Solar Thermal Modelling

Sustainable and energy efficient ablution facility for informal settlements

An ablution block is to be built in the informal settlement of Joe Slovo in an attempt to provide the local community with safe, clean and reliable access to sanitation. This will ensure that the community’s basic needs are met, employment is created through managing the facility and energy dependency is limited. The project also aims to ensure that the relevant stakeholders (NGOs, local government and communities) develop a better understanding of new technology and how it can support financial and environmental sustainability in Joe Slovo and elsewhere in South Africa.

The ablution block will draw from experiences in India and Zimbabwe, where the community there are directly involved in the operation and management of ablution facilities. The community in Joe Slovo will be expected to financially contribute to cover the costs of running and maintaining it.

Grey Green’s involvement in this project was to develop a model for ablution facilities that is not only socially, but financially and environmentally sustainable. We looked to achieve this by using technology to minimise the energy required to heat water as well as the amount of water used.

National Zoo Solar PV & Golf Carts

This 4kW fixed ground mounted Solar PV system  is intended to be used to offset the power needs of charging two electric golf carts, which are used by visitors. The solar powered carts showcase that electric vehicles are effective and can be charged using renewable energy. The two golf carts are also fitted with solar panel roofs which reduce charging time by more than 50%, and branded to attract attention. The surplus energy produced by the PV system is fed into the Zoo’s main supply to reduce daily electricity consumption.

Thermochar Waste Heat Recovery System


We conducted a feasibility study regarding the design of a waste heat recovery system to supply power for a series of char plants. The waste heat from the plant is used to power the rankine cycle which ultimately produces the electricity needs of the entire plant, approximately 500kW. This makes the plant resistant to electricity shortages and allows it to be installed in remote areas without the need for a power supply.

Project 90×2030 Renewable Energy Demonstration Sites Program

Grey Green was contracted by environmental NGO Project 90×2030 to manage the installation of 12 renewable energy demonstration sites across the country. The program was funded by the German government and aimed to create awareness around renewable energy systems and to demonstrate that the technology exists and is effective in many different environments. Grey Green project managed the installation of these renewable energy systems, which include off grid solar PV, hydro power, biogas digesters, solar water heating and wind systems to name a few…