Tag Archives: feasibility studies

Come Wine with Grey Green

Grey Green have audited six wineries in the Western Cape during the harvest period over the past few months with another two winery energy audits in progress and a further three in the pipeline.

On average, the energy saving opportunities identified at each site could potentially save the wineries approximately R 370 000 per annum with a promising average pay-back period of 3 years. We also calculated an average of 400 tonnes of equivalent carbon dioxide emissions saved through our recommendations.

Highlights of the proposed interventions included: 

  • Effluent Treatment Optimizations
  • Feasibility Studies for Solar PV
  • Waste-Heat Recovery System design
  • Energy Efficient Extraction System design
  • Efficient Lighting Retro-fit proposals
  • Chiller System Optimizations including. insulation

Interestingly, chillers (cooling/refrigeration) accounted for approximately 40% of the total energy consumption, with the exception of those wineries with a distillery. The distillery accounted for 18% electrically and when converting the boiler fuel into equivalent kWh (using the calorific value of the fuel), the fuel accounted for 94% of the total energy consumption!

Lauren almost overshadowed by grape skins
Lauren almost overshadowed by grape skins


Feasibility Study for 1MW & 600kW Rooftop Solar PV

Grey Green’s assessment dealt with each of the client’s 10 buildings at different sites around the country as follows:

Perform detailed electricity consumption assessments,  determined each building’s electrical reticulation boundaries, performed structural assessment of the roof structure of each of the buildings with respect to its ability to accommodate the anticipated wind loads imposed by the fitment of a PV system; performed a site assessment of each building roof with regard to the likely impact of shading, space available and ease of access on the production and maintenance of the system.

Arising from those assessments, we proposed with detailed specifications and budget estimates, the largest yielding PV installation possible, stating R/kWh given a 25 year lifetime for the plant. We also prepared a yield assessment for the proposed PV Plant in terms of solar irradiation and electricity production. Our financial analysis presented the simple cost effectiveness based on the capital cost, operating cost and value of the offset electricity savings over the system life span assuming instantaneous embedded consumption and using the tariff applicable to the building as well as payback period.


Feasibility Study for 11.6MW Solar PV Plants

This study was conducted as part of a due diligence exercise for a client who was interested in investing in 3 separate projects spread across SA, and developed for the Small Scale IPP bid round. Grey Green completed a high-level concept design and costing exercise as part of this feasibility study in order to enable our client to determine whether the project was feasible, both in terms of the total EPCM costs as well as the long term returns from the PV plant’s generation over its 25 year lifespan. This project was completed with the assistance of our Spanish partner DISEPROSA.

Feasibility Study for Piggery

The objective of this study was to assess the feasibility of a number of renewable energy interventions that could reduce the piggery’s dependence on the electricity supply. The piggery buildings and abattoir were inspected with the goal of identifying opportunities to reduce electricity consumption by making use of existing waste being generated by the process. This includes the water being used to clean
the piggery, as well as the waste being generated in the abattoir. Furthermore, opportunities to make use of other renewable energy technologies as well as reduce wasted electricity through efficiency measures were also investigated and presented to our client.

Feasibiity of Solar Water Heating for SA Hotels

This intensive study into South Africa’s hotel industry was carried out to assess how energy was being used and to determine if solar water heating was an technically and economically feasible option. This study included a very detailed analysis of electricity consumption data from 16 local hotels, as well as a comprehensive case study at one hotel. A highly detailed model was created to assess the technical and economic feasibility of solar water heating systems to supplement hot water production in the hotel industry.

Feasibility of Solar Thermal Collectors to Supply Industrial Process Heat

This was a similar study to the water heating study however this was focuses on the feasibility of providing process heat for the food and beverage industry. The focus of this study was to establish the potential for solar thermal energy in the Western Cape food and beverage industry. This was a two part study – the first was establishing the potential size of the energy consumption in this sector, on a provincial level, and estimating with reasonable assumptions what quantity could be supplied by solar energy. The second was to model solar water heating systems, using actual processes used in three local manufacturing plants, to establish the cost at which the various solar water heating technologies could be implemented at and how much energy these systems could supply.