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From a very quick look at current pricing, a 1MW solar array may cost 1M USD to install. See this link: https://news.energysage.com/solar-farms-start-one/ as the first one I tried.
If you have an existent installed electricity grid as you state, the panel field installation would then be the majority of the costs, however a distributive generating system would probably work better in a refuggee camp environment.
You should be thinking in terms of panels laid out at ground level on mounts set at the correct angle for your location rather than the considering expensive the dish structures you have provided a link to.
Solar panels and their control gear is all solid state, you may need to dust them sometimes and protect the inverters form excess dust and heat, but that is the majority of their maintenance requirement.
Cost and technical complexity to install a 1 - 3 MW hydro system supposing the water volume and water 'head' were to be available, would likely have a significantly higher upfront cost and also maintenance requirement.