Solar and battery systems for commercial buildings, from survey to operation

You can check the conditions on your roof by searching for your address at solkart.no. For commercial buildings, housing co-operatives and jointly-owned properties, farms and solar parks, you can also contact our advisers at bedrift@solcellespesialisten.no. We are always happy to come out for a site survey.

South-facing roof surfaces usually give the highest annual output, peaking around the middle of the day. East- and west-facing surfaces generate more in the morning and the afternoon, which spreads production more evenly across the day. In our own PV calculator on solkart.no, a roof in Oslo gives around 1 006 kWh per kWp a year when the surface is pitched 25 degrees to the south, against around 800 kWh per kWp on a flat roof with panels at 10 degrees to the east and west (run on 17 September 2026, P50, 5% system loss, snow and soiling losses included). Shading from neighbouring rows and the surroundings is not included in the figures. Total annual output is somewhat lower, but east/west can suit you particularly well if your consumption is heaviest early or late in the day. This holds for any type of building, whether a housing co-operative, a barn or an industrial building with a flat roof. You get the figure for your own roof in Solsjekk.

In principle you can have panels on several roof surfaces. Technical requirements place certain limits on the number of panels per surface. The more surfaces involved, the more expensive it can become, as additional inverters may be needed.

It has to be assessed building by building. A solar energy installation is a building services installation under the Norwegian Planning and Building Act (pbl. § 20-1 bokstav f). Installing or altering one within a single dwelling unit or fire compartment counts as a simple installation and is exempt from the permit requirement, but on a commercial building the array often spans several fire compartments, and then the exemption does not apply. The same goes if the building sits within a conservation area or close to the shoreline or a railway line. The new exemption for solar energy installations that applies from 1 July 2026 covers small houses and certain detached buildings – not commercial buildings. We help you check this with the local authority before installation.

Every solar installation must be registered with the grid operator. We take care of that process. All we need from you is your meter number. The role your building takes on the grid depends on how much the installation can export to the grid. As long as the installation exports no more than 100 kW, you are registered as a plus customer, the formal term for a prosumer – a customer who both uses and produces electricity – and you are paid for the surplus exported to the grid. If it exports more, you become a producer, with separate terms for feed-in and settlement. We establish which category your building falls into before the system is designed.

Once the quote is confirmed, the project manager agrees the installation date with you. When it can happen depends on the scope of the project, delivery of materials and any applications to the local authority and the grid company.

If the goods are marked “registrert skade” (damage recorded), this is a routine note from the supplier and something we will follow up. In most cases only the packaging is damaged and the contents are unaffected. If you can see that the goods are extensively damaged, please contact us as soon as possible on 45 72 87 80.

Solcellespesialisten has its own installation teams, experienced in solar installation and with a strong background in both the electrical and the structural side of the work. We have the capacity to install around two in three projects with our own employees. The rest are carried out by regular subcontractors we have worked with for many years.

We usually have our own teams for connecting the system to the grid. They normally come once the roof work is finished. You will receive a separate email with the connection date.

Solar panels are essentially self-cleaning. The installation should still be inspected in line with the manufacturer’s recommendations. The largest installations should have an on-site inspection several times a year, the smallest every three years. An inspection can include a visual check from ground level, plus a look at whether the cabling is secured and protected. If the panels are unusually dirty even after rain, they can be rinsed down gently. Avoid brushes and snow clearing, as these can scratch the panels and void the warranty. For commercial installations we offer a service agreement with an annual inspection.

An inverter converts the direct current (DC) from the solar panels into the alternating current (AC) that the grid uses. Its size depends on the output of the installation. Cables run from the inverter both to the array and to the consumer unit, which may be inside the building. An inverter can make some noise while generating, and there are also several fire safety requirements governing where it can go. Our installers will help you find the best position for it when they fit the panels.

We supply solar panels in different sizes and power ratings from several manufacturers, and choose the panel to suit each project. Today we use panels from LONGi, Tongwei, AIKO and JA Solar. We weigh performance, the roof structure and how the building is used to find the best solution.

Panel size varies from manufacturer to manufacturer and generally increases with the output of the panel. Smaller panels are usually around 1.7 metres tall, while larger panels for industrial buildings can be up to 2.4 metres. We choose the panel to suit each project.

The panels cope with a great deal of snow. In areas with heavy snowfall we fit an extra rail beneath the panels so that the snow load cannot break them. The project manager assesses this before installation.

The wind load is calculated for every project to NS-EN 1991-1-4 with the Norwegian national annex. The calculation takes in the reference wind velocity for the municipality, the terrain category where the building stands and the height of the building – a low warehouse inside an industrial estate and an office block standing alone by the fjord do not get the same load. On a flat roof one value for the whole surface is not enough: the standard divides the roof into zones, and uplift along the roof edge and in the corners is many times higher than in the middle. That is where ballast is increased or the installation is fixed mechanically. We determine the terrain category from map data rather than by judgement – see how we do it.

A turnkey installation from us includes everything: grid notification, design and engineering, installation, protection, commissioning, AC connection and final documentation.

The surplus is sold to your electricity supplier under the agreement you have with them, and the terms vary between suppliers. If the installation can export more than 100 kW to the grid, you are no longer a plus customer but a producer, and selling the power requires a separate agreement. We establish which category the installation falls into before it is designed.

No. Electricity produced by the panels always goes first to whatever is drawing power in the building. If the panels produce more than the building consumes, the surplus is exported to the grid automatically.

Solar panels always generate something as long as they are not covered and daylight is falling on the surface of the panel. In winter there is generally little sun, and snow will cover the panels. We have calculated the seasonal split in our own PV calculator on solkart.no, run on 17.09.2026: in Oslo 97% of the annual output falls between March and October on a flat roof with panels at 10° facing east and west, and 93% on a south-facing roof pitched at 25°. Across the country the share ranges from 91% (Stavanger, south-facing 25°) to close to 100% (Tromsø, flat roof) – the further north, the shorter the season. The assumptions are the same as in our calculator: 5% system losses, crystalline panels, free-standing mounting, a P50 solar year, terrain horizon, and snow and soiling losses included. Shading from neighbouring rows and the surroundings is not included in the figures. You get the figure for your own roof in Solsjekk.

All of our inverters come with output monitoring in the form of a phone app. The electrician who commissions the system will set this up and show you how to use the app.

With a grid-connected inverter, a power cut on the grid causes the inverter to stop supplying electricity. Nor will the panels cover your own consumption while the grid is down.

Kilowatt-peak (kWp) is the rated output of each panel under standard test conditions (STC). STC specifies a temperature, an irradiance and an angle that are only met on certain occasions in Norway. Output through the rest of the year is a percentage of the stated kWp. Kilowatt-hours (kWh) are a measure of energy, given by output multiplied by time. If a solar panel generates at 1 kW for one hour, it has produced 1 kWh of electrical energy.

DC stands for direct current, while AC stands for alternating current. Solar panels produce DC. The electricity in a building and on the grid is always AC, which is why an inverter is needed to turn DC into AC.