by Desislava Kemalova

Until not that many years ago the idea of converting sunlight to electricity in our homes for the purposes of our day-to-day needs may have seemed like a notion taken out of the pages of a futuristic novel. Yet, since then we have witnessed and are continuing to witness, an exponential development of technologies. One of the greatest technological niches appears to be the research and development of renewable energy sources. The five main types of renewable energy sources include biomass, hydropower, geothermal, wind and solar. The latter two types were less widely used until around the late 1990s – early 2000s but since then the consumption of energy obtained from wind and sun has significantly increased in percentage throughout Europe and the US. According to Eurostat1the quantity of electricity generated in 2016 in the European Union from solar power was 44.4 times higher than in 2006 – a dramatic growth indeed. Over the span of these ten years, the contribution of solar power to the overall renewable source generated electricity in the EU has risen from 0.3% to 11.6%. Of course these statistics reflect the average results of the twenty-eight member states; naturally the numbers vary from one country to another and while some excel, others still have some catching up to do, but even so, it’s probably safe to say that we have a game changer in the face of solar power use.    

One of the greatest advantages of photovoltaic systems (a system that uses solar panels to absorb sunlight and convert it into electricity via the so-called photovoltaic effect, to put it in more simple terms) is that they already have a relatively favourable ratio of produced electricity to occupied space and there is still room for improvement on that account. The efficiency of a single solar panel will grow with the advancement of the technology used in the construction since it is contingent on the properties of the semiconductor material used to build it, among other obvious objective factors such as the geographical position of the building and the time of day and the year. Presently, on average one megawatt hours’ worth of energy is produced by approximately ten thousand square metres of solar panels and there is huge potential for increasing the efficiency.     

This makes photovoltaic systems one of the best options for domestic use since usually a house has enough rooftop space to place a solar PV module large enough to provide for a significant percentage of the electricity consumption of the household. Furthermore, the roofs aren’t the only areas which can be used for this purpose. A very recent technological achievement is the production of windows with photovoltaic properties, which are essentially transparent solar panels. These are particularly useful for tall office buildings with large window area.  

Another significant argument in favour of the installation of domestic PV systems is that they have proven to be a good investment. The pay-back time of a photovoltaic system depends on many factors, including the initial price of the system, possibly the financing costs (if for instance a bank credit has been drawn, and depending on the interest rates), the maintenance costs, and of course the price of the grid electricity on which the household is saving. Typically a PV system pays off in less than ten years. Considering that they usually come with a warranty of twenty years, this means that their actual lifespan is much more than that and it is argued that they can last well over thirty years. Of course, the venture does require an initial capital expenditure which might turn out to be prohibitive for some households if they don’t have the funds and financing is not available. On the other hand, the option could be made feasible for more consumers if the governments decide to introduce some sort of incentives such as tax credits, feed-in tariffs or direct funding through programmes for improving energy efficiency.  

The one obvious drawback of PV modules is that they have a limited working period on a 24-hour basis and on a yearly basis as well, especially in the northernmost European countries where they are almost or completely inapplicable during polar nights. Whereas this issue is not technically insurmountable, it does pose a challenge. Energy storing technologies (that is to say, batteries) are an apparent solution to this problem. However, they have a few debatable aspects of their own. One of them is the additional price of the investment they would entail, but other possibly more concerning ones, are the fact that some people are not quite convinced that their production does not have a damaging environmental impact, and that their recycling may be too expensive for them to serve the purpose of efficiency. Another possible way to alleviate the problem are the digital smart grids – systems in which the consumers of energy and the generators of energy are interconnected and ‘communicate’ bilaterally via special devices such as smart meters, and which control the distribution and consumption of energy inside the system. This is pretty advanced technology and naturally quite expensive, and doesn’t provide a solution for the limited access to sunlight during certain parts of the year. 

It is probably safer to say that for the time being completely energy independent homes will remain a rarity rather than a common practice due to the exorbitant cost of such a project. It would not be justifiable to claim that the introduction of domestic photovoltaic systems to the mass consumers will eliminate the need for other energy sources whatsoever. It seems that the best and most viable option is for the building to remain connected to the grid but obtain as much energy from solar power as possible. One could however legitimately argue that there is a steady trend towards a shift in the energy production model. The number of households with PV installation goes up every year. Moreover, some surveys find that solar power has the highest level of public support among citizens of the European Union.  

The Sun is undeniably the most abundant energy source on our planet. Scientists argue that the Sun has the capacity to provide for all of humanity’s estimated energy consumption more than a thousandfold. All we have to do is learn how to harness that seemingly inexhaustible energy. We have already come a long way down the path. More and more people have realised the enormous potential of solar energy and all the benefits it involves. Whereas we may not be witnessing a complete shift to domestically produced energy in the next couple of years, the consumption of energy supplied from big power plants might very well decrease significantly in favour of one obtained from residential PV systems. They are installed not only in homes, but also in schools, hospitals, and office buildings, and thus alleviate a large financial burden for the consumers while at the same time contributing to the global fight against pollution. The modern man is environmentally conscious, readily embraces new technologies, and has an acute necessity for independence. All of these factors spell out the inevitable change of the paradigm of energy production. 

18 December 2018
74
This text was published in Bullseye issue 74