More countries are committing to going green in their energy use for a number of reasons ranging from climate change to energy independence.
However, depending on a country’s location, weather patterns, policies and supply-demand dynamics, the path to a green status is anything but a glide slope. Multiple obstacles stand in the way.
Nature itself could either be the first protagonist or antagonist in a country’s energy story.
Take rain, for instance. In Kenya, rainfall is proving a double-edged blade in the country’s clean energy drive.
Kenya’s generation mix is currently over 90% green, comprising geothermal, hydropower, wind and solar. Thermal power—diesel/kerosene-fired stations—comprise the remaining 10% or thereabout.
Excluding geothermal power, other renewable sources that Kenya has tapped are somehow dependent on weather conditions, more so rainfall—its availability or lack thereof.
While hydropower production peaks during periods of heavy downpour as dams fill up, solar parks produce less electricity on rainy, cloudy days. Rain clouds block sunlight radiation, hurting solar power generation.
And depending on the rain type, wind speeds can either slow down or pick up whenever it rains in the highlands.
“At times when it rains in the highlands, wind speeds flowing through Lake Turkana wind farm (in northern Kenya) lose intensity and generation drops,” according to the managers of the 310MW Lake Turkana Wind Power Ltd.
“Other times, some rain come along with excess wind speeds forcing us to switch off turbines to avoid them snapping or getting destroyed.”
Kenya has so far developed 437MW of grid-tied wind energy and 173MW for solar.
While it may curtail generation, rain water is considered beneficial for solar panels and wind blades as it washes clean their surface, removing dust and other debris and improving their operational efficiency.
Since rain affects hydropower, wind and solar power differently, the net result is some semblance of stability in consumer power bills.
Wind and solar farms are serving as cheaper alternatives to expensive diesel generated electricity whenever hydropower generation drops during drought. At the same time, hydropower swings into action fully during rainy seasons, mitigating the drops in solar and wind power production, leaving power bills in a relatively neutral position. Hydropower stations also serve as spinning reserve in the sense that they can be ramped up and down in real-time to match fluctuations in intermittent sources like wind and solar, acting as national grid stabilisers.