Ravolva

1. Create or open a project

A project is one home: its location, its data and its results. Start from the front page.

• With an account, your projects are saved and you can reopen, rename or archive them later.
• Without an account, the project is tied to your current browser session. Once that session ends, you can no longer get back to it. Create an account or sign in before then, and the project moves to your account.
• To see what a finished analysis looks like before using your own data, open the example project.

2. Location, price zone and grid company

The location decides three things: how much sun the roof gets, which price zone your spot price comes from, and which grid company bills you.

• Enter an address, type in GPS coordinates, or click the map. Coordinates alone are enough.
• Look up your postal code. This fills in the price zone, the grid company and its tariff, including the stepped capacity charge.
• Tell Ravolva whether you already have solar panels. If you do, step 2 asks for your production data as well.

3. Import consumption and existing solar production

Everything that follows is calculated from your hourly consumption, so this is the most important step. A full year or more gives the best answer, because a winter and a summer behave very differently.

• Tibber: sign in with Tibber, or paste an access token, and choose how many months to fetch. The import runs in the background, so you can leave the page. If you have solar panels, tick the box to fetch net production too.
• Elhub: Ravolva generates a small snippet that downloads your monthly files from Min Side after you sign in there with BankID. Upload all the files at once, and they are joined into one series. The snippet runs in your own browser; nothing is sent to Ravolva until you upload.
• Other CSV or Excel files: upload hourly data with a time column and a value column. The columns are detected automatically; if that fails, choose them yourself under "Advanced: column overrides".

If you have solar panels, the data comes in up to three series. Your meter measures net consumption and net production; total solar production comes from the inverter. Import what you have; the terms are explained below.

The price settings are also in this step. Check them after importing, and click "Apply price settings" when you change something.

4. Check your data

Before anything is calculated, look at the data. A mistake here carries through to every result.

• Do the monthly totals look like your electricity bills? A month that is far too low often means missing days.
• Are there gaps? Step 2 lists the days that are missing. A partial year is marked where it affects the figures.
• Do the daily profiles make sense: more use in winter, and export at midday in summer if you have panels?
• The end-use chart estimates how much of your consumption goes to heating and hot water. It is an estimate, not a measurement.

5. Solar panels, battery and other measures

Describe each roof surface the panels would go on: its tilt, which way it faces, and how many kWp it can hold. Surfaces facing the same way share one solar calculation.

• Azimuth is the compass direction: 0 is south, −90 east and 90 west.
• Under "Advanced" you can set the panel type, bifacial panels, and shading from trees or buildings.
• Click "Load PV data" to fetch the solar data from PVGIS. It runs in the background and is reused as long as the surfaces do not change.
• If you already have panels, compare estimated and actual production. A large difference means the surfaces or shading are not described correctly.

The battery and the hot water tank are set in step 5. A hot water tank is storage you probably already own: a 200 litre tank holds about as much energy as a typical home battery, although it can only be used for hot water.

6. Run the optimisation

Choose what to calculate:

• "Find optimal kWp" finds the largest system that still uses at least the share of its own production you set as the target.
• "Evaluate SC" takes a system size you choose and shows how much of its production you would use yourself.

For a battery, choose between storing surplus solar for the evening, or following the hourly prices. Following prices needs spot price history for your period.

The results show annual production, consumption, self-consumption and self-sufficiency, each with a range from P10 to P90. The range shows how much the answer moves between good and poor years.

7. Economics, support schemes and uncertainty

Step 6 uses the result from step 5, so run the optimisation first. Then enter what the installation would cost; a quote from a supplier is better than the rule of thumb shown.

• Payback time and NPV are shown together with a cash-flow chart over the whole analysis period.
• The year-1 savings are split into what you avoid buying, what you earn from export, and what you save on the capacity charge. Each can be checked on its own.
• "What should you buy first?" ranks the measures by NPV. Each one is priced against your home as it is today, so two measures bought together save less than their two figures added up.
• Choose a support scheme to see the results with strømstøtte or Norgespris. A scheme can change which measure comes first, not only the totals: it narrows the gap between cheap and expensive hours, which is what a battery or a scheduled hot water tank earns from.

Prices, weather and your own use will change. Read the results as a range and a ranking, not as a promise. Before you buy, get quotes and compare them with the numbers here.

Terms explained

Net consumption

The electricity you buy from the grid, as your meter measures it. With solar panels, this is what is left after the panels have covered what they can.

Net production

The electricity you sell to the grid: solar production you did not use yourself in that hour.

Total solar production

Everything the panels produce, measured by the inverter, before anything is used or exported.

Self-consumption

The share of your solar production you use yourself instead of exporting. It matters because a kilowatt-hour you avoid buying is usually worth more than one you sell.

Self-sufficiency

The share of your total consumption that your own solar production covers.

kWp

Kilowatt peak: the size of a solar installation, meaning the power it delivers in full sun under standard test conditions.

Spot price

The hourly market price of electricity in your price zone, from ENTSO-E. Your supplier adds a markup, and electricity tax and VAT come on top.

Grid tariff (nettleie)

What your grid company charges to deliver the power. It has an energy part per kWh, often cheaper at night, and a monthly capacity charge. The capacity charge is set by the average of the three hours in the month when you used the most power, and the three hours must fall on different days.

Support schemes

Strømstøtte covers most of the spot price above a threshold. Norgespris replaces the spot price with a fixed price. Both change only the energy part of the bill, not the grid tariff or the taxes.

NPV (net present value)

All future savings minus all costs, with money in later years counted as worth less than money today. A positive NPV means the investment pays off at the discount rate you chose.

Payback time

How many years it takes before the savings have covered the investment. Discounted payback takes into account that later savings are worth less.

P10, P50 and P90

The spread of a result across years. P50 is the middle outcome; one year in ten is expected to come out below P10, and one in ten above P90.

When something goes wrong

The file will not import

• The error message lists the columns Ravolva found in the file. Choose the right time and value columns under "Advanced: column overrides", or rename them in the file.
• If the numbers come out wrong or no rows are read, check the CSV separator. Norwegian files usually use a semicolon.
• If the text cannot be read, save the file again as UTF-8 CSV.
• For a file that holds both consumption and export, the direction must be labelled, or the values signed: plus for import and minus for export.

Tibber

• If a token is not accepted, copy it again in full; it is long and easy to cut short.
• If the token works but no home is found, the Tibber account has no home linked to it yet.
• Tibber only has data from when your home became a Tibber customer. For older history, import from Elhub.
• A large import takes a while and continues if you leave the page. Come back to step 2 later to see it.

Missing price data

• If a message says spot prices are missing for some of the hours, those hours are estimated from the hours around them, so the cost figures for them are approximate. This is most common for the last few days, and the figures are updated once the prices have been fetched.
• If no spot prices are available for your period at all, the cost charts are incomplete. In the meantime you can choose a fixed price in step 2: the cost figures are then complete, but a battery can no longer be scheduled against hourly prices.
• If the grid company was not found from your postal code, enter the tariff from your grid company’s website in step 2.