” is in place.

It is important to understand the worries of the regulator here;

Given the high fixed costs of the system, further reductions of electricity demand (as with self-consumption) increase the price of energy in a Grid independence cycle. The goal of increasing the toll on self-consumption is to ensure the system costs are covered, delay the implementation of self-consumption (starting in the islands and small systems), delay consumer energy storage (in fact it is also a “battery tax”) and (try to) avoid further political problems. Of course, it is not the best solution, academics and regulatory experts agree that politically fixed costs that have to be paid by all citizens shouldn’t be in the tariff but evenly paid from the nation’s bugdet (like the extra-costs for electricity in the islands).

Image by Cancia Leirissa on

“Grid Emergency Exit”                                                       Image by Cancia Leirissa on

What are the consequences? Rising prices, and the fact that fixed costs (for the contracted power) are surging, push the active consumer to look for the following solutions:

Sigue leyendo

No es la crisis, es la eficiencia!

Uno de los motivos principales de la sobrecapacidad de generación en España, fueron las expectativas de crecimiento de la demanda eléctrica erróneas. Este menor consumo contribuye al déficit de tarifa, porque hay menos kWh consumidos entre los que repartir los costes crecientes del sistema y si no se sube suficiente (la parte política) el precio… ¡Voilá deficit!

Creo que lo explicado brevemente arriba es fácil de entender para cualquiera. Por otro lado, la razón por la que se asume que el consumo eléctrico ha descendido en los últimos años es la crisis económica que comenzó en España en 2008. Si la causa es la crisis, en cuanto se supere, volverá a crecer el consumo de manera lineal durante al menos 5 o 6 años*.

Esto obviamente es así para los consumos industriales, donde si las empresas cierran se reduce el consumo. Sin embargo, en el sector residencial, que supone aproximadamente un 25% del consumo eléctrico, quizás no esté tan claro. Y eso por qué?

Sigue leyendo

From 0 to 5-star Microgrids

Every building, office or home is a microgrid.

The question is, how good a microgrid do you want it to be?

Here is a simple 5-star rating for microgrids, an approach for anyone to understand;

You get one star for adding each of the following technologies:

1. Control

2. Generation

3. Electric Vehicle charging

4. Energy Storage

5. Microgrid Islanding functionality

Star Microgrid

A normal 0-star microgrid is a conventional building or home, with no automation or else.

It happens you upgraded your home and installed a smart thermostat for electric heating/cooling? Sigue leyendo

Take the panel with you

Solar Panels are getting cheaper every day, so this idea might convince you less today than it could have some time ago…

Anyway, suppose you have bought yourself one 300 W solar panel for your flat. In fact you found a smart orientation that covers your “base load” for the fridge and all the stand-by consumption and also lowers your consumption once you arrive home. It happens you have a e-bike that is prepared for you to plug your panel, for your daily commuting, keeping your battery fine or even charging while you are working. Additionally, you own an Electric Vehicle. During the week-ends, you can dock your panel for the journey and lower your consumption. And it happens that you are as wealthy as to have a second house in the forest, which is off-grid, so you use the battery of the Electric Vehicle for your consumption and you also plug your panel when you arrive.

Panel cycle

This is just an example of maximizing the asset utilization of a panel, for house self-consumption in two locations, and also for mobility. This will not be the case for most people, of course. Besides, regulatory frameworks may promote the use of the panel to feed the grid when it would be underused only for self-consumption and could be connected elsewhere for other purposes. Anyhow, the point of having portable generation opens more possibilities for generating one’s own energy, in this case at home and also for transportation. It is also an application for extending the access to electricity in developing countries.

In fact, if a person consumes (as it is the case in Spain) 3487 kWh/year of electricity and 9908 kWh of total energy at the home, together with 12000 km/year of driving, which can be calculated as 2400 kWh (with an EV doing 20 kWh/100 km) it makes a total of 12308 kWh. In order to source this with solar PV, he would need approximately 6 kW of solar panels working 2000 equivalent hours. These 20 solar panels he cannot take around with him that easily. For the moment…

P.S.: Allow me to include the crowded house video as the song I thought about while writing…

Partial/progressive off-grid, a proposal

I already commented on the self-consumtion regulation in draft in Spain, (basically a retroactive measure to stop any development). The reason behind is the excess of fixed system costs; with decreasing energy consumption, power and energy prices increase in a feedback loop. Blocking self-consumption is an attemp to avoid further grid energy consumption decrease.

