Greenbuddies Tips – September 2022

Maximising the performance of rooftop PV

The quickest solution to reducing electricity costs is to cover your own consumption with a rooftop PV plant. It is apparent that commercial real estate investors are becoming increasingly aware of this fact. To maximise electricity production, it is advisable to incorporate the requirements of a future rooftop PV system into the detailed design of a production or storage hall. 

An example model project is the Dagab food logistics centre in Balsta, near the Swedish capital. The 65,000 m2 flat roof is designed entirely according to the “PV rooftop ready” rules. The main area is free of any obstructions, i.e., the technologies are placed island-style to avoid shading of the PV panels (ideally placing the panels towards the northern edge of the buildings). Other important elements that contribute to maximising the output per m2 are appropriately placed drainage channels and the direction of the roof pitch due to the use of an east-west system.

Newly finished rooftop project in Sweden

Three years ago, standard practice was to build 1 MW on a roof with 10 people per month. Currently, thanks to an ideally designed roof and choice of components, we built almost 9 MW in a record of 3 months. The main reasons for the fast construction and subsequently early commissioning are that the materials on the roof were manoeuvred with a helicopter, there is an even distribution on the roof which is as close to the installation site as possible, and we use JA Solar 535 Wp Jumbo panels of 2285×1135 mm which are placed on the Esdec mounting system.

Having installed over 25 different roof mounting systems, we can virtually confirm that Esdec FlatFixWave Plus is the fastest substructure on the market. The biggest advantage is that the substructure is pre-assembled and only needs to be unfolded and set in place. FlatFixWave is the only structure that assembles without the use of power hand tools, screws, or panel clips. There is no need to check the tightening torques of panel attachment screws or other bolted connections. Using FlatFixWave ensures a quick and flawless installation without the need for lengthy torque wrench checks. 

Dagab food logistics center in Balsta

Our Swedish customers have entrusted us to build 30 MW on five rooftops this year, where we installed 16,554 panels on the largest of them. In a series of mega rooftop PV projects that we will be building, the upcoming one is a 9.5 MW project in Germany, which will start in October.

Together, let’s break the 10 MW mark on one roof. Our teams, led by experienced construction managers, are waiting for your next mega project.

Hydrogen as an alternative energy source

Hydrogen is the most abundant gas in the universe, accounting for 80% of the atoms of the elements found here. Although the Earth contains much less of it, it is the third most abundant element after oxygen and silicon (15.4% of atoms), so there is certainly no shortage. However, its functionality is reduced since elemental hydrogen is rarely found on Earth and must be extracted from natural gas, oil, coal, or electrolysis from water for industrial use.

Hydrogen is the new “holy grail” of energy. Hydrogen, also claimed to be the fuel of the future, is an efficient fuel that has the highest combustion energy per pound compared to other fuels in use. It offers up to three times more energy for the same volume of fuel. It is also a clean-burning fuel that produces no harmful by-products. Currently, most hydrogen is produced by a chemical process from fossil fuels. Although this is the most efficient method of production, with an efficiency of around 80%, the downside is that for every kilogram of hydrogen, 5.5 kilogrammes of carbon dioxide are also produced. If this waste carbon dioxide is released into the atmosphere, the resulting hydrogen is called “grey”; if it is captured and stored, it is called “blue”.

Illustrative photo, Source:

This offers production by electrolysis of water. However, the efficiency of production is significantly lower, at just 60 % and 9 litres of water are used per kilogramme of ‘green’ hydrogen. However, the efficiency can be increased when there is a surplus of production and energy that has no use at the time, which is used to produce “green” hydrogen.

Thus, hydrogen production from solar energy is proposed in a system that includes a conventional photovoltaic power plant, either on the roof or on the ground, to which a storage system is connected combining battery storage and a hydrogen tank. The left-over energy produced by the sun is stored partly in the battery and partly in the form of hydrogen. The hydrogen that is produced is not only useful for powering vehicles or for heating but can also be reused to generate electricity when it is scarce or in an island system that is not connected to the grid.

Schematic of the interconnection of photovoltaic panels and a hydrogen storage system,


In addition to electrolysis from water using electricity from nuclear power plants, hydrogen is also available as a by-product of waste treatment. Toyota, the Japanese automaker, plans to produce hydrogen from household plastic waste. In Japan, this is currently not recycled as 8% ends up in landfills, 12% is exported, and two thirds end up in incinerators. Although production in this way does not produce carbon waste, it is still significantly more profitable than incineration.

In the current energy crisis, hydrogen is also helping to counter regional differences in the availability of raw materials. For example, hydrogen can be obtained through electrolysis from water in any country, even if it is otherwise mineral poor. Hydrogen as a chemical is always the same. Moreover, it can be added to natural gas and heated without any infrastructure modification, as current gas boilers are tested to run on natural gas enriched with up to 20% hydrogen.

Q&A Session with Greenbuddies

As our Greenbuddies team in the planning and building phase is growing each month, we would like to introduce our newest additions with the following questionnaire.

Consulting Buddy Nella Maslák – a young professional with a background from electrical engineering and civil engineering

Project & Delivery Buddy Jan Noga – a skilled professional with work experience in Spanish-speaking countries and in logistics and machinery

Site Buddy Lukáš Bílek – multilingual professional with work experience from all over the world


You can meet Nella, Jan, and Lukáš on the sites of your projects. Learn something about them from their responses to our Q&A.

Nella Maslák

• What was your first impression of Greenbuddies?

When I joined the company, I was pleasantly surprised at how kind and supportive the GB people were and what a great team worked here.

• If you could change one thing about the solar industry, what would it be?

Considering that I work at Greenbuddies Consulting, I would simplify the permitting process for the construction of photovoltaic power plants.

What do you do when you aren’t working?

When I’m not working, I try to divide my free time into two parts: the part I dedicate to my children and the time I spend with friends. I like to travel and do sports, especially skiing.

Jan Noga

• What was your first impression of Greenbuddies?

It was a pleasant surprise to see that everyone at Greenbuddies enjoys their jobs and cares about the company. I worked in a big industrial concern before and I did not feel this there.

• What do you find most challenging about your job?

Sometimes it’s the language barrier that makes my work difficult.

• What do you do when you aren’t working?

Mountain biking is my form of relaxation. So whenever I have some free time, I try to find the perfect trail.

Lukáš Bílek

• What do you find most challenging about your job?

Project management as a complex business matter: give people a sense of what is really going on; achieve a few things each day; get results so we can move on and have a better day than the day before.

• What do you think will change in the PV world over the next five years?

 I believe that the world is now going through many principal changes and the question of using renewable resources is becoming more and more important than ever. So PV, new technologies, engineering, new business ideas and solutions will be more in demand than ever before.

• If you weren’t in Greenbuddies, what would you be doing instead, or what would your life be like?

You can describe me in a few words, which are: foreign relations and languages; travelling and integration abroad; Sport and creative mind, always on the lookout for new opportunities and involvements in study, project management, and start-up environment. So if I was not involved with Greenbuddies, I would be looking for this scope of work.