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The sun is an abundant, powerful source of energy, and it’s clean. The price of solar has come down so much its reached grid parity in many states. But what are the challenges of scaling solar energy? Dr Scott Tinker explains.

"The key points on solar? It’s very clean. And it’s very expensive. Capturing the sun’s energy is the most low impact way to make electricity. The fuel is free and produces zero emissions. Building the facility is fast and simple. And in most cases, the space has already been developed.

Solar is intermittent – it only makes electricity when the sun shines – but it tends to be on when we need it most, in the heat of the day, when air conditioning load is highest. Which means that solar makes the most power, when the electricity it’s replacing is most expensive. These are all good things. Even so, cost is the big challenge of solar. The technology -- panels and everything else – are gradually coming down. But solar is still more expensive than any other power source, making it highly dependent on subsidies. And it’s inefficient. It doesn’t produce much power for the cost.

That’s partly because it’s dark half the time, and cloudy parts of the other. But also because the technology itself doesn’t turn light or heat into power very effectively. This means, that until the price of solar comes way down, its applications are limited. Especially for solar power plants. It’s hard to build expensive transmission lines, out to an expensive, intermittent, low power generation plant. So solar is super clean, but super expensive. Let’s hope the price continues to fall – so that we can eventually build more of it.

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