by Conrad Roedern
Grid parity is currently arriving in Namibia. Re-visiting the 2009 forecast (ETANGO 2/2009, page 6) on grid parity makes quite interesting reading. Several large-scale PV solar project applications are pending with the Electricity Control Board (ECB). The authorities are currently re-thinking their strategies of how to introduce and to regulate PV into the grid. There has been a long debate and “net-metering” had been earmarked as the choice of accommodating PV into the grid. But suddenly it looks like the role model of the South African bidding process (for the cheapest kWh-unit on offer) is looked at favorably, although the public and the Namibian Solar Industry are pretty much excluded from current deliberations.
Whatever the outcome will be, the following considerations should help to guide a beneficial roll-out of grid-connected PV power plants.
1. PV – a de-centralized way of electricity generation
Almost by definition, Solar energy is available at any corner of Namibia and should therefore be harvested in a distributed way. The following advantages are obvious:
- Generation at (or very close to) the point of consumption
- Investment often by the electricity consumer
- Reducing (or avoiding) line losses
- Reducing (or avoiding) wear and tear of switch gear
- Smaller and distributed generation capacities can normally be accommodated without reinforcing the grid
- Only distributed systems (country-wide) avoid meaningful loss of generation capacity when large cloud covers or cloudbanks scatter over Namibia
- Un-bundling of the monopolistic structure of electricity generation
Amongst the current ECB applications and in circulations on the Internet one finds proposals which reach from 20 MW to 1GW!
In terms of the above points, such large concentrated projects do not make much sense. A concentrated 100 MW solar station would constitute some 25% of Namibia’s current requirements but could be choked off just by one massive cloudbank sailing above it. Therefore a look at cloud coverage statistics from weather satellites for all seasons (and for the time of the day) is a prerequisite for planning larger scaled systems. The great advantages of distributed system become obvious.
2. What sizes should we think of?
In the Namibian context I suggest to look at 3 categories when it comes to size:
- 0.5 to 1000 kW(peak) for residential and industrial systems which are owneroperated. The own roof is often the most ideal place to install.
- 1000 to 5000 kW(peak) for system operated by rural municipalities or other regional entities
- 5000 to 20000 kW(peak) for systems operated near or around larger towns and systems in support of large-scale mining activities
20000 kW(peak) or 20 MW(peak) should be seen as an upper power range. If more capacity is required (for example in the vicinity of Windhoek or in mining areas) one should think of several independent stations at different locations near the center of consumption. Site selection would obviously go hand in hand with the capacities of power lines and sub-stations etc.
Large scale PV power plants in Germany – too big for Namibia?
In conclusion one can say: many distributed PV power plants will have a multitude of advantages above a few concentrated multi-mega-plants. It will mean bidding farewell to the traditional way of power generation. But this holds in store investment opportunities for many operators all over the country. What a bright outlook!