PROJECT EASY GREEN

A common refrain about the limitations of solar power is that it only works while the sun is shining. That's certainly true of photovoltaic (PV) solar technology.

Concentrating solar power (CSP), while more expensive than PV technology with its recent runaway cost plunge, has an absolute advantage over PV — the ability to store thermal energy long after the sun goes down. This quality improves CSP's capacity factor and dispatchability, and has the potential to improve CSP's levelized cost of energy (LCOE).

The 19.9-megawatt Gemasolar CSP power tower plant in Seville, Spain (see pictures below) has just set a milestone for solar power plants — it offers 24 hours of uninterrupted operation. This is a first, according to Torresol Energy (a joint venture between Masdar and Sener). The system is capable of 15 hours of electricity production without solar radiation by storing the thermal energy in molten salt (15 hours applies to sunny summer days).

The salt storage system allows the plant to stretch its electrical production hours beyond sunset, regardless of cloud cover. The 19.9-megawatt steam turbine can supply electricity to a population of 25,000 households using a 140-meter-tall tower and a field using 2,650 heliostats. That's small by BrightSource Energy standards with its more than 300 megawatts and 173,000 heliostats — but BrightSource doesn't incorporate storage.

Molten salt storage has been used with trough CSP systems, but Gemasolar is the first plant to use the thermal-storage system in a central "power tower" and heliostat architecture. The system dispenses with oil and uses molten salt as a transfer fluid — allowing for a much higher operating temperature (over 500°C).

That translates to hotter steam, higher pressures and improved plant efficiency.

This accomplishment would seem to change the real practicality of solar power if the costs are right. But at the moment — the costs are not right.

Brett Prior, a senior solar analyst at GTM Research, has looked at the LCOE economics of CSP in a recent report, Concentrating Solar Power 2011: Technology, Costs and Markets. Cost per watt — a key piece of the LCOE calculation — is very high for the Gemasolar plant. (See chart below and report for more details.) Gas combined cycle plants are a mature, dispatchable technology and have an LCOE of $0.062 per kilowatt-hour. That is the harrowing number that solar and all new energy must compete with if going after baseload, dispatchable, wholesale power.

Another entrant in the CSP with molten salt storage field is Santa Monica, Calif.-based SolarReserve, which is building a 110-megawatt solar thermal plant in Nevada with help from a $737 million DOE loan guarantee. Solar Reserve has set its wholesale price for electricity at 13.5 cents per kilowatt-hour, according to this interview with Marc Gunther.   

The MIT Club of Northern California, as part of their Energy and Clean Tech Series, brought together some solar notables in a panel discussion last week to discuss solar power growing up to utility scale. Hal La Flash, Director of Emerging Clean Technologies at utility Pacific Gas & Electric, was the moderator and one of his questions regarding utility-scale solar was, "What's taking so long?"

I'll cover that event in a separate post — but I wanted to focus a bit on BrightSource Energy and the early stages of construction at the Ivanpah site.

BrightSource has filed their S-1 registration for the IPO and is in their quiet period. Here's a link to the S-1 form and some more details on BrightSource's recent financing activity.

But Ian Copeland, President, Renewable Power at Bechtel, the BrightSource EPC (and an Ivanpah investor) is not in a quiet period. Copeland spoke on the challenges and progress so far in the  early stages of this major construction project.

Within 20 days of receiving site access in early October, Bechtel had installed 16 miles of fence around unit one, the common area for the three units and the power block for unit two and working with BrightSource's biologists had swept every square foot of the 1,329 acre area of the 3,600 acre site as part of the rare plant and animal conservation and relocation effort.

The Ivanpah plant, slated for completion in 2013, has been the target of legal action from an environmental group despite approval of the project by both the Department of the Interior and the state of California. To mollify some objections, BrightSource scaled down the size of the project as part of the environmental mitigation process.

BrightSource has had to mitigate their environmental footprint to contend with the desert tortoise by avoiding long-term impacts to 433 acres of habitat, as well as acquiring additional land off the Ivanpah site for tortoise relocation within their home range. The 433 acres of habitat on the site and the additional mitigation land would remain available to tortoises for foraging, cover, and other life cycle requirements. While it is unknown how many tortoises would be in this area at the time of construction; three of the 20 live tortoises observed within the project boundary during the 2007 and 2008 surveys would be avoided, resulting in the need to relocate about 15 percent fewer tortoises.  At a minimum, 17 existing burrows in this area would also be preserved. Here's a link to a Biological Mitigation Document involving desert tortoises, rare plants, soil, and visual impact.

