US funds 'tallest molten salt tower in the world'

Nevada could soon be home to the tallest molten salt tower in the world, and it doesn’t want to hear any jokes about possible Vegas-Sodom-Gomorrah-Lot’s wife connections. This is all about energy: clean solar power and cutting-edge energy storage.

The Crescent Dunes Solar Energy Project is on its way to moving forward now that the US Department of Energy (DOE) has offered a conditional commitment for a $737 million load guarantee for the proposed 100-megawatt molten salt concentrating solar power (CSP) tower plant.  The funding is just a small part of the $8 billion the DOE has committed in loan guarantees for solar generation projects … proof of the utility-scale investment now being seen in renewables.

Sponsored by SolarReserve LLC, the Crescent Dunes project will be the first of its kind in the US. The deployment of molten salt technology will allow the plant to store extra energy, negating the intermittency effect seen from other renewables such as wind and solar photovoltaics (PV).

The 640-foot tall solar power tower structure will be partnered with up to 17,500 heliostats (tracking mirrors) to produce an expected 500,000 megawatt-hours of energy annually, enough to power over 43,000 homes. The high-temperature thermal storage using molten salt technology will provide up to 10 hours’ worth of equivalent energy storage, so even during nighttime or cloudy conditions, the solar power plant will still feed electricity into the grid.

The 2,250-acre site has been leased from the Bureau of Land Management. As well as providing renewable electricity, the plant is also expected to create 600 construction jobs and 45 operations jobs.

One more benefit: the facility should help to avoid nearly 290,000 tonnes of carbon dioxide pollution annually. With the long lifetimes for concentrating solar power plants, this could add up to several million tonnes saved over the course of the facility’s operations.

With some of the highest levels of solar irradiation in the US, Nevada is an ideal location for further development of CSP projects. CSP has an edge over large-scale solar photovoltaics in desert regions because the performance of solar PV cells declines as temperatures increase. With CSP, the hotter the temperature, the more efficient the system.

The Crescent Dunes project needs DOE support because the power tower CSP structure being used still requires further development (as do the other CSP technologies). If the plant proves to be successful and costs can be reduced further, Nevada could become — pardon the hackneyed energy expression — the Saudi Arabia of concentrating solar power.

Actually, Saudi Arabia could also become the Saudi Arabia of concentrating solar power. Desert regions across the globe are now being considered for CSP plants, with the Desertec scheme proposed for the Sahara being the most ambitious. China, too, has considerable resources in this area, both naturally and economically.

One note: there has been some speculation recently that solar PV is actually now cheaper than CSP. While PV has traditionally been the more expensive technology, rapid price drops have created a more competitive environment in the solar power market. It will be interesting to see how solar technologies develop further. The impact on the energy market will be significant, whether solar PV keeps growing increasingly affordable or whether prices level off as further technological advances prove harder to come by.

Meanwhile, if more investment is ploughed into CSP plants such as Crescent Dunes — and if research breakthroughs can lead to cheaper technologies — we should expect to see a lot more solar power towers rising up in the world’s desert regions.