Well, the match was great… A big win for the US team. Maybe Ghana should have let power lapse during the match…

In case you missed it, I posted on Monday about how Ghanaians have a power shortage, and they “purchased power” from Ivory Coast to make sure TVs stayed on during the World Cup match against the United States. To tie this into solar power, I wanted to point out how Ghana can alleviate some (but not all) of their power woes – by installing solar panels, of course!

Ghana’s power comes largely from capacity built up in a reservoir behind a dam. The Lake Volta reservoir is the largest man-made lake in the world, making it one of the largest “batteries” in the world, providing a “fuel” source for the 1 Gigawatt Akosombo Dam hydroelectric plant. The amount of power and energy that can be produced is limited by the power rating of the generation plant and the amount of energy stored in the elevated reservoir.

Solar photovoltaic panels add to power generation capacity, but in a very different way than a hydroelectric plant. They can help keep the lights – and TVs – on during the day. The bad news is that grid-interconnected solar energy systems are typically installed without batteries. The capacity to generate power is variable with the amount of sunlight available. If production does not coincide with consumption, solar energy does not contribute toward correcting power woes. In the case of the Ghana vs. USA match on Monday, it was already dark in Ghana by the time the match started, so solar power would not have effectively contributed to solving the problem. Solar power Monday night would have been like a dam in front of an empty lake.

Think of these three components in any generation system: power rating, fuel source, and storage capacity. With solar plants the power rating is based on the number of panels; the fuel source (solar radiation) can be massive, but is always variable and somewhat unpredictable; and the storage capacity is nil. In a hydroelectric dam the power rating is based on the size of the turbines; the fuel source is steady, predictable, and finite (but replenished over time); and the storage capacity (water in the reservoir) is variable. In traditional fossil fuel burning plants the power rating is based on the size of the generator; the fuel source is steady, very predictable, and virtually unlimited (in relation to the power rating); and storage is nil.

There are other factors, like ability to ramp up and down production, and other sources, like nuclear and wind.

Because each source of energy has it’s pros and cons, and no source can currently supply all electricity needs reliably in the short- or the long-term, we need to understand and accept the reality of the situation and adopt a good energy mix. Regardless of how much solar capacity we install, without storage we cannot function on solar power alone. The relationship between power production sources is critical to grid stability, but with smart planning, many energy sources can form an economical and reliable mix so we can continue to quench our thirst for more and more electricity. For now, the relative amount of solar energy installed is minuscule, so few technical barriers to expansion exist.

Unfortunately, Ghana would not have benefited in this case from solar energy. Being the country closest to 0º Latitude, 0º Longitude, the solar resource capabilities in the country are tremendous. However, with excellent natural gas reserves and an electricity grid focused on hydroelectric power for baseline demand, solar energy may not become a large part of their energy mix any time soon. Without additional peak demand plants (likely natural gas fueled), Ghana will probably need to continue purchasing power to meet peak demand from its neighbors.