How Shams Dubai Credits the Solar Power You Export

Most questions we get about Shams Dubai come down to one thing: what happens to the solar power you do not use at the moment it is generated? The answers online disagree. Some say exports earn a fixed "feed-in" rate, some say a lower "standard" rate, some say credits expire at year end. We went to the legislation that set the scheme up, and this article quotes what it says and then works through what it means for an actual bill.

What the Resolution Says

Shams Dubai rests on Dubai Executive Council Resolution No. 46 of 2014, on connecting renewable generation to DEWA's distribution network. Article 9 sets out how exports are treated. In summary:

• Article 9.3: exported units are set off against imported units for the same period.
• Article 9.4: where exported units exceed imported units for the period of a bill, the surplus accrues to the customer's DEWA account, to be set off against imported units in later bills.
• Article 9.5: the customer is not entitled to any money for surplus electricity, only to the set-off.

The key word is units. The resolution nets kilowatt-hours, not dirhams. Your bill is then calculated on the net units, using DEWA's normal residential slabs. That is why there is no export rate to look up: an export simply removes an imported unit from your bill.

What That Means for a Real Bill

DEWA's residential tariff is stepped by monthly consumption: 23 fils per kWh for the first 2,000 kWh, 28 fils up to 4,000, 32 fils up to 6,000 and 38 fils above that, plus a 6 fils fuel surcharge and 5% VAT (DEWA slab tariff). Because solar reduces the number of units billed, it removes units from the top of the bill first, where they are most expensive.

Take a 10 kWp system generating about 16,000 kWh a year, roughly 1,333 kWh a month at a typical Dubai yield of 1,600 kWh per kWp. It makes no difference to the bill whether a given kWh is used in the house as it is generated or exported and netted later: either way, one fewer unit is billed. Here is the monthly effect on three households (energy charges only, including fuel surcharge and VAT, excluding meter and other fees):

The same 1,333 kWh is worth more to the 5,000 kWh household, because it cancels units billed at 32 and 28 fils. For the 1,500 kWh household it reaches all the way down into the 23 fils slab. This is the same model our solar calculator uses.

Consequence 1: Size to Consumption, Not to Roof Area

Two things push the right system size below "as big as the roof allows". First, each extra kWh of solar cancels a cheaper unit than the one before, as the table shows. Second, once solar exceeds what the property uses, the surplus accrues on your DEWA account and DEWA pays nothing for it, so capacity beyond your consumption earns nothing unless your use rises later.

That is why our calculator sizes a system to cover about 75% of your consumption rather than all of it. Summer and winter matter too: a Dubai home uses far more electricity in summer, while solar output varies less, so a system sized to the summer bill exports a winter surplus that then has to be used up in later months.

Consequence 2: A Battery Is for Backup, Not for the Bill

In many countries a home battery earns money because exported power is paid less than imported power, or because evening electricity costs more. Neither applies to a Dubai home: exports cancel imports at the same rate within a bill, and the residential tariff has no time-of-day pricing. Storing a kWh for the evening instead of exporting it at noon leaves the bill unchanged, apart from the few per cent the battery loses in charging and discharging.

A battery still has real uses: backup during an outage, and keeping critical loads running. We set out the full numbers in our solar battery storage guide.

What We Do Not Know

The resolution sets the principle; DEWA's detailed Shams Dubai rules govern how it is applied on a bill, and we have not quoted them here. Article 9 does not mention an expiry for carried-forward units, but we would not promise that none applies. Commercial and industrial tariffs differ from the residential slabs used above. If your bill shows exports treated differently, the bill is the authority, and we would like to see it.

Frequently Asked Questions

Sources

• Dubai Executive Council Resolution No. 46 of 2014, Dubai Legislation Portal (Article 9)
• DEWA residential slab tariff