Off-grid balance

As in other countries with similar fixed costs, decreasing demand pushes towards higher energy prices, and taxing self-consumption is seen as a regulatory solution. Apparently off-grid is becoming already a cheaper option. As it is not the best solution for the system as a whole, an intermediate solution could be the following: Sigue leyendo

Solar Panel 3D printing

Solar panel manufacturing has benefited from economies of scale in the race to lower the costs, following an impressive learning curve (see BNEF curve). But will the future bring the cheapest solar panels, being printed where needed from a simple and cheap device?

This is already happening in manufacturing, as described brilliantly by Chris Anderson in Makers. With technology already available for printing solar cells on paper, innovation improving efficiency and durability, is set to revolutionize solar panel manufacturing. Centralized production would be complemented by local micro-manufacturing.


Solar photovoltaics is today the best example/solution for democratization of power generation, as it allows simple and scalable self-consumption. Democratizing also the manufacturing of the panel would take it a step further, boosting solar generation capacity well above the actual double digit yearly growth.

Sigue leyendo

Building the Smart Grid bottom-up

I strongly support the democratization of energy, understood as the access to energy for all and the open participation of the people in the energy market, for example by generating energy for self-consumption or through energy cooperatives. (I already posted on this subject here)

I see energy independence is of less importance. Having energy inter-dependencies with other countries may be positive. As an example, electric grid interconnections, even if they meant energy dependence, are built for increased efficiency and optimized use of generation assets. Increasing the interconnection of France and Spain, would increase competition and efficiency, although it could lead to greater inter-dependence. How about islands interconnections? That makes them dependent on the mainland, but energy less costly, more reliable and allowing greater renewable penetration.

Democratization gives an additional momentum to any change, with this I mean, once some technology market is democratized, accessible to all, and each individual can invest in it, the speed of it’s implementation and development is exponential. An example that anyone can understand is the development of apps for mobile devices.

In the energy industry, the democratization of power generation is mainly due to solar power. Germany has built more than 30 GW of solar power plants, thanks to individuals and cooperatives, not concentrated by traditional big utilities and concentrated power plants, now more decentralized.

Ulm church bottom up (tallest church in the world, built by the citizens of Ulm), by Szeder László (Own work) [GFDL ( or CC-BY-SA-4.0-3.0-2.5-2.0-1.0 (], via Wikimedia Commons

Ulm church bottom up (tallest church in the world, built by the citizens of Ulm), by Szeder László (Own work) [GFDL ( or CC-BY-SA-4.0-3.0-2.5-2.0-1.0 (, via Wikimedia Commons

On this subject, in wrote an article in Energética s.XXI for their international edition of July/August 2013 (read it as a pdf). Individuals not only can have important effects on the grid, they have also have the responsibility to act with sustainability and energy efficiency.

Smart grids have brought the prosumer, as part of a more democratized system where the consumer can also be a producer of energy and participate in the energy market. Building rehabilitation, making homes prosumer microgrids increases the efficiency, the reliability, the sustainability, the security of supply and is also has a very good return on investment. (An example I also wrote about is the V2H business case, part of these home microgrids)

A widespread implementation of smart homes as microgrids would build a smart grid, from the bottom up, from where the energy is consumed, but with effects on the whole grid and energy landscape.

The missing toll – (El peaje que falta…)

*This post is in english with the goal of sharing internationally the latest retroactive and (in my opinion) “desperate” energy policy in Spain, as well as the draft for what would be the most deleterious microgeneration legislation in the world.

As I already posted before, Spain’s electrical system is in a “grid independence cycle“, where fixed costs are higher than variable and therefore, reductions in consumption are followed by increases in final prices, even with decreasing variable (market energy prices), leading to further consumption reduction (and ultimately grid disconnections –here some examples in US-).

Grid independence fee

The latest legislation (published 12/07/2013) tries to fight against the growing deficit, by retroactively deleting Feed in tariffs, reducing retribution to transport, distribution, and increasing end user tariffs (mainly on the fixed toll)

Once the irretroactivity principle was broken (limiting hours, introducing taxes, etc), why not delete the FIT completely? Sigue leyendo