Central Solar PV System

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Polly Ward
6 years ago
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1 Central Solar PV System How it works: A large, central Solar PV system is installed in a communal area within the estate (typically on the roof of a shared building). The system generates electricity which is fed into the estate grid. This replaces electricity that would have been purchased from the grid, reducing the estates electricity bill. This saving can be used by the Home Owners Association (HoA) or estate management company to reduce levies or invest in the estate. There will be no impact on residents within the estate they simply draw power from the estate supply as per usual. There are generally no modifications required to the electrical network within the estate and the system can be included in the initial design or retrofitted to an existing building. The benefits: 1) Electricity can be produced more cheaply than the grid alternative a saving in perpetuity for the HoA 2) The carbon footprint of the estate is significantly reduced, providing a marketing benefit. 3) If the developer invests in the system, they can earn an ongoing revenue. Where it can be applied: System installation is straightforward and can be done on a new or existing development. 1) Systems will be feasible from 25kWp or larger. This means that: There must be a communal building with at least 150 m 2 of suitable roof space available There should be at least 20 kw daytime consumption. This is likely if the estate has 30+ units or if the there is significant daytime activity on site (e.g. restaurant, fitness centre) 2) The estate must be on a suitable tariff. Tariffs in the Western Cape that would qualify include: City of Cape Town - Small power user 1 Drakenstein Commercial 3 phase Stellenbosch Commercial Renewable energy (COM6) Breede River Small power user 1 and 2 Witzenberg Commercial prepaid, commercial 3 phase, Agricultural Typical costs and savings: Exact costs will vary depending on several factors (location, type of roof, complexity of installation etc.). The table below shows typical values for the minimum sized system. If the developer or the HoA would prefer not to invest their own capital in owning the system, EPHS lease the system to the estate. In this case no upfront capital is required and the estate would still get a net saving. Ownership model Table 1: Saving and Paybacks for a 25 kwp system* Upfront Investment Saving on Bill (per year) Lease Payments (per year) Net Effect Purchase R 395,000 R 59,800 R 0 ROI =22% (over 20 years) Lease R 0 R 59,800 R 48,400 R 11,400 (year 1) *Figures are based north facing roof in Cape Town at a tilt of 30 degrees. The tariff used is the City of Cape Town small power user 1.

Case Study: Stonehurst Mountain Estate Stonehurst Mountain Estate is located in Tokai, Cape Town. They have 184 housing sites and several communal areas and a shared building.

2 Case Study: Stonehurst Mountain Estate Stonehurst Mountain Estate is located in Tokai, Cape Town. They have 184 housing sites and several communal areas and a shared building. They contacted Energy Partners to look for a way to reduce their electricity bills and to green the estate in line with their eco-estate image. Energy Partners evaluated the site and it was agreed that the fitness centre was a suitable location for a central rooftop PV system. Even though the roof was not North facing, a split East/West orientation was used which still provided excellent output. The total system included 70 x 320W panels, split across 2 arrays. A single SMA 3 phase commercial inverter was used. The installation took 6 days. The project is done on a lease basis the system is owned by Energy Partners and the estate pays a lease fee each month, which is calculated based on system performance. The main centre of the estate is on the City of Cape Town residential domestic tariff (2.00 R/kWh) but leased the system from Energy Partners at 1.60 R/kWh. As a result, the estate is saving apprx. R14k per year. Table 2: Actual performance of the Stonehurst system* Month kwh Savings Saving on Bill Net saving after lease January 4,406 R 8,812 R 1,762 February 4,006 R 8,012 R 1,602 March 3,538 R 7,076 R 1, 410 April 2,433 R 4,866 R 969 Estimated annual 35,470 R 70,940 R 14,188 Figure 1: Aerial view, Stonehurst system*

