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