Highly efficient solar power for grid-connected commercial and industrial buildings
Context : Shams Dubai Solar Program
HH Sheikh Mohammed bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE and Ruler of Dubai has called for solar panels to be installed on every roof in Dubai by 2030, as part of the Emirates vision to produce 75% of its energy from clean sources by 2050. To get there in time, the Dubai Clean Energy Strategy 2050 also calls for interim targets of 7% of solar power by 2020, and 25% by 2030.
As one of the first steps to facilitate this goal, the Dubai Electricity & Water Authority (DEWA) created the Shams Dubai solar program in early 2015. This program allows DEWA customers to install solar panels on their property, and utilize the produced solar energy to reduce their monthly electricity bill. Any surplus electricity that can not be used immediately will be credited by DEWA at the retail rate, further reducing the electricity bill in the next month.
Solar panels can be installed on the roof, parking shades or on the ground, depending on available space and orientation. The best locations are clear, unobstructed roofs, parking or other areas facing south, with no shading. North-facing surfaces can be utilized with mounting structures that tilt the panels so that they face south.
How it works
This program is based on the principle of ‘net metering’, and allows customers to install solar panels to produce their own power, reducing their electricity bill every month. Any surplus electricity not used immediately is sold back to the grid at the same price, and at the end of the month only the net amount is billed to the customer. Should a customer produce more energy in one month than he / she has consumed, DEWA allows rolling over these kWhs to the next month.
The big advantage of net metering is that customers stay connected to DEWA’s grid, thereby combining the 24/7 reliability of a grid connection with the lower costs of solar energy.
Enerwhere is among the first solar companies in the UAE certified by DEWA to carry out solar system installation under this initiative.
Solar Rooftop Systems
Solar rooftop systems are popular in urban locations, where ground space is limited.
Of course, the first step to installing a solar rooftop plant is to make sure that the roof is strong enough to carry the additional load of the solar panels. Enerwhere’s engineering team has analyzed dozens of commercial and industrial rooftops in the UAE, and has all the right expertise to execute your project on time and on budget.
Commercial and industrial buildings in the UAE are built from variety of different materials:
Sandwich panel roofs are common for cold-storage warehouses, factories and other buildings that require insulation. The panels consist of a thick layer of insulating foam, which is sandwiched between two metal sheets (hence the name). The solar panels can be installed in one of two ways. The first is to attach the panels with self-tapping screws from the top. The screws come with rubber seals to prevent water leakage after they are fixed to the roof. This method is tried and tested in thousands of installations in Europe and North America, and can withstand very high wind loads.
Alternatively, the solar panels can be attached to the panels with industrial-strength adhesive tape. This mounting method does not require any roof penetration, thereby further reducing the risk of leakages. The minimal metal structure also helps reduce the weight of the installation, thereby making it ideally suited to roofs with limited weight-carrying capacity.
Sheet metal roofs are common for ambient warehouses, factories, sheds and other utility buildings. Made from galvanized steel or aluminum, the sheets are typically attached to a steel structure underneath with self-penetrating screws. Because the weight-carrying capacity of single sheet roofs is typically very limited, the solar installation needs to be designed to minimize the weight and wind forces acting on the panels.
The best way to achieve this is to attach the panels to short rails, which in turn are connected to the roof by self-tapping screws . The screws come with rubber seals to prevent water ingress after they are fixed to the roof. This method is tried and tested in thousands of installations around the world, and can withstand very high wind loads.
Concrete roofs are are a common feature of schools, universities, hospitals, labor accommodation and other public buildings. Given the strong concrete structure, weight is hardly ever an issue for the solar installation. However, shading from obstacles (air-conditioners, elevator shafts, satellite dishes, etc.) can be a concern.The easiest way to install a solar system on a concrete roof is by using ballasted structures. These have the big advantage of not needing any roof penetration, and can therefore be installed with little preparation. The structures can be optimized for maximum yield (e.g. facing straight south, at an angle of 20-25°) or for maximum energy density (typically facing east-west at a tilt angle of around 10°).
The Enerwhere team has carried out more than a dozen installations using ballasted systems and we believe that this is one of the easiest and most cost-effective ways to put solar on your roof.