Municipal Solar Power Plants  

Nanosolar have a blog posting announcing that their first thin film solar products will be for municipal power plants, and make an argument for why these are most efficient and cost effective starting point. Hopefully they start producing in volume soon - I think the competition between CSP, PV and thin film vendors will make the solar power market develop a lot fatser than would otherwise be the case.

At Nanosolar, we believe very much that meaningful scale for solar will come foremost from utility-scale solar power plants, in particular from municipal solar power plants of 2-10MW in size. These are rows of solar panels mounted onto the ground of free fields at the outskirts of towns and cities, feeding electricity directly into the municipal power grid.

A 2MW municipal solar power plant requires about 10 acres of land to serve a city of 1,000 homes — that’s acreage generally easily available at the outskirts of any city of such size in even the most developed countries. Have one of these in each of several hundred cities and a Gigawatt of power is delivered — locally to where the power is needed and in a digestible size each.

In a municipal solar power plant, solar panels are mounted onto rails above the ground so that grass and flowers can continue to flourish in between and below the rows of panels. Care is taken that sufficient amounts of rainwater can drop through between adjoining panels so that the flowers and organisms below are not starved. In fact, in dry regions, the solar panels even benefit the ecosystem by increasing the moisture level in the soil.

Municipal solar power plants integrate very naturally into the existing landscape as well as the existing electricity grid. By feeding power directly into the (local, medium-voltage) distribution grid, they avoid the (long-haul, high-voltage) transmission grid which is expensive to build and expand, and they also avoid the expense of a substation for down-transforming transmission voltage to municipal voltage. It’s a form of distributed generation but at the wholesale level — ”Wholesale Distributed Generation” (WDG) – and it has been determined (using CPUC methodolgy and data) that there is a locational benefit of about 35% over wholesale power cost. These are real dollars that WDG power providers and rate payers can split in a win-win cost advantage.

In any region with a decent amount of sunshine, there is no more economic way of reliably providing municipal power during the day than through a municipal solar power plant. That’s because municipal solar power plants combine the locational benefit of avoided transmission with the time-of-day benefit of solar and the economics of scale.

Ground-mounted solar power plants are installed in industrially streamlined ways, with specialized tractors deploying standardized substructure components according to standard system block designs to achieve optimal cost efficiency.

While rooftops are surely a good application too for solar panels, it is a business that’s difficult to scale rapidly in a truly meaningful way. Crawling onto rooftops and mounting solar panels in compliance with building codes is fundamentally always a somewhat less efficient proposition.

In fact, municipal solar power plants are one of the most rapidly deployable forms of power: whereas it takes 10-15 years to get a new coal plant done (if ever given their carbon risk) or 5 years for a concentrating solar-thermal plant (also requiring a connection to the transmission grid), a municipal solar plant can be completed in as little as 12 months.

Furthermore, a unique feature of photovoltaic power plants is that they utilize power inverter electronics with increasingly intelligent features. Enlightened utilities around the world are now recognizing these as a very good way to manage and improve grid power quality. This is especially a point of pain at the outer branches of the electric grid where power quality is hard to manage otherwise.