BrightSource has spent "a surprising amount of money" for tortoise mitigation — the firm has to buy mitigation land whether they find a tortoise or not. BrightSource also has to monitor each tortoise for five years and perform a blood analysis to check for respiratory diseases. BrightSource has up to 100 biologists working at the Ivanpah site (!).

When construction of the solar field starts in earnest later this year, Bechtel will be deploying heliostats at a rate of one per minute during working hours and completing about 6 acres of the solar field per day. In total, for all three units, they will be installing about 173,000 pylons and heliostats throughout the solar field. 

Copeland said that he thought Ivanpah was an important milestone in the US energy landscape and in that regard it was similar to the Hoover Dam, another milestone project worked on by Bechtel.  (I don't imagine a great amount of species mitigation was done on that project.) The company is also working with SolFocus on concentrating PV projects as well as other projects using flat plate PV and other CSP solar thermal technologies.

Copeland finished his presentation with these points:

• Coal and natural gas dominate today and will dominate tomorrow without change
• Climate and other externalities have not been valued — to date
• U.S., China, and India dominate the carbon issue
• Policy and relative economics are as important as technology
• Renewables as well as nuclear power are critical
• We need a robust, interlocking, consistent set of technologies and policies
• Solar energy is essentially limitless — but not free
• Efficiency, cost, reliability, and resource adequacy matters
• We need all solutions — there is no silver bullet

The picture below shows grading at Ivanpah Unit One. This design minimizes the amount of land that needs to be graded in comparison to other technologies that grade the entire site. The heliostats will be placed in between the radial access roads and will be inserted directly in the ground, without the need for cement posts and avoiding areas of sensitive habitat. Photo from BSE's Ivanpah website.

CPV looks to be making its big move — and it's happening in San Diego, Caliifornia.

San Diego Gas & Electric (SDG&E) and Soitec just announced two additional 25-year contracts for a total of 125 megawatts of power from concentrated photovoltaics (CPV) to be generated in the utility's service territory.  The energy will be produced with solar modules manufactured in a new Soitec factory to be built in the San Diego area.

That's 125 megawatts added to three San Diego contracts the two companies signed in April for 30 megawatts of CPV-generated solar power.  Combine that with the 150-megawatt Tenaska project, also undertaken with Soitec, and all of the sudden, CPV is on the map in the U.S. 

The Tenaska CPV solar power plant, known as Imperial Solar Energy Center (ISEC) West, will be built on a 1057-acre former farmland site in southern California’s western Imperial County; completion is targeted in 2015.  The plant, if active today, would be the largest CPV power station in operation.  

Anyway, that's 305 megawatts of CPV soon to be powered up in San Diego alone from a single vendor. Total photovoltaics installed in the U.S. in 2010 was about 980 megawatts.

While the CPV market is currently just a small portion of the world’s total installed solar base at just 28 megawatts of the total 33,000 megawatts, CPV technology is finally gaining momentum with multiple utility-scale project announcements over the past year. This growing pipeline of CPV projects would seem to be a vote of confidence from solar developers for a technology that, to date, has been marginalized because it was considered unproven and risky.

GTM Research’s report, Concentrating Photovoltaics 2011: Technology, Costs and Markets, authored by Senior Solar Analyst Brett Prior, looks at the competitive dynamics affecting global CPV market potential. The report focuses on CPV’s position within the greater solar power landscape, with an examination of how CPV stacks up against non-concentrating solar technologies on a series of key technological and financial metrics.

Overall, GTM Research’s report forecasts annual CPV installations to surpass 1,000 MW per year by 2015. The forecast is predicated upon CPV companies successfully achieving their cost reduction roadmaps, and bringing the installed cost of a CPV system down by more than 30 percent over the next 4 years.  

For more in-depth coverage of the CPV market, check out the report: Concentrating Photovoltaics 2011: Technology, Costs and Markets.