3 Centralized hot water systems How it works: Hot water is generated at a cost lower than conventional or even solar geysers and sold to tenants on a prepaid basis by either the body corporate or by the developer. A single heat pump plant is installed either on a roof slab or next to an apartment block. The size of the heat pump plant is dependent on the number of tenants that will occupy the building, but typically the hot water storage size will range from 2,500L to 10,000L. Due to the high efficiency of the heat pump system a small profit can be made by selling the hot water. This profit can cover maintenance and other costs within the development. Multiple plants can be installed for larger buildings. Hot water ring main piping is installed throughout the apartment building through which hot water is constantly circulated, resulting in apartments having constant hot water on demand. Benefits 1) Creates an additional revenue stream which can be used to cover maintenance and other costs. 2) If hot water is sold on a prepaid basis, then the revenue collection rate will be 100%. This billing method also requires minimal admin. 3) Significantly reduces the electricity demand of the development. 4) Ease of maintenance only 1 system per building instead of 1 system per apartment. Our heat pumps are very reliable and easy to maintain. Where it can be applied: These systems are most effective in high-density developments with high hot water consumption. 1) Each building needs to have an occupancy of at least 20 people. 2) There should be an allowable space on the ground next to the building or on a suitable roof slab for the heat pump plant. 3) There should be suitable spaces for the piping to run throughout the building. Significant costs can be saved if sufficient space within the service ducts is allowed for the hot water piping. Typical costs and profit: The table below gives a rough estimate of the system costs and expected annual profit for different sizes of apartment blocks (all prices are excl. VAT)*. These savings are dependent on the comparative municipal tariffs. Table 1: Typical Costs and savings from central hot water systems* # Apartments Total Cost Per Apartment Annual Profit (year 1) 10 R R R R R R R R R R R R R R R R R R *The costs are dependent on building layout and size, plant location, piping routes, etc. The profit is calculated using a water tariff of R11/kL and electricity tariff of R1.50/kWh.

4 INSTALLATION PICTURES Marketing purposes

5 Residential Projects (3kWp-10kWp) Full Home System Panels, inverter, Heat Pump 3kWp Durbanville PV Only 8 kwp Stellenbosch 1

6 Solar PV + Heat Pump Paarl 5 kwp Heat Pump Only Cape Town 500l tank 2

7 Off grid system PV + Batteries Hermanus 3 kwp Solar PV + Battery + ICON Cape Town 3

8 Estate/Small commercial (10kWp-50kWp) Restaurant, Cape Town, 10 kwp system Guest house, Somerset West 12kWp system Veterinary Clinic Durbanville 28kWp 4

9 Estate Lifestyle Center, Tokai, 28 kwp Factory Epping, 25 kwp system 5

10 Large Commercial (50 kwp +) More images available at: Wine Farm Robertson 242 kwp Hospital and Day Clinic Johannesburg 347 kwp Distribution Center Johannesburg 363 kwp 6

Energy Saving Solutions for Individual Homes How it works: For developers/ estates that want to give home owners a way to go green and reduce their bills.

The Solar PV system would generate electricity to power loads in the house. In addition, an optional lithium Ion battery can be included.

11 Energy Saving Solutions for Individual Homes How it works: For developers/ estates that want to give home owners a way to go green and reduce their bills. EPHS would design and provide each house with a combined heat pump and PV system. The heat pump would substitute a conventional geyser, providing efficiency savings and an energy storage function. The Solar PV system would generate electricity to power loads in the house. In addition, an optional lithium Ion battery can be included. Such a system can reduce a home s energy consumption by up to 70%. Benefits 1) Electricity can be produced more cheaply than the grid alternative a saving in perpetuity for the home owner 2) Increases the value of a home 3) Reduces the carbon footprint of the home owner significantly 4) Batteries can be added to the system to give backup power Where can it be applied: The exact system to be used would depend on the details of the design. In general: 1) Houses must be detached from each other 2) Houses should have a north facing roof with at least 16m 2 available 3) Cannot be in an Eskom directly supplied area 4) domestic.costs are ex VAT but include installation and commissioning. The ICON system For developers looking for a distinctive system that adds sophistication to high end living, we have our ICON TM system. It offers best in class technology, in a sleek enclose and a seamless mobile app. Figure 1: ICON inverter and battery Typical costs and savings: System costs can vary significantly, depending on the size and needs of the home. Typical costs are indicated in Table 1 below. Discounts of up to 8% are available for estates that purchase systems in bulk. Table 1: Costs and savings of standard PV and heat pump systems System Cost (Ex. VAT) Estimated 1 st year savings per home* Icon PV system (3 kw) + Heat Pump R 97 k R 9.8 k Infinisolar system (5kW) R 110 k R 14 9 k *Figures are based north facing roof in Cape Town at a tilt of 30 degrees and a 90% self-consumption. The tariff used is the City of Cape residential

Case Study: Val de Vie Estate Val de Vie lifestyle and Polo estate outside of Paarl wanted to offer their residents an integrated home management solution.

