Although large-scale wind power has made the greatest gains in the renewables field around the world over the last few years, solar photovoltaic (PV) power may eventually be the largest resource.

And, while wind farms are necessarily located wherever the wind blows the hardest and most consistently – increasingly out to sea – PV equipment can often be located actually on the building to which it is delivering energy, or in an adjacent parking lot or field.

 

Large-scale wind farms share some energy transmission shortcomings of centralized, fossil fuel power stations. Often located in remote areas, or offshore, new power transmission networks have to be financed and built, so that the electricity generated can reach the power grid.

 Apple Maiden Data Centre

By contrast, solar power plants (plus inverters to convert the DC output to alternating current) can do the whole job on-site. However, PV outputs are small, and the structure of few buildings can accommodate sufficient panels to generate all their power needs. One alternative is to expand the PV installation onto adjacent parking facilities and any other available land. Either way, the PV-generated electricity can be routed directly to the energy customer.

Computer and mobile phones giant Apple is characteristically showing the way forward for some of its data centres in the US. The company is building a third, 17 MW solar power plant on land close to its Maiden, North Carolina, facility, adding to two existing 20 MW PV plants. Add to this a new, 18 MW concentrating PV installation being built at its facility in Reno, Nevada. I also noticed news of a 3 MW solar power installation planned to serve tenants of an industrial park in Pakistan. Renewable energy, generated on-site, or very nearly.

Another way forward is for energy users, or groups of users, to commission the building of large-scale solar power plants. Not exactly on-site energy, but building new long distance energy transmission facilities can usually be avoided. One example is a 52 MW PV installation to be built to serve two universities and a hospital in Washington, DC. Orchestrated by a company called Customer First Renewables (CFR), the project will be built in North Carolina, and operated by a utility, Duke Energy. Solar power will meet more than half of the needs of the two universities, and a third of that of the hospital.

CFR has a radical view of how renewable energy projects should developed – with customers, not project developers in charge. Maximizing the use of true on-site generation comes first; the CFR model is a fine second step.