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DOE Eyes ‘Small CSP’
For Cogeneration

The U.S. Department of Energy (DOE) hopes the $10 million it awarded the Sacramento Municipal Utility District (SMUD) to develop a hybrid concentrating solar power (CSP) and gas-fired power plant could serve as a model for such hybrids all across the U.S. Minh Le, solar energy technologies program manager of the DOE’s Office of Energy Efficiency and Renewable Energy, says between 11-21 GW of CSP can be integrated with existing power plants in the U.S.

“Connecting CSP to the pool of existing fossil plants represents a tremendous opportunity,” he says.

Moreover, the DOE believes CSP cogeneration technology represents a great export opportunity for U.S. companies. The DOE promotes the notion of CSP cogeneration, both in the U.S. and internationally.

The idea of cogeneration based on solar power is not new. In November 2010, Florida Power & Light Co. fired up its Martin Next Generation Solar Energy Center - a 75 MW parabolic-trough CSP system colocated with an existing 3.7 GW combined-cycle natural gas power plant. The solar portion, which incorporates over 190,000 mirrors, pipes steam into the turbines of the gas plant, saving on fuel.

The scale of the Sacramento project is much more modest. The CSP portion is currently planned at 10 MW and will be colocated with the existing 500 MW Cosumnes gas-fired power plant. Technologically, however, SMUD’s facility will be a leap forward in that the CSP portion will operate at much higher temperatures. According to Le, the CSP portion will contribute direct, high-pressure steam at about 550˚C.

“CSP and fossil have never been put together in this fashion before,” he says. Integration of high-pressure steam from CSP plants into the turbines of existing fossil plants is a challenge from a design and engineering perspective. “The work we are funding is innovative but based on sound scientific and engineering principles.”

Large-scale CSP plants are coming online in the U.S. and elsewhere. Many others are under development. The vast majority of these are stand-alone facilities, providing power to the grid just like any other AC-generating asset. Le says the purpose of the SMUD award is to develop small-scale CSP as an augmentation technology for existing fossil plants.

Unlike stand-alone CSP facilities, which are typically located in remote areas such as deserts, cogeneration CSP would have to be shoehorned into locations with existing plants, many of which are located in populated areas where space is at a premium. In each case, the CSP portion might provide an average of 5%-10% of the steam for the cogeneration facility. Nevertheless, this would produce a commensurate reduction in the amount of fossil fuels consumed.

An important feature of the Sacramento project is the integration of thermal energy storage into the cogeneration facility. The fluids or slurries heated by concentrating mirrors remain capable of producing steam and, thus, electricity for hours after the sun sets or is occluded. In addition, Le says, solar thermal storage acts as a buffer, enabling operators to decouple the CSP portion from the system.

As the award recipient, SMUD will have the responsibility for all procurement activities and will be doing its own solicitations for vendors and suppliers on the project. At the same time, the DOE will be performing technical reviews during the design phase, both to better understand the process and provide whatever assistance it can. Le says the DOE will also remain involved in the project in order to develop seasonal and daily operating profiles of the facility that could be an important factor in developing successful projects elsewhere.

“The DOE’s goal is to catalyze the industry,” Le says. “We also want to be financially viable.” - Michael Puttré

 

IREC Proposes New PV
Grid-Connect Process

The Interstate Renewable Energy Council (IREC) is making an effort to address the skyrocketing number of interconnection applications swamping utility inboxes.

According to the IREC, there were 65,000 grid-connected PV installations of all sizes in the U.S. in 2011. In 2012, the number of connections jumped to 95,000, meaning that utilities had to approve 30,000 new interconnection applications over the course of a single year. This figure does not count applications that were considered and rejected.

Residential-type installations are generally put on a “fast track” evaluation process; nevertheless, the sheer volume is a tremendous strain on the small generator interconnection procedures the Federal Energy Regulatory Commission enacted in 2005, when there were a mere 7,000 PV grid connections in the U.S.

“Most interconnection procedures were designed for a different era,” says Sky Stanfield, an attorney at Keyes, Fox & Wiedman LLP, working on behalf of the IREC to develop a new approach to integrated distribution planning (IDP). “The problem is that by 2015, there are projected to be 150,000 grid-connected PV systems.”

According to Stanfield, the current interconnection procedures are largely reactive in that the utility waits for the application to study whether it will be the proverbial straw that breaks the camel’s back. For most fast-tracked applications, studies are perfunctory and generally involve checking whether the prospective PV system triggers a review of the circuit’s theoretical hosting capacity.

But there is nothing theoretical about the effect the threshold can have on PV installations. In Hawaii, for example, over 20% of distribution circuits are reported as being over the 15% peak load threshold that triggers a hold on applications. This means panels are already on the roofs of residents who are waiting for word on whether they will be allowed to connect their new system to the grid.