12 Case Study: Val de Vie Estate Val de Vie lifestyle and Polo estate outside of Paarl wanted to offer their residents an integrated home management solution. However, it was important for them that a standard solution be implemented that would not detract from the look of the estate. As a result, they decided to partner with Energy Partners and utilize the ICON system. To date we have installed 11 systems for Val de Vie residents. The system includes a 4.8 kw heat pump and 500 litre storage tank to allow homes to generate all of their required hot water during the day. This is paired with a 3kW solar PV system and ICON inverter and battery Both the client and Energy Partners can monitor the system via the ICON mobile app. This allows the client to see how the system is performing as well as savings. Table 2 shows the cost and savings typical of homes that have installed the system. Table 2: Costs and savings of combining a heat pump and ICON system Monthly electricity bill prior to solution R System Cost (ex. VAT) R Average monthly savings (year 1) R ROI (20 years) 14% Figure 2: ICON system at Val de Vie Estate

13 Solar PV Systems to reduce/ replace grid supply How it works: For developments that have inadequate grid supply, a solar PV + storage plant can provide reliable energy to either supplement the grid or even go completely off grid. This makes it possible to increase the scale of a development or to avoid costly network upgrades. Typically, the solution would include a combination of solar PV panels, battery storage, load management and generator backup. Solutions can either be centralized and fed into the grid, or each building can have its own plant. Extensive design would need to be done on a case by case basis to make sure the solution is right for the development. Benefits to developer 1) Save on costly grid and connection upgrades 2) Limit financial exposure to grid tariff increases 3) Promote a sustainable approach 4) Speed up planning approval and implementation Where it can be applied: These systems are costly and typically do not provide a good payback simply due to the energy saved to make financial sense, there should be a significant infrastructure cost saving. Alternatively, there needs to be a motivation for going off grid above and beyond financial savings. Typical costs Costs are highly dependent on several factors including the total energy requirement for each home, the split between day time/night time energy, the willingness to use a generator, amount of sunshine at the location and whether the plant is centralized or not. Some example costs from recent projects: Table 1: Costs of standard off grid systems Description Solution Type PV Capacity per dwelling Battery Capacity per dwelling Cost per home Off grid Hotel development 20 person capacity Off grid Housing estate 17 homes Centralized 2.1 kw 5.2 kwh R180k Individual systems 7 kw 20 kwh R385k per home Centralized 5 kw 14 kwh R292k

4 bedrooms, approximately 480 m 2 under roof Energy conscious building from ground up Mix of full time residents and weekend/ holiday users Energy Partners modelled the expected energy consumption,

14 Case study: Rust de Winter Figure 1: Front view, Rust de Winter architect rendering Rust de Winter is a brand new, premium eco estate ~35 minutes outside Pretoria. Although there was existing grid access, the capacity was limited. As a result, 17 of the homes needed to be completely independent of the grid. 4 bedrooms, approximately 480 m 2 under roof Energy conscious building from ground up Mix of full time residents and weekend/ holiday users Energy Partners modelled the expected energy consumption, the local weather patterns and proposed systems based on the results. The houses were estimated to use an average of 23 kwh per day and solar radiation at the site was good. In addition, it was agreed that the homes would have generator backup when there were periods of low sunshine for > 24 hours. In addition, 2 solutions were developed a smaller system for weekend users and a larger system for permanent residents. Overall, the lifecycle cost of these systems was less than the cost of upgrading the grid. Table 2: Estimated costs of building a grid vs. off grid solution Figure 2: Aerial view, Rust de Winter site Off-grid solution (small) Upgraded municipal grid Upfront cost R R *The cost of building a grid is estimated using prior projects ** Off-grid annual running costs assume using a generator for 10% of total energy usage. Build a grid annual running costs are using City of Tshwane domestic bulk supply tariffs Annual running costs** R R

The PowerOptimal Elon TM The Most Cost-Effective Solar Water Heating Solution

The PowerOptimal Elon TM The Most Cost-Effective Solar Water Heating Solution Conventional wisdom has it that solar thermal is the most cost-effective solar water heating solution. Well, it is time to