The central hypothesis of this study is to test if combining innovative architecture with solar energy production into a single housing unit is a bold and scalable solution that can make a meaningful impact on the global issue of affordable housing and energy production.
We worked together with experts to develop the design and floor plans of ENERCUBE. Our final design integrates a photovoltaic (PV) system in the roof. We propose that the energy generation associated with ENERCUBE is linked to the property ownership and sold back to the grid through purchase agreements with electricity providers in blocks of 200 units. These future cash flows are guaranteed and can be securitized giving people access to capital. In economic terms, these families effectively receive a rent from the grid for making their land available for energy production. This in turn helps them finance a housing unit that substantially raises their living standards.
Overall, our research shows that the combination of sophisticated design and solar energy production delivers an affordable housing solution that has the potential to dramatically improve living conditions for the poor.
02. BENCHMARK LOCATION
Selecting a benchmark location for our hypothesis will make the analysis more feasible and comprehensive. The main two factors driving our choice are: (a) critical housing problems and (b) radiation ratings. We identified South Africa as a location that fulfills the above two criteria.
(a) Poor urban areas in South Africa are referred to as Townships and they suffer from overcrowding and squatter and backyard buildings around urban areas. Given the scale of the housing backlog and the rapid growth in housing needs, there is an incentive for government to spend money in this area and embrace innovative new solutions. The South African government spent R16-billion on building new houses and sustainable human settlements for poor South African in 2010/11, a domestic record only second to that of China.
(b) Radiation ratings are the key driver to identify locations where solar energy production is optimal. South Africa is a prime location for solar energy as it receives over 2,500 hours of sunshine a year; its solar radiation output is more than twice that of Europe, making it one of the highest in the world (24-hour global solar radiation average is 220 W/m2 for South Africa, compared to 150 W/m2 for the USA and about 100 W/m2 for Europe.
We also favor a location that incentivizes investment in solar energy. In recent years, South Africa saw a significant rise in the number of PV installations as well as general interest in the technology. An example of the growing PV interest in South Africa is the million-dollar plant being built by state controlled energy monopoly, Eskom in the Northern Cape.
Other factors we looked at include the stability of the political and economic environment (SA ranks 35 in the “doing business ranking” vs. India at 132), the level of sophistication of the financial system, housing inequalities and backlogs, poverty (46% of the population), a mature energy sector, familiarity with the area and possible networking opportunities through personal connections.
03. ENERCUBE :: THE PROTOTYPE
Our intention is the name of our product to reveal its core attributes. As a creative blend of the words energy and cube, the archetypical symbol of spacing unit, we chose ENERCUBE as an intriguing name that accurately reveals the essence of the project.
Maximizing energy production, adapting to the local climate and addressing South African living customs has led our team of design experts to reconsider some aspects of the original plan and section by extending the effective surface of the roof, both for energy harvest and rainwater collection, and by incorporating a semi-private, covered porch to the benefit of every unit, taking into account the time South Africans like to spend outdoors. The size of each module has been fixed to a 3,50 meters width by 8,40 meters length, an effective space of 29,50 m2.
Indoors we insisted on a scheme that maximizes functionality while addressing the issue of flexibility; a unit that is easily reprogrammable and can compensate for future family needs. With the exception of the wet areas of the kitchen and the bathroom, the rest of the interior walls are envisioned as demountable partitions. Storage room is considered critical and is incorporated as an integral part of the design.
Enercube is presented 100% as a long-term housing solution and in fact demands a multi-faceted approach and all of the above parties to collaborate closely. We consider other lightweight designs currently available in the market as extremely more efficient for the purpose of disaster-relief temporary housing. Enercube's strength comparing to other similar initiatives lies in the direct association of the housing design with the energy production process, a design that at the same time does not disregard basic aesthetic and architectural features, strongly opposing the common misconception that low-income housing shouldn't or can't look nice.
CONSTRUCTION OPTIMIZATION :: KEEPING IT SIMPLE
Our main concerns regarding the construction method is scalability, ease of production and low cost of transport. The chosen method will have the potential to provide a global solution in diverse geographical areas with growing needs. We identified industrialized, prefabricated modular construction as the optimal building method capable to catch up with the emerging urbanization trends and the housing deficits that they create.
The house is designed in wall, roof and floor panels with a width of 1.20m, ensuring a standardized prefabrication process. Each panel is broken down in four elements - a lightweight metal substructure , water-resistant plywood panels as the outer layer, Isotherm thermal insulation as a middle layer and low-cost Oriented Strand Board panels as interior finishing. Due to its modularity, each house can be flat-packed, transported in pieces and mounted on site. Medium skilled workers with the support of local labor can assemble each module in the course of a day or two. The maintenance of each unit and of the communal spaces will be a joined responsibility of the home-owners and the utility company.
Energy generation will be coupled with efficiency in energy consumption. The installation of Solar Water Heaters combined with Energy Efficient Lighting will contribute to the overall performance of each unit. The benefits of such technologies were made obvious in the recent Kuyasa low-cost urban housing energy upgrade project in Khayelitsha, near Cape Town.
04. ENERCITY :: THE URBAN PLAN
The laying out of the emerging urban plan becomes of primary importance to the Enercube Project. The Enercube is less about the single unit than it is about the composition of these units into a meaningful aggregation that achieves urban qualities - it is less about the single user or family than it is about the community as a whole. In the same way that a community is more than the sum of its individual members, the urban plan of the Enercube project will be more than the sum of its individual modules.
We approach the problem of urban form through criteria of density and scale, while addressing questions of program, circulation and aesthetics. The design will be customized on a project by project basis, given the plot characteristics, size, morphology and orientation, as well as the ethnic and tribal characteristics of the population group for which the project is intended. The plan is estimated to be broken down in neighborhoods of approximately 0.25 Hectares in size, housing 20 Enercube modules in average. This figure is translated to a population density index of around 28.000 inhabitants per square Kilometer (estimated 3.5 per household as an average). A critical balance needs to be established between social well-being (personal safety, health and wellness, shelter, sanitation, equity, personal freedom and choice) and energy production. Special purpose buildings (schools, medical centers, nurseries, etc.) will be erected in designated areas of the plan. These buildings could follow the general guidelines of Enercube, but do not necessarily need to follow the module architecture.
05. BUSINESS MODEL INNOVATION
Expanding access to finance can play a very important role in reducing poverty among underserved communities. Among other things, access to finance can facilitate income-generating opportunities. The poor can also take advantage to build capital and improve their living conditions, especially when they are homeowners themselves. So how do we provide people with sustained income and secure tenure based on their own merits while creating a viable investment proposition for commercial investors?
The answer is scale. As already mentioned the energy production associated with each housing unit is linked to the property ownership and will be sold back to the grid through purchase agreements with utilities. These future cash flows are guaranteed and can be securitized in the form of a mortgage. In the case of South Africa, Eskom, the dominant, government-owned utility company, tenders for solar projects based on a minimum capacity of 1.00 MW. Provided that according to our calculations, a single unit produces 5,160 KWh/year and the feed-in tariffs are 2.5 ZAR/KWh, purchase agreements need to be bundled in minimum blocks of 200 units!
Based on an investment horizon of 20 years, we estimate that a cash flow of $1,677 per year can be generated per unit. The overall unit cost, including PV equipment, transportation and installation amounts to $11,700 resulting in an NPV of $1,122.75 per ENERCUBE. This provides a good basis to attract private investors but we argue that government and the country’s utility provider will have a key role to play to make that happen.