Another problem with the grid interconnection application process, Stanfield says, is that the party deemed responsible for exceeding a circuit’s capacity has to foot the bill for upgrading the circuit to handle the proposed interconnection. When the applicant is a generating plant or a large commercial or municipal facility, the required upgrade is something that probably would have been factored into the project. When a residential PV installation tips the balance, the homeowner is responsible for the upgrade, which is a non-starter.

Stanfield says the purpose of the IDP proposal the IREC is developing is to get utilities to perform studies to establish the hosting capacity and allowable penetration for all of its circuits. Such planning would also entail forecasting interconnection penetration - PV and otherwise - to enable them to prioritize upgrades to the distribution infrastructure.

Ideally, Stanfield says, circuits that were forecast to exceed interconnection penetration levels could have their hosting capacity upgraded as part of ongoing maintenance instead of having the upgrade triggered by a given interconnection application. Also ideally, the utility would publish the results of its estimated capacity and allowable penetration.

“The utility could plan and expedite interconnect procedures based on IDP,” she says.

As we do not live in an ideal world, the issue of cost must be considered. Under the IDP proposal, the utility would bear the costs of the required proactive study. Thus, a state’s public utilities commission would have to make rules requiring utilities to do such studies and to publish the results. Furthermore, some mechanism for encouraging - or compelling - utilities to perform circuit upgrades to accommodate anticipated residential PV interconnections will have to be found.

- Michael Puttré

 

EDF Unveils Solar
Development Atlas

The Environmental Defense Fund (EDF) and the University of California Los Angeles (UCLA) Luskin Center for Innovation have released an in-depth solar energy and efficiency study for Los Angeles (LA) County that details investment potentials and development opportunities.

The “Los Angeles Solar and Efficiency Report (LASER): Atlas of Investment Potential for Los Angeles County” is built around an atlas of maps representing the vulnerability of communities in LA County to the effects of climate change, as well as the potential for clean energy investments. The study is broken down by state senatorial districts and sub-regions across the county as a guide for legislators and other community stakeholders.

For each sub-region, the LASER provides maps depicting vulnerability to climate change, environmental health risk and potential solar capacity. Each map is accompanied by supporting statistics, as well as relevant state policies and initiatives. The solar potential maps, for example, are accompanied by funding opportunities stemming from legislation and utility programs specific to each area.

The report opens with warming projections for the LA region for the years 2041-60 that say temperatures are expected to rise by an average of 4-5˚F. Unlike many purely alarmist reports, a main purpose of the LASER is to present information for potential solar energy and green building project developers.

“We want to pivot from vulnerability to investment opportunity,” says Jorge Madrid, an EDF fellow and coordinator of partnerships and alliances. “Not only are we driving the deployment of clean energy, we’re piloting new models to move public and private dollars into clean energy.”

The very specific geographic and policy focus on clean energy opportunities could make the atlas useful to developers as a practical tool for finding new business.

The EDF says it commissioned Luskin to produce the LASER atlas to provide a tool to help local decision-makers think strategically about investing state funding made available by recent legislation. In particular, 25% of the cap-and-trade proceeds from the California Global Warming Solutions Act are earmarked for clean energy investment. Proposition 39, the California Clean Energy Jobs Act, is expected to make billions of dollars available for expanding renewable energy generation and renovating buildings to make them energy efficient.

“The cities most prepared to receive funding will probably get more of it,” says Colleen Callahan, deputy director of the Luskin Center and project manager of the report. “The atlas highlights areas that could be prioritized.”

While the LASER report is focused like its namesake on LA County, its producers hope that it could serve as a model of highlighting clean energy investment opportunities in other communities. - Michael Puttré

 

DOE Awards $12M To
Cut Solar Soft Costs

The U.S. Department of Energy (DOE) is awarding eight teams a total of $12 million to develop streamlined and standardized solar permitting, zoning, metering and connection processes for communities across the country. The awards represent the second phase of the Rooftop Solar Challenge program, which is part of the DOE’s SunShot Initiative.

According to the DOE, permitting, installation, design and maintenance now account for more than 60% of the total cost of installed rooftop photovoltaic systems in the U.S. These so-called “soft costs” are often cited by installers as having a significant drag on the penetration of solar energy systems.

Across the nation, the DOE says, there are more than 18,000 local jurisdictions with their own PV permitting requirements, as well as more than 5,000 utilities that set rules for connecting to the power grid. The Rooftop Solar Challenge encourages city, county and state officials; regulatory entities; private industry; universities; local utilities; and other regional stakeholders to address processes required to install and finance residential and small commercial solar power systems.

During the program’s first round, 22 regional teams worked to reduce the soft costs of solar. According to the DOE, these efforts helped cut permitting time by 40% and reduce fees by over 10%. Some of the eight teams of the second round are also addressing permitting and interconnection processes. Others are focusing on purchasing practices, online applications and regional planning.

In August, the East Bay Green Corridor in California fielded an independent initiative to streamline the permitting process for residential solar installations in the region’s nine cities. The group, working with state officials and area cleantech businesses, also received funding from the SunShot Initiative. S