Writer: Gigi Lam

In order to achieve the goal of net zero target, many countries speed up their renewable energy development. However, building more renewable energy facilities would take up lots of lands.

Is that true? Actually, solar systems could be built on rooftops and parking lots instead. However, many countries build solar plants on undeveloped lands instead of on top of buildings. For example, in the United States, about half of utility-scale solar facilities are in deserts and 33 percent are on croplands. Just 2.5 percent of U.S. solar power comes from urban areas. Why? It’s because it is cheaper to build on undeveloped land than on rooftops, and the installation takes less time. It’s also easier to manage a few big solar farms in an open landscape than a thousand small ones scattered across urban areas. Nonetheless, undeveloped lands are very valuable. They can be used for growing food, storing and purifying water, sheltering wildlife, etc. And developers tend to bulldoze sites when building solar plants. For example, a proposed 530-megawatt solar project in California would destroy 4,300 western Joshua trees (a species imperiled, ironically, by development and climate change), endangered desert tortoises end up being translocated.

In fact, building solar canopies in parking lots is a better method to increase renewable energy generation. There are lots of parking lots in the US, especially besides shopping malls or large supermarkets. Installing solar canopies there have many advantages: the energy generated could power the building and even neighboring facilities, it could power electric vehicles, and the canopies could shelter the customers from wind and rain, and could also lower the heat (imagine pushing a gigantic shopping cart to your car parked far away under the blazing sun!). Also, these lands are already developed, so there’s no need to develop new lands.     

A typical Walmart supercenter has a five-acre parking lot, enough to support a three-megawatt three-megawatt solar array, according to a recent study by Western University in Canada. If Walmart did that at all 3,571 of its U.S. supercenters, the total capacity would be 11.1 gigawatts of solar power, roughly equivalent to a dozen large coal-fired power plants. How about the higher building cost (compared to building on undeveloped lands) mentioned earlier? Joshu Pearce, one of the researchers of this study said, “If I can give you a greater-than-four-percent return on a guaranteed infrastructure investment that will last for 25 years minimum, It’s also possible to avoid the upfront cost entirely, with a third-party business or nonprofit paying for the installation under a power purchase agreement.”

Although Hong Know doesn’t have as many parking lots (and not as big) as in the US, considering “Optimising Land Use” is one of Hong Konger’s core values, this is a solar project that’s worth considering. In fact, an owner of a parking lot in Yueng Long has installed solar canopies in his parking lot. It could be of reference to other parking lot owners.  

Story and image source :
https://e360.yale.edu